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authorDarrick J. Wong <darrick.wong@oracle.com>2016-10-03 09:11:43 -0700
committerDarrick J. Wong <darrick.wong@oracle.com>2016-10-05 16:26:26 -0700
commitf7ca35227253dc8244fd908140b06010e67a31e5 (patch)
tree2e2731cafe2a8e8f6679d2a58eef031c1a84ffba /fs/xfs/xfs_bmap_util.c
parent98cc2db5b8b2c9f38aebf54a7b03657406b6de26 (diff)
downloadlinux-f7ca35227253dc8244fd908140b06010e67a31e5.tar.gz
xfs: create a separate cow extent size hint for the allocator
Create a per-inode extent size allocator hint for copy-on-write.  This
hint is separate from the existing extent size hint so that CoW can
take advantage of the fragmentation-reducing properties of extent size
hints without disabling delalloc for regular writes.

The extent size hint that's fed to the allocator during a copy on
write operation is the greater of the cowextsize and regular extsize
hint.

During reflink, if we're sharing the entire source file to the entire
destination file and the destination file doesn't already have a
cowextsize hint, propagate the source file's cowextsize hint to the
destination file.

Furthermore, zero the bulkstat buffer prior to setting the fields
so that we don't copy kernel memory contents into userspace.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/xfs/xfs_bmap_util.c')
-rw-r--r--fs/xfs/xfs_bmap_util.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index e2f46e645612..4a807f05e460 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -582,8 +582,13 @@ xfs_getbmap(
 		if (ip->i_cformat != XFS_DINODE_FMT_EXTENTS)
 			return -EINVAL;
 
-		prealloced = 0;
-		fixlen = XFS_ISIZE(ip);
+		if (xfs_get_cowextsz_hint(ip)) {
+			prealloced = 1;
+			fixlen = mp->m_super->s_maxbytes;
+		} else {
+			prealloced = 0;
+			fixlen = XFS_ISIZE(ip);
+		}
 		break;
 	default:
 		if (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS &&