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Diffstat (limited to 'fs/ext4/mballoc.c')
| -rw-r--r-- | fs/ext4/mballoc.c | 4552 |
1 files changed, 4552 insertions, 0 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c new file mode 100644 index 000000000000..76e5fedc0a0b --- /dev/null +++ b/fs/ext4/mballoc.c @@ -0,0 +1,4552 @@ +/* + * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com + * Written by Alex Tomas <alex@clusterfs.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public Licens + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- + */ + + +/* + * mballoc.c contains the multiblocks allocation routines + */ + +#include <linux/time.h> +#include <linux/fs.h> +#include <linux/namei.h> +#include <linux/ext4_jbd2.h> +#include <linux/ext4_fs.h> +#include <linux/quotaops.h> +#include <linux/buffer_head.h> +#include <linux/module.h> +#include <linux/swap.h> +#include <linux/proc_fs.h> +#include <linux/pagemap.h> +#include <linux/seq_file.h> +#include <linux/version.h> +#include "group.h" + +/* + * MUSTDO: + * - test ext4_ext_search_left() and ext4_ext_search_right() + * - search for metadata in few groups + * + * TODO v4: + * - normalization should take into account whether file is still open + * - discard preallocations if no free space left (policy?) + * - don't normalize tails + * - quota + * - reservation for superuser + * + * TODO v3: + * - bitmap read-ahead (proposed by Oleg Drokin aka green) + * - track min/max extents in each group for better group selection + * - mb_mark_used() may allocate chunk right after splitting buddy + * - tree of groups sorted by number of free blocks + * - error handling + */ + +/* + * The allocation request involve request for multiple number of blocks + * near to the goal(block) value specified. + * + * During initialization phase of the allocator we decide to use the group + * preallocation or inode preallocation depending on the size file. The + * size of the file could be the resulting file size we would have after + * allocation or the current file size which ever is larger. If the size is + * less that sbi->s_mb_stream_request we select the group + * preallocation. The default value of s_mb_stream_request is 16 + * blocks. This can also be tuned via + * /proc/fs/ext4/<partition>/stream_req. The value is represented in terms + * of number of blocks. + * + * The main motivation for having small file use group preallocation is to + * ensure that we have small file closer in the disk. + * + * First stage the allocator looks at the inode prealloc list + * ext4_inode_info->i_prealloc_list contain list of prealloc spaces for + * this particular inode. The inode prealloc space is represented as: + * + * pa_lstart -> the logical start block for this prealloc space + * pa_pstart -> the physical start block for this prealloc space + * pa_len -> lenght for this prealloc space + * pa_free -> free space available in this prealloc space + * + * The inode preallocation space is used looking at the _logical_ start + * block. If only the logical file block falls within the range of prealloc + * space we will consume the particular prealloc space. This make sure that + * that the we have contiguous physical blocks representing the file blocks + * + * The important thing to be noted in case of inode prealloc space is that + * we don't modify the values associated to inode prealloc space except + * pa_free. + * + * If we are not able to find blocks in the inode prealloc space and if we + * have the group allocation flag set then we look at the locality group + * prealloc space. These are per CPU prealloc list repreasented as + * + * ext4_sb_info.s_locality_groups[smp_processor_id()] + * + * The reason for having a per cpu locality group is to reduce the contention + * between CPUs. It is possible to get scheduled at this point. + * + * The locality group prealloc space is used looking at whether we have + * enough free space (pa_free) withing the prealloc space. + * + * If we can't allocate blocks via inode prealloc or/and locality group + * prealloc then we look at the buddy cache. The buddy cache is represented + * by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets + * mapped to the buddy and bitmap information regarding different + * groups. The buddy information is attached to buddy cache inode so that + * we can access them through the page cache. The information regarding + * each group is loaded via ext4_mb_load_buddy. The information involve + * block bitmap and buddy information. The information are stored in the + * inode as: + * + * { page } + * [ group 0 buddy][ group 0 bitmap] [group 1][ group 1]... + * + * + * one block each for bitmap and buddy information. So for each group we + * take up 2 blocks. A page can contain blocks_per_page (PAGE_CACHE_SIZE / + * blocksize) blocks. So it can have information regarding groups_per_page + * which is blocks_per_page/2 + * + * The buddy cache inode is not stored on disk. The inode is thrown + * away when the filesystem is unmounted. + * + * We look for count number of blocks in the buddy cache. If we were able + * to locate that many free blocks we return with additional information + * regarding rest of the contiguous physical block available + * + * Before allocating blocks via buddy cache we normalize the request + * blocks. This ensure we ask for more blocks that we needed. The extra + * blocks that we get after allocation is added to the respective prealloc + * list. In case of inode preallocation we follow a list of heuristics + * based on file size. This can be found in ext4_mb_normalize_request. If + * we are doing a group prealloc we try to normalize the request to + * sbi->s_mb_group_prealloc. Default value of s_mb_group_prealloc is set to + * 512 blocks. This can be tuned via + * /proc/fs/ext4/<partition/group_prealloc. The value is represented in + * terms of number of blocks. If we have mounted the file system with -O + * stripe=<value> option the group prealloc request is normalized to the + * stripe value (sbi->s_stripe) + * + * The regular allocator(using the buddy cache) support few tunables. + * + * /proc/fs/ext4/<partition>/min_to_scan + * /proc/fs/ext4/<partition>/max_to_scan + * /proc/fs/ext4/<partition>/order2_req + * + * The regular allocator use buddy scan only if the request len is power of + * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The + * value of s_mb_order2_reqs can be tuned via + * /proc/fs/ext4/<partition>/order2_req. If the request len is equal to + * stripe size (sbi->s_stripe), we try to search for contigous block in + * stripe size. This should result in better allocation on RAID setup. If + * not we search in the specific group using bitmap for best extents. The + * tunable min_to_scan and max_to_scan controll the behaviour here. + * min_to_scan indicate how long the mballoc __must__ look for a best + * extent and max_to_scanindicate how long the mballoc __can__ look for a + * best extent in the found extents. Searching for the blocks starts with + * the group specified as the goal value in allocation context via + * ac_g_ex. Each group is first checked based on the criteria whether it + * can used for allocation. ext4_mb_good_group explains how the groups are + * checked. + * + * Both the prealloc space are getting populated as above. So for the first + * request we will hit the buddy cache which will result in this prealloc + * space getting filled. The prealloc space is then later used for the + * subsequent request. + */ + +/* + * mballoc operates on the following data: + * - on-disk bitmap + * - in-core buddy (actually includes buddy and bitmap) + * - preallocation descriptors (PAs) + * + * there are two types of preallocations: + * - inode + * assiged to specific inode and can be used for this inode only. + * it describes part of inode's space preallocated to specific + * physical blocks. any block from that preallocated can be used + * independent. the descriptor just tracks number of blocks left + * unused. so, before taking some block from descriptor, one must + * make sure corresponded logical block isn't allocated yet. this + * also means that freeing any block within descriptor's range + * must discard all preallocated blocks. + * - locality group + * assigned to specific locality group which does not translate to + * permanent set of inodes: inode can join and leave group. space + * from this type of preallocation can be used for any inode. thus + * it's consumed from the beginning to the end. + * + * relation between them can be expressed as: + * in-core buddy = on-disk bitmap + preallocation descriptors + * + * this mean blocks mballoc considers used are: + * - allocated blocks (persistent) + * - preallocated blocks (non-persistent) + * + * consistency in mballoc world means that at any time a block is either + * free or used in ALL structures. notice: "any time" should not be read + * literally -- time is discrete and delimited by locks. + * + * to keep it simple, we don't use block numbers, instead we count number of + * blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA. + * + * all operations can be expressed as: + * - init buddy: buddy = on-disk + PAs + * - new PA: buddy += N; PA = N + * - use inode PA: on-disk += N; PA -= N + * - discard inode PA buddy -= on-disk - PA; PA = 0 + * - use locality group PA on-disk += N; PA -= N + * - discard locality group PA buddy -= PA; PA = 0 + * note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap + * is used in real operation because we can't know actual used + * bits from PA, only from on-disk bitmap + * + * if we follow this strict logic, then all operations above should be atomic. + * given some of them can block, we'd have to use something like semaphores + * killing performance on high-end SMP hardware. let's try to relax it using + * the following knowledge: + * 1) if buddy is referenced, it's already initialized + * 2) while block is used in buddy and the buddy is referenced, + * nobody can re-allocate that block + * 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has + * bit set and PA claims same block, it's OK. IOW, one can set bit in + * on-disk bitmap if buddy has same bit set or/and PA covers corresponded + * block + * + * so, now we're building a concurrency table: + * - init buddy vs. + * - new PA + * blocks for PA are allocated in the buddy, buddy must be referenced + * until PA is linked to allocation group to avoid concurrent buddy init + * - use inode PA + * we need to make sure that either on-disk bitmap or PA has uptodate data + * given (3) we care that PA-=N operation doesn't interfere with init + * - discard inode PA + * the simplest way would be to have buddy initialized by the discard + * - use locality group PA + * again PA-=N must be serialized with init + * - discard locality group PA + * the simplest way would be to have buddy initialized by the discard + * - new PA vs. + * - use inode PA + * i_data_sem serializes them + * - discard inode PA + * discard process must wait until PA isn't used by another process + * - use locality group PA + * some mutex should serialize them + * - discard locality group PA + * discard process must wait until PA isn't used by another process + * - use inode PA + * - use inode PA + * i_data_sem or another mutex should serializes them + * - discard inode PA + * discard process must wait until PA isn't used by another process + * - use locality group PA + * nothing wrong here -- they're different PAs covering different blocks + * - discard locality group PA + * discard process must wait until PA isn't used by another process + * + * now we're ready to make few consequences: + * - PA is referenced and while it is no discard is possible + * - PA is referenced until block isn't marked in on-disk bitmap + * - PA changes only after on-disk bitmap + * - discard must not compete with init. either init is done before + * any discard or they're serialized somehow + * - buddy init as sum of on-disk bitmap and PAs is done atomically + * + * a special case when we've used PA to emptiness. no need to modify buddy + * in this case, but we should care about concurrent init + * + */ + + /* + * Logic in few words: + * + * - allocation: + * load group + * find blocks + * mark bits in on-disk bitmap + * release group + * + * - use preallocation: + * find proper PA (per-inode or group) + * load group + * mark bits in on-disk bitmap + * release group + * release PA + * + * - free: + * load group + * mark bits in on-disk bitmap + * release group + * + * - discard preallocations in group: + * mark PAs deleted + * move them onto local list + * load on-disk bitmap + * load group + * remove PA from object (inode or locality group) + * mark free blocks in-core + * + * - discard inode's preallocations: + */ + +/* + * Locking rules + * + * Locks: + * - bitlock on a group (group) + * - object (inode/locality) (object) + * - per-pa lock (pa) + * + * Paths: + * - new pa + * object + * group + * + * - find and use pa: + * pa + * + * - release consumed pa: + * pa + * group + * object + * + * - generate in-core bitmap: + * group + * pa + * + * - discard all for given object (inode, locality group): + * object + * pa + * group + * + * - discard all for given group: + * group + * pa + * group + * object + * + */ + +/* + * with AGGRESSIVE_CHECK allocator runs consistency checks over + * structures. these checks slow things down a lot + */ +#define AGGRESSIVE_CHECK__ + +/* + * with DOUBLE_CHECK defined mballoc creates persistent in-core + * bitmaps, maintains and uses them to check for double allocations + */ +#define DOUBLE_CHECK__ + +/* + */ +#define MB_DEBUG__ +#ifdef MB_DEBUG +#define mb_debug(fmt, a...) printk(fmt, ##a) +#else +#define mb_debug(fmt, a...) +#endif + +/* + * with EXT4_MB_HISTORY mballoc stores last N allocations in memory + * and you can monitor it in /proc/fs/ext4/<dev>/mb_history + */ +#define EXT4_MB_HISTORY +#define EXT4_MB_HISTORY_ALLOC 1 /* allocation */ +#define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */ +#define EXT4_MB_HISTORY_DISCARD 4 /* preallocation discarded */ +#define EXT4_MB_HISTORY_FREE 8 /* free */ + +#define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC | \ + EXT4_MB_HISTORY_PREALLOC) + +/* + * How long mballoc can look for a best extent (in found extents) + */ +#define MB_DEFAULT_MAX_TO_SCAN 200 + +/* + * How long mballoc must look for a best extent + */ +#define MB_DEFAULT_MIN_TO_SCAN 10 + +/* + * How many groups mballoc will scan looking for the best chunk + */ +#define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5 + +/* + * with 'ext4_mb_stats' allocator will collect stats that will be + * shown at umount. The collecting costs though! + */ +#define MB_DEFAULT_STATS 1 + +/* + * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served + * by the stream allocator, which purpose is to pack requests + * as close each to other as possible to produce smooth I/O traffic + * We use locality group prealloc space for stream request. + * We can tune the same via /proc/fs/ext4/<parition>/stream_req + */ +#define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */ + +/* + * for which requests use 2^N search using buddies + */ +#define MB_DEFAULT_ORDER2_REQS 2 + +/* + * default group prealloc size 512 blocks + */ +#define MB_DEFAULT_GROUP_PREALLOC 512 + +static struct kmem_cache *ext4_pspace_cachep; + +#ifdef EXT4_BB_MAX_BLOCKS +#undef EXT4_BB_MAX_BLOCKS +#endif +#define EXT4_BB_MAX_BLOCKS 30 + +struct ext4_free_metadata { + ext4_group_t group; + unsigned short num; + ext4_grpblk_t blocks[EXT4_BB_MAX_BLOCKS]; + struct list_head list; +}; + +struct ext4_group_info { + unsigned long bb_state; + unsigned long bb_tid; + struct ext4_free_metadata *bb_md_cur; + unsigned short bb_first_free; + unsigned short bb_free; + unsigned short bb_fragments; + struct list_head bb_prealloc_list; +#ifdef DOUBLE_CHECK + void *bb_bitmap; +#endif + unsigned short bb_counters[]; +}; + +#define EXT4_GROUP_INFO_NEED_INIT_BIT 0 +#define EXT4_GROUP_INFO_LOCKED_BIT 1 + +#define EXT4_MB_GRP_NEED_INIT(grp) \ + (test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state))) + + +struct ext4_prealloc_space { + struct list_head pa_inode_list; + struct list_head pa_group_list; + union { + struct list_head pa_tmp_list; + struct rcu_head pa_rcu; + } u; + spinlock_t pa_lock; + atomic_t pa_count; + unsigned pa_deleted; + ext4_fsblk_t pa_pstart; /* phys. block */ + ext4_lblk_t pa_lstart; /* log. block */ + unsigned short pa_len; /* len of preallocated chunk */ + unsigned short pa_free; /* how many blocks are free */ + unsigned short pa_linear; /* consumed in one direction + * strictly, for grp prealloc */ + spinlock_t *pa_obj_lock; + struct inode *pa_inode; /* hack, for history only */ +}; + + +struct ext4_free_extent { + ext4_lblk_t fe_logical; + ext4_grpblk_t fe_start; + ext4_group_t fe_group; + int fe_len; +}; + +/* + * Locality group: + * we try to group all related changes together + * so that writeback can flush/allocate them together as well + */ +struct ext4_locality_group { + /* for allocator */ + struct mutex lg_mutex; /* to serialize allocates */ + struct list_head lg_prealloc_list;/* list of preallocations */ + spinlock_t lg_prealloc_lock; +}; + +struct ext4_allocation_context { + struct inode *ac_inode; + struct super_block *ac_sb; + + /* original request */ + struct ext4_free_extent ac_o_ex; + + /* goal request (after normalization) */ + struct ext4_free_extent ac_g_ex; + + /* the best found extent */ + struct ext4_free_extent ac_b_ex; + + /* copy of the bext found extent taken before preallocation efforts */ + struct ext4_free_extent ac_f_ex; + + /* number of iterations done. we have to track to limit searching */ + unsigned long ac_ex_scanned; + __u16 ac_groups_scanned; + __u16 ac_found; + __u16 ac_tail; + __u16 ac_buddy; + __u16 ac_flags; /* allocation hints */ + __u8 ac_status; + __u8 ac_criteria; + __u8 ac_repeats; + __u8 ac_2order; /* if request is to allocate 2^N blocks and + * N > 0, the field stores N, otherwise 0 */ + __u8 ac_op; /* operation, for history only */ + struct page *ac_bitmap_page; + struct page *ac_buddy_page; + struct ext4_prealloc_space *ac_pa; + struct ext4_locality_group *ac_lg; +}; + +#define AC_STATUS_CONTINUE 1 +#define AC_STATUS_FOUND 2 +#define AC_STATUS_BREAK 3 + +struct ext4_mb_history { + struct ext4_free_extent orig; /* orig allocation */ + struct ext4_free_extent goal; /* goal allocation */ + struct ext4_free_extent result; /* result allocation */ + unsigned pid; + unsigned ino; + __u16 found; /* how many extents have been found */ + __u16 groups; /* how many groups have been scanned */ + __u16 tail; /* what tail broke some buddy */ + __u16 buddy; /* buddy the tail ^^^ broke */ + __u16 flags; + __u8 cr:3; /* which phase the result extent was found at */ + __u8 op:4; + __u8 merged:1; +}; + +struct ext4_buddy { + struct page *bd_buddy_page; + void *bd_buddy; + struct page *bd_bitmap_page; + void *bd_bitmap; + struct ext4_group_info *bd_info; + struct super_block *bd_sb; + __u16 bd_blkbits; + ext4_group_t bd_group; +}; +#define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap) +#define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy) + +#ifndef EXT4_MB_HISTORY +static inline void ext4_mb_store_history(struct ext4_allocation_context *ac) +{ + return; +} +#else +static void ext4_mb_store_history(struct ext4_allocation_context *ac); +#endif + +#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) + +static struct proc_dir_entry *proc_root_ext4; +struct buffer_head *read_block_bitmap(struct super_block *, ext4_group_t); +ext4_fsblk_t ext4_new_blocks_old(handle_t *handle, struct inode *inode, + ext4_fsblk_t goal, unsigned long *count, int *errp); + +static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap, + ext4_group_t group); +static void ext4_mb_poll_new_transaction(struct super_block *, handle_t *); +static void ext4_mb_free_committed_blocks(struct super_block *); +static void ext4_mb_return_to_preallocation(struct inode *inode, + struct ext4_buddy *e4b, sector_t block, + int count); +static void ext4_mb_put_pa(struct ext4_allocation_context *, + struct super_block *, struct ext4_prealloc_space *pa); +static int ext4_mb_init_per_dev_proc(struct super_block *sb); +static int ext4_mb_destroy_per_dev_proc(struct super_block *sb); + + +static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group) +{ + struct ext4_group_info *grinfo = ext4_get_group_info(sb, group); + + bit_spin_lock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state)); +} + +static inline void ext4_unlock_group(struct super_block *sb, + ext4_group_t group) +{ + struct ext4_group_info *grinfo = ext4_get_group_info(sb, group); + + bit_spin_unlock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state)); +} + +static inline int ext4_is_group_locked(struct super_block *sb, + ext4_group_t group) +{ + struct ext4_group_info *grinfo = ext4_get_group_info(sb, group); + + return bit_spin_is_locked(EXT4_GROUP_INFO_LOCKED_BIT, + &(grinfo->bb_state)); +} + +static ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb, + struct ext4_free_extent *fex) +{ + ext4_fsblk_t block; + + block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb) + + fex->fe_start + + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); + return block; +} + +#if BITS_PER_LONG == 64 +#define mb_correct_addr_and_bit(bit, addr) \ +{ \ + bit += ((unsigned long) addr & 7UL) << 3; \ + addr = (void *) ((unsigned long) addr & ~7UL); \ +} +#elif BITS_PER_LONG == 32 +#define mb_correct_addr_and_bit(bit, addr) \ +{ \ + bit += ((unsigned long) addr & 3UL) << 3; \ + addr = (void *) ((unsigned long) addr & ~3UL); \ +} +#else +#error "how many bits you are?!" +#endif + +static inline int mb_test_bit(int bit, void *addr) +{ + /* + * ext4_test_bit on architecture like powerpc + * needs unsigned long aligned address + */ + mb_correct_addr_and_bit(bit, addr); + return ext4_test_bit(bit, addr); +} + +static inline void mb_set_bit(int bit, void *addr) +{ + mb_correct_addr_and_bit(bit, addr); + ext4_set_bit(bit, addr); +} + +static inline void mb_set_bit_atomic(spinlock_t *lock, int bit, void *addr) +{ + mb_correct_addr_and_bit(bit, addr); + ext4_set_bit_atomic(lock, bit, addr); +} + +static inline void mb_clear_bit(int bit, void *addr) +{ + mb_correct_addr_and_bit(bit, addr); + ext4_clear_bit(bit, addr); +} + +static inline void mb_clear_bit_atomic(spinlock_t *lock, int bit, void *addr) +{ + mb_correct_addr_and_bit(bit, addr); + ext4_clear_bit_atomic(lock, bit, addr); +} + +static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max) +{ + char *bb; + + /* FIXME!! is this needed */ + BUG_ON(EXT4_MB_BITMAP(e4b) == EXT4_MB_BUDDY(e4b)); + BUG_ON(max == NULL); + + if (order > e4b->bd_blkbits + 1) { + *max = 0; + return NULL; + } + + /* at order 0 we see each particular block */ + *max = 1 << (e4b->bd_blkbits + 3); + if (order == 0) + return EXT4_MB_BITMAP(e4b); + + bb = EXT4_MB_BUDDY(e4b) + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order]; + *max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order]; + + return bb; +} + +#ifdef DOUBLE_CHECK +static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b, + int first, int count) +{ + int i; + struct super_block *sb = e4b->bd_sb; + + if (unlikely(e4b->bd_info->bb_bitmap == NULL)) + return; + BUG_ON(!ext4_is_group_locked(sb, e4b->bd_group)); + for (i = 0; i < count; i++) { + if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) { + ext4_fsblk_t blocknr; + blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb); + blocknr += first + i; + blocknr += + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); + + ext4_error(sb, __FUNCTION__, "double-free of inode" + " %lu's block %llu(bit %u in group %lu)\n", + inode ? inode->i_ino : 0, blocknr, + first + i, e4b->bd_group); + } + mb_clear_bit(first + i, e4b->bd_info->bb_bitmap); + } +} + +static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count) +{ + int i; + + if (unlikely(e4b->bd_info->bb_bitmap == NULL)) + return; + BUG_ON(!ext4_is_group_locked(e4b->bd_sb, e4b->bd_group)); + for (i = 0; i < count; i++) { + BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap)); + mb_set_bit(first + i, e4b->bd_info->bb_bitmap); + } +} + +static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap) +{ + if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) { + unsigned char *b1, *b2; + int i; + b1 = (unsigned char *) e4b->bd_info->bb_bitmap; + b2 = (unsigned char *) bitmap; + for (i = 0; i < e4b->bd_sb->s_blocksize; i++) { + if (b1[i] != b2[i]) { + printk("corruption in group %lu at byte %u(%u):" + " %x in copy != %x on disk/prealloc\n", + e4b->bd_group, i, i * 8, b1[i], b2[i]); + BUG(); + } + } + } +} + +#else +static inline void mb_free_blocks_double(struct inode *inode, + struct ext4_buddy *e4b, int first, int count) +{ + return; +} +static inline void mb_mark_used_double(struct ext4_buddy *e4b, + int first, int count) +{ + return; +} +static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap) +{ + return; +} +#endif + +#ifdef AGGRESSIVE_CHECK + +#define MB_CHECK_ASSERT(assert) \ +do { \ + if (!(assert)) { \ + printk(KERN_EMERG \ + "Assertion failure in %s() at %s:%d: \"%s\"\n", \ + function, file, line, # assert); \ + BUG(); \ + } \ +} while (0) + +static int __mb_check_buddy(struct ext4_buddy *e4b, char *file, + const char *function, int line) +{ + struct super_block *sb = e4b->bd_sb; + int order = e4b->bd_blkbits + 1; + int max; + int max2; + int i; + int j; + int k; + int count; + struct ext4_group_info *grp; + int fragments = 0; + int fstart; + struct list_head *cur; + void *buddy; + void *buddy2; + + if (!test_opt(sb, MBALLOC)) + return 0; + + { + static int mb_check_counter; + if (mb_check_counter++ % 100 != 0) + return 0; + } + + while (order > 1) { + buddy = mb_find_buddy(e4b, order, &max); + MB_CHECK_ASSERT(buddy); + buddy2 = mb_find_buddy(e4b, order - 1, &max2); + MB_CHECK_ASSERT(buddy2); + MB_CHECK_ASSERT(buddy != buddy2); + MB_CHECK_ASSERT(max * 2 == max2); + + count = 0; + for (i = 0; i < max; i++) { + + if (mb_test_bit(i, buddy)) { + /* only single bit in buddy2 may be 1 */ + if (!mb_test_bit(i << 1, buddy2)) { + MB_CHECK_ASSERT( + mb_test_bit((i<<1)+1, buddy2)); + } else if (!mb_test_bit((i << 1) + 1, buddy2)) { + MB_CHECK_ASSERT( + mb_test_bit(i << 1, buddy2)); + } + continue; + } + + /* both bits in buddy2 must be 0 */ + MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2)); + MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2)); + + for (j = 0; j < (1 << order); j++) { + k = (i * (1 << order)) + j; + MB_CHECK_ASSERT( + !mb_test_bit(k, EXT4_MB_BITMAP(e4b))); + } + count++; + } + MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count); + order--; + } + + fstart = -1; + buddy = mb_find_buddy(e4b, 0, &max); + for (i = 0; i < max; i++) { + if (!mb_test_bit(i, buddy)) { + MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free); + if (fstart == -1) { + fragments++; + fstart = i; + } + continue; + } + fstart = -1; + /* check used bits only */ + for (j = 0; j < e4b->bd_blkbits + 1; j++) { + buddy2 = mb_find_buddy(e4b, j, &max2); + k = i >> j; + MB_CHECK_ASSERT(k < max2); + MB_CHECK_ASSERT(mb_test_bit(k, buddy2)); + } + } + MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info)); + MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments); + + grp = ext4_get_group_info(sb, e4b->bd_group); + buddy = mb_find_buddy(e4b, 0, &max); + list_for_each(cur, &grp->bb_prealloc_list) { + ext4_group_t groupnr; + struct ext4_prealloc_space *pa; + pa = list_entry(cur, struct ext4_prealloc_space, group_list); + ext4_get_group_no_and_offset(sb, pa->pstart, &groupnr, &k); + MB_CHECK_ASSERT(groupnr == e4b->bd_group); + for (i = 0; i < pa->len; i++) + MB_CHECK_ASSERT(mb_test_bit(k + i, buddy)); + } + return 0; +} +#undef MB_CHECK_ASSERT +#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \ + __FILE__, __FUNCTION__, __LINE__) +#else +#define mb_check_buddy(e4b) +#endif + +/* FIXME!! need more doc */ +static void ext4_mb_mark_free_simple(struct super_block *sb, + void *buddy, unsigned first, int len, + struct ext4_group_info *grp) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + unsigned short min; + unsigned short max; + unsigned short chunk; + unsigned short border; + + BUG_ON(len >= EXT4_BLOCKS_PER_GROUP(sb)); + + border = 2 << sb->s_blocksize_bits; + + while (len > 0) { + /* find how many blocks can be covered since this position */ + max = ffs(first | border) - 1; + + /* find how many blocks of power 2 we need to mark */ + min = fls(len) - 1; + + if (max < min) + min = max; + chunk = 1 << min; + + /* mark multiblock chunks only */ + grp->bb_counters[min]++; + if (min > 0) + mb_clear_bit(first >> min, + buddy + sbi->s_mb_offsets[min]); + + len -= chunk; + first += chunk; + } +} + +static void ext4_mb_generate_buddy(struct super_block *sb, + void *buddy, void *bitmap, ext4_group_t group) +{ + struct ext4_group_info *grp = ext4_get_group_info(sb, group); + unsigned short max = EXT4_BLOCKS_PER_GROUP(sb); + unsigned short i = 0; + unsigned short first; + unsigned short len; + unsigned free = 0; + unsigned fragments = 0; + unsigned long long period = get_cycles(); + + /* initialize buddy from bitmap which is aggregation + * of on-disk bitmap and preallocations */ + i = ext4_find_next_zero_bit(bitmap, max, 0); + grp->bb_first_free = i; + while (i < max) { + fragments++; + first = i; + i = ext4_find_next_bit(bitmap, max, i); + len = i - first; + free += len; + if (len > 1) + ext4_mb_mark_free_simple(sb, buddy, first, len, grp); + else + grp->bb_counters[0]++; + if (i < max) + i = ext4_find_next_zero_bit(bitmap, max, i); + } + grp->bb_fragments = fragments; + + if (free != grp->bb_free) { + printk(KERN_DEBUG + "EXT4-fs: group %lu: %u blocks in bitmap, %u in gd\n", + group, free, grp->bb_free); + grp->bb_free = free; + } + + clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state)); + + period = get_cycles() - period; + spin_lock(&EXT4_SB(sb)->s_bal_lock); + EXT4_SB(sb)->s_mb_buddies_generated++; + EXT4_SB(sb)->s_mb_generation_time += period; + spin_unlock(&EXT4_SB(sb)->s_bal_lock); +} + +/* The buddy information is attached the buddy cache inode + * for convenience. The information regarding each group + * is loaded via ext4_mb_load_buddy. The information involve + * block bitmap and buddy information. The information are + * stored in the inode as + * + * { page } + * [ group 0 buddy][ group 0 bitmap] [group 1][ group 1]... + * + * + * one block each for bitmap and buddy information. + * So for each group we take up 2 blocks. A page can + * contain blocks_per_page (PAGE_CACHE_SIZE / blocksize) blocks. + * So it can have information regarding groups_per_page which + * is blocks_per_page/2 + */ + +static int ext4_mb_init_cache(struct page *page, char *incore) +{ + int blocksize; + int blocks_per_page; + int groups_per_page; + int err = 0; + int i; + ext4_group_t first_group; + int first_block; + struct super_block *sb; + struct buffer_head *bhs; + struct buffer_head **bh; + struct inode *inode; + char *data; + char *bitmap; + + mb_debug("init page %lu\n", page->index); + + inode = page->mapping->host; + sb = inode->i_sb; + blocksize = 1 << inode->i_blkbits; + blocks_per_page = PAGE_CACHE_SIZE / blocksize; + + groups_per_page = blocks_per_page >> 1; + if (groups_per_page == 0) + groups_per_page = 1; + + /* allocate buffer_heads to read bitmaps */ + if (groups_per_page > 1) { + err = -ENOMEM; + i = sizeof(struct buffer_head *) * groups_per_page; + bh = kzalloc(i, GFP_NOFS); + if (bh == NULL) + goto out; + } else + bh = &bhs; + + first_group = page->index * blocks_per_page / 2; + + /* read all groups the page covers into the cache */ + for (i = 0; i < groups_per_page; i++) { + struct ext4_group_desc *desc; + + if (first_group + i >= EXT4_SB(sb)->s_groups_count) + break; + + err = -EIO; + desc = ext4_get_group_desc(sb, first_group + i, NULL); + if (desc == NULL) + goto out; + + err = -ENOMEM; + bh[i] = sb_getblk(sb, ext4_block_bitmap(sb, desc)); + if (bh[i] == NULL) + goto out; + + if (bh_uptodate_or_lock(bh[i])) + continue; + + if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { + ext4_init_block_bitmap(sb, bh[i], + first_group + i, desc); + set_buffer_uptodate(bh[i]); + unlock_buffer(bh[i]); + continue; + } + get_bh(bh[i]); + bh[i]->b_end_io = end_buffer_read_sync; + submit_bh(READ, bh[i]); + mb_debug("read bitmap for group %lu\n", first_group + i); + } + + /* wait for I/O completion */ + for (i = 0; i < groups_per_page && bh[i]; i++) + wait_on_buffer(bh[i]); + + err = -EIO; + for (i = 0; i < groups_per_page && bh[i]; i++) + if (!buffer_uptodate(bh[i])) + goto out; + + first_block = page->index * blocks_per_page; + for (i = 0; i < blocks_per_page; i++) { + int group; + struct ext4_group_info *grinfo; + + group = (first_block + i) >> 1; + if (group >= EXT4_SB(sb)->s_groups_count) + break; + + /* + * data carry information regarding this + * particular group in the format specified + * above + * + */ + data = page_address(page) + (i * blocksize); + bitmap = bh[group - first_group]->b_data; + + /* + * We place the buddy block and bitmap block + * close together + */ + if ((first_block + i) & 1) { + /* this is block of buddy */ + BUG_ON(incore == NULL); + mb_debug("put buddy for group %u in page %lu/%x\n", + group, page->index, i * blocksize); + memset(data, 0xff, blocksize); + grinfo = ext4_get_group_info(sb, group); + grinfo->bb_fragments = 0; + memset(grinfo->bb_counters, 0, + sizeof(unsigned short)*(sb->s_blocksize_bits+2)); + /* + * incore got set to the group block bitmap below + */ + ext4_mb_generate_buddy(sb, data, incore, group); + incore = NULL; + } else { + /* this is block of bitmap */ + BUG_ON(incore != NULL); + mb_debug("put bitmap for group %u in page %lu/%x\n", + group, page->index, i * blocksize); + + /* see comments in ext4_mb_put_pa() */ + ext4_lock_group(sb, group); + memcpy(data, bitmap, blocksize); + + /* mark all preallocated blks used in in-core bitmap */ + ext4_mb_generate_from_pa(sb, data, group); + ext4_unlock_group(sb, group); + + /* set incore so that the buddy information can be + * generated using this + */ + incore = data; + } + } + SetPageUptodate(page); + +out: + if (bh) { + for (i = 0; i < groups_per_page && bh[i]; i++) + brelse(bh[i]); + if (bh != &bhs) + kfree(bh); + } + return err; +} + +static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group, + struct ext4_buddy *e4b) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct inode *inode = sbi->s_buddy_cache; + int blocks_per_page; + int block; + int pnum; + int poff; + struct page *page; + + mb_debug("load group %lu\n", group); + + blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize; + + e4b->bd_blkbits = sb->s_blocksize_bits; + e4b->bd_info = ext4_get_group_info(sb, group); + e4b->bd_sb = sb; + e4b->bd_group = group; + e4b->bd_buddy_page = NULL; + e4b->bd_bitmap_page = NULL; + + /* + * the buddy cache inode stores the block bitmap + * and buddy information in consecutive blocks. + * So for each group we need two blocks. + */ + block = group * 2; + pnum = block / blocks_per_page; + poff = block % blocks_per_page; + + /* we could use find_or_create_page(), but it locks page + * what we'd like to avoid in fast path ... */ + page = find_get_page(inode->i_mapping, pnum); + if (page == NULL || !PageUptodate(page)) { + if (page) + page_cache_release(page); + page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS); + if (page) { + BUG_ON(page->mapping != inode->i_mapping); + if (!PageUptodate(page)) { + ext4_mb_init_cache(page, NULL); + mb_cmp_bitmaps(e4b, page_address(page) + + (poff * sb->s_blocksize)); + } + unlock_page(page); + } + } + if (page == NULL || !PageUptodate(page)) + goto err; + e4b->bd_bitmap_page = page; + e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize); + mark_page_accessed(page); + + block++; + pnum = block / blocks_per_page; + poff = block % blocks_per_page; + + page = find_get_page(inode->i_mapping, pnum); + if (page == NULL || !PageUptodate(page)) { + if (page) + page_cache_release(page); + page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS); + if (page) { + BUG_ON(page->mapping != inode->i_mapping); + if (!PageUptodate(page)) + ext4_mb_init_cache(page, e4b->bd_bitmap); + + unlock_page(page); + } + } + if (page == NULL || !PageUptodate(page)) + goto err; + e4b->bd_buddy_page = page; + e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize); + mark_page_accessed(page); + + BUG_ON(e4b->bd_bitmap_page == NULL); + BUG_ON(e4b->bd_buddy_page == NULL); + + return 0; + +err: + if (e4b->bd_bitmap_page) + page_cache_release(e4b->bd_bitmap_page); + if (e4b->bd_buddy_page) + page_cache_release(e4b->bd_buddy_page); + e4b->bd_buddy = NULL; + e4b->bd_bitmap = NULL; + return -EIO; +} + +static void ext4_mb_release_desc(struct ext4_buddy *e4b) +{ + if (e4b->bd_bitmap_page) + page_cache_release(e4b->bd_bitmap_page); + if (e4b->bd_buddy_page) + page_cache_release(e4b->bd_buddy_page); +} + + +static int mb_find_order_for_block(struct ext4_buddy *e4b, int block) +{ + int order = 1; + void *bb; + + BUG_ON(EXT4_MB_BITMAP(e4b) == EXT4_MB_BUDDY(e4b)); + BUG_ON(block >= (1 << (e4b->bd_blkbits + 3))); + + bb = EXT4_MB_BUDDY(e4b); + while (order <= e4b->bd_blkbits + 1) { + block = block >> 1; + if (!mb_test_bit(block, bb)) { + /* this block is part of buddy of order 'order' */ + return order; + } + bb += 1 << (e4b->bd_blkbits - order); + order++; + } + return 0; +} + +static void mb_clear_bits(spinlock_t *lock, void *bm, int cur, int len) +{ + __u32 *addr; + + len = cur + len; + while (cur < len) { + if ((cur & 31) == 0 && (len - cur) >= 32) { + /* fast path: clear whole word at once */ + addr = bm + (cur >> 3); + *addr = 0; + cur += 32; + continue; + } + mb_clear_bit_atomic(lock, cur, bm); + cur++; + } +} + +static void mb_set_bits(spinlock_t *lock, void *bm, int cur, int len) +{ + __u32 *addr; + + len = cur + len; + while (cur < len) { + if ((cur & 31) == 0 && (len - cur) >= 32) { + /* fast path: set whole word at once */ + addr = bm + (cur >> 3); + *addr = 0xffffffff; + cur += 32; + continue; + } + mb_set_bit_atomic(lock, cur, bm); + cur++; + } +} + +static int mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b, + int first, int count) +{ + int block = 0; + int max = 0; + int order; + void *buddy; + void *buddy2; + struct super_block *sb = e4b->bd_sb; + + BUG_ON(first + count > (sb->s_blocksize << 3)); + BUG_ON(!ext4_is_group_locked(sb, e4b->bd_group)); + mb_check_buddy(e4b); + mb_free_blocks_double(inode, e4b, first, count); + + e4b->bd_info->bb_free += count; + if (first < e4b->bd_info->bb_first_free) + e4b->bd_info->bb_first_free = first; + + /* let's maintain fragments counter */ + if (first != 0) + block = !mb_test_bit(first - 1, EXT4_MB_BITMAP(e4b)); + if (first + count < EXT4_SB(sb)->s_mb_maxs[0]) + max = !mb_test_bit(first + count, EXT4_MB_BITMAP(e4b)); + if (block && max) + e4b->bd_info->bb_fragments--; + else if (!block && !max) + e4b->bd_info->bb_fragments++; + + /* let's maintain buddy itself */ + while (count-- > 0) { + block = first++; + order = 0; + + if (!mb_test_bit(block, EXT4_MB_BITMAP(e4b))) { + ext4_fsblk_t blocknr; + blocknr = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb); + blocknr += block; + blocknr += + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block); + + ext4_error(sb, __FUNCTION__, "double-free of inode" + " %lu's block %llu(bit %u in group %lu)\n", + inode ? inode->i_ino : 0, blocknr, block, + e4b->bd_group); + } + mb_clear_bit(block, EXT4_MB_BITMAP(e4b)); + e4b->bd_info->bb_counters[order]++; + + /* start of the buddy */ + buddy = mb_find_buddy(e4b, order, &max); + + do { + block &= ~1UL; + if (mb_test_bit(block, buddy) || + mb_test_bit(block + 1, buddy)) + break; + + /* both the buddies are free, try to coalesce them */ + buddy2 = mb_find_buddy(e4b, order + 1, &max); + + if (!buddy2) + break; + + if (order > 0) { + /* for special purposes, we don't set + * free bits in bitmap */ + mb_set_bit(block, buddy); + mb_set_bit(block + 1, buddy); + } + e4b->bd_info->bb_counters[order]--; + e4b->bd_info->bb_counters[order]--; + + block = block >> 1; + order++; + e4b->bd_info->bb_counters[order]++; + + mb_clear_bit(block, buddy2); + buddy = buddy2; + } while (1); + } + mb_check_buddy(e4b); + + return 0; +} + +static int mb_find_extent(struct ext4_buddy *e4b, int order, int block, + int needed, struct ext4_free_extent *ex) +{ + int next = block; + int max; + int ord; + void *buddy; + + BUG_ON(!ext4_is_group_locked(e4b->bd_sb, e4b->bd_group)); + BUG_ON(ex == NULL); + + buddy = mb_find_buddy(e4b, order, &max); + BUG_ON(buddy == NULL); + BUG_ON(block >= max); + if (mb_test_bit(block, buddy)) { + ex->fe_len = 0; + ex->fe_start = 0; + ex->fe_group = 0; + return 0; + } + + /* FIXME dorp order completely ? */ + if (likely(order == 0)) { + /* find actual order */ + order = mb_find_order_for_block(e4b, block); + block = block >> order; + } + + ex->fe_len = 1 << order; + ex->fe_start = block << order; + ex->fe_group = e4b->bd_group; + + /* calc difference from given start */ + next = next - ex->fe_start; + ex->fe_len -= next; + ex->fe_start += next; + + while (needed > ex->fe_len && + (buddy = mb_find_buddy(e4b, order, &max))) { + + if (block + 1 >= max) + break; + + next = (block + 1) * (1 << order); + if (mb_test_bit(next, EXT4_MB_BITMAP(e4b))) + break; + + ord = mb_find_order_for_block(e4b, next); + + order = ord; + block = next >> order; + ex->fe_len += 1 << order; + } + + BUG_ON(ex->fe_start + ex->fe_len > (1 << (e4b->bd_blkbits + 3))); + return ex->fe_len; +} + +static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex) +{ + int ord; + int mlen = 0; + int max = 0; + int cur; + int start = ex->fe_start; + int len = ex->fe_len; + unsigned ret = 0; + int len0 = len; + void *buddy; + + BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3)); + BUG_ON(e4b->bd_group != ex->fe_group); + BUG_ON(!ext4_is_group_locked(e4b->bd_sb, e4b->bd_group)); + mb_check_buddy(e4b); + mb_mark_used_double(e4b, start, len); + + e4b->bd_info->bb_free -= len; + if (e4b->bd_info->bb_first_free == start) + e4b->bd_info->bb_first_free += len; + + /* let's maintain fragments counter */ + if (start != 0) + mlen = !mb_test_bit(start - 1, EXT4_MB_BITMAP(e4b)); + if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0]) + max = !mb_test_bit(start + len, EXT4_MB_BITMAP(e4b)); + if (mlen && max) + e4b->bd_info->bb_fragments++; + else if (!mlen && !max) + e4b->bd_info->bb_fragments--; + + /* let's maintain buddy itself */ + while (len) { + ord = mb_find_order_for_block(e4b, start); + + if (((start >> ord) << ord) == start && len >= (1 << ord)) { + /* the whole chunk may be allocated at once! */ + mlen = 1 << ord; + buddy = mb_find_buddy(e4b, ord, &max); + BUG_ON((start >> ord) >= max); + mb_set_bit(start >> ord, buddy); + e4b->bd_info->bb_counters[ord]--; + start += mlen; + len -= mlen; + BUG_ON(len < 0); + continue; + } + + /* store for history */ + if (ret == 0) + ret = len | (ord << 16); + + /* we have to split large buddy */ + BUG_ON(ord <= 0); + buddy = mb_find_buddy(e4b, ord, &max); + mb_set_bit(start >> ord, buddy); + e4b->bd_info->bb_counters[ord]--; + + ord--; + cur = (start >> ord) & ~1U; + buddy = mb_find_buddy(e4b, ord, &max); + mb_clear_bit(cur, buddy); + mb_clear_bit(cur + 1, buddy); + e4b->bd_info->bb_counters[ord]++; + e4b->bd_info->bb_counters[ord]++; + } + + mb_set_bits(sb_bgl_lock(EXT4_SB(e4b->bd_sb), ex->fe_group), + EXT4_MB_BITMAP(e4b), ex->fe_start, len0); + mb_check_buddy(e4b); + + return ret; +} + +/* + * Must be called under group lock! + */ +static void ext4_mb_use_best_found(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + int ret; + + BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group); + BUG_ON(ac->ac_status == AC_STATUS_FOUND); + + ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len); + ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical; + ret = mb_mark_used(e4b, &ac->ac_b_ex); + + /* preallocation can change ac_b_ex, thus we store actually + * allocated blocks for history */ + ac->ac_f_ex = ac->ac_b_ex; + + ac->ac_status = AC_STATUS_FOUND; + ac->ac_tail = ret & 0xffff; + ac->ac_buddy = ret >> 16; + + /* XXXXXXX: SUCH A HORRIBLE **CK */ + /*FIXME!! Why ? */ + ac->ac_bitmap_page = e4b->bd_bitmap_page; + get_page(ac->ac_bitmap_page); + ac->ac_buddy_page = e4b->bd_buddy_page; + get_page(ac->ac_buddy_page); + + /* store last allocated for subsequent stream allocation */ + if ((ac->ac_flags & EXT4_MB_HINT_DATA)) { + spin_lock(&sbi->s_md_lock); + sbi->s_mb_last_group = ac->ac_f_ex.fe_group; + sbi->s_mb_last_start = ac->ac_f_ex.fe_start; + spin_unlock(&sbi->s_md_lock); + } +} + +/* + * regular allocator, for general purposes allocation + */ + +static void ext4_mb_check_limits(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b, + int finish_group) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + struct ext4_free_extent *bex = &ac->ac_b_ex; + struct ext4_free_extent *gex = &ac->ac_g_ex; + struct ext4_free_extent ex; + int max; + + /* + * We don't want to scan for a whole year + */ + if (ac->ac_found > sbi->s_mb_max_to_scan && + !(ac->ac_flags & EXT4_MB_HINT_FIRST)) { + ac->ac_status = AC_STATUS_BREAK; + return; + } + + /* + * Haven't found good chunk so far, let's continue + */ + if (bex->fe_len < gex->fe_len) + return; + + if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan) + && bex->fe_group == e4b->bd_group) { + /* recheck chunk's availability - we don't know + * when it was found (within this lock-unlock + * period or not) */ + max = mb_find_extent(e4b, 0, bex->fe_start, gex->fe_len, &ex); + if (max >= gex->fe_len) { + ext4_mb_use_best_found(ac, e4b); + return; + } + } +} + +/* + * The routine checks whether found extent is good enough. If it is, + * then the extent gets marked used and flag is set to the context + * to stop scanning. Otherwise, the extent is compared with the + * previous found extent and if new one is better, then it's stored + * in the context. Later, the best found extent will be used, if + * mballoc can't find good enough extent. + * + * FIXME: real allocation policy is to be designed yet! + */ +static void ext4_mb_measure_extent(struct ext4_allocation_context *ac, + struct ext4_free_extent *ex, + struct ext4_buddy *e4b) +{ + struct ext4_free_extent *bex = &ac->ac_b_ex; + struct ext4_free_extent *gex = &ac->ac_g_ex; + + BUG_ON(ex->fe_len <= 0); + BUG_ON(ex->fe_len >= EXT4_BLOCKS_PER_GROUP(ac->ac_sb)); + BUG_ON(ex->fe_start >= EXT4_BLOCKS_PER_GROUP(ac->ac_sb)); + BUG_ON(ac->ac_status != AC_STATUS_CONTINUE); + + ac->ac_found++; + + /* + * The special case - take what you catch first + */ + if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) { + *bex = *ex; + ext4_mb_use_best_found(ac, e4b); + return; + } + + /* + * Let's check whether the chuck is good enough + */ + if (ex->fe_len == gex->fe_len) { + *bex = *ex; + ext4_mb_use_best_found(ac, e4b); + return; + } + + /* + * If this is first found extent, just store it in the context + */ + if (bex->fe_len == 0) { + *bex = *ex; + return; + } + + /* + * If new found extent is better, store it in the context + */ + if (bex->fe_len < gex->fe_len) { + /* if the request isn't satisfied, any found extent + * larger than previous best one is better */ + if (ex->fe_len > bex->fe_len) + *bex = *ex; + } else if (ex->fe_len > gex->fe_len) { + /* if the request is satisfied, then we try to find + * an extent that still satisfy the request, but is + * smaller than previous one */ + if (ex->fe_len < bex->fe_len) + *bex = *ex; + } + + ext4_mb_check_limits(ac, e4b, 0); +} + +static int ext4_mb_try_best_found(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + struct ext4_free_extent ex = ac->ac_b_ex; + ext4_group_t group = ex.fe_group; + int max; + int err; + + BUG_ON(ex.fe_len <= 0); + err = ext4_mb_load_buddy(ac->ac_sb, group, e4b); + if (err) + return err; + + ext4_lock_group(ac->ac_sb, group); + max = mb_find_extent(e4b, 0, ex.fe_start, ex.fe_len, &ex); + + if (max > 0) { + ac->ac_b_ex = ex; + ext4_mb_use_best_found(ac, e4b); + } + + ext4_unlock_group(ac->ac_sb, group); + ext4_mb_release_desc(e4b); + + return 0; +} + +static int ext4_mb_find_by_goal(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + ext4_group_t group = ac->ac_g_ex.fe_group; + int max; + int err; + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + struct ext4_super_block *es = sbi->s_es; + struct ext4_free_extent ex; + + if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL)) + return 0; + + err = ext4_mb_load_buddy(ac->ac_sb, group, e4b); + if (err) + return err; + + ext4_lock_group(ac->ac_sb, group); + max = mb_find_extent(e4b, 0, ac->ac_g_ex.fe_start, + ac->ac_g_ex.fe_len, &ex); + + if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) { + ext4_fsblk_t start; + + start = (e4b->bd_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb)) + + ex.fe_start + le32_to_cpu(es->s_first_data_block); + /* use do_div to get remainder (would be 64-bit modulo) */ + if (do_div(start, sbi->s_stripe) == 0) { + ac->ac_found++; + ac->ac_b_ex = ex; + ext4_mb_use_best_found(ac, e4b); + } + } else if (max >= ac->ac_g_ex.fe_len) { + BUG_ON(ex.fe_len <= 0); + BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group); + BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start); + ac->ac_found++; + ac->ac_b_ex = ex; + ext4_mb_use_best_found(ac, e4b); + } else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) { + /* Sometimes, caller may want to merge even small + * number of blocks to an existing extent */ + BUG_ON(ex.fe_len <= 0); + BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group); + BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start); + ac->ac_found++; + ac->ac_b_ex = ex; + ext4_mb_use_best_found(ac, e4b); + } + ext4_unlock_group(ac->ac_sb, group); + ext4_mb_release_desc(e4b); + + return 0; +} + +/* + * The routine scans buddy structures (not bitmap!) from given order + * to max order and tries to find big enough chunk to satisfy the req + */ +static void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_group_info *grp = e4b->bd_info; + void *buddy; + int i; + int k; + int max; + + BUG_ON(ac->ac_2order <= 0); + for (i = ac->ac_2order; i <= sb->s_blocksize_bits + 1; i++) { + if (grp->bb_counters[i] == 0) + continue; + + buddy = mb_find_buddy(e4b, i, &max); + BUG_ON(buddy == NULL); + + k = ext4_find_next_zero_bit(buddy, max, 0); + BUG_ON(k >= max); + + ac->ac_found++; + + ac->ac_b_ex.fe_len = 1 << i; + ac->ac_b_ex.fe_start = k << i; + ac->ac_b_ex.fe_group = e4b->bd_group; + + ext4_mb_use_best_found(ac, e4b); + + BUG_ON(ac->ac_b_ex.fe_len != ac->ac_g_ex.fe_len); + + if (EXT4_SB(sb)->s_mb_stats) + atomic_inc(&EXT4_SB(sb)->s_bal_2orders); + + break; + } +} + +/* + * The routine scans the group and measures all found extents. + * In order to optimize scanning, caller must pass number of + * free blocks in the group, so the routine can know upper limit. + */ +static void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + struct super_block *sb = ac->ac_sb; + void *bitmap = EXT4_MB_BITMAP(e4b); + struct ext4_free_extent ex; + int i; + int free; + + free = e4b->bd_info->bb_free; + BUG_ON(free <= 0); + + i = e4b->bd_info->bb_first_free; + + while (free && ac->ac_status == AC_STATUS_CONTINUE) { + i = ext4_find_next_zero_bit(bitmap, + EXT4_BLOCKS_PER_GROUP(sb), i); + if (i >= EXT4_BLOCKS_PER_GROUP(sb)) { + BUG_ON(free != 0); + break; + } + + mb_find_extent(e4b, 0, i, ac->ac_g_ex.fe_len, &ex); + BUG_ON(ex.fe_len <= 0); + BUG_ON(free < ex.fe_len); + + ext4_mb_measure_extent(ac, &ex, e4b); + + i += ex.fe_len; + free -= ex.fe_len; + } + + ext4_mb_check_limits(ac, e4b, 1); +} + +/* + * This is a special case for storages like raid5 + * we try to find stripe-aligned chunks for stripe-size requests + * XXX should do so at least for multiples of stripe size as well + */ +static void ext4_mb_scan_aligned(struct ext4_allocation_context *ac, + struct ext4_buddy *e4b) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + void *bitmap = EXT4_MB_BITMAP(e4b); + struct ext4_free_extent ex; + ext4_fsblk_t first_group_block; + ext4_fsblk_t a; + ext4_grpblk_t i; + int max; + + BUG_ON(sbi->s_stripe == 0); + + /* find first stripe-aligned block in group */ + first_group_block = e4b->bd_group * EXT4_BLOCKS_PER_GROUP(sb) + + le32_to_cpu(sbi->s_es->s_first_data_block); + a = first_group_block + sbi->s_stripe - 1; + do_div(a, sbi->s_stripe); + i = (a * sbi->s_stripe) - first_group_block; + + while (i < EXT4_BLOCKS_PER_GROUP(sb)) { + if (!mb_test_bit(i, bitmap)) { + max = mb_find_extent(e4b, 0, i, sbi->s_stripe, &ex); + if (max >= sbi->s_stripe) { + ac->ac_found++; + ac->ac_b_ex = ex; + ext4_mb_use_best_found(ac, e4b); + break; + } + } + i += sbi->s_stripe; + } +} + +static int ext4_mb_good_group(struct ext4_allocation_context *ac, + ext4_group_t group, int cr) +{ + unsigned free, fragments; + unsigned i, bits; + struct ext4_group_desc *desc; + struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group); + + BUG_ON(cr < 0 || cr >= 4); + BUG_ON(EXT4_MB_GRP_NEED_INIT(grp)); + + free = grp->bb_free; + fragments = grp->bb_fragments; + if (free == 0) + return 0; + if (fragments == 0) + return 0; + + switch (cr) { + case 0: + BUG_ON(ac->ac_2order == 0); + /* If this group is uninitialized, skip it initially */ + desc = ext4_get_group_desc(ac->ac_sb, group, NULL); + if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) + return 0; + + bits = ac->ac_sb->s_blocksize_bits + 1; + for (i = ac->ac_2order; i <= bits; i++) + if (grp->bb_counters[i] > 0) + return 1; + break; + case 1: + if ((free / fragments) >= ac->ac_g_ex.fe_len) + return 1; + break; + case 2: + if (free >= ac->ac_g_ex.fe_len) + return 1; + break; + case 3: + return 1; + default: + BUG(); + } + + return 0; +} + +static int ext4_mb_regular_allocator(struct ext4_allocation_context *ac) +{ + ext4_group_t group; + ext4_group_t i; + int cr; + int err = 0; + int bsbits; + struct ext4_sb_info *sbi; + struct super_block *sb; + struct ext4_buddy e4b; + loff_t size, isize; + + sb = ac->ac_sb; + sbi = EXT4_SB(sb); + BUG_ON(ac->ac_status == AC_STATUS_FOUND); + + /* first, try the goal */ + err = ext4_mb_find_by_goal(ac, &e4b); + if (err || ac->ac_status == AC_STATUS_FOUND) + goto out; + + if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)) + goto out; + + /* + * ac->ac2_order is set only if the fe_len is a power of 2 + * if ac2_order is set we also set criteria to 0 so that we + * try exact allocation using buddy. + */ + i = fls(ac->ac_g_ex.fe_len); + ac->ac_2order = 0; + /* + * We search using buddy data only if the order of the request + * is greater than equal to the sbi_s_mb_order2_reqs + * You can tune it via /proc/fs/ext4/<partition>/order2_req + */ + if (i >= sbi->s_mb_order2_reqs) { + /* + * This should tell if fe_len is exactly power of 2 + */ + if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0) + ac->ac_2order = i - 1; + } + + bsbits = ac->ac_sb->s_blocksize_bits; + /* if stream allocation is enabled, use global goal */ + size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len; + isize = i_size_read(ac->ac_inode) >> bsbits; + if (size < isize) + size = isize; + + if (size < sbi->s_mb_stream_request && + (ac->ac_flags & EXT4_MB_HINT_DATA)) { + /* TBD: may be hot point */ + spin_lock(&sbi->s_md_lock); + ac->ac_g_ex.fe_group = sbi->s_mb_last_group; + ac->ac_g_ex.fe_start = sbi->s_mb_last_start; + spin_unlock(&sbi->s_md_lock); + } + + /* searching for the right group start from the goal value specified */ + group = ac->ac_g_ex.fe_group; + + /* Let's just scan groups to find more-less suitable blocks */ + cr = ac->ac_2order ? 0 : 1; + /* + * cr == 0 try to get exact allocation, + * cr == 3 try to get anything + */ +repeat: + for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) { + ac->ac_criteria = cr; + for (i = 0; i < EXT4_SB(sb)->s_groups_count; group++, i++) { + struct ext4_group_info *grp; + struct ext4_group_desc *desc; + + if (group == EXT4_SB(sb)->s_groups_count) + group = 0; + + /* quick check to skip empty groups */ + grp = ext4_get_group_info(ac->ac_sb, group); + if (grp->bb_free == 0) + continue; + + /* + * if the group is already init we check whether it is + * a good group and if not we don't load the buddy + */ + if (EXT4_MB_GRP_NEED_INIT(grp)) { + /* + * we need full data about the group + * to make a good selection + */ + err = ext4_mb_load_buddy(sb, group, &e4b); + if (err) + goto out; + ext4_mb_release_desc(&e4b); + } + + /* + * If the particular group doesn't satisfy our + * criteria we continue with the next group + */ + if (!ext4_mb_good_group(ac, group, cr)) + continue; + + err = ext4_mb_load_buddy(sb, group, &e4b); + if (err) + goto out; + + ext4_lock_group(sb, group); + if (!ext4_mb_good_group(ac, group, cr)) { + /* someone did allocation from this group */ + ext4_unlock_group(sb, group); + ext4_mb_release_desc(&e4b); + continue; + } + + ac->ac_groups_scanned++; + desc = ext4_get_group_desc(sb, group, NULL); + if (cr == 0 || (desc->bg_flags & + cpu_to_le16(EXT4_BG_BLOCK_UNINIT) && + ac->ac_2order != 0)) + ext4_mb_simple_scan_group(ac, &e4b); + else if (cr == 1 && + ac->ac_g_ex.fe_len == sbi->s_stripe) + ext4_mb_scan_aligned(ac, &e4b); + else + ext4_mb_complex_scan_group(ac, &e4b); + + ext4_unlock_group(sb, group); + ext4_mb_release_desc(&e4b); + + if (ac->ac_status != AC_STATUS_CONTINUE) + break; + } + } + + if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND && + !(ac->ac_flags & EXT4_MB_HINT_FIRST)) { + /* + * We've been searching too long. Let's try to allocate + * the best chunk we've found so far + */ + + ext4_mb_try_best_found(ac, &e4b); + if (ac->ac_status != AC_STATUS_FOUND) { + /* + * Someone more lucky has already allocated it. + * The only thing we can do is just take first + * found block(s) + printk(KERN_DEBUG "EXT4-fs: someone won our chunk\n"); + */ + ac->ac_b_ex.fe_group = 0; + ac->ac_b_ex.fe_start = 0; + ac->ac_b_ex.fe_len = 0; + ac->ac_status = AC_STATUS_CONTINUE; + ac->ac_flags |= EXT4_MB_HINT_FIRST; + cr = 3; + atomic_inc(&sbi->s_mb_lost_chunks); + goto repeat; + } + } +out: + return err; +} + +#ifdef EXT4_MB_HISTORY +struct ext4_mb_proc_session { + struct ext4_mb_history *history; + struct super_block *sb; + int start; + int max; +}; + +static void *ext4_mb_history_skip_empty(struct ext4_mb_proc_session *s, + struct ext4_mb_history *hs, + int first) +{ + if (hs == s->history + s->max) + hs = s->history; + if (!first && hs == s->history + s->start) + return NULL; + while (hs->orig.fe_len == 0) { + hs++; + if (hs == s->history + s->max) + hs = s->history; + if (hs == s->history + s->start) + return NULL; + } + return hs; +} + +static void *ext4_mb_seq_history_start(struct seq_file *seq, loff_t *pos) +{ + struct ext4_mb_proc_session *s = seq->private; + struct ext4_mb_history *hs; + int l = *pos; + + if (l == 0) + return SEQ_START_TOKEN; + hs = ext4_mb_history_skip_empty(s, s->history + s->start, 1); + if (!hs) + return NULL; + while (--l && (hs = ext4_mb_history_skip_empty(s, ++hs, 0)) != NULL); + return hs; +} + +static void *ext4_mb_seq_history_next(struct seq_file *seq, void *v, + loff_t *pos) +{ + struct ext4_mb_proc_session *s = seq->private; + struct ext4_mb_history *hs = v; + + ++*pos; + if (v == SEQ_START_TOKEN) + return ext4_mb_history_skip_empty(s, s->history + s->start, 1); + else + return ext4_mb_history_skip_empty(s, ++hs, 0); +} + +static int ext4_mb_seq_history_show(struct seq_file *seq, void *v) +{ + char buf[25], buf2[25], buf3[25], *fmt; + struct ext4_mb_history *hs = v; + + if (v == SEQ_START_TOKEN) { + seq_printf(seq, "%-5s %-8s %-23s %-23s %-23s %-5s " + "%-5s %-2s %-5s %-5s %-5s %-6s\n", + "pid", "inode", "original", "goal", "result", "found", + "grps", "cr", "flags", "merge", "tail", "broken"); + return 0; + } + + if (hs->op == EXT4_MB_HISTORY_ALLOC) { + fmt = "%-5u %-8u %-23s %-23s %-23s %-5u %-5u %-2u " + "%-5u %-5s %-5u %-6u\n"; + sprintf(buf2, "%lu/%d/%u@%u", hs->result.fe_group, + hs->result.fe_start, hs->result.fe_len, + hs->result.fe_logical); + sprintf(buf, "%lu/%d/%u@%u", hs->orig.fe_group, + hs->orig.fe_start, hs->orig.fe_len, + hs->orig.fe_logical); + sprintf(buf3, "%lu/%d/%u@%u", hs->goal.fe_group, + hs->goal.fe_start, hs->goal.fe_len, + hs->goal.fe_logical); + seq_printf(seq, fmt, hs->pid, hs->ino, buf, buf3, buf2, + hs->found, hs->groups, hs->cr, hs->flags, + hs->merged ? "M" : "", hs->tail, + hs->buddy ? 1 << hs->buddy : 0); + } else if (hs->op == EXT4_MB_HISTORY_PREALLOC) { + fmt = "%-5u %-8u %-23s %-23s %-23s\n"; + sprintf(buf2, "%lu/%d/%u@%u", hs->result.fe_group, + hs->result.fe_start, hs->result.fe_len, + hs->result.fe_logical); + sprintf(buf, "%lu/%d/%u@%u", hs->orig.fe_group, + hs->orig.fe_start, hs->orig.fe_len, + hs->orig.fe_logical); + seq_printf(seq, fmt, hs->pid, hs->ino, buf, "", buf2); + } else if (hs->op == EXT4_MB_HISTORY_DISCARD) { + sprintf(buf2, "%lu/%d/%u", hs->result.fe_group, + hs->result.fe_start, hs->result.fe_len); + seq_printf(seq, "%-5u %-8u %-23s discard\n", + hs->pid, hs->ino, buf2); + } else if (hs->op == EXT4_MB_HISTORY_FREE) { + sprintf(buf2, "%lu/%d/%u", hs->result.fe_group, + hs->result.fe_start, hs->result.fe_len); + seq_printf(seq, "%-5u %-8u %-23s free\n", + hs->pid, hs->ino, buf2); + } + return 0; +} + +static void ext4_mb_seq_history_stop(struct seq_file *seq, void *v) +{ +} + +static struct seq_operations ext4_mb_seq_history_ops = { + .start = ext4_mb_seq_history_start, + .next = ext4_mb_seq_history_next, + .stop = ext4_mb_seq_history_stop, + .show = ext4_mb_seq_history_show, +}; + +static int ext4_mb_seq_history_open(struct inode *inode, struct file *file) +{ + struct super_block *sb = PDE(inode)->data; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_mb_proc_session *s; + int rc; + int size; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (s == NULL) + return -ENOMEM; + s->sb = sb; + size = sizeof(struct ext4_mb_history) * sbi->s_mb_history_max; + s->history = kmalloc(size, GFP_KERNEL); + if (s->history == NULL) { + kfree(s); + return -ENOMEM; + } + + spin_lock(&sbi->s_mb_history_lock); + memcpy(s->history, sbi->s_mb_history, size); + s->max = sbi->s_mb_history_max; + s->start = sbi->s_mb_history_cur % s->max; + spin_unlock(&sbi->s_mb_history_lock); + + rc = seq_open(file, &ext4_mb_seq_history_ops); + if (rc == 0) { + struct seq_file *m = (struct seq_file *)file->private_data; + m->private = s; + } else { + kfree(s->history); + kfree(s); + } + return rc; + +} + +static int ext4_mb_seq_history_release(struct inode *inode, struct file *file) +{ + struct seq_file *seq = (struct seq_file *)file->private_data; + struct ext4_mb_proc_session *s = seq->private; + kfree(s->history); + kfree(s); + return seq_release(inode, file); +} + +static ssize_t ext4_mb_seq_history_write(struct file *file, + const char __user *buffer, + size_t count, loff_t *ppos) +{ + struct seq_file *seq = (struct seq_file *)file->private_data; + struct ext4_mb_proc_session *s = seq->private; + struct super_block *sb = s->sb; + char str[32]; + int value; + + if (count >= sizeof(str)) { + printk(KERN_ERR "EXT4-fs: %s string too long, max %u bytes\n", + "mb_history", (int)sizeof(str)); + return -EOVERFLOW; + } + + if (copy_from_user(str, buffer, count)) + return -EFAULT; + + value = simple_strtol(str, NULL, 0); + if (value < 0) + return -ERANGE; + EXT4_SB(sb)->s_mb_history_filter = value; + + return count; +} + +static struct file_operations ext4_mb_seq_history_fops = { + .owner = THIS_MODULE, + .open = ext4_mb_seq_history_open, + .read = seq_read, + .write = ext4_mb_seq_history_write, + .llseek = seq_lseek, + .release = ext4_mb_seq_history_release, +}; + +static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos) +{ + struct super_block *sb = seq->private; + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_group_t group; + + if (*pos < 0 || *pos >= sbi->s_groups_count) + return NULL; + + group = *pos + 1; + return (void *) group; +} + +static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct super_block *sb = seq->private; + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_group_t group; + + ++*pos; + if (*pos < 0 || *pos >= sbi->s_groups_count) + return NULL; + group = *pos + 1; + return (void *) group;; +} + +static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v) +{ + struct super_block *sb = seq->private; + long group = (long) v; + int i; + int err; + struct ext4_buddy e4b; + struct sg { + struct ext4_group_info info; + unsigned short counters[16]; + } sg; + + group--; + if (group == 0) + seq_printf(seq, "#%-5s: %-5s %-5s %-5s " + "[ %-5s %-5s %-5s %-5s %-5s %-5s %-5s " + "%-5s %-5s %-5s %-5s %-5s %-5s %-5s ]\n", + "group", "free", "frags", "first", + "2^0", "2^1", "2^2", "2^3", "2^4", "2^5", "2^6", + "2^7", "2^8", "2^9", "2^10", "2^11", "2^12", "2^13"); + + i = (sb->s_blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) + + sizeof(struct ext4_group_info); + err = ext4_mb_load_buddy(sb, group, &e4b); + if (err) { + seq_printf(seq, "#%-5lu: I/O error\n", group); + return 0; + } + ext4_lock_group(sb, group); + memcpy(&sg, ext4_get_group_info(sb, group), i); + ext4_unlock_group(sb, group); + ext4_mb_release_desc(&e4b); + + seq_printf(seq, "#%-5lu: %-5u %-5u %-5u [", group, sg.info.bb_free, + sg.info.bb_fragments, sg.info.bb_first_free); + for (i = 0; i <= 13; i++) + seq_printf(seq, " %-5u", i <= sb->s_blocksize_bits + 1 ? + sg.info.bb_counters[i] : 0); + seq_printf(seq, " ]\n"); + + return 0; +} + +static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v) +{ +} + +static struct seq_operations ext4_mb_seq_groups_ops = { + .start = ext4_mb_seq_groups_start, + .next = ext4_mb_seq_groups_next, + .stop = ext4_mb_seq_groups_stop, + .show = ext4_mb_seq_groups_show, +}; + +static int ext4_mb_seq_groups_open(struct inode *inode, struct file *file) +{ + struct super_block *sb = PDE(inode)->data; + int rc; + + rc = seq_open(file, &ext4_mb_seq_groups_ops); + if (rc == 0) { + struct seq_file *m = (struct seq_file *)file->private_data; + m->private = sb; + } + return rc; + +} + +static struct file_operations ext4_mb_seq_groups_fops = { + .owner = THIS_MODULE, + .open = ext4_mb_seq_groups_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static void ext4_mb_history_release(struct super_block *sb) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + + remove_proc_entry("mb_groups", sbi->s_mb_proc); + remove_proc_entry("mb_history", sbi->s_mb_proc); + + kfree(sbi->s_mb_history); +} + +static void ext4_mb_history_init(struct super_block *sb) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + int i; + + if (sbi->s_mb_proc != NULL) { + struct proc_dir_entry *p; + p = create_proc_entry("mb_history", S_IRUGO, sbi->s_mb_proc); + if (p) { + p->proc_fops = &ext4_mb_seq_history_fops; + p->data = sb; + } + p = create_proc_entry("mb_groups", S_IRUGO, sbi->s_mb_proc); + if (p) { + p->proc_fops = &ext4_mb_seq_groups_fops; + p->data = sb; + } + } + + sbi->s_mb_history_max = 1000; + sbi->s_mb_history_cur = 0; + spin_lock_init(&sbi->s_mb_history_lock); + i = sbi->s_mb_history_max * sizeof(struct ext4_mb_history); + sbi->s_mb_history = kmalloc(i, GFP_KERNEL); + if (likely(sbi->s_mb_history != NULL)) + memset(sbi->s_mb_history, 0, i); + /* if we can't allocate history, then we simple won't use it */ +} + +static void ext4_mb_store_history(struct ext4_allocation_context *ac) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + struct ext4_mb_history h; + + if (unlikely(sbi->s_mb_history == NULL)) + return; + + if (!(ac->ac_op & sbi->s_mb_history_filter)) + return; + + h.op = ac->ac_op; + h.pid = current->pid; + h.ino = ac->ac_inode ? ac->ac_inode->i_ino : 0; + h.orig = ac->ac_o_ex; + h.result = ac->ac_b_ex; + h.flags = ac->ac_flags; + h.found = ac->ac_found; + h.groups = ac->ac_groups_scanned; + h.cr = ac->ac_criteria; + h.tail = ac->ac_tail; + h.buddy = ac->ac_buddy; + h.merged = 0; + if (ac->ac_op == EXT4_MB_HISTORY_ALLOC) { + if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start && + ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group) + h.merged = 1; + h.goal = ac->ac_g_ex; + h.result = ac->ac_f_ex; + } + + spin_lock(&sbi->s_mb_history_lock); + memcpy(sbi->s_mb_history + sbi->s_mb_history_cur, &h, sizeof(h)); + if (++sbi->s_mb_history_cur >= sbi->s_mb_history_max) + sbi->s_mb_history_cur = 0; + spin_unlock(&sbi->s_mb_history_lock); +} + +#else +#define ext4_mb_history_release(sb) +#define ext4_mb_history_init(sb) +#endif + +static int ext4_mb_init_backend(struct super_block *sb) +{ + ext4_group_t i; + int j, len, metalen; + struct ext4_sb_info *sbi = EXT4_SB(sb); + int num_meta_group_infos = + (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) >> + EXT4_DESC_PER_BLOCK_BITS(sb); + struct ext4_group_info **meta_group_info; + + /* An 8TB filesystem with 64-bit pointers requires a 4096 byte + * kmalloc. A 128kb malloc should suffice for a 256TB filesystem. + * So a two level scheme suffices for now. */ + sbi->s_group_info = kmalloc(sizeof(*sbi->s_group_info) * + num_meta_group_infos, GFP_KERNEL); + if (sbi->s_group_info == NULL) { + printk(KERN_ERR "EXT4-fs: can't allocate buddy meta group\n"); + return -ENOMEM; + } + sbi->s_buddy_cache = new_inode(sb); + if (sbi->s_buddy_cache == NULL) { + printk(KERN_ERR "EXT4-fs: can't get new inode\n"); + goto err_freesgi; + } + EXT4_I(sbi->s_buddy_cache)->i_disksize = 0; + + metalen = sizeof(*meta_group_info) << EXT4_DESC_PER_BLOCK_BITS(sb); + for (i = 0; i < num_meta_group_infos; i++) { + if ((i + 1) == num_meta_group_infos) + metalen = sizeof(*meta_group_info) * + (sbi->s_groups_count - + (i << EXT4_DESC_PER_BLOCK_BITS(sb))); + meta_group_info = kmalloc(metalen, GFP_KERNEL); + if (meta_group_info == NULL) { + printk(KERN_ERR "EXT4-fs: can't allocate mem for a " + "buddy group\n"); + goto err_freemeta; + } + sbi->s_group_info[i] = meta_group_info; + } + + /* + * calculate needed size. if change bb_counters size, + * don't forget about ext4_mb_generate_buddy() + */ + len = sizeof(struct ext4_group_info); + len += sizeof(unsigned short) * (sb->s_blocksize_bits + 2); + for (i = 0; i < sbi->s_groups_count; i++) { + struct ext4_group_desc *desc; + + meta_group_info = + sbi->s_group_info[i >> EXT4_DESC_PER_BLOCK_BITS(sb)]; + j = i & (EXT4_DESC_PER_BLOCK(sb) - 1); + + meta_group_info[j] = kzalloc(len, GFP_KERNEL); + if (meta_group_info[j] == NULL) { + printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n"); + i--; + goto err_freebuddy; + } + desc = ext4_get_group_desc(sb, i, NULL); + if (desc == NULL) { + printk(KERN_ERR + "EXT4-fs: can't read descriptor %lu\n", i); + goto err_freebuddy; + } + memset(meta_group_info[j], 0, len); + set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, + &(meta_group_info[j]->bb_state)); + + /* + * initialize bb_free to be able to skip + * empty groups without initialization + */ + if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { + meta_group_info[j]->bb_free = + ext4_free_blocks_after_init(sb, i, desc); + } else { + meta_group_info[j]->bb_free = + le16_to_cpu(desc->bg_free_blocks_count); + } + + INIT_LIST_HEAD(&meta_group_info[j]->bb_prealloc_list); + +#ifdef DOUBLE_CHECK + { + struct buffer_head *bh; + meta_group_info[j]->bb_bitmap = + kmalloc(sb->s_blocksize, GFP_KERNEL); + BUG_ON(meta_group_info[j]->bb_bitmap == NULL); + bh = read_block_bitmap(sb, i); + BUG_ON(bh == NULL); + memcpy(meta_group_info[j]->bb_bitmap, bh->b_data, + sb->s_blocksize); + put_bh(bh); + } +#endif + + } + + return 0; + +err_freebuddy: + while (i >= 0) { + kfree(ext4_get_group_info(sb, i)); + i--; + } + i = num_meta_group_infos; +err_freemeta: + while (--i >= 0) + kfree(sbi->s_group_info[i]); + iput(sbi->s_buddy_cache); +err_freesgi: + kfree(sbi->s_group_info); + return -ENOMEM; +} + +int ext4_mb_init(struct super_block *sb, int needs_recovery) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + unsigned i; + unsigned offset; + unsigned max; + + if (!test_opt(sb, MBALLOC)) + return 0; + + i = (sb->s_blocksize_bits + 2) * sizeof(unsigned short); + + sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL); + if (sbi->s_mb_offsets == NULL) { + clear_opt(sbi->s_mount_opt, MBALLOC); + return -ENOMEM; + } + sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL); + if (sbi->s_mb_maxs == NULL) { + clear_opt(sbi->s_mount_opt, MBALLOC); + kfree(sbi->s_mb_maxs); + return -ENOMEM; + } + + /* order 0 is regular bitmap */ + sbi->s_mb_maxs[0] = sb->s_blocksize << 3; + sbi->s_mb_offsets[0] = 0; + + i = 1; + offset = 0; + max = sb->s_blocksize << 2; + do { + sbi->s_mb_offsets[i] = offset; + sbi->s_mb_maxs[i] = max; + offset += 1 << (sb->s_blocksize_bits - i); + max = max >> 1; + i++; + } while (i <= sb->s_blocksize_bits + 1); + + /* init file for buddy data */ + i = ext4_mb_init_backend(sb); + if (i) { + clear_opt(sbi->s_mount_opt, MBALLOC); + kfree(sbi->s_mb_offsets); + kfree(sbi->s_mb_maxs); + return i; + } + + spin_lock_init(&sbi->s_md_lock); + INIT_LIST_HEAD(&sbi->s_active_transaction); + INIT_LIST_HEAD(&sbi->s_closed_transaction); + INIT_LIST_HEAD(&sbi->s_committed_transaction); + spin_lock_init(&sbi->s_bal_lock); + + sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN; + sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN; + sbi->s_mb_stats = MB_DEFAULT_STATS; + sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD; + sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS; + sbi->s_mb_history_filter = EXT4_MB_HISTORY_DEFAULT; + sbi->s_mb_group_prealloc = MB_DEFAULT_GROUP_PREALLOC; + + i = sizeof(struct ext4_locality_group) * NR_CPUS; + sbi->s_locality_groups = kmalloc(i, GFP_KERNEL); + if (sbi->s_locality_groups == NULL) { + clear_opt(sbi->s_mount_opt, MBALLOC); + kfree(sbi->s_mb_offsets); + kfree(sbi->s_mb_maxs); + return -ENOMEM; + } + for (i = 0; i < NR_CPUS; i++) { + struct ext4_locality_group *lg; + lg = &sbi->s_locality_groups[i]; + mutex_init(&lg->lg_mutex); + INIT_LIST_HEAD(&lg->lg_prealloc_list); + spin_lock_init(&lg->lg_prealloc_lock); + } + + ext4_mb_init_per_dev_proc(sb); + ext4_mb_history_init(sb); + + printk("EXT4-fs: mballoc enabled\n"); + return 0; +} + +/* need to called with ext4 group lock (ext4_lock_group) */ +static void ext4_mb_cleanup_pa(struct ext4_group_info *grp) +{ + struct ext4_prealloc_space *pa; + struct list_head *cur, *tmp; + int count = 0; + + list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) { + pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list); + list_del(&pa->pa_group_list); + count++; + kfree(pa); + } + if (count) + mb_debug("mballoc: %u PAs left\n", count); + +} + +int ext4_mb_release(struct super_block *sb) +{ + ext4_group_t i; + int num_meta_group_infos; + struct ext4_group_info *grinfo; + struct ext4_sb_info *sbi = EXT4_SB(sb); + + if (!test_opt(sb, MBALLOC)) + return 0; + + /* release freed, non-committed blocks */ + spin_lock(&sbi->s_md_lock); + list_splice_init(&sbi->s_closed_transaction, + &sbi->s_committed_transaction); + list_splice_init(&sbi->s_active_transaction, + &sbi->s_committed_transaction); + spin_unlock(&sbi->s_md_lock); + ext4_mb_free_committed_blocks(sb); + + if (sbi->s_group_info) { + for (i = 0; i < sbi->s_groups_count; i++) { + grinfo = ext4_get_group_info(sb, i); +#ifdef DOUBLE_CHECK + kfree(grinfo->bb_bitmap); +#endif + ext4_lock_group(sb, i); + ext4_mb_cleanup_pa(grinfo); + ext4_unlock_group(sb, i); + kfree(grinfo); + } + num_meta_group_infos = (sbi->s_groups_count + + EXT4_DESC_PER_BLOCK(sb) - 1) >> + EXT4_DESC_PER_BLOCK_BITS(sb); + for (i = 0; i < num_meta_group_infos; i++) + kfree(sbi->s_group_info[i]); + kfree(sbi->s_group_info); + } + kfree(sbi->s_mb_offsets); + kfree(sbi->s_mb_maxs); + if (sbi->s_buddy_cache) + iput(sbi->s_buddy_cache); + if (sbi->s_mb_stats) { + printk(KERN_INFO + "EXT4-fs: mballoc: %u blocks %u reqs (%u success)\n", + atomic_read(&sbi->s_bal_allocated), + atomic_read(&sbi->s_bal_reqs), + atomic_read(&sbi->s_bal_success)); + printk(KERN_INFO + "EXT4-fs: mballoc: %u extents scanned, %u goal hits, " + "%u 2^N hits, %u breaks, %u lost\n", + atomic_read(&sbi->s_bal_ex_scanned), + atomic_read(&sbi->s_bal_goals), + atomic_read(&sbi->s_bal_2orders), + atomic_read(&sbi->s_bal_breaks), + atomic_read(&sbi->s_mb_lost_chunks)); + printk(KERN_INFO + "EXT4-fs: mballoc: %lu generated and it took %Lu\n", + sbi->s_mb_buddies_generated++, + sbi->s_mb_generation_time); + printk(KERN_INFO + "EXT4-fs: mballoc: %u preallocated, %u discarded\n", + atomic_read(&sbi->s_mb_preallocated), + atomic_read(&sbi->s_mb_discarded)); + } + + kfree(sbi->s_locality_groups); + + ext4_mb_history_release(sb); + ext4_mb_destroy_per_dev_proc(sb); + + return 0; +} + +static void ext4_mb_free_committed_blocks(struct super_block *sb) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + int err; + int i; + int count = 0; + int count2 = 0; + struct ext4_free_metadata *md; + struct ext4_buddy e4b; + + if (list_empty(&sbi->s_committed_transaction)) + return; + + /* there is committed blocks to be freed yet */ + do { + /* get next array of blocks */ + md = NULL; + spin_lock(&sbi->s_md_lock); + if (!list_empty(&sbi->s_committed_transaction)) { + md = list_entry(sbi->s_committed_transaction.next, + struct ext4_free_metadata, list); + list_del(&md->list); + } + spin_unlock(&sbi->s_md_lock); + + if (md == NULL) + break; + + mb_debug("gonna free %u blocks in group %lu (0x%p):", + md->num, md->group, md); + + err = ext4_mb_load_buddy(sb, md->group, &e4b); + /* we expect to find existing buddy because it's pinned */ + BUG_ON(err != 0); + + /* there are blocks to put in buddy to make them really free */ + count += md->num; + count2++; + ext4_lock_group(sb, md->group); + for (i = 0; i < md->num; i++) { + mb_debug(" %u", md->blocks[i]); + err = mb_free_blocks(NULL, &e4b, md->blocks[i], 1); + BUG_ON(err != 0); + } + mb_debug("\n"); + ext4_unlock_group(sb, md->group); + + /* balance refcounts from ext4_mb_free_metadata() */ + page_cache_release(e4b.bd_buddy_page); + page_cache_release(e4b.bd_bitmap_page); + + kfree(md); + ext4_mb_release_desc(&e4b); + + } while (md); + + mb_debug("freed %u blocks in %u structures\n", count, count2); +} + +#define EXT4_ROOT "ext4" +#define EXT4_MB_STATS_NAME "stats" +#define EXT4_MB_MAX_TO_SCAN_NAME "max_to_scan" +#define EXT4_MB_MIN_TO_SCAN_NAME "min_to_scan" +#define EXT4_MB_ORDER2_REQ "order2_req" +#define EXT4_MB_STREAM_REQ "stream_req" +#define EXT4_MB_GROUP_PREALLOC "group_prealloc" + + + +#define MB_PROC_VALUE_READ(name) \ +static int ext4_mb_read_##name(char *page, char **start, \ + off_t off, int count, int *eof, void *data) \ +{ \ + struct ext4_sb_info *sbi = data; \ + int len; \ + *eof = 1; \ + if (off != 0) \ + return 0; \ + len = sprintf(page, "%ld\n", sbi->s_mb_##name); \ + *start = page; \ + return len; \ +} + +#define MB_PROC_VALUE_WRITE(name) \ +static int ext4_mb_write_##name(struct file *file, \ + const char __user *buf, unsigned long cnt, void *data) \ +{ \ + struct ext4_sb_info *sbi = data; \ + char str[32]; \ + long value; \ + if (cnt >= sizeof(str)) \ + return -EINVAL; \ + if (copy_from_user(str, buf, cnt)) \ + return -EFAULT; \ + value = simple_strtol(str, NULL, 0); \ + if (value <= 0) \ + return -ERANGE; \ + sbi->s_mb_##name = value; \ + return cnt; \ +} + +MB_PROC_VALUE_READ(stats); +MB_PROC_VALUE_WRITE(stats); +MB_PROC_VALUE_READ(max_to_scan); +MB_PROC_VALUE_WRITE(max_to_scan); +MB_PROC_VALUE_READ(min_to_scan); +MB_PROC_VALUE_WRITE(min_to_scan); +MB_PROC_VALUE_READ(order2_reqs); +MB_PROC_VALUE_WRITE(order2_reqs); +MB_PROC_VALUE_READ(stream_request); +MB_PROC_VALUE_WRITE(stream_request); +MB_PROC_VALUE_READ(group_prealloc); +MB_PROC_VALUE_WRITE(group_prealloc); + +#define MB_PROC_HANDLER(name, var) \ +do { \ + proc = create_proc_entry(name, mode, sbi->s_mb_proc); \ + if (proc == NULL) { \ + printk(KERN_ERR "EXT4-fs: can't to create %s\n", name); \ + goto err_out; \ + } \ + proc->data = sbi; \ + proc->read_proc = ext4_mb_read_##var ; \ + proc->write_proc = ext4_mb_write_##var; \ +} while (0) + +static int ext4_mb_init_per_dev_proc(struct super_block *sb) +{ + mode_t mode = S_IFREG | S_IRUGO | S_IWUSR; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct proc_dir_entry *proc; + char devname[64]; + + snprintf(devname, sizeof(devname) - 1, "%s", + bdevname(sb->s_bdev, devname)); + sbi->s_mb_proc = proc_mkdir(devname, proc_root_ext4); + + MB_PROC_HANDLER(EXT4_MB_STATS_NAME, stats); + MB_PROC_HANDLER(EXT4_MB_MAX_TO_SCAN_NAME, max_to_scan); + MB_PROC_HANDLER(EXT4_MB_MIN_TO_SCAN_NAME, min_to_scan); + MB_PROC_HANDLER(EXT4_MB_ORDER2_REQ, order2_reqs); + MB_PROC_HANDLER(EXT4_MB_STREAM_REQ, stream_request); + MB_PROC_HANDLER(EXT4_MB_GROUP_PREALLOC, group_prealloc); + + return 0; + +err_out: + printk(KERN_ERR "EXT4-fs: Unable to create %s\n", devname); + remove_proc_entry(EXT4_MB_GROUP_PREALLOC, sbi->s_mb_proc); + remove_proc_entry(EXT4_MB_STREAM_REQ, sbi->s_mb_proc); + remove_proc_entry(EXT4_MB_ORDER2_REQ, sbi->s_mb_proc); + remove_proc_entry(EXT4_MB_MIN_TO_SCAN_NAME, sbi->s_mb_proc); + remove_proc_entry(EXT4_MB_MAX_TO_SCAN_NAME, sbi->s_mb_proc); + remove_proc_entry(EXT4_MB_STATS_NAME, sbi->s_mb_proc); + remove_proc_entry(devname, proc_root_ext4); + sbi->s_mb_proc = NULL; + + return -ENOMEM; +} + +static int ext4_mb_destroy_per_dev_proc(struct super_block *sb) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + char devname[64]; + + if (sbi->s_mb_proc == NULL) + return -EINVAL; + + snprintf(devname, sizeof(devname) - 1, "%s", + bdevname(sb->s_bdev, devname)); + remove_proc_entry(EXT4_MB_GROUP_PREALLOC, sbi->s_mb_proc); + remove_proc_entry(EXT4_MB_STREAM_REQ, sbi->s_mb_proc); + remove_proc_entry(EXT4_MB_ORDER2_REQ, sbi->s_mb_proc); + remove_proc_entry(EXT4_MB_MIN_TO_SCAN_NAME, sbi->s_mb_proc); + remove_proc_entry(EXT4_MB_MAX_TO_SCAN_NAME, sbi->s_mb_proc); + remove_proc_entry(EXT4_MB_STATS_NAME, sbi->s_mb_proc); + remove_proc_entry(devname, proc_root_ext4); + + return 0; +} + +int __init init_ext4_mballoc(void) +{ + ext4_pspace_cachep = + kmem_cache_create("ext4_prealloc_space", + sizeof(struct ext4_prealloc_space), + 0, SLAB_RECLAIM_ACCOUNT, NULL); + if (ext4_pspace_cachep == NULL) + return -ENOMEM; + +#ifdef CONFIG_PROC_FS + proc_root_ext4 = proc_mkdir(EXT4_ROOT, proc_root_fs); + if (proc_root_ext4 == NULL) + printk(KERN_ERR "EXT4-fs: Unable to create %s\n", EXT4_ROOT); +#endif + + return 0; +} + +void exit_ext4_mballoc(void) +{ + /* XXX: synchronize_rcu(); */ + kmem_cache_destroy(ext4_pspace_cachep); +#ifdef CONFIG_PROC_FS + remove_proc_entry(EXT4_ROOT, proc_root_fs); +#endif +} + + +/* + * Check quota and mark choosed space (ac->ac_b_ex) non-free in bitmaps + * Returns 0 if success or error code + */ +static int ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, + handle_t *handle) +{ + struct buffer_head *bitmap_bh = NULL; + struct ext4_super_block *es; + struct ext4_group_desc *gdp; + struct buffer_head *gdp_bh; + struct ext4_sb_info *sbi; + struct super_block *sb; + ext4_fsblk_t block; + int err; + + BUG_ON(ac->ac_status != AC_STATUS_FOUND); + BUG_ON(ac->ac_b_ex.fe_len <= 0); + + sb = ac->ac_sb; + sbi = EXT4_SB(sb); + es = sbi->s_es; + + ext4_debug("using block group %lu(%d)\n", ac->ac_b_ex.fe_group, + gdp->bg_free_blocks_count); + + err = -EIO; + bitmap_bh = read_block_bitmap(sb, ac->ac_b_ex.fe_group); + if (!bitmap_bh) + goto out_err; + + err = ext4_journal_get_write_access(handle, bitmap_bh); + if (err) + goto out_err; + + err = -EIO; + gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh); + if (!gdp) + goto out_err; + + err = ext4_journal_get_write_access(handle, gdp_bh); + if (err) + goto out_err; + + block = ac->ac_b_ex.fe_group * EXT4_BLOCKS_PER_GROUP(sb) + + ac->ac_b_ex.fe_start + + le32_to_cpu(es->s_first_data_block); + + if (block == ext4_block_bitmap(sb, gdp) || + block == ext4_inode_bitmap(sb, gdp) || + in_range(block, ext4_inode_table(sb, gdp), + EXT4_SB(sb)->s_itb_per_group)) { + + ext4_error(sb, __FUNCTION__, + "Allocating block in system zone - block = %llu", + block); + } +#ifdef AGGRESSIVE_CHECK + { + int i; + for (i = 0; i < ac->ac_b_ex.fe_len; i++) { + BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i, + bitmap_bh->b_data)); + } + } +#endif + mb_set_bits(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group), bitmap_bh->b_data, + ac->ac_b_ex.fe_start, ac->ac_b_ex.fe_len); + + spin_lock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group)); + if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { + gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT); + gdp->bg_free_blocks_count = + cpu_to_le16(ext4_free_blocks_after_init(sb, + ac->ac_b_ex.fe_group, + gdp)); + } + gdp->bg_free_blocks_count = + cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) + - ac->ac_b_ex.fe_len); + gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp); + spin_unlock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group)); + percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len); + + err = ext4_journal_dirty_metadata(handle, bitmap_bh); + if (err) + goto out_err; + err = ext4_journal_dirty_metadata(handle, gdp_bh); + +out_err: + sb->s_dirt = 1; + put_bh(bitmap_bh); + return err; +} + +/* + * here we normalize request for locality group + * Group request are normalized to s_strip size if we set the same via mount + * option. If not we set it to s_mb_group_prealloc which can be configured via + * /proc/fs/ext4/<partition>/group_prealloc + * + * XXX: should we try to preallocate more than the group has now? + */ +static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_locality_group *lg = ac->ac_lg; + + BUG_ON(lg == NULL); + if (EXT4_SB(sb)->s_stripe) + ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_stripe; + else + ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc; + mb_debug("#%u: goal %lu blocks for locality group\n", + current->pid, ac->ac_g_ex.fe_len); +} + +/* + * Normalization means making request better in terms of + * size and alignment + */ +static void ext4_mb_normalize_request(struct ext4_allocation_context *ac, + struct ext4_allocation_request *ar) +{ + int bsbits, max; + ext4_lblk_t end; + struct list_head *cur; + loff_t size, orig_size, start_off; + ext4_lblk_t start, orig_start; + struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); + + /* do normalize only data requests, metadata requests + do not need preallocation */ + if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) + return; + + /* sometime caller may want exact blocks */ + if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)) + return; + + /* caller may indicate that preallocation isn't + * required (it's a tail, for example) */ + if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC) + return; + + if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) { + ext4_mb_normalize_group_request(ac); + return ; + } + + bsbits = ac->ac_sb->s_blocksize_bits; + + /* first, let's learn actual file size + * given current request is allocated */ + size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len; + size = size << bsbits; + if (size < i_size_read(ac->ac_inode)) + size = i_size_read(ac->ac_inode); + + /* max available blocks in a free group */ + max = EXT4_BLOCKS_PER_GROUP(ac->ac_sb) - 1 - 1 - + EXT4_SB(ac->ac_sb)->s_itb_per_group; + +#define NRL_CHECK_SIZE(req, size, max,bits) \ + (req <= (size) || max <= ((size) >> bits)) + + /* first, try to predict filesize */ + /* XXX: should this table be tunable? */ + start_off = 0; + if (size <= 16 * 1024) { + size = 16 * 1024; + } else if (size <= 32 * 1024) { + size = 32 * 1024; + } else if (size <= 64 * 1024) { + size = 64 * 1024; + } else if (size <= 128 * 1024) { + size = 128 * 1024; + } else if (size <= 256 * 1024) { + size = 256 * 1024; + } else if (size <= 512 * 1024) { + size = 512 * 1024; + } else if (size <= 1024 * 1024) { + size = 1024 * 1024; + } else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, bsbits)) { + start_off = ((loff_t)ac->ac_o_ex.fe_logical >> + (20 - bsbits)) << 20; + size = 1024 * 1024; + } else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, bsbits)) { + start_off = ((loff_t)ac->ac_o_ex.fe_logical >> + (22 - bsbits)) << 22; + size = 4 * 1024 * 1024; + } else if (NRL_CHECK_SIZE(ac->ac_o_ex.fe_len, + (8<<20)>>bsbits, max, bsbits)) { + start_off = ((loff_t)ac->ac_o_ex.fe_logical >> + (23 - bsbits)) << 23; + size = 8 * 1024 * 1024; + } else { + start_off = (loff_t)ac->ac_o_ex.fe_logical << bsbits; + size = ac->ac_o_ex.fe_len << bsbits; + } + orig_size = size = size >> bsbits; + orig_start = start = start_off >> bsbits; + + /* don't cover already allocated blocks in selected range */ + if (ar->pleft && start <= ar->lleft) { + size -= ar->lleft + 1 - start; + start = ar->lleft + 1; + } + if (ar->pright && start + size - 1 >= ar->lright) + size -= start + size - ar->lright; + + end = start + size; + + /* check we don't cross already preallocated blocks */ + rcu_read_lock(); + list_for_each_rcu(cur, &ei->i_prealloc_list) { + struct ext4_prealloc_space *pa; + unsigned long pa_end; + + pa = list_entry(cur, struct ext4_prealloc_space, pa_inode_list); + + if (pa->pa_deleted) + continue; + spin_lock(&pa->pa_lock); + if (pa->pa_deleted) { + spin_unlock(&pa->pa_lock); + continue; + } + + pa_end = pa->pa_lstart + pa->pa_len; + + /* PA must not overlap original request */ + BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end || + ac->ac_o_ex.fe_logical < pa->pa_lstart)); + + /* skip PA normalized request doesn't overlap with */ + if (pa->pa_lstart >= end) { + spin_unlock(&pa->pa_lock); + continue; + } + if (pa_end <= start) { + spin_unlock(&pa->pa_lock); + continue; + } + BUG_ON(pa->pa_lstart <= start && pa_end >= end); + + if (pa_end <= ac->ac_o_ex.fe_logical) { + BUG_ON(pa_end < start); + start = pa_end; + } + + if (pa->pa_lstart > ac->ac_o_ex.fe_logical) { + BUG_ON(pa->pa_lstart > end); + end = pa->pa_lstart; + } + spin_unlock(&pa->pa_lock); + } + rcu_read_unlock(); + size = end - start; + + /* XXX: extra loop to check we really don't overlap preallocations */ + rcu_read_lock(); + list_for_each_rcu(cur, &ei->i_prealloc_list) { + struct ext4_prealloc_space *pa; + unsigned long pa_end; + pa = list_entry(cur, struct ext4_prealloc_space, pa_inode_list); + spin_lock(&pa->pa_lock); + if (pa->pa_deleted == 0) { + pa_end = pa->pa_lstart + pa->pa_len; + BUG_ON(!(start >= pa_end || end <= pa->pa_lstart)); + } + spin_unlock(&pa->pa_lock); + } + rcu_read_unlock(); + + if (start + size <= ac->ac_o_ex.fe_logical && + start > ac->ac_o_ex.fe_logical) { + printk(KERN_ERR "start %lu, size %lu, fe_logical %lu\n", + (unsigned long) start, (unsigned long) size, + (unsigned long) ac->ac_o_ex.fe_logical); + } + BUG_ON(start + size <= ac->ac_o_ex.fe_logical && + start > ac->ac_o_ex.fe_logical); + BUG_ON(size <= 0 || size >= EXT4_BLOCKS_PER_GROUP(ac->ac_sb)); + + /* now prepare goal request */ + + /* XXX: is it better to align blocks WRT to logical + * placement or satisfy big request as is */ + ac->ac_g_ex.fe_logical = start; + ac->ac_g_ex.fe_len = size; + + /* define goal start in order to merge */ + if (ar->pright && (ar->lright == (start + size))) { + /* merge to the right */ + ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size, + &ac->ac_f_ex.fe_group, + &ac->ac_f_ex.fe_start); + ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL; + } + if (ar->pleft && (ar->lleft + 1 == start)) { + /* merge to the left */ + ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1, + &ac->ac_f_ex.fe_group, + &ac->ac_f_ex.fe_start); + ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL; + } + + mb_debug("goal: %u(was %u) blocks at %u\n", (unsigned) size, + (unsigned) orig_size, (unsigned) start); +} + +static void ext4_mb_collect_stats(struct ext4_allocation_context *ac) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + + if (sbi->s_mb_stats && ac->ac_g_ex.fe_len > 1) { + atomic_inc(&sbi->s_bal_reqs); + atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated); + if (ac->ac_o_ex.fe_len >= ac->ac_g_ex.fe_len) + atomic_inc(&sbi->s_bal_success); + atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned); + if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start && + ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group) + atomic_inc(&sbi->s_bal_goals); + if (ac->ac_found > sbi->s_mb_max_to_scan) + atomic_inc(&sbi->s_bal_breaks); + } + + ext4_mb_store_history(ac); +} + +/* + * use blocks preallocated to inode + */ +static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac, + struct ext4_prealloc_space *pa) +{ + ext4_fsblk_t start; + ext4_fsblk_t end; + int len; + + /* found preallocated blocks, use them */ + start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart); + end = min(pa->pa_pstart + pa->pa_len, start + ac->ac_o_ex.fe_len); + len = end - start; + ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group, + &ac->ac_b_ex.fe_start); + ac->ac_b_ex.fe_len = len; + ac->ac_status = AC_STATUS_FOUND; + ac->ac_pa = pa; + + BUG_ON(start < pa->pa_pstart); + BUG_ON(start + len > pa->pa_pstart + pa->pa_len); + BUG_ON(pa->pa_free < len); + pa->pa_free -= len; + + mb_debug("use %llu/%lu from inode pa %p\n", start, len, pa); +} + +/* + * use blocks preallocated to locality group + */ +static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac, + struct ext4_prealloc_space *pa) +{ + unsigned len = ac->ac_o_ex.fe_len; + + ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart, + &ac->ac_b_ex.fe_group, + &ac->ac_b_ex.fe_start); + ac->ac_b_ex.fe_len = len; + ac->ac_status = AC_STATUS_FOUND; + ac->ac_pa = pa; + + /* we don't correct pa_pstart or pa_plen here to avoid + * possible race when tte group is being loaded concurrently + * instead we correct pa later, after blocks are marked + * in on-disk bitmap -- see ext4_mb_release_context() */ + /* + * FIXME!! but the other CPUs can look at this particular + * pa and think that it have enought free blocks if we + * don't update pa_free here right ? + */ + mb_debug("use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa); +} + +/* + * search goal blocks in preallocated space + */ +static int ext4_mb_use_preallocated(struct ext4_allocation_context *ac) +{ + struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); + struct ext4_locality_group *lg; + struct ext4_prealloc_space *pa; + struct list_head *cur; + + /* only data can be preallocated */ + if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) + return 0; + + /* first, try per-file preallocation */ + rcu_read_lock(); + list_for_each_rcu(cur, &ei->i_prealloc_list) { + pa = list_entry(cur, struct ext4_prealloc_space, pa_inode_list); + + /* all fields in this condition don't change, + * so we can skip locking for them */ + if (ac->ac_o_ex.fe_logical < pa->pa_lstart || + ac->ac_o_ex.fe_logical >= pa->pa_lstart + pa->pa_len) + continue; + + /* found preallocated blocks, use them */ + spin_lock(&pa->pa_lock); + if (pa->pa_deleted == 0 && pa->pa_free) { + atomic_inc(&pa->pa_count); + ext4_mb_use_inode_pa(ac, pa); + spin_unlock(&pa->pa_lock); + ac->ac_criteria = 10; + rcu_read_unlock(); + return 1; + } + spin_unlock(&pa->pa_lock); + } + rcu_read_unlock(); + + /* can we use group allocation? */ + if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)) + return 0; + + /* inode may have no locality group for some reason */ + lg = ac->ac_lg; + if (lg == NULL) + return 0; + + rcu_read_lock(); + list_for_each_rcu(cur, &lg->lg_prealloc_list) { + pa = list_entry(cur, struct ext4_prealloc_space, pa_inode_list); + spin_lock(&pa->pa_lock); + if (pa->pa_deleted == 0 && pa->pa_free >= ac->ac_o_ex.fe_len) { + atomic_inc(&pa->pa_count); + ext4_mb_use_group_pa(ac, pa); + spin_unlock(&pa->pa_lock); + ac->ac_criteria = 20; + rcu_read_unlock(); + return 1; + } + spin_unlock(&pa->pa_lock); + } + rcu_read_unlock(); + + return 0; +} + +/* + * the function goes through all preallocation in this group and marks them + * used in in-core bitmap. buddy must be generated from this bitmap + * Need to be called with ext4 group lock (ext4_lock_group) + */ +static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap, + ext4_group_t group) +{ + struct ext4_group_info *grp = ext4_get_group_info(sb, group); + struct ext4_prealloc_space *pa; + struct list_head *cur; + ext4_group_t groupnr; + ext4_grpblk_t start; + int preallocated = 0; + int count = 0; + int len; + + /* all form of preallocation discards first load group, + * so the only competing code is preallocation use. + * we don't need any locking here + * notice we do NOT ignore preallocations with pa_deleted + * otherwise we could leave used blocks available for + * allocation in buddy when concurrent ext4_mb_put_pa() + * is dropping preallocation + */ + list_for_each(cur, &grp->bb_prealloc_list) { + pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list); + spin_lock(&pa->pa_lock); + ext4_get_group_no_and_offset(sb, pa->pa_pstart, + &groupnr, &start); + len = pa->pa_len; + spin_unlock(&pa->pa_lock); + if (unlikely(len == 0)) + continue; + BUG_ON(groupnr != group); + mb_set_bits(sb_bgl_lock(EXT4_SB(sb), group), + bitmap, start, len); + preallocated += len; + count++; + } + mb_debug("prellocated %u for group %lu\n", preallocated, group); +} + +static void ext4_mb_pa_callback(struct rcu_head *head) +{ + struct ext4_prealloc_space *pa; + pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu); + kmem_cache_free(ext4_pspace_cachep, pa); +} + +/* + * drops a reference to preallocated space descriptor + * if this was the last reference and the space is consumed + */ +static void ext4_mb_put_pa(struct ext4_allocation_context *ac, + struct super_block *sb, struct ext4_prealloc_space *pa) +{ + unsigned long grp; + + if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) + return; + + /* in this short window concurrent discard can set pa_deleted */ + spin_lock(&pa->pa_lock); + if (pa->pa_deleted == 1) { + spin_unlock(&pa->pa_lock); + return; + } + + pa->pa_deleted = 1; + spin_unlock(&pa->pa_lock); + + /* -1 is to protect from crossing allocation group */ + ext4_get_group_no_and_offset(sb, pa->pa_pstart - 1, &grp, NULL); + + /* + * possible race: + * + * P1 (buddy init) P2 (regular allocation) + * find block B in PA + * copy on-disk bitmap to buddy + * mark B in on-disk bitmap + * drop PA from group + * mark all PAs in buddy + * + * thus, P1 initializes buddy with B available. to prevent this + * we make "copy" and "mark all PAs" atomic and serialize "drop PA" + * against that pair + */ + ext4_lock_group(sb, grp); + list_del(&pa->pa_group_list); + ext4_unlock_group(sb, grp); + + spin_lock(pa->pa_obj_lock); + list_del_rcu(&pa->pa_inode_list); + spin_unlock(pa->pa_obj_lock); + + call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); +} + +/* + * creates new preallocated space for given inode + */ +static int ext4_mb_new_inode_pa(struct ext4_allocation_context *ac) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_prealloc_space *pa; + struct ext4_group_info *grp; + struct ext4_inode_info *ei; + + /* preallocate only when found space is larger then requested */ + BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len); + BUG_ON(ac->ac_status != AC_STATUS_FOUND); + BUG_ON(!S_ISREG(ac->ac_inode->i_mode)); + + pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS); + if (pa == NULL) + return -ENOMEM; + + if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) { + int winl; + int wins; + int win; + int offs; + + /* we can't allocate as much as normalizer wants. + * so, found space must get proper lstart + * to cover original request */ + BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical); + BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len); + + /* we're limited by original request in that + * logical block must be covered any way + * winl is window we can move our chunk within */ + winl = ac->ac_o_ex.fe_logical - ac->ac_g_ex.fe_logical; + + /* also, we should cover whole original request */ + wins = ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len; + + /* the smallest one defines real window */ + win = min(winl, wins); + + offs = ac->ac_o_ex.fe_logical % ac->ac_b_ex.fe_len; + if (offs && offs < win) + win = offs; + + ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical - win; + BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical); + BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len); + } + + /* preallocation can change ac_b_ex, thus we store actually + * allocated blocks for history */ + ac->ac_f_ex = ac->ac_b_ex; + + pa->pa_lstart = ac->ac_b_ex.fe_logical; + pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex); + pa->pa_len = ac->ac_b_ex.fe_len; + pa->pa_free = pa->pa_len; + atomic_set(&pa->pa_count, 1); + spin_lock_init(&pa->pa_lock); + pa->pa_deleted = 0; + pa->pa_linear = 0; + + mb_debug("new inode pa %p: %llu/%u for %u\n", pa, + pa->pa_pstart, pa->pa_len, pa->pa_lstart); + + ext4_mb_use_inode_pa(ac, pa); + atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated); + + ei = EXT4_I(ac->ac_inode); + grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group); + + pa->pa_obj_lock = &ei->i_prealloc_lock; + pa->pa_inode = ac->ac_inode; + + ext4_lock_group(sb, ac->ac_b_ex.fe_group); + list_add(&pa->pa_group_list, &grp->bb_prealloc_list); + ext4_unlock_group(sb, ac->ac_b_ex.fe_group); + + spin_lock(pa->pa_obj_lock); + list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list); + spin_unlock(pa->pa_obj_lock); + + return 0; +} + +/* + * creates new preallocated space for locality group inodes belongs to + */ +static int ext4_mb_new_group_pa(struct ext4_allocation_context *ac) +{ + struct super_block *sb = ac->ac_sb; + struct ext4_locality_group *lg; + struct ext4_prealloc_space *pa; + struct ext4_group_info *grp; + + /* preallocate only when found space is larger then requested */ + BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len); + BUG_ON(ac->ac_status != AC_STATUS_FOUND); + BUG_ON(!S_ISREG(ac->ac_inode->i_mode)); + + BUG_ON(ext4_pspace_cachep == NULL); + pa = kmem_cache_alloc(ext4_pspace_cachep, GFP_NOFS); + if (pa == NULL) + return -ENOMEM; + + /* preallocation can change ac_b_ex, thus we store actually + * allocated blocks for history */ + ac->ac_f_ex = ac->ac_b_ex; + + pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex); + pa->pa_lstart = pa->pa_pstart; + pa->pa_len = ac->ac_b_ex.fe_len; + pa->pa_free = pa->pa_len; + atomic_set(&pa->pa_count, 1); + spin_lock_init(&pa->pa_lock); + pa->pa_deleted = 0; + pa->pa_linear = 1; + + mb_debug("new group pa %p: %llu/%u for %u\n", pa, + pa->pa_pstart, pa->pa_len, pa->pa_lstart); + + ext4_mb_use_group_pa(ac, pa); + atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated); + + grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group); + lg = ac->ac_lg; + BUG_ON(lg == NULL); + + pa->pa_obj_lock = &lg->lg_prealloc_lock; + pa->pa_inode = NULL; + + ext4_lock_group(sb, ac->ac_b_ex.fe_group); + list_add(&pa->pa_group_list, &grp->bb_prealloc_list); + ext4_unlock_group(sb, ac->ac_b_ex.fe_group); + + spin_lock(pa->pa_obj_lock); + list_add_tail_rcu(&pa->pa_inode_list, &lg->lg_prealloc_list); + spin_unlock(pa->pa_obj_lock); + + return 0; +} + +static int ext4_mb_new_preallocation(struct ext4_allocation_context *ac) +{ + int err; + + if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) + err = ext4_mb_new_group_pa(ac); + else + err = ext4_mb_new_inode_pa(ac); + return err; +} + +/* + * finds all unused blocks in on-disk bitmap, frees them in + * in-core bitmap and buddy. + * @pa must be unlinked from inode and group lists, so that + * nobody else can find/use it. + * the caller MUST hold group/inode locks. + * TODO: optimize the case when there are no in-core structures yet + */ +static int ext4_mb_release_inode_pa(struct ext4_buddy *e4b, + struct buffer_head *bitmap_bh, + struct ext4_prealloc_space *pa) +{ + struct ext4_allocation_context ac; + struct super_block *sb = e4b->bd_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + unsigned long end; + unsigned long next; + ext4_group_t group; + ext4_grpblk_t bit; + sector_t start; + int err = 0; + int free = 0; + + BUG_ON(pa->pa_deleted == 0); + ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit); + BUG_ON(group != e4b->bd_group && pa->pa_len != 0); + end = bit + pa->pa_len; + + ac.ac_sb = sb; + ac.ac_inode = pa->pa_inode; + ac.ac_op = EXT4_MB_HISTORY_DISCARD; + + while (bit < end) { + bit = ext4_find_next_zero_bit(bitmap_bh->b_data, end, bit); + if (bit >= end) + break; + next = ext4_find_next_bit(bitmap_bh->b_data, end, bit); + if (next > end) + next = end; + start = group * EXT4_BLOCKS_PER_GROUP(sb) + bit + + le32_to_cpu(sbi->s_es->s_first_data_block); + mb_debug(" free preallocated %u/%u in group %u\n", + (unsigned) start, (unsigned) next - bit, + (unsigned) group); + free += next - bit; + + ac.ac_b_ex.fe_group = group; + ac.ac_b_ex.fe_start = bit; + ac.ac_b_ex.fe_len = next - bit; + ac.ac_b_ex.fe_logical = 0; + ext4_mb_store_history(&ac); + + mb_free_blocks(pa->pa_inode, e4b, bit, next - bit); + bit = next + 1; + } + if (free != pa->pa_free) { + printk(KERN_ERR "pa %p: logic %lu, phys. %lu, len %lu\n", + pa, (unsigned long) pa->pa_lstart, + (unsigned long) pa->pa_pstart, + (unsigned long) pa->pa_len); + printk(KERN_ERR "free %u, pa_free %u\n", free, pa->pa_free); + } + BUG_ON(free != pa->pa_free); + atomic_add(free, &sbi->s_mb_discarded); + + return err; +} + +static int ext4_mb_release_group_pa(struct ext4_buddy *e4b, + struct ext4_prealloc_space *pa) +{ + struct ext4_allocation_context ac; + struct super_block *sb = e4b->bd_sb; + ext4_group_t group; + ext4_grpblk_t bit; + + ac.ac_op = EXT4_MB_HISTORY_DISCARD; + + BUG_ON(pa->pa_deleted == 0); + ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit); + BUG_ON(group != e4b->bd_group && pa->pa_len != 0); + mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len); + atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded); + + ac.ac_sb = sb; + ac.ac_inode = NULL; + ac.ac_b_ex.fe_group = group; + ac.ac_b_ex.fe_start = bit; + ac.ac_b_ex.fe_len = pa->pa_len; + ac.ac_b_ex.fe_logical = 0; + ext4_mb_store_history(&ac); + + return 0; +} + +/* + * releases all preallocations in given group + * + * first, we need to decide discard policy: + * - when do we discard + * 1) ENOSPC + * - how many do we discard + * 1) how many requested + */ +static int ext4_mb_discard_group_preallocations(struct super_block *sb, + ext4_group_t group, int needed) +{ + struct ext4_group_info *grp = ext4_get_group_info(sb, group); + struct buffer_head *bitmap_bh = NULL; + struct ext4_prealloc_space *pa, *tmp; + struct list_head list; + struct ext4_buddy e4b; + int err; + int busy = 0; + int free = 0; + + mb_debug("discard preallocation for group %lu\n", group); + + if (list_empty(&grp->bb_prealloc_list)) + return 0; + + bitmap_bh = read_block_bitmap(sb, group); + if (bitmap_bh == NULL) { + /* error handling here */ + ext4_mb_release_desc(&e4b); + BUG_ON(bitmap_bh == NULL); + } + + err = ext4_mb_load_buddy(sb, group, &e4b); + BUG_ON(err != 0); /* error handling here */ + + if (needed == 0) + needed = EXT4_BLOCKS_PER_GROUP(sb) + 1; + + grp = ext4_get_group_info(sb, group); + INIT_LIST_HEAD(&list); + +repeat: + ext4_lock_group(sb, group); + list_for_each_entry_safe(pa, tmp, + &grp->bb_prealloc_list, pa_group_list) { + spin_lock(&pa->pa_lock); + if (atomic_read(&pa->pa_count)) { + spin_unlock(&pa->pa_lock); + busy = 1; + continue; + } + if (pa->pa_deleted) { + spin_unlock(&pa->pa_lock); + continue; + } + + /* seems this one can be freed ... */ + pa->pa_deleted = 1; + + /* we can trust pa_free ... */ + free += pa->pa_free; + + spin_unlock(&pa->pa_lock); + + list_del(&pa->pa_group_list); + list_add(&pa->u.pa_tmp_list, &list); + } + + /* if we still need more blocks and some PAs were used, try again */ + if (free < needed && busy) { + busy = 0; + ext4_unlock_group(sb, group); + /* + * Yield the CPU here so that we don't get soft lockup + * in non preempt case. + */ + yield(); + goto repeat; + } + + /* found anything to free? */ + if (list_empty(&list)) { + BUG_ON(free != 0); + goto out; + } + + /* now free all selected PAs */ + list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) { + + /* remove from object (inode or locality group) */ + spin_lock(pa->pa_obj_lock); + list_del_rcu(&pa->pa_inode_list); + spin_unlock(pa->pa_obj_lock); + + if (pa->pa_linear) + ext4_mb_release_group_pa(&e4b, pa); + else + ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa); + + list_del(&pa->u.pa_tmp_list); + call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); + } + +out: + ext4_unlock_group(sb, group); + ext4_mb_release_desc(&e4b); + put_bh(bitmap_bh); + return free; +} + +/* + * releases all non-used preallocated blocks for given inode + * + * It's important to discard preallocations under i_data_sem + * We don't want another block to be served from the prealloc + * space when we are discarding the inode prealloc space. + * + * FIXME!! Make sure it is valid at all the call sites + */ +void ext4_mb_discard_inode_preallocations(struct inode *inode) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + struct super_block *sb = inode->i_sb; + struct buffer_head *bitmap_bh = NULL; + struct ext4_prealloc_space *pa, *tmp; + ext4_group_t group = 0; + struct list_head list; + struct ext4_buddy e4b; + int err; + + if (!test_opt(sb, MBALLOC) || !S_ISREG(inode->i_mode)) { + /*BUG_ON(!list_empty(&ei->i_prealloc_list));*/ + return; + } + + mb_debug("discard preallocation for inode %lu\n", inode->i_ino); + + INIT_LIST_HEAD(&list); + +repeat: + /* first, collect all pa's in the inode */ + spin_lock(&ei->i_prealloc_lock); + while (!list_empty(&ei->i_prealloc_list)) { + pa = list_entry(ei->i_prealloc_list.next, + struct ext4_prealloc_space, pa_inode_list); + BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock); + spin_lock(&pa->pa_lock); + if (atomic_read(&pa->pa_count)) { + /* this shouldn't happen often - nobody should + * use preallocation while we're discarding it */ + spin_unlock(&pa->pa_lock); + spin_unlock(&ei->i_prealloc_lock); + printk(KERN_ERR "uh-oh! used pa while discarding\n"); + WARN_ON(1); + schedule_timeout_uninterruptible(HZ); + goto repeat; + + } + if (pa->pa_deleted == 0) { + pa->pa_deleted = 1; + spin_unlock(&pa->pa_lock); + list_del_rcu(&pa->pa_inode_list); + list_add(&pa->u.pa_tmp_list, &list); + continue; + } + + /* someone is deleting pa right now */ + spin_unlock(&pa->pa_lock); + spin_unlock(&ei->i_prealloc_lock); + + /* we have to wait here because pa_deleted + * doesn't mean pa is already unlinked from + * the list. as we might be called from + * ->clear_inode() the inode will get freed + * and concurrent thread which is unlinking + * pa from inode's list may access already + * freed memory, bad-bad-bad */ + + /* XXX: if this happens too often, we can + * add a flag to force wait only in case + * of ->clear_inode(), but not in case of + * regular truncate */ + schedule_timeout_uninterruptible(HZ); + goto repeat; + } + spin_unlock(&ei->i_prealloc_lock); + + list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) { + BUG_ON(pa->pa_linear != 0); + ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL); + + err = ext4_mb_load_buddy(sb, group, &e4b); + BUG_ON(err != 0); /* error handling here */ + + bitmap_bh = read_block_bitmap(sb, group); + if (bitmap_bh == NULL) { + /* error handling here */ + ext4_mb_release_desc(&e4b); + BUG_ON(bitmap_bh == NULL); + } + + ext4_lock_group(sb, group); + list_del(&pa->pa_group_list); + ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa); + ext4_unlock_group(sb, group); + + ext4_mb_release_desc(&e4b); + put_bh(bitmap_bh); + + list_del(&pa->u.pa_tmp_list); + call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback); + } +} + +/* + * finds all preallocated spaces and return blocks being freed to them + * if preallocated space becomes full (no block is used from the space) + * then the function frees space in buddy + * XXX: at the moment, truncate (which is the only way to free blocks) + * discards all preallocations + */ +static void ext4_mb_return_to_preallocation(struct inode *inode, + struct ext4_buddy *e4b, + sector_t block, int count) +{ + BUG_ON(!list_empty(&EXT4_I(inode)->i_prealloc_list)); +} +#ifdef MB_DEBUG +static void ext4_mb_show_ac(struct ext4_allocation_context *ac) +{ + struct super_block *sb = ac->ac_sb; + ext4_group_t i; + + printk(KERN_ERR "EXT4-fs: Can't allocate:" + " Allocation context details:\n"); + printk(KERN_ERR "EXT4-fs: status %d flags %d\n", + ac->ac_status, ac->ac_flags); + printk(KERN_ERR "EXT4-fs: orig %lu/%lu/%lu@%lu, goal %lu/%lu/%lu@%lu, " + "best %lu/%lu/%lu@%lu cr %d\n", + (unsigned long)ac->ac_o_ex.fe_group, + (unsigned long)ac->ac_o_ex.fe_start, + (unsigned long)ac->ac_o_ex.fe_len, + (unsigned long)ac->ac_o_ex.fe_logical, + (unsigned long)ac->ac_g_ex.fe_group, + (unsigned long)ac->ac_g_ex.fe_start, + (unsigned long)ac->ac_g_ex.fe_len, + (unsigned long)ac->ac_g_ex.fe_logical, + (unsigned long)ac->ac_b_ex.fe_group, + (unsigned long)ac->ac_b_ex.fe_start, + (unsigned long)ac->ac_b_ex.fe_len, + (unsigned long)ac->ac_b_ex.fe_logical, + (int)ac->ac_criteria); + printk(KERN_ERR "EXT4-fs: %lu scanned, %d found\n", ac->ac_ex_scanned, + ac->ac_found); + printk(KERN_ERR "EXT4-fs: groups: \n"); + for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) { + struct ext4_group_info *grp = ext4_get_group_info(sb, i); + struct ext4_prealloc_space *pa; + ext4_grpblk_t start; + struct list_head *cur; + ext4_lock_group(sb, i); + list_for_each(cur, &grp->bb_prealloc_list) { + pa = list_entry(cur, struct ext4_prealloc_space, + pa_group_list); + spin_lock(&pa->pa_lock); + ext4_get_group_no_and_offset(sb, pa->pa_pstart, + NULL, &start); + spin_unlock(&pa->pa_lock); + printk(KERN_ERR "PA:%lu:%d:%u \n", i, + start, pa->pa_len); + } + ext4_lock_group(sb, i); + + if (grp->bb_free == 0) + continue; + printk(KERN_ERR "%lu: %d/%d \n", + i, grp->bb_free, grp->bb_fragments); + } + printk(KERN_ERR "\n"); +} +#else +static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac) +{ + return; +} +#endif + +/* + * We use locality group preallocation for small size file. The size of the + * file is determined by the current size or the resulting size after + * allocation which ever is larger + * + * One can tune this size via /proc/fs/ext4/<partition>/stream_req + */ +static void ext4_mb_group_or_file(struct ext4_allocation_context *ac) +{ + struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); + int bsbits = ac->ac_sb->s_blocksize_bits; + loff_t size, isize; + + if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) + return; + + size = ac->ac_o_ex.fe_logical + ac->ac_o_ex.fe_len; + isize = i_size_read(ac->ac_inode) >> bsbits; + size = max(size, isize); + + /* don't use group allocation for large files */ + if (size >= sbi->s_mb_stream_request) + return; + + if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY)) + return; + + BUG_ON(ac->ac_lg != NULL); + /* + * locality group prealloc space are per cpu. The reason for having + * per cpu locality group is to reduce the contention between block + * request from multiple CPUs. + */ + ac->ac_lg = &sbi->s_locality_groups[get_cpu()]; + put_cpu(); + + /* we're going to use group allocation */ + ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC; + + /* serialize all allocations in the group */ + mutex_lock(&ac->ac_lg->lg_mutex); +} + +static int ext4_mb_initialize_context(struct ext4_allocation_context *ac, + struct ext4_allocation_request *ar) +{ + struct super_block *sb = ar->inode->i_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + ext4_group_t group; + unsigned long len; + unsigned long goal; + ext4_grpblk_t block; + + /* we can't allocate > group size */ + len = ar->len; + + /* just a dirty hack to filter too big requests */ + if (len >= EXT4_BLOCKS_PER_GROUP(sb) - 10) + len = EXT4_BLOCKS_PER_GROUP(sb) - 10; + + /* start searching from the goal */ + goal = ar->goal; + if (goal < le32_to_cpu(es->s_first_data_block) || + goal >= ext4_blocks_count(es)) + goal = le32_to_cpu(es->s_first_data_block); + ext4_get_group_no_and_offset(sb, goal, &group, &block); + + /* set up allocation goals */ + ac->ac_b_ex.fe_logical = ar->logical; + ac->ac_b_ex.fe_group = 0; + ac->ac_b_ex.fe_start = 0; + ac->ac_b_ex.fe_len = 0; + ac->ac_status = AC_STATUS_CONTINUE; + ac->ac_groups_scanned = 0; + ac->ac_ex_scanned = 0; + ac->ac_found = 0; + ac->ac_sb = sb; + ac->ac_inode = ar->inode; + ac->ac_o_ex.fe_logical = ar->logical; + ac->ac_o_ex.fe_group = group; + ac->ac_o_ex.fe_start = block; + ac->ac_o_ex.fe_len = len; + ac->ac_g_ex.fe_logical = ar->logical; + ac->ac_g_ex.fe_group = group; + ac->ac_g_ex.fe_start = block; + ac->ac_g_ex.fe_len = len; + ac->ac_f_ex.fe_len = 0; + ac->ac_flags = ar->flags; + ac->ac_2order = 0; + ac->ac_criteria = 0; + ac->ac_pa = NULL; + ac->ac_bitmap_page = NULL; + ac->ac_buddy_page = NULL; + ac->ac_lg = NULL; + + /* we have to define context: we'll we work with a file or + * locality group. this is a policy, actually */ + ext4_mb_group_or_file(ac); + + mb_debug("init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, " + "left: %u/%u, right %u/%u to %swritable\n", + (unsigned) ar->len, (unsigned) ar->logical, + (unsigned) ar->goal, ac->ac_flags, ac->ac_2order, + (unsigned) ar->lleft, (unsigned) ar->pleft, + (unsigned) ar->lright, (unsigned) ar->pright, + atomic_read(&ar->inode->i_writecount) ? "" : "non-"); + return 0; + +} + +/* + * release all resource we used in allocation + */ +static int ext4_mb_release_context(struct ext4_allocation_context *ac) +{ + if (ac->ac_pa) { + if (ac->ac_pa->pa_linear) { + /* see comment in ext4_mb_use_group_pa() */ + spin_lock(&ac->ac_pa->pa_lock); + ac->ac_pa->pa_pstart += ac->ac_b_ex.fe_len; + ac->ac_pa->pa_lstart += ac->ac_b_ex.fe_len; + ac->ac_pa->pa_free -= ac->ac_b_ex.fe_len; + ac->ac_pa->pa_len -= ac->ac_b_ex.fe_len; + spin_unlock(&ac->ac_pa->pa_lock); + } + ext4_mb_put_pa(ac, ac->ac_sb, ac->ac_pa); + } + if (ac->ac_bitmap_page) + page_cache_release(ac->ac_bitmap_page); + if (ac->ac_buddy_page) + page_cache_release(ac->ac_buddy_page); + if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) + mutex_unlock(&ac->ac_lg->lg_mutex); + ext4_mb_collect_stats(ac); + return 0; +} + +static int ext4_mb_discard_preallocations(struct super_block *sb, int needed) +{ + ext4_group_t i; + int ret; + int freed = 0; + + for (i = 0; i < EXT4_SB(sb)->s_groups_count && needed > 0; i++) { + ret = ext4_mb_discard_group_preallocations(sb, i, needed); + freed += ret; + needed -= ret; + } + + return freed; +} + +/* + * Main entry point into mballoc to allocate blocks + * it tries to use preallocation first, then falls back + * to usual allocation + */ +ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle, + struct ext4_allocation_request *ar, int *errp) +{ + struct ext4_allocation_context ac; + struct ext4_sb_info *sbi; + struct super_block *sb; + ext4_fsblk_t block = 0; + int freed; + int inquota; + + sb = ar->inode->i_sb; + sbi = EXT4_SB(sb); + + if (!test_opt(sb, MBALLOC)) { + block = ext4_new_blocks_old(handle, ar->inode, ar->goal, + &(ar->len), errp); + return block; + } + + while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) { + ar->flags |= EXT4_MB_HINT_NOPREALLOC; + ar->len--; + } + if (ar->len == 0) { + *errp = -EDQUOT; + return 0; + } + inquota = ar->len; + + ext4_mb_poll_new_transaction(sb, handle); + + *errp = ext4_mb_initialize_context(&ac, ar); + if (*errp) { + ar->len = 0; + goto out; + } + + ac.ac_op = EXT4_MB_HISTORY_PREALLOC; + if (!ext4_mb_use_preallocated(&ac)) { + + ac.ac_op = EXT4_MB_HISTORY_ALLOC; + ext4_mb_normalize_request(&ac, ar); + +repeat: + /* allocate space in core */ + ext4_mb_regular_allocator(&ac); + + /* as we've just preallocated more space than + * user requested orinally, we store allocated + * space in a special descriptor */ + if (ac.ac_status == AC_STATUS_FOUND && + ac.ac_o_ex.fe_len < ac.ac_b_ex.fe_len) + ext4_mb_new_preallocation(&ac); + } + + if (likely(ac.ac_status == AC_STATUS_FOUND)) { + ext4_mb_mark_diskspace_used(&ac, handle); + *errp = 0; + block = ext4_grp_offs_to_block(sb, &ac.ac_b_ex); + ar->len = ac.ac_b_ex.fe_len; + } else { + freed = ext4_mb_discard_preallocations(sb, ac.ac_o_ex.fe_len); + if (freed) + goto repeat; + *errp = -ENOSPC; + ac.ac_b_ex.fe_len = 0; + ar->len = 0; + ext4_mb_show_ac(&ac); + } + + ext4_mb_release_context(&ac); + +out: + if (ar->len < inquota) + DQUOT_FREE_BLOCK(ar->inode, inquota - ar->len); + + return block; +} +static void ext4_mb_poll_new_transaction(struct super_block *sb, + handle_t *handle) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + + if (sbi->s_last_transaction == handle->h_transaction->t_tid) + return; + + /* new transaction! time to close last one and free blocks for + * committed transaction. we know that only transaction can be + * active, so previos transaction can be being logged and we + * know that transaction before previous is known to be already + * logged. this means that now we may free blocks freed in all + * transactions before previous one. hope I'm clear enough ... */ + + spin_lock(&sbi->s_md_lock); + if (sbi->s_last_transaction != handle->h_transaction->t_tid) { + mb_debug("new transaction %lu, old %lu\n", + (unsigned long) handle->h_transaction->t_tid, + (unsigned long) sbi->s_last_transaction); + list_splice_init(&sbi->s_closed_transaction, + &sbi->s_committed_transaction); + list_splice_init(&sbi->s_active_transaction, + &sbi->s_closed_transaction); + sbi->s_last_transaction = handle->h_transaction->t_tid; + } + spin_unlock(&sbi->s_md_lock); + + ext4_mb_free_committed_blocks(sb); +} + +static int ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b, + ext4_group_t group, ext4_grpblk_t block, int count) +{ + struct ext4_group_info *db = e4b->bd_info; + struct super_block *sb = e4b->bd_sb; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_free_metadata *md; + int i; + + BUG_ON(e4b->bd_bitmap_page == NULL); + BUG_ON(e4b->bd_buddy_page == NULL); + + ext4_lock_group(sb, group); + for (i = 0; i < count; i++) { + md = db->bb_md_cur; + if (md && db->bb_tid != handle->h_transaction->t_tid) { + db->bb_md_cur = NULL; + md = NULL; + } + + if (md == NULL) { + ext4_unlock_group(sb, group); + md = kmalloc(sizeof(*md), GFP_NOFS); + if (md == NULL) + return -ENOMEM; + md->num = 0; + md->group = group; + + ext4_lock_group(sb, group); + if (db->bb_md_cur == NULL) { + spin_lock(&sbi->s_md_lock); + list_add(&md->list, &sbi->s_active_transaction); + spin_unlock(&sbi->s_md_lock); + /* protect buddy cache from being freed, + * otherwise we'll refresh it from + * on-disk bitmap and lose not-yet-available + * blocks */ + page_cache_get(e4b->bd_buddy_page); + page_cache_get(e4b->bd_bitmap_page); + db->bb_md_cur = md; + db->bb_tid = handle->h_transaction->t_tid; + mb_debug("new md 0x%p for group %lu\n", + md, md->group); + } else { + kfree(md); + md = db->bb_md_cur; + } + } + + BUG_ON(md->num >= EXT4_BB_MAX_BLOCKS); + md->blocks[md->num] = block + i; + md->num++; + if (md->num == EXT4_BB_MAX_BLOCKS) { + /* no more space, put full container on a sb's list */ + db->bb_md_cur = NULL; + } + } + ext4_unlock_group(sb, group); + return 0; +} + +/* + * Main entry point into mballoc to free blocks + */ +void ext4_mb_free_blocks(handle_t *handle, struct inode *inode, + unsigned long block, unsigned long count, + int metadata, unsigned long *freed) +{ + struct buffer_head *bitmap_bh = 0; + struct super_block *sb = inode->i_sb; + struct ext4_allocation_context ac; + struct ext4_group_desc *gdp; + struct ext4_super_block *es; + unsigned long overflow; + ext4_grpblk_t bit; + struct buffer_head *gd_bh; + ext4_group_t block_group; + struct ext4_sb_info *sbi; + struct ext4_buddy e4b; + int err = 0; + int ret; + + *freed = 0; + + ext4_mb_poll_new_transaction(sb, handle); + + sbi = EXT4_SB(sb); + es = EXT4_SB(sb)->s_es; + if (block < le32_to_cpu(es->s_first_data_block) || + block + count < block || + block + count > ext4_blocks_count(es)) { + ext4_error(sb, __FUNCTION__, + "Freeing blocks not in datazone - " + "block = %lu, count = %lu", block, count); + goto error_return; + } + + ext4_debug("freeing block %lu\n", block); + + ac.ac_op = EXT4_MB_HISTORY_FREE; + ac.ac_inode = inode; + ac.ac_sb = sb; + +do_more: + overflow = 0; + ext4_get_group_no_and_offset(sb, block, &block_group, &bit); + + /* + * Check to see if we are freeing blocks across a group + * boundary. + */ + if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) { + overflow = bit + count - EXT4_BLOCKS_PER_GROUP(sb); + count -= overflow; + } + bitmap_bh = read_block_bitmap(sb, block_group); + if (!bitmap_bh) + goto error_return; + gdp = ext4_get_group_desc(sb, block_group, &gd_bh); + if (!gdp) + goto error_return; + + if (in_range(ext4_block_bitmap(sb, gdp), block, count) || + in_range(ext4_inode_bitmap(sb, gdp), block, count) || + in_range(block, ext4_inode_table(sb, gdp), + EXT4_SB(sb)->s_itb_per_group) || + in_range(block + count - 1, ext4_inode_table(sb, gdp), + EXT4_SB(sb)->s_itb_per_group)) { + + ext4_error(sb, __FUNCTION__, + "Freeing blocks in system zone - " + "Block = %lu, count = %lu", block, count); + } + + BUFFER_TRACE(bitmap_bh, "getting write access"); + err = ext4_journal_get_write_access(handle, bitmap_bh); + if (err) + goto error_return; + + /* + * We are about to modify some metadata. Call the journal APIs + * to unshare ->b_data if a currently-committing transaction is + * using it + */ + BUFFER_TRACE(gd_bh, "get_write_access"); + err = ext4_journal_get_write_access(handle, gd_bh); + if (err) + goto error_return; + + err = ext4_mb_load_buddy(sb, block_group, &e4b); + if (err) + goto error_return; + +#ifdef AGGRESSIVE_CHECK + { + int i; + for (i = 0; i < count; i++) + BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data)); + } +#endif + mb_clear_bits(sb_bgl_lock(sbi, block_group), bitmap_bh->b_data, + bit, count); + + /* We dirtied the bitmap block */ + BUFFER_TRACE(bitmap_bh, "dirtied bitmap block"); + err = ext4_journal_dirty_metadata(handle, bitmap_bh); + + ac.ac_b_ex.fe_group = block_group; + ac.ac_b_ex.fe_start = bit; + ac.ac_b_ex.fe_len = count; + ext4_mb_store_history(&ac); + + if (metadata) { + /* blocks being freed are metadata. these blocks shouldn't + * be used until this transaction is committed */ + ext4_mb_free_metadata(handle, &e4b, block_group, bit, count); + } else { + ext4_lock_group(sb, block_group); + err = mb_free_blocks(inode, &e4b, bit, count); + ext4_mb_return_to_preallocation(inode, &e4b, block, count); + ext4_unlock_group(sb, block_group); + BUG_ON(err != 0); + } + + spin_lock(sb_bgl_lock(sbi, block_group)); + gdp->bg_free_blocks_count = + cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) + count); + gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp); + spin_unlock(sb_bgl_lock(sbi, block_group)); + percpu_counter_add(&sbi->s_freeblocks_counter, count); + + ext4_mb_release_desc(&e4b); + + *freed += count; + + /* And the group descriptor block */ + BUFFER_TRACE(gd_bh, "dirtied group descriptor block"); + ret = ext4_journal_dirty_metadata(handle, gd_bh); + if (!err) + err = ret; + + if (overflow && !err) { + block += count; + count = overflow; + put_bh(bitmap_bh); + goto do_more; + } + sb->s_dirt = 1; +error_return: + brelse(bitmap_bh); + ext4_std_error(sb, err); + return; +} |