6.12-stable review patch. If anyone has any objections, please let me know.
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From: Qu Wenruo wqu@suse.com
[ Upstream commit 8511074c42b6255e03eceb09396338572572f1c7 ]
This function is not really suitable to lock a folio, as it lacks the proper mapping checks, thus the locked folio may not even belong to btrfs.
And due to the above reason, the last user inside lock_delalloc_folios() is already removed, and we can remove this function.
Signed-off-by: Qu Wenruo wqu@suse.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Stable-dep-of: 8bf334beb349 ("btrfs: fix double accounting race when extent_writepage_io() failed") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/subpage.c | 47 ---------------------------------------------- fs/btrfs/subpage.h | 2 -- 2 files changed, 49 deletions(-)
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c index c4950e04f481a..99341e98bbcc7 100644 --- a/fs/btrfs/subpage.c +++ b/fs/btrfs/subpage.c @@ -295,26 +295,6 @@ static void btrfs_subpage_clamp_range(struct folio *folio, u64 *start, u32 *len) orig_start + orig_len) - *start; }
-static void btrfs_subpage_start_writer(const struct btrfs_fs_info *fs_info, - struct folio *folio, u64 start, u32 len) -{ - struct btrfs_subpage *subpage = folio_get_private(folio); - const int start_bit = subpage_calc_start_bit(fs_info, folio, locked, start, len); - const int nbits = (len >> fs_info->sectorsize_bits); - unsigned long flags; - int ret; - - btrfs_subpage_assert(fs_info, folio, start, len); - - spin_lock_irqsave(&subpage->lock, flags); - ASSERT(atomic_read(&subpage->readers) == 0); - ASSERT(bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits)); - bitmap_set(subpage->bitmaps, start_bit, nbits); - ret = atomic_add_return(nbits, &subpage->writers); - ASSERT(ret == nbits); - spin_unlock_irqrestore(&subpage->lock, flags); -} - static bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_info, struct folio *folio, u64 start, u32 len) { @@ -351,33 +331,6 @@ static bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_inf return last; }
-/* - * Lock a folio for delalloc page writeback. - * - * Return -EAGAIN if the page is not properly initialized. - * Return 0 with the page locked, and writer counter updated. - * - * Even with 0 returned, the page still need extra check to make sure - * it's really the correct page, as the caller is using - * filemap_get_folios_contig(), which can race with page invalidating. - */ -int btrfs_folio_start_writer_lock(const struct btrfs_fs_info *fs_info, - struct folio *folio, u64 start, u32 len) -{ - if (unlikely(!fs_info) || !btrfs_is_subpage(fs_info, folio->mapping)) { - folio_lock(folio); - return 0; - } - folio_lock(folio); - if (!folio_test_private(folio) || !folio_get_private(folio)) { - folio_unlock(folio); - return -EAGAIN; - } - btrfs_subpage_clamp_range(folio, &start, &len); - btrfs_subpage_start_writer(fs_info, folio, start, len); - return 0; -} - /* * Handle different locked folios: * diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h index 197ec6c0b07b2..6289d6f65b87d 100644 --- a/fs/btrfs/subpage.h +++ b/fs/btrfs/subpage.h @@ -100,8 +100,6 @@ void btrfs_subpage_start_reader(const struct btrfs_fs_info *fs_info, void btrfs_subpage_end_reader(const struct btrfs_fs_info *fs_info, struct folio *folio, u64 start, u32 len);
-int btrfs_folio_start_writer_lock(const struct btrfs_fs_info *fs_info, - struct folio *folio, u64 start, u32 len); void btrfs_folio_end_writer_lock(const struct btrfs_fs_info *fs_info, struct folio *folio, u64 start, u32 len); void btrfs_folio_set_writer_lock(const struct btrfs_fs_info *fs_info,