diff options
Diffstat (limited to 'fs/zonefs/file.c')
-rw-r--r-- | fs/zonefs/file.c | 902 |
1 files changed, 902 insertions, 0 deletions
diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c new file mode 100644 index 000000000000..132f01d3461f --- /dev/null +++ b/fs/zonefs/file.c @@ -0,0 +1,902 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Simple file system for zoned block devices exposing zones as files. + * + * Copyright (C) 2022 Western Digital Corporation or its affiliates. + */ +#include <linux/module.h> +#include <linux/pagemap.h> +#include <linux/iomap.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/blkdev.h> +#include <linux/statfs.h> +#include <linux/writeback.h> +#include <linux/quotaops.h> +#include <linux/seq_file.h> +#include <linux/parser.h> +#include <linux/uio.h> +#include <linux/mman.h> +#include <linux/sched/mm.h> +#include <linux/task_io_accounting_ops.h> + +#include "zonefs.h" + +#include "trace.h" + +static int zonefs_read_iomap_begin(struct inode *inode, loff_t offset, + loff_t length, unsigned int flags, + struct iomap *iomap, struct iomap *srcmap) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_zone *z = zonefs_inode_zone(inode); + struct super_block *sb = inode->i_sb; + loff_t isize; + + /* + * All blocks are always mapped below EOF. If reading past EOF, + * act as if there is a hole up to the file maximum size. + */ + mutex_lock(&zi->i_truncate_mutex); + iomap->bdev = inode->i_sb->s_bdev; + iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize); + isize = i_size_read(inode); + if (iomap->offset >= isize) { + iomap->type = IOMAP_HOLE; + iomap->addr = IOMAP_NULL_ADDR; + iomap->length = length; + } else { + iomap->type = IOMAP_MAPPED; + iomap->addr = (z->z_sector << SECTOR_SHIFT) + iomap->offset; + iomap->length = isize - iomap->offset; + } + mutex_unlock(&zi->i_truncate_mutex); + + trace_zonefs_iomap_begin(inode, iomap); + + return 0; +} + +static const struct iomap_ops zonefs_read_iomap_ops = { + .iomap_begin = zonefs_read_iomap_begin, +}; + +static int zonefs_write_iomap_begin(struct inode *inode, loff_t offset, + loff_t length, unsigned int flags, + struct iomap *iomap, struct iomap *srcmap) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_zone *z = zonefs_inode_zone(inode); + struct super_block *sb = inode->i_sb; + loff_t isize; + + /* All write I/Os should always be within the file maximum size */ + if (WARN_ON_ONCE(offset + length > z->z_capacity)) + return -EIO; + + /* + * Sequential zones can only accept direct writes. This is already + * checked when writes are issued, so warn if we see a page writeback + * operation. + */ + if (WARN_ON_ONCE(zonefs_zone_is_seq(z) && !(flags & IOMAP_DIRECT))) + return -EIO; + + /* + * For conventional zones, all blocks are always mapped. For sequential + * zones, all blocks after always mapped below the inode size (zone + * write pointer) and unwriten beyond. + */ + mutex_lock(&zi->i_truncate_mutex); + iomap->bdev = inode->i_sb->s_bdev; + iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize); + iomap->addr = (z->z_sector << SECTOR_SHIFT) + iomap->offset; + isize = i_size_read(inode); + if (iomap->offset >= isize) { + iomap->type = IOMAP_UNWRITTEN; + iomap->length = z->z_capacity - iomap->offset; + } else { + iomap->type = IOMAP_MAPPED; + iomap->length = isize - iomap->offset; + } + mutex_unlock(&zi->i_truncate_mutex); + + trace_zonefs_iomap_begin(inode, iomap); + + return 0; +} + +static const struct iomap_ops zonefs_write_iomap_ops = { + .iomap_begin = zonefs_write_iomap_begin, +}; + +static int zonefs_read_folio(struct file *unused, struct folio *folio) +{ + return iomap_read_folio(folio, &zonefs_read_iomap_ops); +} + +static void zonefs_readahead(struct readahead_control *rac) +{ + iomap_readahead(rac, &zonefs_read_iomap_ops); +} + +/* + * Map blocks for page writeback. This is used only on conventional zone files, + * which implies that the page range can only be within the fixed inode size. + */ +static int zonefs_write_map_blocks(struct iomap_writepage_ctx *wpc, + struct inode *inode, loff_t offset) +{ + struct zonefs_zone *z = zonefs_inode_zone(inode); + + if (WARN_ON_ONCE(zonefs_zone_is_seq(z))) + return -EIO; + if (WARN_ON_ONCE(offset >= i_size_read(inode))) + return -EIO; + + /* If the mapping is already OK, nothing needs to be done */ + if (offset >= wpc->iomap.offset && + offset < wpc->iomap.offset + wpc->iomap.length) + return 0; + + return zonefs_write_iomap_begin(inode, offset, + z->z_capacity - offset, + IOMAP_WRITE, &wpc->iomap, NULL); +} + +static const struct iomap_writeback_ops zonefs_writeback_ops = { + .map_blocks = zonefs_write_map_blocks, +}; + +static int zonefs_writepages(struct address_space *mapping, + struct writeback_control *wbc) +{ + struct iomap_writepage_ctx wpc = { }; + + return iomap_writepages(mapping, wbc, &wpc, &zonefs_writeback_ops); +} + +static int zonefs_swap_activate(struct swap_info_struct *sis, + struct file *swap_file, sector_t *span) +{ + struct inode *inode = file_inode(swap_file); + + if (zonefs_inode_is_seq(inode)) { + zonefs_err(inode->i_sb, + "swap file: not a conventional zone file\n"); + return -EINVAL; + } + + return iomap_swapfile_activate(sis, swap_file, span, + &zonefs_read_iomap_ops); +} + +const struct address_space_operations zonefs_file_aops = { + .read_folio = zonefs_read_folio, + .readahead = zonefs_readahead, + .writepages = zonefs_writepages, + .dirty_folio = filemap_dirty_folio, + .release_folio = iomap_release_folio, + .invalidate_folio = iomap_invalidate_folio, + .migrate_folio = filemap_migrate_folio, + .is_partially_uptodate = iomap_is_partially_uptodate, + .error_remove_page = generic_error_remove_page, + .direct_IO = noop_direct_IO, + .swap_activate = zonefs_swap_activate, +}; + +int zonefs_file_truncate(struct inode *inode, loff_t isize) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_zone *z = zonefs_inode_zone(inode); + loff_t old_isize; + enum req_op op; + int ret = 0; + + /* + * Only sequential zone files can be truncated and truncation is allowed + * only down to a 0 size, which is equivalent to a zone reset, and to + * the maximum file size, which is equivalent to a zone finish. + */ + if (!zonefs_zone_is_seq(z)) + return -EPERM; + + if (!isize) + op = REQ_OP_ZONE_RESET; + else if (isize == z->z_capacity) + op = REQ_OP_ZONE_FINISH; + else + return -EPERM; + + inode_dio_wait(inode); + + /* Serialize against page faults */ + filemap_invalidate_lock(inode->i_mapping); + + /* Serialize against zonefs_iomap_begin() */ + mutex_lock(&zi->i_truncate_mutex); + + old_isize = i_size_read(inode); + if (isize == old_isize) + goto unlock; + + ret = zonefs_inode_zone_mgmt(inode, op); + if (ret) + goto unlock; + + /* + * If the mount option ZONEFS_MNTOPT_EXPLICIT_OPEN is set, + * take care of open zones. + */ + if (z->z_flags & ZONEFS_ZONE_OPEN) { + /* + * Truncating a zone to EMPTY or FULL is the equivalent of + * closing the zone. For a truncation to 0, we need to + * re-open the zone to ensure new writes can be processed. + * For a truncation to the maximum file size, the zone is + * closed and writes cannot be accepted anymore, so clear + * the open flag. + */ + if (!isize) + ret = zonefs_inode_zone_mgmt(inode, REQ_OP_ZONE_OPEN); + else + z->z_flags &= ~ZONEFS_ZONE_OPEN; + } + + zonefs_update_stats(inode, isize); + truncate_setsize(inode, isize); + z->z_wpoffset = isize; + zonefs_inode_account_active(inode); + +unlock: + mutex_unlock(&zi->i_truncate_mutex); + filemap_invalidate_unlock(inode->i_mapping); + + return ret; +} + +static int zonefs_file_fsync(struct file *file, loff_t start, loff_t end, + int datasync) +{ + struct inode *inode = file_inode(file); + int ret = 0; + + if (unlikely(IS_IMMUTABLE(inode))) + return -EPERM; + + /* + * Since only direct writes are allowed in sequential files, page cache + * flush is needed only for conventional zone files. + */ + if (zonefs_inode_is_cnv(inode)) + ret = file_write_and_wait_range(file, start, end); + if (!ret) + ret = blkdev_issue_flush(inode->i_sb->s_bdev); + + if (ret) + zonefs_io_error(inode, true); + + return ret; +} + +static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf) +{ + struct inode *inode = file_inode(vmf->vma->vm_file); + vm_fault_t ret; + + if (unlikely(IS_IMMUTABLE(inode))) + return VM_FAULT_SIGBUS; + + /* + * Sanity check: only conventional zone files can have shared + * writeable mappings. + */ + if (zonefs_inode_is_seq(inode)) + return VM_FAULT_NOPAGE; + + sb_start_pagefault(inode->i_sb); + file_update_time(vmf->vma->vm_file); + + /* Serialize against truncates */ + filemap_invalidate_lock_shared(inode->i_mapping); + ret = iomap_page_mkwrite(vmf, &zonefs_write_iomap_ops); + filemap_invalidate_unlock_shared(inode->i_mapping); + + sb_end_pagefault(inode->i_sb); + return ret; +} + +static const struct vm_operations_struct zonefs_file_vm_ops = { + .fault = filemap_fault, + .map_pages = filemap_map_pages, + .page_mkwrite = zonefs_filemap_page_mkwrite, +}; + +static int zonefs_file_mmap(struct file *file, struct vm_area_struct *vma) +{ + /* + * Conventional zones accept random writes, so their files can support + * shared writable mappings. For sequential zone files, only read + * mappings are possible since there are no guarantees for write + * ordering between msync() and page cache writeback. + */ + if (zonefs_inode_is_seq(file_inode(file)) && + (vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) + return -EINVAL; + + file_accessed(file); + vma->vm_ops = &zonefs_file_vm_ops; + + return 0; +} + +static loff_t zonefs_file_llseek(struct file *file, loff_t offset, int whence) +{ + loff_t isize = i_size_read(file_inode(file)); + + /* + * Seeks are limited to below the zone size for conventional zones + * and below the zone write pointer for sequential zones. In both + * cases, this limit is the inode size. + */ + return generic_file_llseek_size(file, offset, whence, isize, isize); +} + +static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size, + int error, unsigned int flags) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + + if (error) { + zonefs_io_error(inode, true); + return error; + } + + if (size && zonefs_inode_is_seq(inode)) { + /* + * Note that we may be seeing completions out of order, + * but that is not a problem since a write completed + * successfully necessarily means that all preceding writes + * were also successful. So we can safely increase the inode + * size to the write end location. + */ + mutex_lock(&zi->i_truncate_mutex); + if (i_size_read(inode) < iocb->ki_pos + size) { + zonefs_update_stats(inode, iocb->ki_pos + size); + zonefs_i_size_write(inode, iocb->ki_pos + size); + } + mutex_unlock(&zi->i_truncate_mutex); + } + + return 0; +} + +static const struct iomap_dio_ops zonefs_write_dio_ops = { + .end_io = zonefs_file_write_dio_end_io, +}; + +static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct zonefs_zone *z = zonefs_inode_zone(inode); + struct block_device *bdev = inode->i_sb->s_bdev; + unsigned int max = bdev_max_zone_append_sectors(bdev); + pgoff_t start, end; + struct bio *bio; + ssize_t size = 0; + int nr_pages; + ssize_t ret; + + max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize); + iov_iter_truncate(from, max); + + /* + * If the inode block size (zone write granularity) is smaller than the + * page size, we may be appending data belonging to the last page of the + * inode straddling inode->i_size, with that page already cached due to + * a buffered read or readahead. So make sure to invalidate that page. + * This will always be a no-op for the case where the block size is + * equal to the page size. + */ + start = iocb->ki_pos >> PAGE_SHIFT; + end = (iocb->ki_pos + iov_iter_count(from) - 1) >> PAGE_SHIFT; + if (invalidate_inode_pages2_range(inode->i_mapping, start, end)) + return -EBUSY; + + nr_pages = iov_iter_npages(from, BIO_MAX_VECS); + if (!nr_pages) + return 0; + + bio = bio_alloc(bdev, nr_pages, + REQ_OP_ZONE_APPEND | REQ_SYNC | REQ_IDLE, GFP_NOFS); + bio->bi_iter.bi_sector = z->z_sector; + bio->bi_ioprio = iocb->ki_ioprio; + if (iocb_is_dsync(iocb)) + bio->bi_opf |= REQ_FUA; + + ret = bio_iov_iter_get_pages(bio, from); + if (unlikely(ret)) + goto out_release; + + size = bio->bi_iter.bi_size; + task_io_account_write(size); + + if (iocb->ki_flags & IOCB_HIPRI) + bio_set_polled(bio, iocb); + + ret = submit_bio_wait(bio); + + /* + * If the file zone was written underneath the file system, the zone + * write pointer may not be where we expect it to be, but the zone + * append write can still succeed. So check manually that we wrote where + * we intended to, that is, at zi->i_wpoffset. + */ + if (!ret) { + sector_t wpsector = + z->z_sector + (z->z_wpoffset >> SECTOR_SHIFT); + + if (bio->bi_iter.bi_sector != wpsector) { + zonefs_warn(inode->i_sb, + "Corrupted write pointer %llu for zone at %llu\n", + bio->bi_iter.bi_sector, z->z_sector); + ret = -EIO; + } + } + + zonefs_file_write_dio_end_io(iocb, size, ret, 0); + trace_zonefs_file_dio_append(inode, size, ret); + +out_release: + bio_release_pages(bio, false); + bio_put(bio); + + if (ret >= 0) { + iocb->ki_pos += size; + return size; + } + + return ret; +} + +/* + * Do not exceed the LFS limits nor the file zone size. If pos is under the + * limit it becomes a short access. If it exceeds the limit, return -EFBIG. + */ +static loff_t zonefs_write_check_limits(struct file *file, loff_t pos, + loff_t count) +{ + struct inode *inode = file_inode(file); + struct zonefs_zone *z = zonefs_inode_zone(inode); + loff_t limit = rlimit(RLIMIT_FSIZE); + loff_t max_size = z->z_capacity; + + if (limit != RLIM_INFINITY) { + if (pos >= limit) { + send_sig(SIGXFSZ, current, 0); + return -EFBIG; + } + count = min(count, limit - pos); + } + + if (!(file->f_flags & O_LARGEFILE)) + max_size = min_t(loff_t, MAX_NON_LFS, max_size); + + if (unlikely(pos >= max_size)) + return -EFBIG; + + return min(count, max_size - pos); +} + +static ssize_t zonefs_write_checks(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file_inode(file); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_zone *z = zonefs_inode_zone(inode); + loff_t count; + + if (IS_SWAPFILE(inode)) + return -ETXTBSY; + + if (!iov_iter_count(from)) + return 0; + + if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT)) + return -EINVAL; + + if (iocb->ki_flags & IOCB_APPEND) { + if (zonefs_zone_is_cnv(z)) + return -EINVAL; + mutex_lock(&zi->i_truncate_mutex); + iocb->ki_pos = z->z_wpoffset; + mutex_unlock(&zi->i_truncate_mutex); + } + + count = zonefs_write_check_limits(file, iocb->ki_pos, + iov_iter_count(from)); + if (count < 0) + return count; + + iov_iter_truncate(from, count); + return iov_iter_count(from); +} + +/* + * Handle direct writes. For sequential zone files, this is the only possible + * write path. For these files, check that the user is issuing writes + * sequentially from the end of the file. This code assumes that the block layer + * delivers write requests to the device in sequential order. This is always the + * case if a block IO scheduler implementing the ELEVATOR_F_ZBD_SEQ_WRITE + * elevator feature is being used (e.g. mq-deadline). The block layer always + * automatically select such an elevator for zoned block devices during the + * device initialization. + */ +static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_zone *z = zonefs_inode_zone(inode); + struct super_block *sb = inode->i_sb; + bool sync = is_sync_kiocb(iocb); + bool append = false; + ssize_t ret, count; + + /* + * For async direct IOs to sequential zone files, refuse IOCB_NOWAIT + * as this can cause write reordering (e.g. the first aio gets EAGAIN + * on the inode lock but the second goes through but is now unaligned). + */ + if (zonefs_zone_is_seq(z) && !sync && (iocb->ki_flags & IOCB_NOWAIT)) + return -EOPNOTSUPP; + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock(inode)) + return -EAGAIN; + } else { + inode_lock(inode); + } + + count = zonefs_write_checks(iocb, from); + if (count <= 0) { + ret = count; + goto inode_unlock; + } + + if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) { + ret = -EINVAL; + goto inode_unlock; + } + + /* Enforce sequential writes (append only) in sequential zones */ + if (zonefs_zone_is_seq(z)) { + mutex_lock(&zi->i_truncate_mutex); + if (iocb->ki_pos != z->z_wpoffset) { + mutex_unlock(&zi->i_truncate_mutex); + ret = -EINVAL; + goto inode_unlock; + } + mutex_unlock(&zi->i_truncate_mutex); + append = sync; + } + + if (append) { + ret = zonefs_file_dio_append(iocb, from); + } else { + /* + * iomap_dio_rw() may return ENOTBLK if there was an issue with + * page invalidation. Overwrite that error code with EBUSY to + * be consistent with zonefs_file_dio_append() return value for + * similar issues. + */ + ret = iomap_dio_rw(iocb, from, &zonefs_write_iomap_ops, + &zonefs_write_dio_ops, 0, NULL, 0); + if (ret == -ENOTBLK) + ret = -EBUSY; + } + + if (zonefs_zone_is_seq(z) && + (ret > 0 || ret == -EIOCBQUEUED)) { + if (ret > 0) + count = ret; + + /* + * Update the zone write pointer offset assuming the write + * operation succeeded. If it did not, the error recovery path + * will correct it. Also do active seq file accounting. + */ + mutex_lock(&zi->i_truncate_mutex); + z->z_wpoffset += count; + zonefs_inode_account_active(inode); + mutex_unlock(&zi->i_truncate_mutex); + } + +inode_unlock: + inode_unlock(inode); + + return ret; +} + +static ssize_t zonefs_file_buffered_write(struct kiocb *iocb, + struct iov_iter *from) +{ + struct inode *inode = file_inode(iocb->ki_filp); + ssize_t ret; + + /* + * Direct IO writes are mandatory for sequential zone files so that the + * write IO issuing order is preserved. + */ + if (zonefs_inode_is_seq(inode)) + return -EIO; + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock(inode)) + return -EAGAIN; + } else { + inode_lock(inode); + } + + ret = zonefs_write_checks(iocb, from); + if (ret <= 0) + goto inode_unlock; + + ret = iomap_file_buffered_write(iocb, from, &zonefs_write_iomap_ops); + if (ret > 0) + iocb->ki_pos += ret; + else if (ret == -EIO) + zonefs_io_error(inode, true); + +inode_unlock: + inode_unlock(inode); + if (ret > 0) + ret = generic_write_sync(iocb, ret); + + return ret; +} + +static ssize_t zonefs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct zonefs_zone *z = zonefs_inode_zone(inode); + + if (unlikely(IS_IMMUTABLE(inode))) + return -EPERM; + + if (sb_rdonly(inode->i_sb)) + return -EROFS; + + /* Write operations beyond the zone capacity are not allowed */ + if (iocb->ki_pos >= z->z_capacity) + return -EFBIG; + + if (iocb->ki_flags & IOCB_DIRECT) { + ssize_t ret = zonefs_file_dio_write(iocb, from); + + if (ret != -ENOTBLK) + return ret; + } + + return zonefs_file_buffered_write(iocb, from); +} + +static int zonefs_file_read_dio_end_io(struct kiocb *iocb, ssize_t size, + int error, unsigned int flags) +{ + if (error) { + zonefs_io_error(file_inode(iocb->ki_filp), false); + return error; + } + + return 0; +} + +static const struct iomap_dio_ops zonefs_read_dio_ops = { + .end_io = zonefs_file_read_dio_end_io, +}; + +static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_zone *z = zonefs_inode_zone(inode); + struct super_block *sb = inode->i_sb; + loff_t isize; + ssize_t ret; + + /* Offline zones cannot be read */ + if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777))) + return -EPERM; + + if (iocb->ki_pos >= z->z_capacity) + return 0; + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock_shared(inode)) + return -EAGAIN; + } else { + inode_lock_shared(inode); + } + + /* Limit read operations to written data */ + mutex_lock(&zi->i_truncate_mutex); + isize = i_size_read(inode); + if (iocb->ki_pos >= isize) { + mutex_unlock(&zi->i_truncate_mutex); + ret = 0; + goto inode_unlock; + } + iov_iter_truncate(to, isize - iocb->ki_pos); + mutex_unlock(&zi->i_truncate_mutex); + + if (iocb->ki_flags & IOCB_DIRECT) { + size_t count = iov_iter_count(to); + + if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) { + ret = -EINVAL; + goto inode_unlock; + } + file_accessed(iocb->ki_filp); + ret = iomap_dio_rw(iocb, to, &zonefs_read_iomap_ops, + &zonefs_read_dio_ops, 0, NULL, 0); + } else { + ret = generic_file_read_iter(iocb, to); + if (ret == -EIO) + zonefs_io_error(inode, false); + } + +inode_unlock: + inode_unlock_shared(inode); + + return ret; +} + +/* + * Write open accounting is done only for sequential files. + */ +static inline bool zonefs_seq_file_need_wro(struct inode *inode, + struct file *file) +{ + if (zonefs_inode_is_cnv(inode)) + return false; + + if (!(file->f_mode & FMODE_WRITE)) + return false; + + return true; +} + +static int zonefs_seq_file_write_open(struct inode *inode) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_zone *z = zonefs_inode_zone(inode); + int ret = 0; + + mutex_lock(&zi->i_truncate_mutex); + + if (!zi->i_wr_refcnt) { + struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb); + unsigned int wro = atomic_inc_return(&sbi->s_wro_seq_files); + + if (sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) { + + if (sbi->s_max_wro_seq_files + && wro > sbi->s_max_wro_seq_files) { + atomic_dec(&sbi->s_wro_seq_files); + ret = -EBUSY; + goto unlock; + } + + if (i_size_read(inode) < z->z_capacity) { + ret = zonefs_inode_zone_mgmt(inode, + REQ_OP_ZONE_OPEN); + if (ret) { + atomic_dec(&sbi->s_wro_seq_files); + goto unlock; + } + z->z_flags |= ZONEFS_ZONE_OPEN; + zonefs_inode_account_active(inode); + } + } + } + + zi->i_wr_refcnt++; + +unlock: + mutex_unlock(&zi->i_truncate_mutex); + + return ret; +} + +static int zonefs_file_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = generic_file_open(inode, file); + if (ret) + return ret; + + if (zonefs_seq_file_need_wro(inode, file)) + return zonefs_seq_file_write_open(inode); + + return 0; +} + +static void zonefs_seq_file_write_close(struct inode *inode) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_zone *z = zonefs_inode_zone(inode); + struct super_block *sb = inode->i_sb; + struct zonefs_sb_info *sbi = ZONEFS_SB(sb); + int ret = 0; + + mutex_lock(&zi->i_truncate_mutex); + + zi->i_wr_refcnt--; + if (zi->i_wr_refcnt) + goto unlock; + + /* + * The file zone may not be open anymore (e.g. the file was truncated to + * its maximum size or it was fully written). For this case, we only + * need to decrement the write open count. + */ + if (z->z_flags & ZONEFS_ZONE_OPEN) { + ret = zonefs_inode_zone_mgmt(inode, REQ_OP_ZONE_CLOSE); + if (ret) { + __zonefs_io_error(inode, false); + /* + * Leaving zones explicitly open may lead to a state + * where most zones cannot be written (zone resources + * exhausted). So take preventive action by remounting + * read-only. + */ + if (z->z_flags & ZONEFS_ZONE_OPEN && + !(sb->s_flags & SB_RDONLY)) { + zonefs_warn(sb, + "closing zone at %llu failed %d\n", + z->z_sector, ret); + zonefs_warn(sb, + "remounting filesystem read-only\n"); + sb->s_flags |= SB_RDONLY; + } + goto unlock; + } + + z->z_flags &= ~ZONEFS_ZONE_OPEN; + zonefs_inode_account_active(inode); + } + + atomic_dec(&sbi->s_wro_seq_files); + +unlock: + mutex_unlock(&zi->i_truncate_mutex); +} + +static int zonefs_file_release(struct inode *inode, struct file *file) +{ + /* + * If we explicitly open a zone we must close it again as well, but the + * zone management operation can fail (either due to an IO error or as + * the zone has gone offline or read-only). Make sure we don't fail the + * close(2) for user-space. + */ + if (zonefs_seq_file_need_wro(inode, file)) + zonefs_seq_file_write_close(inode); + + return 0; +} + +const struct file_operations zonefs_file_operations = { + .open = zonefs_file_open, + .release = zonefs_file_release, + .fsync = zonefs_file_fsync, + .mmap = zonefs_file_mmap, + .llseek = zonefs_file_llseek, + .read_iter = zonefs_file_read_iter, + .write_iter = zonefs_file_write_iter, + .splice_read = generic_file_splice_read, + .splice_write = iter_file_splice_write, + .iopoll = iocb_bio_iopoll, +}; |