/* * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com * Written by Alex Tomas <alex@clusterfs.com> * * Architecture independence: * Copyright (c) 2005, Bull S.A. * Written by Pierre Peiffer <pierre.peiffer@bull.net> * * 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- */ /* * Extents support for EXT4 * * TODO: * - ext4*_error() should be used in some situations * - analyze all BUG()/BUG_ON(), use -EIO where appropriate * - smart tree reduction */ #include <linux/module.h> #include <linux/fs.h> #include <linux/time.h> #include <linux/ext4_jbd2.h> #include <linux/jbd2.h> #include <linux/highuid.h> #include <linux/pagemap.h> #include <linux/quotaops.h> #include <linux/string.h> #include <linux/slab.h> #include <linux/falloc.h> #include <linux/ext4_fs_extents.h> #include <asm/uaccess.h> /* * ext_pblock: * combine low and high parts of physical block number into ext4_fsblk_t */ static ext4_fsblk_t ext_pblock(struct ext4_extent *ex) { ext4_fsblk_t block; block = le32_to_cpu(ex->ee_start_lo); block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1; return block; } /* * idx_pblock: * combine low and high parts of a leaf physical block number into ext4_fsblk_t */ ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix) { ext4_fsblk_t block; block = le32_to_cpu(ix->ei_leaf_lo); block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1; return block; } /* * ext4_ext_store_pblock: * stores a large physical block number into an extent struct, * breaking it into parts */ void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb) { ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); } /* * ext4_idx_store_pblock: * stores a large physical block number into an index struct, * breaking it into parts */ static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb) { ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); } static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed) { int err; if (handle->h_buffer_credits > needed) return handle; if (!ext4_journal_extend(handle, needed)) return handle; err = ext4_journal_restart(handle, needed); return handle; } /* * could return: * - EROFS * - ENOMEM */ static int ext4_ext_get_access(handle_t *handle, struct inode *inode, struct ext4_ext_path *path) { if (path->p_bh) { /* path points to block */ return ext4_journal_get_write_access(handle, path->p_bh); } /* path points to leaf/index in inode body */ /* we use in-core data, no need to protect them */ return 0; } /* * could return: * - EROFS * - ENOMEM * - EIO */ static int ext4_ext_dirty(handle_t *handle, struct inode *inode, struct ext4_ext_path *path) { int err; if (path->p_bh) { /* path points to block */ err = ext4_journal_dirty_metadata(handle, path->p_bh); } else { /* path points to leaf/index in inode body */ err = ext4_mark_inode_dirty(handle, inode); } return err; } static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, struct ext4_ext_path *path, ext4_lblk_t block) { struct ext4_inode_info *ei = EXT4_I(inode); ext4_fsblk_t bg_start; ext4_grpblk_t colour; int depth; if (path) { struct ext4_extent *ex; depth = path->p_depth; /* try to predict block placement */ ex = path[depth].p_ext; if (ex) return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block)); /* it looks like index is empty; * try to find starting block from index itself */ if (path[depth].p_bh) return path[depth].p_bh->b_blocknr; } /* OK. use inode's group */ bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) + le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block); colour = (current->pid % 16) * (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); return bg_start + colour + block; } static ext4_fsblk_t ext4_ext_new_block(handle_t *handle, struct inode *inode, struct ext4_ext_path *path, struct ext4_extent *ex, int *err) { ext4_fsblk_t goal, newblock; goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); newblock = ext4_new_block(handle, inode, goal, err); return newblock; } static int ext4_ext_space_block(struct inode *inode) { int size; size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) / sizeof(struct ext4_extent); #ifdef AGGRESSIVE_TEST if (size > 6) size = 6; #endif return size; } static int ext4_ext_space_block_idx(struct inode *inode) { int size; size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) / sizeof(struct ext4_extent_idx); #ifdef AGGRESSIVE_TEST if (size > 5) size = 5; #endif return size; } static int ext4_ext_space_root(struct inode *inode) { int size; size = sizeof(EXT4_I(inode)->i_data); size -= sizeof(struct ext4_extent_header); size /= sizeof(struct ext4_extent); #ifdef AGGRESSIVE_TEST if (size > 3) size = 3; #endif return size; } static int ext4_ext_space_root_idx(struct inode *inode) { int size; size = sizeof(EXT4_I(inode)->i_data); size -= sizeof(struct ext4_extent_header); size /= sizeof(struct ext4_extent_idx); #ifdef AGGRESSIVE_TEST if (size > 4) size = 4; #endif return size; } static int ext4_ext_max_entries(struct inode *inode, int depth) { int max; if (depth == ext_depth(inode)) { if (depth == 0) max = ext4_ext_space_root(inode); else max = ext4_ext_space_root_idx(inode); } else { if (depth == 0) max = ext4_ext_space_block(inode); else max = ext4_ext_space_block_idx(inode); } return max; } static int __ext4_ext_check_header(const char *function, struct inode *inode, struct ext4_extent_header *eh, int depth) { const char *error_msg; int max = 0; if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { error_msg = "invalid magic"; goto corrupted; } if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { error_msg = "unexpected eh_depth"; goto corrupted; } if (unlikely(eh->eh_max == 0)) { error_msg = "invalid eh_max"; goto corrupted; } max = ext4_ext_max_entries(inode, depth); if (unlikely(le16_to_cpu(eh->eh_max) > max)) { error_msg = "too large eh_max"; goto corrupted; } if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { error_msg = "invalid eh_entries"; goto corrupted; } return 0; corrupted: ext4_error(inode->i_sb, function, "bad header in inode #%lu: %s - magic %x, " "entries %u, max %u(%u), depth %u(%u)", inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic), le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), max, le16_to_cpu(eh->eh_depth), depth); return -EIO; } #define ext4_ext_check_header(inode, eh, depth) \ __ext4_ext_check_header(__FUNCTION__, inode, eh, depth) #ifdef EXT_DEBUG static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) { int k, l = path->p_depth; ext_debug("path:"); for (k = 0; k <= l; k++, path++) { if (path->p_idx) { ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block), idx_pblock(path->p_idx)); } else if (path->p_ext) { ext_debug(" %d:%d:%llu ", le32_to_cpu(path->p_ext->ee_block), ext4_ext_get_actual_len(path->p_ext), ext_pblock(path->p_ext)); } else ext_debug(" []"); } ext_debug("\n"); } static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) { int depth = ext_depth(inode); struct ext4_extent_header *eh; struct ext4_extent *ex; int i; if (!path) return; eh = path[depth].p_hdr; ex = EXT_FIRST_EXTENT(eh); for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block), ext4_ext_get_actual_len(ex), ext_pblock(ex)); } ext_debug("\n"); } #else #define ext4_ext_show_path(inode,path) #define ext4_ext_show_leaf(inode,path) #endif static void ext4_ext_drop_refs(struct ext4_ext_path *path) { int depth = path->p_depth; int i; for (i = 0; i <= depth; i++, path++) if (path->p_bh) { brelse(path->p_bh); path->p_bh = NULL; } } /* * ext4_ext_binsearch_idx: * binary search for the closest index of the given block * the header must be checked before calling this */ static void ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, ext4_lblk_t block) { struct ext4_extent_header *eh = path->p_hdr; struct ext4_extent_idx *r, *l, *m; ext_debug("binsearch for %u(idx): ", block); l = EXT_FIRST_INDEX(eh) + 1; r = EXT_LAST_INDEX(eh); while (l <= r) { m = l + (r - l) / 2; if (block < le32_to_cpu(m->ei_block)) r = m - 1; else l = m + 1; ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block), m, le32_to_cpu(m->ei_block), r, le32_to_cpu(r->ei_block)); } path->p_idx = l - 1; ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block), idx_pblock(path->p_idx)); #ifdef CHECK_BINSEARCH { struct ext4_extent_idx *chix, *ix; int k; chix = ix = EXT_FIRST_INDEX(eh); for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { if (k != 0 && le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { printk("k=%d, ix=0x%p, first=0x%p\n", k, ix, EXT_FIRST_INDEX(eh)); printk("%u <= %u\n", le32_to_cpu(ix->ei_block), le32_to_cpu(ix[-1].ei_block)); } BUG_ON(k && le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)); if (block < le32_to_cpu(ix->ei_block)) break; chix = ix; } BUG_ON(chix != path->p_idx); } #endif } /* * ext4_ext_binsearch: * binary search for closest extent of the given block * the header must be checked before calling this */ static void ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, ext4_lblk_t block) { struct ext4_extent_header *eh = path->p_hdr; struct ext4_extent *r, *l, *m; if (eh->eh_entries == 0) { /* * this leaf is empty: * we get such a leaf in split/add case */ return; } ext_debug("binsearch for %u: ", block); l = EXT_FIRST_EXTENT(eh) + 1; r = EXT_LAST_EXTENT(eh); while (l <= r) { m = l + (r - l) / 2; if (block < le32_to_cpu(m->ee_block)) r = m - 1; else l = m + 1; ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block), m, le32_to_cpu(m->ee_block), r, le32_to_cpu(r->ee_block)); } path->p_ext = l - 1; ext_debug(" -> %d:%llu:%d ", le32_to_cpu(path->p_ext->ee_block), ext_pblock(path->p_ext), ext4_ext_get_actual_len(path->p_ext)); #ifdef CHECK_BINSEARCH { struct ext4_extent *chex, *ex; int k; chex = ex = EXT_FIRST_EXTENT(eh); for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { BUG_ON(k && le32_to_cpu(ex->ee_block) <= le32_to_cpu(ex[-1].ee_block)); if (block < le32_to_cpu(ex->ee_block)) break; chex = ex; } BUG_ON(chex != path->p_ext); } #endif } int ext4_ext_tree_init(handle_t *handle, struct inode *inode) { struct ext4_extent_header *eh; eh = ext_inode_hdr(inode); eh->eh_depth = 0; eh->eh_entries = 0; eh->eh_magic = EXT4_EXT_MAGIC; eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode)); ext4_mark_inode_dirty(handle, inode); ext4_ext_invalidate_cache(inode); return 0; } struct ext4_ext_path * ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, struct ext4_ext_path *path) { struct ext4_extent_header *eh; struct buffer_head *bh; short int depth, i, ppos = 0, alloc = 0; eh = ext_inode_hdr(inode); depth = ext_depth(inode); if (ext4_ext_check_header(inode, eh, depth)) return ERR_PTR(-EIO); /* account possible depth increase */ if (!path) { path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), GFP_NOFS); if (!path) return ERR_PTR(-ENOMEM); alloc = 1; } path[0].p_hdr = eh; i = depth; /* walk through the tree */ while (i) { ext_debug("depth %d: num %d, max %d\n", ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); ext4_ext_binsearch_idx(inode, path + ppos, block); path[ppos].p_block = idx_pblock(path[ppos].p_idx); path[ppos].p_depth = i; path[ppos].p_ext = NULL; bh = sb_bread(inode->i_sb, path[ppos].p_block); if (!bh) goto err; eh = ext_block_hdr(bh); ppos++; BUG_ON(ppos > depth); path[ppos].p_bh = bh; path[ppos].p_hdr = eh; i--; if (ext4_ext_check_header(inode, eh, i)) goto err; } path[ppos].p_depth = i; path[ppos].p_hdr = eh; path[ppos].p_ext = NULL; path[ppos].p_idx = NULL; /* find extent */ ext4_ext_binsearch(inode, path + ppos, block); ext4_ext_show_path(inode, path); return path; err: ext4_ext_drop_refs(path); if (alloc) kfree(path); return ERR_PTR(-EIO); } /* * ext4_ext_insert_index: * insert new index [@logical;@ptr] into the block at @curp; * check where to insert: before @curp or after @curp */ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, struct ext4_ext_path *curp, int logical, ext4_fsblk_t ptr) { struct ext4_extent_idx *ix; int len, err; err = ext4_ext_get_access(handle, inode, curp); if (err) return err; BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block)); len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx; if (logical > le32_to_cpu(curp->p_idx->ei_block)) { /* insert after */ if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) { len = (len - 1) * sizeof(struct ext4_extent_idx); len = len < 0 ? 0 : len; ext_debug("insert new index %d after: %llu. " "move %d from 0x%p to 0x%p\n", logical, ptr, len, (curp->p_idx + 1), (curp->p_idx + 2)); memmove(curp->p_idx + 2, curp->p_idx + 1, len); } ix = curp->p_idx + 1; } else { /* insert before */ len = len * sizeof(struct ext4_extent_idx); len = len < 0 ? 0 : len; ext_debug("insert new index %d before: %llu. " "move %d from 0x%p to 0x%p\n", logical, ptr, len, curp->p_idx, (curp->p_idx + 1)); memmove(curp->p_idx + 1, curp->p_idx, len); ix = curp->p_idx; } ix->ei_block = cpu_to_le32(logical); ext4_idx_store_pblock(ix, ptr); curp->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(curp->p_hdr->eh_entries)+1); BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries) > le16_to_cpu(curp->p_hdr->eh_max)); BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr)); err = ext4_ext_dirty(handle, inode, curp); ext4_std_error(inode->i_sb, err); return err; } /* * ext4_ext_split: * inserts new subtree into the path, using free index entry * at depth @at: * - allocates all needed blocks (new leaf and all intermediate index blocks) * - makes decision where to split * - moves remaining extents and index entries (right to the split point) * into the newly allocated blocks * - initializes subtree */ static int ext4_ext_split(handle_t *handle, struct inode *inode, struct ext4_ext_path *path, struct ext4_extent *newext, int at) { struct buffer_head *bh = NULL; int depth = ext_depth(inode); struct ext4_extent_header *neh; struct ext4_extent_idx *fidx; struct ext4_extent *ex; int i = at, k, m, a; ext4_fsblk_t newblock, oldblock; __le32 border; ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ int err = 0; /* make decision: where to split? */ /* FIXME: now decision is simplest: at current extent */ /* if current leaf will be split, then we should use * border from split point */ BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr)); if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { border = path[depth].p_ext[1].ee_block; ext_debug("leaf will be split." " next leaf starts at %d\n", le32_to_cpu(border)); } else { border = newext->ee_block; ext_debug("leaf will be added." " next leaf starts at %d\n", le32_to_cpu(border)); } /* * If error occurs, then we break processing * and mark filesystem read-only. index won't * be inserted and tree will be in consistent * state. Next mount will repair buffers too. */ /* * Get array to track all allocated blocks. * We need this to handle errors and free blocks * upon them. */ ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); if (!ablocks) return -ENOMEM; /* allocate all needed blocks */ ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); for (a = 0; a < depth - at; a++) { newblock = ext4_ext_new_block(handle, inode, path, newext, &err); if (newblock == 0) goto cleanup; ablocks[a] = newblock; } /* initialize new leaf */ newblock = ablocks[--a]; BUG_ON(newblock == 0); bh = sb_getblk(inode->i_sb, newblock); if (!bh) { err = -EIO; goto cleanup; } lock_buffer(bh); err = ext4_journal_get_create_access(handle, bh); if (err) goto cleanup; neh = ext_block_hdr(bh); neh->eh_entries = 0; neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); neh->eh_magic = EXT4_EXT_MAGIC; neh->eh_depth = 0; ex = EXT_FIRST_EXTENT(neh); /* move remainder of path[depth] to the new leaf */ BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max); /* start copy from next extent */ /* TODO: we could do it by single memmove */ m = 0; path[depth].p_ext++; while (path[depth].p_ext <= EXT_MAX_EXTENT(path[depth].p_hdr)) { ext_debug("move %d:%llu:%d in new leaf %llu\n", le32_to_cpu(path[depth].p_ext->ee_block), ext_pblock(path[depth].p_ext), ext4_ext_get_actual_len(path[depth].p_ext), newblock); /*memmove(ex++, path[depth].p_ext++, sizeof(struct ext4_extent)); neh->eh_entries++;*/ path[depth].p_ext++; m++; } if (m) { memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m); neh->eh_entries = cpu_to_le16(le16_to_cpu(neh->eh_entries)+m); } set_buffer_uptodate(bh); unlock_buffer(bh); err = ext4_journal_dirty_metadata(handle, bh); if (err) goto cleanup; brelse(bh); bh = NULL; /* correct old leaf */ if (m) { err = ext4_ext_get_access(handle, inode, path + depth); if (err) goto cleanup; path[depth].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m); err = ext4_ext_dirty(handle, inode, path + depth); if (err) goto cleanup; } /* create intermediate indexes */ k = depth - at - 1; BUG_ON(k < 0); if (k) ext_debug("create %d intermediate indices\n", k); /* insert new index into current index block */ /* current depth stored in i var */ i = depth - 1; while (k--) { oldblock = newblock; newblock = ablocks[--a]; bh = sb_getblk(inode->i_sb, newblock); if (!bh) { err = -EIO; goto cleanup; } lock_buffer(bh); err = ext4_journal_get_create_access(handle, bh); if (err) goto cleanup; neh = ext_block_hdr(bh); neh->eh_entries = cpu_to_le16(1); neh->eh_magic = EXT4_EXT_MAGIC; neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); neh->eh_depth = cpu_to_le16(depth - i); fidx = EXT_FIRST_INDEX(neh); fidx->ei_block = border; ext4_idx_store_pblock(fidx, oldblock); ext_debug("int.index at %d (block %llu): %u -> %llu\n", i, newblock, le32_to_cpu(border), oldblock); /* copy indexes */ m = 0; path[i].p_idx++; ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, EXT_MAX_INDEX(path[i].p_hdr)); BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) != EXT_LAST_INDEX(path[i].p_hdr)); while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) { ext_debug("%d: move %d:%llu in new index %llu\n", i, le32_to_cpu(path[i].p_idx->ei_block), idx_pblock(path[i].p_idx), newblock); /*memmove(++fidx, path[i].p_idx++, sizeof(struct ext4_extent_idx)); neh->eh_entries++; BUG_ON(neh->eh_entries > neh->eh_max);*/ path[i].p_idx++; m++; } if (m) { memmove(++fidx, path[i].p_idx - m, sizeof(struct ext4_extent_idx) * m); neh->eh_entries = cpu_to_le16(le16_to_cpu(neh->eh_entries) + m); } set_buffer_uptodate(bh); unlock_buffer(bh); err = ext4_journal_dirty_metadata(handle, bh); if (err) goto cleanup; brelse(bh); bh = NULL; /* correct old index */ if (m) { err = ext4_ext_get_access(handle, inode, path + i); if (err) goto cleanup; path[i].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[i].p_hdr->eh_entries)-m); err = ext4_ext_dirty(handle, inode, path + i); if (err) goto cleanup; } i--; } /* insert new index */ err = ext4_ext_insert_index(handle, inode, path + at, le32_to_cpu(border), newblock); cleanup: if (bh) { if (buffer_locked(bh)) unlock_buffer(bh); brelse(bh); } if (err) { /* free all allocated blocks in error case */ for (i = 0; i < depth; i++) { if (!ablocks[i]) continue; ext4_free_blocks(handle, inode, ablocks[i], 1, 1); } } kfree(ablocks); return err; } /* * ext4_ext_grow_indepth: * implements tree growing procedure: * - allocates new block * - moves top-level data (index block or leaf) into the new block * - initializes new top-level, creating index that points to the * just created block */ static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, struct ext4_ext_path *path, struct ext4_extent *newext) { struct ext4_ext_path *curp = path; struct ext4_extent_header *neh; struct ext4_extent_idx *fidx; struct buffer_head *bh; ext4_fsblk_t newblock; int err = 0; newblock = ext4_ext_new_block(handle, inode, path, newext, &err); if (newblock == 0) return err; bh = sb_getblk(inode->i_sb, newblock); if (!bh) { err = -EIO; ext4_std_error(inode->i_sb, err); return err; } lock_buffer(bh); err = ext4_journal_get_create_access(handle, bh); if (err) { unlock_buffer(bh); goto out; } /* move top-level index/leaf into new block */ memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data)); /* set size of new block */ neh = ext_block_hdr(bh); /* old root could have indexes or leaves * so calculate e_max right way */ if (ext_depth(inode)) neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); else neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); neh->eh_magic = EXT4_EXT_MAGIC; set_buffer_uptodate(bh); unlock_buffer(bh); err = ext4_journal_dirty_metadata(handle, bh); if (err) goto out; /* create index in new top-level index: num,max,pointer */ err = ext4_ext_get_access(handle, inode, curp); if (err) goto out; curp->p_hdr->eh_magic = EXT4_EXT_MAGIC; curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode)); curp->p_hdr->eh_entries = cpu_to_le16(1); curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr); if (path[0].p_hdr->eh_depth) curp->p_idx->ei_block = EXT_FIRST_INDEX(path[0].p_hdr)->ei_block; else curp->p_idx->ei_block = EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block; ext4_idx_store_pblock(curp->p_idx, newblock); neh = ext_inode_hdr(inode); fidx = EXT_FIRST_INDEX(neh); ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), le32_to_cpu(fidx->ei_block), idx_pblock(fidx)); neh->eh_depth = cpu_to_le16(path->p_depth + 1); err = ext4_ext_dirty(handle, inode, curp); out: brelse(bh); return err; } /* * ext4_ext_create_new_leaf: * finds empty index and adds new leaf. * if no free index is found, then it requests in-depth growing. */ static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, struct ext4_ext_path *path, struct ext4_extent *newext) { struct ext4_ext_path *curp; int depth, i, err = 0; repeat: i = depth = ext_depth(inode); /* walk up to the tree and look for free index entry */ curp = path + depth; while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { i--; curp--; } /* we use already allocated block for index block, * so subsequent data blocks should be contiguous */ if (EXT_HAS_FREE_INDEX(curp)) { /* if we found index with free entry, then use that * entry: create all needed subtree and add new leaf */ err = ext4_ext_split(handle, inode, path, newext, i); /* refill path */ ext4_ext_drop_refs(path); path = ext4_ext_find_extent(inode, (ext4_lblk_t)le32_to_cpu(newext->ee_block), path); if (IS_ERR(path)) err = PTR_ERR(path); } else { /* tree is full, time to grow in depth */ err = ext4_ext_grow_indepth(handle, inode, path, newext); if (err) goto out; /* refill path */ ext4_ext_drop_refs(path); path = ext4_ext_find_extent(inode, (ext4_lblk_t)le32_to_cpu(newext->ee_block), path); if (IS_ERR(path)) { err = PTR_ERR(path); goto out; } /* * only first (depth 0 -> 1) produces free space; * in all other cases we have to split the grown tree */ depth = ext_depth(inode); if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { /* now we need to split */ goto repeat; } } out: return err; } /* * search the closest allocated block to the left for *logical * and returns it at @logical + it's physical address at @phys * if *logical is the smallest allocated block, the function * returns 0 at @phys * return value contains 0 (success) or error code */ int ext4_ext_search_left(struct inode *inode, struct ext4_ext_path *path, ext4_lblk_t *logical, ext4_fsblk_t *phys) { struct ext4_extent_idx *ix; struct ext4_extent *ex; int depth, ee_len; BUG_ON(path == NULL); depth = path->p_depth; *phys = 0; if (depth == 0 && path->p_ext == NULL) return 0; /* usually extent in the path covers blocks smaller * then *logical, but it can be that extent is the * first one in the file */ ex = path[depth].p_ext; ee_len = ext4_ext_get_actual_len(ex); if (*logical < le32_to_cpu(ex->ee_block)) { BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); while (--depth >= 0) { ix = path[depth].p_idx; BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); } return 0; } BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); *logical = le32_to_cpu(ex->ee_block) + ee_len - 1; *phys = ext_pblock(ex) + ee_len - 1; return 0; } /* * search the closest allocated block to the right for *logical * and returns it at @logical + it's physical address at @phys * if *logical is the smallest allocated block, the function * returns 0 at @phys * return value contains 0 (success) or error code */ int ext4_ext_search_right(struct inode *inode, struct ext4_ext_path *path, ext4_lblk_t *logical, ext4_fsblk_t *phys) { struct buffer_head *bh = NULL; struct ext4_extent_header *eh; struct ext4_extent_idx *ix; struct ext4_extent *ex; ext4_fsblk_t block; int depth, ee_len; BUG_ON(path == NULL); depth = path->p_depth; *phys = 0; if (depth == 0 && path->p_ext == NULL) return 0; /* usually extent in the path covers blocks smaller * then *logical, but it can be that extent is the * first one in the file */ ex = path[depth].p_ext; ee_len = ext4_ext_get_actual_len(ex); if (*logical < le32_to_cpu(ex->ee_block)) { BUG_ON(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex); while (--depth >= 0) { ix = path[depth].p_idx; BUG_ON(ix != EXT_FIRST_INDEX(path[depth].p_hdr)); } *logical = le32_to_cpu(ex->ee_block); *phys = ext_pblock(ex); return 0; } BUG_ON(*logical < (le32_to_cpu(ex->ee_block) + ee_len)); if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) { /* next allocated block in this leaf */ ex++; *logical = le32_to_cpu(ex->ee_block); *phys = ext_pblock(ex); return 0; } /* go up and search for index to the right */ while (--depth >= 0) { ix = path[depth].p_idx; if (ix != EXT_LAST_INDEX(path[depth].p_hdr)) break; } if (depth < 0) { /* we've gone up to the root and * found no index to the right */ return 0; } /* we've found index to the right, let's * follow it and find the closest allocated * block to the right */ ix++; block = idx_pblock(ix); while (++depth < path->p_depth) { bh = sb_bread(inode->i_sb, block); if (bh == NULL) return -EIO; eh = ext_block_hdr(bh); if (ext4_ext_check_header(inode, eh, depth)) { put_bh(bh); return -EIO; } ix = EXT_FIRST_INDEX(eh); block = idx_pblock(ix); put_bh(bh); } bh = sb_bread(inode->i_sb, block); if (bh == NULL) return -EIO; eh = ext_block_hdr(bh); if (ext4_ext_check_header(inode, eh, path->p_depth - depth)) { put_bh(bh); return -EIO; } ex = EXT_FIRST_EXTENT(eh); *logical = le32_to_cpu(ex->ee_block); *phys = ext_pblock(ex); put_bh(bh); return 0; } /* * ext4_ext_next_allocated_block: * returns allocated block in subsequent extent or EXT_MAX_BLOCK. * NOTE: it considers block number from index entry as * allocated block. Thus, index entries have to be consistent * with leaves. */ static ext4_lblk_t ext4_ext_next_allocated_block(struct ext4_ext_path *path) { int depth; BUG_ON(path == NULL); depth = path->p_depth; if (depth == 0 && path->p_ext == NULL) return EXT_MAX_BLOCK; while (depth >= 0) { if (depth == path->p_depth) { /* leaf */ if (path[depth].p_ext != EXT_LAST_EXTENT(path[depth].p_hdr)) return le32_to_cpu(path[depth].p_ext[1].ee_block); } else { /* index */ if (path[depth].p_idx != EXT_LAST_INDEX(path[depth].p_hdr)) return le32_to_cpu(path[depth].p_idx[1].ei_block); } depth--; } return EXT_MAX_BLOCK; } /* * ext4_ext_next_leaf_block: * returns first allocated block from next leaf or EXT_MAX_BLOCK */ static ext4_lblk_t ext4_ext_next_leaf_block(struct inode *inode, struct ext4_ext_path *path) { int depth; BUG_ON(path == NULL); depth = path->p_depth; /* zero-tree has no leaf blocks at all */ if (depth == 0) return EXT_MAX_BLOCK; /* go to index block */ depth--; while (depth >= 0) { if (path[depth].p_idx != EXT_LAST_INDEX(path[depth].p_hdr)) return (ext4_lblk_t) le32_to_cpu(path[depth].p_idx[1].ei_block); depth--; } return EXT_MAX_BLOCK; } /* * ext4_ext_correct_indexes: * if leaf gets modified and modified extent is first in the leaf, * then we have to correct all indexes above. * TODO: do we need to correct tree in all cases? */ static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, struct ext4_ext_path *path) { struct ext4_extent_header *eh; int depth = ext_depth(inode); struct ext4_extent *ex; __le32 border; int k, err = 0; eh = path[depth].p_hdr; ex = path[depth].p_ext; BUG_ON(ex == NULL); BUG_ON(eh == NULL); if (depth == 0) { /* there is no tree at all */ return 0; } if (ex != EXT_FIRST_EXTENT(eh)) { /* we correct tree if first leaf got modified only */ return 0; } /* * TODO: we need correction if border is smaller than current one */ k = depth - 1; border = path[depth].p_ext->ee_block; err = ext4_ext_get_access(handle, inode, path + k); if (err) return err; path[k].p_idx->ei_block = border; err = ext4_ext_dirty(handle, inode, path + k); if (err) return err; while (k--) { /* change all left-side indexes */ if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) break; err = ext4_ext_get_access(handle, inode, path + k); if (err) break; path[k].p_idx->ei_block = border; err = ext4_ext_dirty(handle, inode, path + k); if (err) break; } return err; } static int ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, struct ext4_extent *ex2) { unsigned short ext1_ee_len, ext2_ee_len, max_len; /* * Make sure that either both extents are uninitialized, or * both are _not_. */ if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2)) return 0; if (ext4_ext_is_uninitialized(ex1)) max_len = EXT_UNINIT_MAX_LEN; else max_len = EXT_INIT_MAX_LEN; ext1_ee_len = ext4_ext_get_actual_len(ex1); ext2_ee_len = ext4_ext_get_actual_len(ex2); if (le32_to_cpu(ex1->ee_block) + ext1_ee_len != le32_to_cpu(ex2->ee_block)) return 0; /* * To allow future support for preallocated extents to be added * as an RO_COMPAT feature, refuse to merge to extents if * this can result in the top bit of ee_len being set. */ if (ext1_ee_len + ext2_ee_len > max_len) return 0; #ifdef AGGRESSIVE_TEST if (ext1_ee_len >= 4) return 0; #endif if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2)) return 1; return 0; } /* * This function tries to merge the "ex" extent to the next extent in the tree. * It always tries to merge towards right. If you want to merge towards * left, pass "ex - 1" as argument instead of "ex". * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns * 1 if they got merged. */ int ext4_ext_try_to_merge(struct inode *inode, struct ext4_ext_path *path, struct ext4_extent *ex) { struct ext4_extent_header *eh; unsigned int depth, len; int merge_done = 0; int uninitialized = 0; depth = ext_depth(inode); BUG_ON(path[depth].p_hdr == NULL); eh = path[depth].p_hdr; while (ex < EXT_LAST_EXTENT(eh)) { if (!ext4_can_extents_be_merged(inode, ex, ex + 1)) break; /* merge with next extent! */ if (ext4_ext_is_uninitialized(ex)) uninitialized = 1; ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) + ext4_ext_get_actual_len(ex + 1)); if (uninitialized) ext4_ext_mark_uninitialized(ex); if (ex + 1 < EXT_LAST_EXTENT(eh)) { len = (EXT_LAST_EXTENT(eh) - ex - 1) * sizeof(struct ext4_extent); memmove(ex + 1, ex + 2, len); } eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries) - 1); merge_done = 1; WARN_ON(eh->eh_entries == 0); if (!eh->eh_entries) ext4_error(inode->i_sb, "ext4_ext_try_to_merge", "inode#%lu, eh->eh_entries = 0!", inode->i_ino); } return merge_done; } /* * check if a portion of the "newext" extent overlaps with an * existing extent. * * If there is an overlap discovered, it updates the length of the newext * such that there will be no overlap, and then returns 1. * If there is no overlap found, it returns 0. */ unsigned int ext4_ext_check_overlap(struct inode *inode, struct ext4_extent *newext, struct ext4_ext_path *path) { ext4_lblk_t b1, b2; unsigned int depth, len1; unsigned int ret = 0; b1 = le32_to_cpu(newext->ee_block); len1 = ext4_ext_get_actual_len(newext); depth = ext_depth(inode); if (!path[depth].p_ext) goto out; b2 = le32_to_cpu(path[depth].p_ext->ee_block); /* * get the next allocated block if the extent in the path * is before the requested block(s) */ if (b2 < b1) { b2 = ext4_ext_next_allocated_block(path); if (b2 == EXT_MAX_BLOCK) goto out; } /* check for wrap through zero on extent logical start block*/ if (b1 + len1 < b1) { len1 = EXT_MAX_BLOCK - b1; newext->ee_len = cpu_to_le16(len1); ret = 1; } /* check for overlap */ if (b1 + len1 > b2) { newext->ee_len = cpu_to_le16(b2 - b1); ret = 1; } out: return ret; } /* * ext4_ext_insert_extent: * tries to merge requsted extent into the existing extent or * inserts requested extent as new one into the tree, * creating new leaf in the no-space case. */ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, struct ext4_ext_path *path, struct ext4_extent *newext) { struct ext4_extent_header * eh; struct ext4_extent *ex, *fex; struct ext4_extent *nearex; /* nearest extent */ struct ext4_ext_path *npath = NULL; int depth, len, err; ext4_lblk_t next; unsigned uninitialized = 0; BUG_ON(ext4_ext_get_actual_len(newext) == 0); depth = ext_depth(inode); ex = path[depth].p_ext; BUG_ON(path[depth].p_hdr == NULL); /* try to insert block into found extent and return */ if (ex && ext4_can_extents_be_merged(inode, ex, newext)) { ext_debug("append %d block to %d:%d (from %llu)\n", ext4_ext_get_actual_len(newext), le32_to_cpu(ex->ee_block), ext4_ext_get_actual_len(ex), ext_pblock(ex)); err = ext4_ext_get_access(handle, inode, path + depth); if (err) return err; /* * ext4_can_extents_be_merged should have checked that either * both extents are uninitialized, or both aren't. Thus we * need to check only one of them here. */ if (ext4_ext_is_uninitialized(ex)) uninitialized = 1; ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex) + ext4_ext_get_actual_len(newext)); if (uninitialized) ext4_ext_mark_uninitialized(ex); eh = path[depth].p_hdr; nearex = ex; goto merge; } repeat: depth = ext_depth(inode); eh = path[depth].p_hdr; if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) goto has_space; /* probably next leaf has space for us? */ fex = EXT_LAST_EXTENT(eh); next = ext4_ext_next_leaf_block(inode, path); if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block) && next != EXT_MAX_BLOCK) { ext_debug("next leaf block - %d\n", next); BUG_ON(npath != NULL); npath = ext4_ext_find_extent(inode, next, NULL); if (IS_ERR(npath)) return PTR_ERR(npath); BUG_ON(npath->p_depth != path->p_depth); eh = npath[depth].p_hdr; if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) { ext_debug("next leaf isnt full(%d)\n", le16_to_cpu(eh->eh_entries)); path = npath; goto repeat; } ext_debug("next leaf has no free space(%d,%d)\n", le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); } /* * There is no free space in the found leaf. * We're gonna add a new leaf in the tree. */ err = ext4_ext_create_new_leaf(handle, inode, path, newext); if (err) goto cleanup; depth = ext_depth(inode); eh = path[depth].p_hdr; has_space: nearex = path[depth].p_ext; err = ext4_ext_get_access(handle, inode, path + depth); if (err) goto cleanup; if (!nearex) { /* there is no extent in this leaf, create first one */ ext_debug("first extent in the leaf: %d:%llu:%d\n", le32_to_cpu(newext->ee_block), ext_pblock(newext), ext4_ext_get_actual_len(newext)); path[depth].p_ext = EXT_FIRST_EXTENT(eh); } else if (le32_to_cpu(newext->ee_block) > le32_to_cpu(nearex->ee_block)) { /* BUG_ON(newext->ee_block == nearex->ee_block); */ if (nearex != EXT_LAST_EXTENT(eh)) { len = EXT_MAX_EXTENT(eh) - nearex; len = (len - 1) * sizeof(struct ext4_extent); len = len < 0 ? 0 : len; ext_debug("insert %d:%llu:%d after: nearest 0x%p, " "move %d from 0x%p to 0x%p\n", le32_to_cpu(newext->ee_block), ext_pblock(newext), ext4_ext_get_actual_len(newext), nearex, len, nearex + 1, nearex + 2); memmove(nearex + 2, nearex + 1, len); } path[depth].p_ext = nearex + 1; } else { BUG_ON(newext->ee_block == nearex->ee_block); len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent); len = len < 0 ? 0 : len; ext_debug("insert %d:%llu:%d before: nearest 0x%p, " "move %d from 0x%p to 0x%p\n", le32_to_cpu(newext->ee_block), ext_pblock(newext), ext4_ext_get_actual_len(newext), nearex, len, nearex + 1, nearex + 2); memmove(nearex + 1, nearex, len); path[depth].p_ext = nearex; } eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)+1); nearex = path[depth].p_ext; nearex->ee_block = newext->ee_block; ext4_ext_store_pblock(nearex, ext_pblock(newext)); nearex->ee_len = newext->ee_len; merge: /* try to merge extents to the right */ ext4_ext_try_to_merge(inode, path, nearex); /* try to merge extents to the left */ /* time to correct all indexes above */ err = ext4_ext_correct_indexes(handle, inode, path); if (err) goto cleanup; err = ext4_ext_dirty(handle, inode, path + depth); cleanup: if (npath) { ext4_ext_drop_refs(npath); kfree(npath); } ext4_ext_tree_changed(inode); ext4_ext_invalidate_cache(inode); return err; } static void ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block, __u32 len, ext4_fsblk_t start, int type) { struct ext4_ext_cache *cex; BUG_ON(len == 0); cex = &EXT4_I(inode)->i_cached_extent; cex->ec_type = type; cex->ec_block = block; cex->ec_len = len; cex->ec_start = start; } /* * ext4_ext_put_gap_in_cache: * calculate boundaries of the gap that the requested block fits into * and cache this gap */ static void ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, ext4_lblk_t block) { int depth = ext_depth(inode); unsigned long len; ext4_lblk_t lblock; struct ext4_extent *ex; ex = path[depth].p_ext; if (ex == NULL) { /* there is no extent yet, so gap is [0;-] */ lblock = 0; len = EXT_MAX_BLOCK; ext_debug("cache gap(whole file):"); } else if (block < le32_to_cpu(ex->ee_block)) { lblock = block; len = le32_to_cpu(ex->ee_block) - block; ext_debug("cache gap(before): %u [%u:%u]", block, le32_to_cpu(ex->ee_block), ext4_ext_get_actual_len(ex)); } else if (block >= le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex)) { ext4_lblk_t next; lblock = le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex); next = ext4_ext_next_allocated_block(path); ext_debug("cache gap(after): [%u:%u] %u", le32_to_cpu(ex->ee_block), ext4_ext_get_actual_len(ex), block); BUG_ON(next == lblock); len = next - lblock; } else { lblock = len = 0; BUG(); } ext_debug(" -> %u:%lu\n", lblock, len); ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP); } static int ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block, struct ext4_extent *ex) { struct ext4_ext_cache *cex; cex = &EXT4_I(inode)->i_cached_extent; /* has cache valid data? */ if (cex->ec_type == EXT4_EXT_CACHE_NO) return EXT4_EXT_CACHE_NO; BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP && cex->ec_type != EXT4_EXT_CACHE_EXTENT); if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) { ex->ee_block = cpu_to_le32(cex->ec_block); ext4_ext_store_pblock(ex, cex->ec_start); ex->ee_len = cpu_to_le16(cex->ec_len); ext_debug("%u cached by %u:%u:%llu\n", block, cex->ec_block, cex->ec_len, cex->ec_start); return cex->ec_type; } /* not in cache */ return EXT4_EXT_CACHE_NO; } /* * ext4_ext_rm_idx: * removes index from the index block. * It's used in truncate case only, thus all requests are for * last index in the block only. */ static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, struct ext4_ext_path *path) { struct buffer_head *bh; int err; ext4_fsblk_t leaf; /* free index block */ path--; leaf = idx_pblock(path->p_idx); BUG_ON(path->p_hdr->eh_entries == 0); err = ext4_ext_get_access(handle, inode, path); if (err) return err; path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1); err = ext4_ext_dirty(handle, inode, path); if (err) return err; ext_debug("index is empty, remove it, free block %llu\n", leaf); bh = sb_find_get_block(inode->i_sb, leaf); ext4_forget(handle, 1, inode, bh, leaf); ext4_free_blocks(handle, inode, leaf, 1, 1); return err; } /* * ext4_ext_calc_credits_for_insert: * This routine returns max. credits that the extent tree can consume. * It should be OK for low-performance paths like ->writepage() * To allow many writing processes to fit into a single transaction, * the caller should calculate credits under i_data_sem and * pass the actual path. */ int ext4_ext_calc_credits_for_insert(struct inode *inode, struct ext4_ext_path *path) { int depth, needed; if (path) { /* probably there is space in leaf? */ depth = ext_depth(inode); if (le16_to_cpu(path[depth].p_hdr->eh_entries) < le16_to_cpu(path[depth].p_hdr->eh_max)) return 1; } /* * given 32-bit logical block (4294967296 blocks), max. tree * can be 4 levels in depth -- 4 * 340^4 == 53453440000. * Let's also add one more level for imbalance. */ depth = 5; /* allocation of new data block(s) */ needed = 2; /* * tree can be full, so it would need to grow in depth: * we need one credit to modify old root, credits for * new root will be added in split accounting */ needed += 1; /* * Index split can happen, we would need: * allocate intermediate indexes (bitmap + group) * + change two blocks at each level, but root (already included) */ needed += (depth * 2) + (depth * 2); /* any allocation modifies superblock */ needed += 1; return needed; } static int ext4_remove_blocks(handle_t *handle, struct inode *inode, struct ext4_extent *ex, ext4_lblk_t from, ext4_lblk_t to) { struct buffer_head *bh; unsigned short ee_len = ext4_ext_get_actual_len(ex); int i, metadata = 0; if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) metadata = 1; #ifdef EXTENTS_STATS { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); spin_lock(&sbi->s_ext_stats_lock); sbi->s_ext_blocks += ee_len; sbi->s_ext_extents++; if (ee_len < sbi->s_ext_min) sbi->s_ext_min = ee_len; if (ee_len > sbi->s_ext_max) sbi->s_ext_max = ee_len; if (ext_depth(inode) > sbi->s_depth_max) sbi->s_depth_max = ext_depth(inode); spin_unlock(&sbi->s_ext_stats_lock); } #endif if (from >= le32_to_cpu(ex->ee_block) && to == le32_to_cpu(ex->ee_block) + ee_len - 1) { /* tail removal */ ext4_lblk_t num; ext4_fsblk_t start; num = le32_to_cpu(ex->ee_block) + ee_len - from; start = ext_pblock(ex) + ee_len - num; ext_debug("free last %u blocks starting %llu\n", num, start); for (i = 0; i < num; i++) { bh = sb_find_get_block(inode->i_sb, start + i); ext4_forget(handle, 0, inode, bh, start + i); } ext4_free_blocks(handle, inode, start, num, metadata); } else if (from == le32_to_cpu(ex->ee_block) && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) { printk(KERN_INFO "strange request: removal %u-%u from %u:%u\n", from, to, le32_to_cpu(ex->ee_block), ee_len); } else { printk(KERN_INFO "strange request: removal(2) " "%u-%u from %u:%u\n", from, to, le32_to_cpu(ex->ee_block), ee_len); } return 0; } static int ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, struct ext4_ext_path *path, ext4_lblk_t start) { int err = 0, correct_index = 0; int depth = ext_depth(inode), credits; struct ext4_extent_header *eh; ext4_lblk_t a, b, block; unsigned num; ext4_lblk_t ex_ee_block; unsigned short ex_ee_len; unsigned uninitialized = 0; struct ext4_extent *ex; /* the header must be checked already in ext4_ext_remove_space() */ ext_debug("truncate since %u in leaf\n", start); if (!path[depth].p_hdr) path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); eh = path[depth].p_hdr; BUG_ON(eh == NULL); /* find where to start removing */ ex = EXT_LAST_EXTENT(eh); ex_ee_block = le32_to_cpu(ex->ee_block); if (ext4_ext_is_uninitialized(ex)) uninitialized = 1; ex_ee_len = ext4_ext_get_actual_len(ex); while (ex >= EXT_FIRST_EXTENT(eh) && ex_ee_block + ex_ee_len > start) { ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len); path[depth].p_ext = ex; a = ex_ee_block > start ? ex_ee_block : start; b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ? ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK; ext_debug(" border %u:%u\n", a, b); if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) { block = 0; num = 0; BUG(); } else if (a != ex_ee_block) { /* remove tail of the extent */ block = ex_ee_block; num = a - block; } else if (b != ex_ee_block + ex_ee_len - 1) { /* remove head of the extent */ block = a; num = b - a; /* there is no "make a hole" API yet */ BUG(); } else { /* remove whole extent: excellent! */ block = ex_ee_block; num = 0; BUG_ON(a != ex_ee_block); BUG_ON(b != ex_ee_block + ex_ee_len - 1); } /* at present, extent can't cross block group: */ /* leaf + bitmap + group desc + sb + inode */ credits = 5; if (ex == EXT_FIRST_EXTENT(eh)) { correct_index = 1; credits += (ext_depth(inode)) + 1; } #ifdef CONFIG_QUOTA credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); #endif handle = ext4_ext_journal_restart(handle, credits); if (IS_ERR(handle)) { err = PTR_ERR(handle); goto out; } err = ext4_ext_get_access(handle, inode, path + depth); if (err) goto out; err = ext4_remove_blocks(handle, inode, ex, a, b); if (err) goto out; if (num == 0) { /* this extent is removed; mark slot entirely unused */ ext4_ext_store_pblock(ex, 0); eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1); } ex->ee_block = cpu_to_le32(block); ex->ee_len = cpu_to_le16(num); /* * Do not mark uninitialized if all the blocks in the * extent have been removed. */ if (uninitialized && num) ext4_ext_mark_uninitialized(ex); err = ext4_ext_dirty(handle, inode, path + depth); if (err) goto out; ext_debug("new extent: %u:%u:%llu\n", block, num, ext_pblock(ex)); ex--; ex_ee_block = le32_to_cpu(ex->ee_block); ex_ee_len = ext4_ext_get_actual_len(ex); } if (correct_index && eh->eh_entries) err = ext4_ext_correct_indexes(handle, inode, path); /* if this leaf is free, then we should * remove it from index block above */ if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) err = ext4_ext_rm_idx(handle, inode, path + depth); out: return err; } /* * ext4_ext_more_to_rm: * returns 1 if current index has to be freed (even partial) */ static int ext4_ext_more_to_rm(struct ext4_ext_path *path) { BUG_ON(path->p_idx == NULL); if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) return 0; /* * if truncate on deeper level happened, it wasn't partial, * so we have to consider current index for truncation */ if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) return 0; return 1; } static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start) { struct super_block *sb = inode->i_sb; int depth = ext_depth(inode); struct ext4_ext_path *path; handle_t *handle; int i = 0, err = 0; ext_debug("truncate since %u\n", start); /* probably first extent we're gonna free will be last in block */ handle = ext4_journal_start(inode, depth + 1); if (IS_ERR(handle)) return PTR_ERR(handle); ext4_ext_invalidate_cache(inode); /* * We start scanning from right side, freeing all the blocks * after i_size and walking into the tree depth-wise. */ path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL); if (path == NULL) { ext4_journal_stop(handle); return -ENOMEM; } path[0].p_hdr = ext_inode_hdr(inode); if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) { err = -EIO; goto out; } path[0].p_depth = depth; while (i >= 0 && err == 0) { if (i == depth) { /* this is leaf block */ err = ext4_ext_rm_leaf(handle, inode, path, start); /* root level has p_bh == NULL, brelse() eats this */ brelse(path[i].p_bh); path[i].p_bh = NULL; i--; continue; } /* this is index block */ if (!path[i].p_hdr) { ext_debug("initialize header\n"); path[i].p_hdr = ext_block_hdr(path[i].p_bh); } if (!path[i].p_idx) { /* this level hasn't been touched yet */ path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; ext_debug("init index ptr: hdr 0x%p, num %d\n", path[i].p_hdr, le16_to_cpu(path[i].p_hdr->eh_entries)); } else { /* we were already here, see at next index */ path[i].p_idx--; } ext_debug("level %d - index, first 0x%p, cur 0x%p\n", i, EXT_FIRST_INDEX(path[i].p_hdr), path[i].p_idx); if (ext4_ext_more_to_rm(path + i)) { struct buffer_head *bh; /* go to the next level */ ext_debug("move to level %d (block %llu)\n", i + 1, idx_pblock(path[i].p_idx)); memset(path + i + 1, 0, sizeof(*path)); bh = sb_bread(sb, idx_pblock(path[i].p_idx)); if (!bh) { /* should we reset i_size? */ err = -EIO; break; } if (WARN_ON(i + 1 > depth)) { err = -EIO; break; } if (ext4_ext_check_header(inode, ext_block_hdr(bh), depth - i - 1)) { err = -EIO; break; } path[i + 1].p_bh = bh; /* save actual number of indexes since this * number is changed at the next iteration */ path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); i++; } else { /* we finished processing this index, go up */ if (path[i].p_hdr->eh_entries == 0 && i > 0) { /* index is empty, remove it; * handle must be already prepared by the * truncatei_leaf() */ err = ext4_ext_rm_idx(handle, inode, path + i); } /* root level has p_bh == NULL, brelse() eats this */ brelse(path[i].p_bh); path[i].p_bh = NULL; i--; ext_debug("return to level %d\n", i); } } /* TODO: flexible tree reduction should be here */ if (path->p_hdr->eh_entries == 0) { /* * truncate to zero freed all the tree, * so we need to correct eh_depth */ err = ext4_ext_get_access(handle, inode, path); if (err == 0) { ext_inode_hdr(inode)->eh_depth = 0; ext_inode_hdr(inode)->eh_max = cpu_to_le16(ext4_ext_space_root(inode)); err = ext4_ext_dirty(handle, inode, path); } } out: ext4_ext_tree_changed(inode); ext4_ext_drop_refs(path); kfree(path); ext4_journal_stop(handle); return err; } /* * called at mount time */ void ext4_ext_init(struct super_block *sb) { /* * possible initialization would be here */ if (test_opt(sb, EXTENTS)) { printk("EXT4-fs: file extents enabled"); #ifdef AGGRESSIVE_TEST printk(", aggressive tests"); #endif #ifdef CHECK_BINSEARCH printk(", check binsearch"); #endif #ifdef EXTENTS_STATS printk(", stats"); #endif printk("\n"); #ifdef EXTENTS_STATS spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); EXT4_SB(sb)->s_ext_min = 1 << 30; EXT4_SB(sb)->s_ext_max = 0; #endif } } /* * called at umount time */ void ext4_ext_release(struct super_block *sb) { if (!test_opt(sb, EXTENTS)) return; #ifdef EXTENTS_STATS if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { struct ext4_sb_info *sbi = EXT4_SB(sb); printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", sbi->s_ext_blocks, sbi->s_ext_extents, sbi->s_ext_blocks / sbi->s_ext_extents); printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); } #endif } /* * This function is called by ext4_ext_get_blocks() if someone tries to write * to an uninitialized extent. It may result in splitting the uninitialized * extent into multiple extents (upto three - one initialized and two * uninitialized). * There are three possibilities: * a> There is no split required: Entire extent should be initialized * b> Splits in two extents: Write is happening at either end of the extent * c> Splits in three extents: Somone is writing in middle of the extent */ static int ext4_ext_convert_to_initialized(handle_t *handle, struct inode *inode, struct ext4_ext_path *path, ext4_lblk_t iblock, unsigned long max_blocks) { struct ext4_extent *ex, newex; struct ext4_extent *ex1 = NULL; struct ext4_extent *ex2 = NULL; struct ext4_extent *ex3 = NULL; struct ext4_extent_header *eh; ext4_lblk_t ee_block; unsigned int allocated, ee_len, depth; ext4_fsblk_t newblock; int err = 0; int ret = 0; depth = ext_depth(inode); eh = path[depth].p_hdr; ex = path[depth].p_ext; ee_block = le32_to_cpu(ex->ee_block); ee_len = ext4_ext_get_actual_len(ex); allocated = ee_len - (iblock - ee_block); newblock = iblock - ee_block + ext_pblock(ex); ex2 = ex; /* ex1: ee_block to iblock - 1 : uninitialized */ if (iblock > ee_block) { ex1 = ex; ex1->ee_len = cpu_to_le16(iblock - ee_block); ext4_ext_mark_uninitialized(ex1); ex2 = &newex; } /* * for sanity, update the length of the ex2 extent before * we insert ex3, if ex1 is NULL. This is to avoid temporary * overlap of blocks. */ if (!ex1 && allocated > max_blocks) ex2->ee_len = cpu_to_le16(max_blocks); /* ex3: to ee_block + ee_len : uninitialised */ if (allocated > max_blocks) { unsigned int newdepth; ex3 = &newex; ex3->ee_block = cpu_to_le32(iblock + max_blocks); ext4_ext_store_pblock(ex3, newblock + max_blocks); ex3->ee_len = cpu_to_le16(allocated - max_blocks); ext4_ext_mark_uninitialized(ex3); err = ext4_ext_insert_extent(handle, inode, path, ex3); if (err) goto out; /* * The depth, and hence eh & ex might change * as part of the insert above. */ newdepth = ext_depth(inode); if (newdepth != depth) { depth = newdepth; path = ext4_ext_find_extent(inode, iblock, NULL); if (IS_ERR(path)) { err = PTR_ERR(path); path = NULL; goto out; } eh = path[depth].p_hdr; ex = path[depth].p_ext; if (ex2 != &newex) ex2 = ex; } allocated = max_blocks; } /* * If there was a change of depth as part of the * insertion of ex3 above, we need to update the length * of the ex1 extent again here */ if (ex1 && ex1 != ex) { ex1 = ex; ex1->ee_len = cpu_to_le16(iblock - ee_block); ext4_ext_mark_uninitialized(ex1); ex2 = &newex; } /* ex2: iblock to iblock + maxblocks-1 : initialised */ ex2->ee_block = cpu_to_le32(iblock); ext4_ext_store_pblock(ex2, newblock); ex2->ee_len = cpu_to_le16(allocated); if (ex2 != ex) goto insert; err = ext4_ext_get_access(handle, inode, path + depth); if (err) goto out; /* * New (initialized) extent starts from the first block * in the current extent. i.e., ex2 == ex * We have to see if it can be merged with the extent * on the left. */ if (ex2 > EXT_FIRST_EXTENT(eh)) { /* * To merge left, pass "ex2 - 1" to try_to_merge(), * since it merges towards right _only_. */ ret = ext4_ext_try_to_merge(inode, path, ex2 - 1); if (ret) { err = ext4_ext_correct_indexes(handle, inode, path); if (err) goto out; depth = ext_depth(inode); ex2--; } } /* * Try to Merge towards right. This might be required * only when the whole extent is being written to. * i.e. ex2 == ex and ex3 == NULL. */ if (!ex3) { ret = ext4_ext_try_to_merge(inode, path, ex2); if (ret) { err = ext4_ext_correct_indexes(handle, inode, path); if (err) goto out; } } /* Mark modified extent as dirty */ err = ext4_ext_dirty(handle, inode, path + depth); goto out; insert: err = ext4_ext_insert_extent(handle, inode, path, &newex); out: return err ? err : allocated; } /* * Need to be called with * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) */ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, ext4_lblk_t iblock, unsigned long max_blocks, struct buffer_head *bh_result, int create, int extend_disksize) { struct ext4_ext_path *path = NULL; struct ext4_extent_header *eh; struct ext4_extent newex, *ex; ext4_fsblk_t goal, newblock; int err = 0, depth, ret; unsigned long allocated = 0; struct ext4_allocation_request ar; __clear_bit(BH_New, &bh_result->b_state); ext_debug("blocks %u/%lu requested for inode %u\n", iblock, max_blocks, inode->i_ino); /* check in cache */ goal = ext4_ext_in_cache(inode, iblock, &newex); if (goal) { if (goal == EXT4_EXT_CACHE_GAP) { if (!create) { /* * block isn't allocated yet and * user doesn't want to allocate it */ goto out2; } /* we should allocate requested block */ } else if (goal == EXT4_EXT_CACHE_EXTENT) { /* block is already allocated */ newblock = iblock - le32_to_cpu(newex.ee_block) + ext_pblock(&newex); /* number of remaining blocks in the extent */ allocated = ext4_ext_get_actual_len(&newex) - (iblock - le32_to_cpu(newex.ee_block)); goto out; } else { BUG(); } } /* find extent for this block */ path = ext4_ext_find_extent(inode, iblock, NULL); if (IS_ERR(path)) { err = PTR_ERR(path); path = NULL; goto out2; } depth = ext_depth(inode); /* * consistent leaf must not be empty; * this situation is possible, though, _during_ tree modification; * this is why assert can't be put in ext4_ext_find_extent() */ BUG_ON(path[depth].p_ext == NULL && depth != 0); eh = path[depth].p_hdr; ex = path[depth].p_ext; if (ex) { ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block); ext4_fsblk_t ee_start = ext_pblock(ex); unsigned short ee_len; /* * Uninitialized extents are treated as holes, except that * we split out initialized portions during a write. */ ee_len = ext4_ext_get_actual_len(ex); /* if found extent covers block, simply return it */ if (iblock >= ee_block && iblock < ee_block + ee_len) { newblock = iblock - ee_block + ee_start; /* number of remaining blocks in the extent */ allocated = ee_len - (iblock - ee_block); ext_debug("%u fit into %lu:%d -> %llu\n", iblock, ee_block, ee_len, newblock); /* Do not put uninitialized extent in the cache */ if (!ext4_ext_is_uninitialized(ex)) { ext4_ext_put_in_cache(inode, ee_block, ee_len, ee_start, EXT4_EXT_CACHE_EXTENT); goto out; } if (create == EXT4_CREATE_UNINITIALIZED_EXT) goto out; if (!create) goto out2; ret = ext4_ext_convert_to_initialized(handle, inode, path, iblock, max_blocks); if (ret <= 0) { err = ret; goto out2; } else allocated = ret; goto outnew; } } /* * requested block isn't allocated yet; * we couldn't try to create block if create flag is zero */ if (!create) { /* * put just found gap into cache to speed up * subsequent requests */ ext4_ext_put_gap_in_cache(inode, path, iblock); goto out2; } /* * Okay, we need to do block allocation. Lazily initialize the block * allocation info here if necessary. */ if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info)) ext4_init_block_alloc_info(inode); /* find neighbour allocated blocks */ ar.lleft = iblock; err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft); if (err) goto out2; ar.lright = iblock; err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright); if (err) goto out2; /* * See if request is beyond maximum number of blocks we can have in * a single extent. For an initialized extent this limit is * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is * EXT_UNINIT_MAX_LEN. */ if (max_blocks > EXT_INIT_MAX_LEN && create != EXT4_CREATE_UNINITIALIZED_EXT) max_blocks = EXT_INIT_MAX_LEN; else if (max_blocks > EXT_UNINIT_MAX_LEN && create == EXT4_CREATE_UNINITIALIZED_EXT) max_blocks = EXT_UNINIT_MAX_LEN; /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */ newex.ee_block = cpu_to_le32(iblock); newex.ee_len = cpu_to_le16(max_blocks); err = ext4_ext_check_overlap(inode, &newex, path); if (err) allocated = ext4_ext_get_actual_len(&newex); else allocated = max_blocks; /* allocate new block */ ar.inode = inode; ar.goal = ext4_ext_find_goal(inode, path, iblock); ar.logical = iblock; ar.len = allocated; if (S_ISREG(inode->i_mode)) ar.flags = EXT4_MB_HINT_DATA; else /* disable in-core preallocation for non-regular files */ ar.flags = 0; newblock = ext4_mb_new_blocks(handle, &ar, &err); if (!newblock) goto out2; ext_debug("allocate new block: goal %llu, found %llu/%lu\n", goal, newblock, allocated); /* try to insert new extent into found leaf and return */ ext4_ext_store_pblock(&newex, newblock); newex.ee_len = cpu_to_le16(ar.len); if (create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */ ext4_ext_mark_uninitialized(&newex); err = ext4_ext_insert_extent(handle, inode, path, &newex); if (err) { /* free data blocks we just allocated */ /* not a good idea to call discard here directly, * but otherwise we'd need to call it every free() */ ext4_mb_discard_inode_preallocations(inode); ext4_free_blocks(handle, inode, ext_pblock(&newex), ext4_ext_get_actual_len(&newex), 0); goto out2; } if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize) EXT4_I(inode)->i_disksize = inode->i_size; /* previous routine could use block we allocated */ newblock = ext_pblock(&newex); allocated = ext4_ext_get_actual_len(&newex); outnew: __set_bit(BH_New, &bh_result->b_state); /* Cache only when it is _not_ an uninitialized extent */ if (create != EXT4_CREATE_UNINITIALIZED_EXT) ext4_ext_put_in_cache(inode, iblock, allocated, newblock, EXT4_EXT_CACHE_EXTENT); out: if (allocated > max_blocks) allocated = max_blocks; ext4_ext_show_leaf(inode, path); __set_bit(BH_Mapped, &bh_result->b_state); bh_result->b_bdev = inode->i_sb->s_bdev; bh_result->b_blocknr = newblock; out2: if (path) { ext4_ext_drop_refs(path); kfree(path); } return err ? err : allocated; } void ext4_ext_truncate(struct inode * inode, struct page *page) { struct address_space *mapping = inode->i_mapping; struct super_block *sb = inode->i_sb; ext4_lblk_t last_block; handle_t *handle; int err = 0; /* * probably first extent we're gonna free will be last in block */ err = ext4_writepage_trans_blocks(inode) + 3; handle = ext4_journal_start(inode, err); if (IS_ERR(handle)) { if (page) { clear_highpage(page); flush_dcache_page(page); unlock_page(page); page_cache_release(page); } return; } if (page) ext4_block_truncate_page(handle, page, mapping, inode->i_size); down_write(&EXT4_I(inode)->i_data_sem); ext4_ext_invalidate_cache(inode); ext4_mb_discard_inode_preallocations(inode); /* * TODO: optimization is possible here. * Probably we need not scan at all, * because page truncation is enough. */ if (ext4_orphan_add(handle, inode)) goto out_stop; /* we have to know where to truncate from in crash case */ EXT4_I(inode)->i_disksize = inode->i_size; ext4_mark_inode_dirty(handle, inode); last_block = (inode->i_size + sb->s_blocksize - 1) >> EXT4_BLOCK_SIZE_BITS(sb); err = ext4_ext_remove_space(inode, last_block); /* In a multi-transaction truncate, we only make the final * transaction synchronous. */ if (IS_SYNC(inode)) handle->h_sync = 1; out_stop: /* * If this was a simple ftruncate() and the file will remain alive, * then we need to clear up the orphan record which we created above. * However, if this was a real unlink then we were called by * ext4_delete_inode(), and we allow that function to clean up the * orphan info for us. */ if (inode->i_nlink) ext4_orphan_del(handle, inode); up_write(&EXT4_I(inode)->i_data_sem); ext4_journal_stop(handle); } /* * ext4_ext_writepage_trans_blocks: * calculate max number of blocks we could modify * in order to allocate new block for an inode */ int ext4_ext_writepage_trans_blocks(struct inode *inode, int num) { int needed; needed = ext4_ext_calc_credits_for_insert(inode, NULL); /* caller wants to allocate num blocks, but note it includes sb */ needed = needed * num - (num - 1); #ifdef CONFIG_QUOTA needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); #endif return needed; } /* * preallocate space for a file. This implements ext4's fallocate inode * operation, which gets called from sys_fallocate system call. * For block-mapped files, posix_fallocate should fall back to the method * of writing zeroes to the required new blocks (the same behavior which is * expected for file systems which do not support fallocate() system call). */ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len) { handle_t *handle; ext4_lblk_t block; unsigned long max_blocks; ext4_fsblk_t nblocks = 0; int ret = 0; int ret2 = 0; int retries = 0; struct buffer_head map_bh; unsigned int credits, blkbits = inode->i_blkbits; /* * currently supporting (pre)allocate mode for extent-based * files _only_ */ if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) return -EOPNOTSUPP; /* preallocation to directories is currently not supported */ if (S_ISDIR(inode->i_mode)) return -ENODEV; block = offset >> blkbits; max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) - block; /* * credits to insert 1 extent into extent tree + buffers to be able to * modify 1 super block, 1 block bitmap and 1 group descriptor. */ credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3; down_write((&EXT4_I(inode)->i_data_sem)); retry: while (ret >= 0 && ret < max_blocks) { block = block + ret; max_blocks = max_blocks - ret; handle = ext4_journal_start(inode, credits); if (IS_ERR(handle)) { ret = PTR_ERR(handle); break; } ret = ext4_ext_get_blocks(handle, inode, block, max_blocks, &map_bh, EXT4_CREATE_UNINITIALIZED_EXT, 0); WARN_ON(ret <= 0); if (ret <= 0) { ext4_error(inode->i_sb, "ext4_fallocate", "ext4_ext_get_blocks returned error: " "inode#%lu, block=%u, max_blocks=%lu", inode->i_ino, block, max_blocks); ret = -EIO; ext4_mark_inode_dirty(handle, inode); ret2 = ext4_journal_stop(handle); break; } if (ret > 0) { /* check wrap through sign-bit/zero here */ if ((block + ret) < 0 || (block + ret) < block) { ret = -EIO; ext4_mark_inode_dirty(handle, inode); ret2 = ext4_journal_stop(handle); break; } if (buffer_new(&map_bh) && ((block + ret) > (EXT4_BLOCK_ALIGN(i_size_read(inode), blkbits) >> blkbits))) nblocks = nblocks + ret; } /* Update ctime if new blocks get allocated */ if (nblocks) { struct timespec now; now = current_fs_time(inode->i_sb); if (!timespec_equal(&inode->i_ctime, &now)) inode->i_ctime = now; } ext4_mark_inode_dirty(handle, inode); ret2 = ext4_journal_stop(handle); if (ret2) break; } if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; up_write((&EXT4_I(inode)->i_data_sem)); /* * Time to update the file size. * Update only when preallocation was requested beyond the file size. */ if (!(mode & FALLOC_FL_KEEP_SIZE) && (offset + len) > i_size_read(inode)) { if (ret > 0) { /* * if no error, we assume preallocation succeeded * completely */ mutex_lock(&inode->i_mutex); i_size_write(inode, offset + len); EXT4_I(inode)->i_disksize = i_size_read(inode); mutex_unlock(&inode->i_mutex); } else if (ret < 0 && nblocks) { /* Handle partial allocation scenario */ loff_t newsize; mutex_lock(&inode->i_mutex); newsize = (nblocks << blkbits) + i_size_read(inode); i_size_write(inode, EXT4_BLOCK_ALIGN(newsize, blkbits)); EXT4_I(inode)->i_disksize = i_size_read(inode); mutex_unlock(&inode->i_mutex); } } return ret > 0 ? ret2 : ret; }