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authorMatthew Wilcox (Oracle) <willy@infradead.org>2020-09-10 18:26:18 +0300
committerDarrick J. Wong <darrick.wong@oracle.com>2020-09-10 18:26:18 +0300
commit14284fedf59f1647264f4603d64418cf1fcd3eb0 (patch)
tree6357691afc92cfdfc3843137ebcff6f03a5f6f11 /fs/iomap
parente6e7ca92623a43156100306861272e04d46385fc (diff)
downloadlinux-14284fedf59f1647264f4603d64418cf1fcd3eb0.tar.xz
iomap: Mark read blocks uptodate in write_begin
When bringing (portions of) a page uptodate, we were marking blocks that were zeroed as being uptodate, but not blocks that were read from storage. Like the previous commit, this problem was found with generic/127 and a kernel which failed readahead I/Os. This bug causes writes to be silently lost when working with flaky storage. Fixes: 9dc55f1389f9 ("iomap: add support for sub-pagesize buffered I/O without buffer heads") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/iomap')
-rw-r--r--fs/iomap/buffered-io.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index c95454784df4..897ab9a26a74 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -574,7 +574,6 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
loff_t block_start = pos & ~(block_size - 1);
loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1);
unsigned from = offset_in_page(pos), to = from + len, poff, plen;
- int status;
if (PageUptodate(page))
return 0;
@@ -595,14 +594,13 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE))
return -EIO;
zero_user_segments(page, poff, from, to, poff + plen);
- iomap_set_range_uptodate(page, poff, plen);
- continue;
+ } else {
+ int status = iomap_read_page_sync(block_start, page,
+ poff, plen, srcmap);
+ if (status)
+ return status;
}
-
- status = iomap_read_page_sync(block_start, page, poff, plen,
- srcmap);
- if (status)
- return status;
+ iomap_set_range_uptodate(page, poff, plen);
} while ((block_start += plen) < block_end);
return 0;