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authorFilipe David Borba Manana <fdmanana@gmail.com>2014-02-15 15:53:16 +0000
committerChris Mason <clm@fb.com>2014-02-15 08:04:27 -0800
commit93de4ba86480a9e0d1062cb1d535fa97fb81af48 (patch)
tree239b6924acc0c5c7758af5495cf2d4d977cfbbf2
parentf085381e6d08f4c8d6882825f31accd455c54d70 (diff)
Btrfs: use right clone root offset for compressed extents
For non compressed extents, iterate_extent_inodes() gives us offsets that take into account the data offset from the file extent items, while for compressed extents it doesn't. Therefore we have to adjust them before placing them in a send clone instruction. Not doing this adjustment leads to the receiving end requesting for a wrong a file range to the clone ioctl, which results in different file content from the one in the original send root. Issue reproducible with the following excerpt from the test I made for xfstests: _scratch_mkfs _scratch_mount "-o compress-force=lzo" $XFS_IO_PROG -f -c "truncate 118811" $SCRATCH_MNT/foo $XFS_IO_PROG -c "pwrite -S 0x0d -b 39987 92267 39987" $SCRATCH_MNT/foo $BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap1 $XFS_IO_PROG -c "pwrite -S 0x3e -b 80000 200000 80000" $SCRATCH_MNT/foo $BTRFS_UTIL_PROG filesystem sync $SCRATCH_MNT $XFS_IO_PROG -c "pwrite -S 0xdc -b 10000 250000 10000" $SCRATCH_MNT/foo $XFS_IO_PROG -c "pwrite -S 0xff -b 10000 300000 10000" $SCRATCH_MNT/foo # will be used for incremental send to be able to issue clone operations $BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/clones_snap $BTRFS_UTIL_PROG subvolume snapshot -r $SCRATCH_MNT $SCRATCH_MNT/mysnap2 $FSSUM_PROG -A -f -w $tmp/1.fssum $SCRATCH_MNT/mysnap1 $FSSUM_PROG -A -f -w $tmp/2.fssum -x $SCRATCH_MNT/mysnap2/mysnap1 \ -x $SCRATCH_MNT/mysnap2/clones_snap $SCRATCH_MNT/mysnap2 $FSSUM_PROG -A -f -w $tmp/clones.fssum $SCRATCH_MNT/clones_snap \ -x $SCRATCH_MNT/clones_snap/mysnap1 -x $SCRATCH_MNT/clones_snap/mysnap2 $BTRFS_UTIL_PROG send $SCRATCH_MNT/mysnap1 -f $tmp/1.snap $BTRFS_UTIL_PROG send $SCRATCH_MNT/clones_snap -f $tmp/clones.snap $BTRFS_UTIL_PROG send -p $SCRATCH_MNT/mysnap1 \ -c $SCRATCH_MNT/clones_snap $SCRATCH_MNT/mysnap2 -f $tmp/2.snap _scratch_unmount _scratch_mkfs _scratch_mount $BTRFS_UTIL_PROG receive $SCRATCH_MNT -f $tmp/1.snap $FSSUM_PROG -r $tmp/1.fssum $SCRATCH_MNT/mysnap1 2>> $seqres.full $BTRFS_UTIL_PROG receive $SCRATCH_MNT -f $tmp/clones.snap $FSSUM_PROG -r $tmp/clones.fssum $SCRATCH_MNT/clones_snap 2>> $seqres.full $BTRFS_UTIL_PROG receive $SCRATCH_MNT -f $tmp/2.snap $FSSUM_PROG -r $tmp/2.fssum $SCRATCH_MNT/mysnap2 2>> $seqres.full Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
-rw-r--r--fs/btrfs/send.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 9c8d1a3fdc3a..9dde9717c1b9 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -1332,6 +1332,16 @@ verbose_printk(KERN_DEBUG "btrfs: find_extent_clone: data_offset=%llu, "
}
if (cur_clone_root) {
+ if (compressed != BTRFS_COMPRESS_NONE) {
+ /*
+ * Offsets given by iterate_extent_inodes() are relative
+ * to the start of the extent, we need to add logical
+ * offset from the file extent item.
+ * (See why at backref.c:check_extent_in_eb())
+ */
+ cur_clone_root->offset += btrfs_file_extent_offset(eb,
+ fi);
+ }
*found = cur_clone_root;
ret = 0;
} else {