This is a note to let you know that I've just added the patch titled
btrfs: remove unused btrfs_folio_start_writer_lock()
to the 6.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-remove-unused-btrfs_folio_start_writer_lock.patch
and it can be found in the queue-6.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1baf5db2f160c880cee80b46c9b89addf514b65a
Author: Qu Wenruo <wqu@xxxxxxxx>
Date: Wed Oct 9 09:37:04 2024 +1030
btrfs: remove unused btrfs_folio_start_writer_lock()
[ 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@xxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Stable-dep-of: 8bf334beb349 ("btrfs: fix double accounting race when extent_writepage_io() failed")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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,
