diff options
| author | Jan Kara <jack@suse.cz> | 2017-05-18 16:36:22 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-07 12:06:01 +0200 |
| commit | b9a7816997a38e4c8643f86757cbc4023f285c51 (patch) | |
| tree | 0c31482ea6e152bb38f366d01e7d0fb5c8fa743f /fs | |
| parent | 03489bfc78304a0be057ec827a67c0d87dd97b2e (diff) | |
xfs: Fix missed holes in SEEK_HOLE implementation
commit 5375023ae1266553a7baa0845e82917d8803f48c upstream.
XFS SEEK_HOLE implementation could miss a hole in an unwritten extent as
can be seen by the following command:
xfs_io -c "falloc 0 256k" -c "pwrite 0 56k" -c "pwrite 128k 8k"
-c "seek -h 0" file
wrote 57344/57344 bytes at offset 0
56 KiB, 14 ops; 0.0000 sec (49.312 MiB/sec and 12623.9856 ops/sec)
wrote 8192/8192 bytes at offset 131072
8 KiB, 2 ops; 0.0000 sec (70.383 MiB/sec and 18018.0180 ops/sec)
Whence Result
HOLE 139264
Where we can see that hole at offset 56k was just ignored by SEEK_HOLE
implementation. The bug is in xfs_find_get_desired_pgoff() which does
not properly detect the case when pages are not contiguous.
Fix the problem by properly detecting when found page has larger offset
than expected.
Fixes: d126d43f631f996daeee5006714fed914be32368
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/xfs/xfs_file.c | 29 |
1 files changed, 9 insertions, 20 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index f5392ab2def1..999761a914c2 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1235,17 +1235,6 @@ xfs_find_get_desired_pgoff( break; } - /* - * At lease we found one page. If this is the first time we - * step into the loop, and if the first page index offset is - * greater than the given search offset, a hole was found. - */ - if (type == HOLE_OFF && lastoff == startoff && - lastoff < page_offset(pvec.pages[0])) { - found = true; - break; - } - for (i = 0; i < nr_pages; i++) { struct page *page = pvec.pages[i]; loff_t b_offset; @@ -1257,18 +1246,18 @@ xfs_find_get_desired_pgoff( * file mapping. However, page->index will not change * because we have a reference on the page. * - * Searching done if the page index is out of range. - * If the current offset is not reaches the end of - * the specified search range, there should be a hole - * between them. + * If current page offset is beyond where we've ended, + * we've found a hole. */ - if (page->index > end) { - if (type == HOLE_OFF && lastoff < endoff) { - *offset = lastoff; - found = true; - } + if (type == HOLE_OFF && lastoff < endoff && + lastoff < page_offset(pvec.pages[i])) { + found = true; + *offset = lastoff; goto out; } + /* Searching done if the page index is out of range. */ + if (page->index > end) + goto out; lock_page(page); /* |