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btrfs: remove unused btrfs_folio_start_writer_lock()

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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>
This commit is contained in:
Qu Wenruo 2024-10-09 09:37:04 +10:30 committed by David Sterba
parent 70958a949d
commit 8511074c42
2 changed files with 0 additions and 49 deletions
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47
fs/btrfs/subpage.c
View File

@ -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:
*

2
fs/btrfs/subpage.h
View File

@ -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,