diff options
| author | Zhang Yi <yi.zhang@huawei.com> | 2026-07-14 16:23:25 +0800 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-07-23 11:26:28 +0200 |
| commit | 09b53b0787ee80b71b1dcceb99d004a33e55b823 (patch) | |
| tree | e4233923b05def6cbf12a4277988a163032895ff /fs/iomap | |
| parent | 9c7d8f7c8994c790fca501dc45ce66e7356cbe05 (diff) | |
iomap: add comments for ifs_clear/set_range_dirty()
The range alignment strategy differs between ifs_clear_range_dirty() and
ifs_set_range_dirty(). The former rounds inwards to clear only
fully-covered blocks, while the latter rounds outwards to mark any
partially-touched block as dirty. Add comments to document this
asymmetry in block range calculation.
Suggested-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20260714082325.325163-6-yi.zhang@huaweicloud.com
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Diffstat (limited to 'fs/iomap')
| -rw-r--r-- | fs/iomap/buffered-io.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 3a3ac3051fb0..6d9a2efd4bee 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -174,6 +174,13 @@ static unsigned iomap_find_dirty_range(struct folio *folio, u64 *range_start, return range_end - *range_start; } +/* + * Clear the per-block dirty bits for the range [@off, @off + @len) within a + * folio. The range is rounded inwards so that only blocks fully covered by + * the range are cleared. This is required for operations like folio + * invalidation, where we must ensure a block is fully clean before discarding + * it. + */ static void ifs_clear_range_dirty(struct folio *folio, struct iomap_folio_state *ifs, size_t off, size_t len) { @@ -201,6 +208,13 @@ static void iomap_clear_range_dirty(struct folio *folio, size_t off, size_t len) ifs_clear_range_dirty(folio, ifs, off, len); } +/* + * Set the per-block dirty bits for the range [@off, @off + @len) within a + * folio. The range is rounded outwards so that any block partially touched + * by the range is marked dirty. This ensures blocks containing even a + * single dirty byte will be included in subsequent writeback, preventing + * data loss when partial blocks are written. + */ static void ifs_set_range_dirty(struct folio *folio, struct iomap_folio_state *ifs, size_t off, size_t len) { |