diff options
Diffstat (limited to 'fs/btrfs/subpage.c')
| -rw-r--r-- | fs/btrfs/subpage.c | 74 |
1 files changed, 58 insertions, 16 deletions
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c index 0e49dab8da..54736f6238 100644 --- a/fs/btrfs/subpage.c +++ b/fs/btrfs/subpage.c @@ -111,6 +111,9 @@ void btrfs_init_subpage_info(struct btrfs_subpage_info *subpage_info, u32 sector subpage_info->checked_offset = cur; cur += nr_bits; + subpage_info->locked_offset = cur; + cur += nr_bits; + subpage_info->total_nr_bits = cur; } @@ -237,28 +240,58 @@ static void btrfs_subpage_assert(const struct btrfs_fs_info *fs_info, start + len <= folio_pos(folio) + PAGE_SIZE); } +#define subpage_calc_start_bit(fs_info, folio, name, start, len) \ +({ \ + unsigned int start_bit; \ + \ + btrfs_subpage_assert(fs_info, folio, start, len); \ + start_bit = offset_in_page(start) >> fs_info->sectorsize_bits; \ + start_bit += fs_info->subpage_info->name##_offset; \ + start_bit; \ +}) + void btrfs_subpage_start_reader(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; + btrfs_subpage_assert(fs_info, folio, start, len); + spin_lock_irqsave(&subpage->lock, flags); + /* + * Even though it's just for reading the page, no one should have + * locked the subpage range. + */ + ASSERT(bitmap_test_range_all_zero(subpage->bitmaps, start_bit, nbits)); + bitmap_set(subpage->bitmaps, start_bit, nbits); atomic_add(nbits, &subpage->readers); + spin_unlock_irqrestore(&subpage->lock, flags); } void btrfs_subpage_end_reader(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; bool is_data; bool last; btrfs_subpage_assert(fs_info, folio, start, len); is_data = is_data_inode(folio->mapping->host); + + spin_lock_irqsave(&subpage->lock, flags); + + /* The range should have already been locked. */ + ASSERT(bitmap_test_range_all_set(subpage->bitmaps, start_bit, nbits)); ASSERT(atomic_read(&subpage->readers) >= nbits); + + bitmap_clear(subpage->bitmaps, start_bit, nbits); last = atomic_sub_and_test(nbits, &subpage->readers); /* @@ -270,6 +303,7 @@ void btrfs_subpage_end_reader(const struct btrfs_fs_info *fs_info, */ if (is_data && last) folio_unlock(folio); + spin_unlock_irqrestore(&subpage->lock, flags); } static void btrfs_subpage_clamp_range(struct folio *folio, u64 *start, u32 *len) @@ -290,28 +324,38 @@ static void btrfs_subpage_clamp_range(struct folio *folio, u64 *start, u32 *len) orig_start + orig_len) - *start; } -void btrfs_subpage_start_writer(const struct btrfs_fs_info *fs_info, - struct folio *folio, u64 start, u32 len) +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); } -bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_info, - struct folio *folio, u64 start, u32 len) +static bool btrfs_subpage_end_and_test_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; + bool last; btrfs_subpage_assert(fs_info, folio, start, len); + spin_lock_irqsave(&subpage->lock, flags); /* * We have call sites passing @lock_page into * extent_clear_unlock_delalloc() for compression path. @@ -319,11 +363,18 @@ bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_info, * This @locked_page is locked by plain lock_page(), thus its * subpage::writers is 0. Handle them in a special way. */ - if (atomic_read(&subpage->writers) == 0) + if (atomic_read(&subpage->writers) == 0) { + spin_unlock_irqrestore(&subpage->lock, flags); return true; + } ASSERT(atomic_read(&subpage->writers) >= nbits); - return atomic_sub_and_test(nbits, &subpage->writers); + /* The target range should have been locked. */ + ASSERT(bitmap_test_range_all_set(subpage->bitmaps, start_bit, nbits)); + bitmap_clear(subpage->bitmaps, start_bit, nbits); + last = atomic_sub_and_test(nbits, &subpage->writers); + spin_unlock_irqrestore(&subpage->lock, flags); + return last; } /* @@ -365,16 +416,6 @@ void btrfs_folio_end_writer_lock(const struct btrfs_fs_info *fs_info, folio_unlock(folio); } -#define subpage_calc_start_bit(fs_info, folio, name, start, len) \ -({ \ - unsigned int start_bit; \ - \ - btrfs_subpage_assert(fs_info, folio, start, len); \ - start_bit = offset_in_page(start) >> fs_info->sectorsize_bits; \ - start_bit += fs_info->subpage_info->name##_offset; \ - start_bit; \ -}) - #define subpage_test_bitmap_all_set(fs_info, subpage, name) \ bitmap_test_range_all_set(subpage->bitmaps, \ fs_info->subpage_info->name##_offset, \ @@ -751,6 +792,7 @@ void __cold btrfs_subpage_dump_bitmap(const struct btrfs_fs_info *fs_info, GET_SUBPAGE_BITMAP(subpage, subpage_info, writeback, &writeback_bitmap); GET_SUBPAGE_BITMAP(subpage, subpage_info, ordered, &ordered_bitmap); GET_SUBPAGE_BITMAP(subpage, subpage_info, checked, &checked_bitmap); + GET_SUBPAGE_BITMAP(subpage, subpage_info, locked, &checked_bitmap); spin_unlock_irqrestore(&subpage->lock, flags); dump_page(folio_page(folio, 0), "btrfs subpage dump"); |