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[1/6] iomap: correct the range of a partial dirty clear

Message ID 20240731091305.2896873-2-yi.zhang@huaweicloud.com (mailing list archive)
State Superseded, archived
Headers show
Series iomap: some minor non-critical fixes and improvements when block size < folio size | expand

Commit Message

Zhang Yi July 31, 2024, 9:13 a.m. UTC 
From: Zhang Yi <yi.zhang@huawei.com>

The block range calculation in ifs_clear_range_dirty() is incorrect when
partial clear a range in a folio. We can't clear the dirty bit of the
first block or the last block if the start or end offset is blocksize
unaligned, this has not yet caused any issue since we always clear a
whole folio in iomap_writepage_map()->iomap_clear_range_dirty(). Fix
this by round up the first block and round down the last block and
correct the calculation of nr_blks.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
 fs/iomap/buffered-io.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index d46558990279..a896d15c191a 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -138,11 +138,14 @@  static void ifs_clear_range_dirty(struct folio *folio,
 {
 	struct inode *inode = folio->mapping->host;
 	unsigned int blks_per_folio = i_blocks_per_folio(inode, folio);
-	unsigned int first_blk = (off >> inode->i_blkbits);
-	unsigned int last_blk = (off + len - 1) >> inode->i_blkbits;
-	unsigned int nr_blks = last_blk - first_blk + 1;
+	unsigned int first_blk = DIV_ROUND_UP(off, i_blocksize(inode));
+	unsigned int last_blk = (off + len) >> inode->i_blkbits;
+	unsigned int nr_blks = last_blk - first_blk;
 	unsigned long flags;
 
+	if (!nr_blks)
+		return;
+
 	spin_lock_irqsave(&ifs->state_lock, flags);
 	bitmap_clear(ifs->state, first_blk + blks_per_folio, nr_blks);
 	spin_unlock_irqrestore(&ifs->state_lock, flags);