From afe990fb59c152adef5a80c9168e990e2610b1f7 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Thu, 20 Mar 2025 13:07:31 +1030 Subject: [PATCH] btrfs: cleanup the reserved space inside loop of btrfs_buffered_write() Inside the main loop of btrfs_buffered_write(), if something wrong happened, there is a out-of-loop cleanup path to release the reserved space. This behavior saves some code lines, but makes it much harder to read, as we need to check release_bytes to make sure when we need to do the cleanup. Factor out the cleanup part into a helper, release_reserved_space(), to do the cleanup inside the main loop, so that we can move @release_bytes inside the loop. This will make later refactoring of the main loop much easier. Reviewed-by: Johannes Thumshirn Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- fs/btrfs/file.c | 45 ++++++++++++++++++++++++++++----------------- 1 file changed, 28 insertions(+), 17 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 53270c93b17a..0b0ae95962b6 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1076,6 +1076,24 @@ int btrfs_write_check(struct kiocb *iocb, size_t count) return 0; } +static void release_space(struct btrfs_inode *inode, struct extent_changeset *data_reserved, + u64 start, u64 len, bool only_release_metadata) +{ + if (len == 0) + return; + + if (only_release_metadata) { + btrfs_check_nocow_unlock(inode); + btrfs_delalloc_release_metadata(inode, len, true); + } else { + const struct btrfs_fs_info *fs_info = inode->root->fs_info; + + btrfs_delalloc_release_space(inode, data_reserved, + round_down(start, fs_info->sectorsize), + len, true); + } +} + ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i) { struct file *file = iocb->ki_filp; @@ -1083,7 +1101,6 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i) struct inode *inode = file_inode(file); struct btrfs_fs_info *fs_info = inode_to_fs_info(inode); struct extent_changeset *data_reserved = NULL; - u64 release_bytes = 0; u64 lockstart; u64 lockend; size_t num_written = 0; @@ -1092,7 +1109,6 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i) unsigned int ilock_flags = 0; const bool nowait = (iocb->ki_flags & IOCB_NOWAIT); unsigned int bdp_flags = (nowait ? BDP_ASYNC : 0); - bool only_release_metadata = false; if (nowait) ilock_flags |= BTRFS_ILOCK_TRY; @@ -1127,7 +1143,9 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i) size_t dirty_sectors; size_t num_sectors; struct folio *folio = NULL; + u64 release_bytes; int extents_locked; + bool only_release_metadata = false; /* * Fault pages before locking them in prepare_one_folio() @@ -1138,7 +1156,6 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i) break; } - only_release_metadata = false; sector_offset = pos & (fs_info->sectorsize - 1); extent_changeset_release(data_reserved); @@ -1193,6 +1210,8 @@ again: ret = balance_dirty_pages_ratelimited_flags(inode->i_mapping, bdp_flags); if (ret) { btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes); + release_space(BTRFS_I(inode), data_reserved, + pos, release_bytes, only_release_metadata); break; } @@ -1200,6 +1219,8 @@ again: if (ret) { btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes); + release_space(BTRFS_I(inode), data_reserved, + pos, release_bytes, only_release_metadata); break; } @@ -1212,6 +1233,8 @@ again: btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes); + release_space(BTRFS_I(inode), data_reserved, + pos, release_bytes, only_release_metadata); ret = extents_locked; break; } @@ -1279,10 +1302,11 @@ again: btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes); if (ret) { btrfs_drop_folio(fs_info, folio, pos, copied); + release_space(BTRFS_I(inode), data_reserved, + pos, release_bytes, only_release_metadata); break; } - release_bytes = 0; if (only_release_metadata) btrfs_check_nocow_unlock(BTRFS_I(inode)); @@ -1294,19 +1318,6 @@ again: num_written += copied; } - if (release_bytes) { - if (only_release_metadata) { - btrfs_check_nocow_unlock(BTRFS_I(inode)); - btrfs_delalloc_release_metadata(BTRFS_I(inode), - release_bytes, true); - } else { - btrfs_delalloc_release_space(BTRFS_I(inode), - data_reserved, - round_down(pos, fs_info->sectorsize), - release_bytes, true); - } - } - extent_changeset_free(data_reserved); if (num_written > 0) { pagecache_isize_extended(inode, old_isize, iocb->ki_pos); -- 2.50.1