3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Filipe Manana <fdmanana@xxxxxxxx>
[ Upstream commit d4dfc0f4d39475ccbbac947880b5464a74c30b99 ]
When doing an incremental send of a filesystem with the no-holes feature
enabled, we end up issuing a write operation when using the no data mode
send flag, instead of issuing an update extent operation. Fix this by
issuing the update extent operation instead.
Trivial reproducer:
$ mkfs.btrfs -f -O no-holes /dev/sdc
$ mkfs.btrfs -f /dev/sdd
$ mount /dev/sdc /mnt/sdc
$ mount /dev/sdd /mnt/sdd
$ xfs_io -f -c "pwrite -S 0xab 0 32K" /mnt/sdc/foobar
$ btrfs subvolume snapshot -r /mnt/sdc /mnt/sdc/snap1
$ xfs_io -c "fpunch 8K 8K" /mnt/sdc/foobar
$ btrfs subvolume snapshot -r /mnt/sdc /mnt/sdc/snap2
$ btrfs send /mnt/sdc/snap1 | btrfs receive /mnt/sdd
$ btrfs send --no-data -p /mnt/sdc/snap1 /mnt/sdc/snap2 \
| btrfs receive -vv /mnt/sdd
Before this change the output of the second receive command is:
receiving snapshot snap2 uuid=f6922049-8c22-e544-9ff9-fc6755918447...
utimes
write foobar, offset 8192, len 8192
utimes foobar
BTRFS_IOC_SET_RECEIVED_SUBVOL uuid=f6922049-8c22-e544-9ff9-...
After this change it is:
receiving snapshot snap2 uuid=564d36a3-ebc8-7343-aec9-bf6fda278e64...
utimes
update_extent foobar: offset=8192, len=8192
utimes foobar
BTRFS_IOC_SET_RECEIVED_SUBVOL uuid=564d36a3-ebc8-7343-aec9-bf6fda278e64...
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/send.c | 3 +++
1 file changed, 3 insertions(+)
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -4485,6 +4485,9 @@ static int send_hole(struct send_ctx *sc
u64 len;
int ret = 0;
+ if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
+ return send_update_extent(sctx, offset, end - offset);
+
p = fs_path_alloc();
if (!p)
return -ENOMEM;
