From 113fa05c2fa1a9ee45a31909e6d78666e426adca Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 3 May 2023 17:24:36 +0200 Subject: [PATCH] btrfs: remove the io_pages field in struct extent_buffer No need to track the number of pages under I/O now that each extent_buffer is read and written using a single bio. For the read side we need to grab an extra reference for the duration of the I/O to prevent eviction, though. Reviewed-by: Johannes Thumshirn Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/extent_io.c | 17 +++++------------ fs/btrfs/extent_io.h | 1 - 2 files changed, 5 insertions(+), 13 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index eebcef557bd8..d8e6c8d5ed98 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1767,8 +1767,6 @@ static void extent_buffer_write_end_io(struct btrfs_bio *bbio) struct page *page = bvec->bv_page; u32 len = bvec->bv_len; - atomic_dec(&eb->io_pages); - if (!uptodate) { btrfs_page_clear_uptodate(fs_info, page, start, len); btrfs_page_set_error(fs_info, page, start, len); @@ -1791,7 +1789,6 @@ static void prepare_eb_write(struct extent_buffer *eb) unsigned long end; clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags); - atomic_set(&eb->io_pages, num_extent_pages(eb)); /* Set btree blocks beyond nritems with 0 to avoid stale content */ nritems = btrfs_header_nritems(eb); @@ -3235,8 +3232,7 @@ static void __free_extent_buffer(struct extent_buffer *eb) static int extent_buffer_under_io(const struct extent_buffer *eb) { - return (atomic_read(&eb->io_pages) || - test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) || + return (test_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags) || test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)); } @@ -3372,7 +3368,6 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start, spin_lock_init(&eb->refs_lock); atomic_set(&eb->refs, 1); - atomic_set(&eb->io_pages, 0); ASSERT(len <= BTRFS_MAX_METADATA_BLOCKSIZE); @@ -3489,9 +3484,9 @@ static void check_buffer_tree_ref(struct extent_buffer *eb) * adequately protected by the refcount, but the TREE_REF bit and * its corresponding reference are not. To protect against this * class of races, we call check_buffer_tree_ref from the codepaths - * which trigger io after they set eb->io_pages. Note that once io is - * initiated, TREE_REF can no longer be cleared, so that is the - * moment at which any such race is best fixed. + * which trigger io. Note that once io is initiated, TREE_REF can no + * longer be cleared, so that is the moment at which any such race is + * best fixed. */ refs = atomic_read(&eb->refs); if (refs >= 2 && test_bit(EXTENT_BUFFER_TREE_REF, &eb->bflags)) @@ -4062,7 +4057,6 @@ static void extent_buffer_read_end_io(struct btrfs_bio *bbio) struct bio_vec *bvec; u32 bio_offset = 0; - atomic_inc(&eb->refs); eb->read_mirror = bbio->mirror_num; if (uptodate && @@ -4077,7 +4071,6 @@ static void extent_buffer_read_end_io(struct btrfs_bio *bbio) } bio_for_each_segment_all(bvec, &bbio->bio, iter_all) { - atomic_dec(&eb->io_pages); end_page_read(bvec->bv_page, uptodate, eb->start + bio_offset, bvec->bv_len); bio_offset += bvec->bv_len; @@ -4100,8 +4093,8 @@ static void __read_extent_buffer_pages(struct extent_buffer *eb, int mirror_num, clear_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags); eb->read_mirror = 0; - atomic_set(&eb->io_pages, num_pages); check_buffer_tree_ref(eb); + atomic_inc(&eb->refs); bbio = btrfs_bio_alloc(INLINE_EXTENT_BUFFER_PAGES, REQ_OP_READ | REQ_META, eb->fs_info, diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index e11ee09ab26b..217c433bb999 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -79,7 +79,6 @@ struct extent_buffer { struct btrfs_fs_info *fs_info; spinlock_t refs_lock; atomic_t refs; - atomic_t io_pages; int read_mirror; struct rcu_head rcu_head; pid_t lock_owner; -- 2.11.0