This is a note to let you know that I've just added the patch titled
xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xfs-honor-falloc_fl_keep_size-when-punching-ends-of-files.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3dd09d5a8589c640abb49cfcf92b4ed669eafad1 Mon Sep 17 00:00:00 2001
From: Calvin Owens <calvinowens@xxxxxx>
Date: Mon, 3 Apr 2017 12:22:29 -0700
Subject: xfs: Honor FALLOC_FL_KEEP_SIZE when punching ends of files
From: Calvin Owens <calvinowens@xxxxxx>
commit 3dd09d5a8589c640abb49cfcf92b4ed669eafad1 upstream.
When punching past EOF on XFS, fallocate(mode=PUNCH_HOLE|KEEP_SIZE) will
round the file size up to the nearest multiple of PAGE_SIZE:
calvinow@vm-disks/generic-xfs-1 ~$ dd if=/dev/urandom of=test bs=2048 count=1
calvinow@vm-disks/generic-xfs-1 ~$ stat test
Size: 2048 Blocks: 8 IO Block: 4096 regular file
calvinow@vm-disks/generic-xfs-1 ~$ fallocate -n -l 2048 -o 2048 -p test
calvinow@vm-disks/generic-xfs-1 ~$ stat test
Size: 4096 Blocks: 8 IO Block: 4096 regular file
Commit 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes") replaced
xfs_zero_remaining_bytes() with calls to iomap helpers. The new helpers
don't enforce that [pos,offset) lies strictly on [0,i_size) when being
called from xfs_free_file_space(), so by "leaking" these ranges into
xfs_zero_range() we get this buggy behavior.
Fix this by reintroducing the checks xfs_zero_remaining_bytes() did
against i_size at the bottom of xfs_free_file_space().
Reported-by: Aaron Gao <gzh@xxxxxx>
Fixes: 3c2bdc912a1cc050 ("xfs: kill xfs_zero_remaining_bytes")
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Brian Foster <bfoster@xxxxxxxxxx>
Signed-off-by: Calvin Owens <calvinowens@xxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/xfs/xfs_bmap_util.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1318,8 +1318,16 @@ xfs_free_file_space(
/*
* Now that we've unmap all full blocks we'll have to zero out any
* partial block at the beginning and/or end. xfs_zero_range is
- * smart enough to skip any holes, including those we just created.
+ * smart enough to skip any holes, including those we just created,
+ * but we must take care not to zero beyond EOF and enlarge i_size.
*/
+
+ if (offset >= XFS_ISIZE(ip))
+ return 0;
+
+ if (offset + len > XFS_ISIZE(ip))
+ len = XFS_ISIZE(ip) - offset;
+
return xfs_zero_range(ip, offset, len, NULL);
}
Patches currently in stable-queue which might be from calvinowens@xxxxxx are
queue-4.9/xfs-honor-falloc_fl_keep_size-when-punching-ends-of-files.patch