Btrfs: send, fix more issues related to directory renames
This is a continuation of the previous changes titled: Btrfs: fix incremental send's decision to delay a dir move/rename Btrfs: part 2, fix incremental send's decision to delay a dir move/rename There's a few more cases where a directory rename/move must be delayed which was previously overlooked. If our immediate ancestor has a lower inode number than ours and it doesn't have a delayed rename/move operation associated to it, it doesn't mean there isn't any non-direct ancestor of our current inode that needs to be renamed/moved before our current inode (i.e. with a higher inode number than ours). So we can't stop the search if our immediate ancestor has a lower inode number than ours, we need to navigate the directory hierarchy upwards until we hit the root or: 1) find an ancestor with an higher inode number that was renamed/moved in the send root too (or already has a pending rename/move registered); 2) find an ancestor that is a new directory (higher inode number than ours and exists only in the send root). Reproducer for case 1) $ mkfs.btrfs -f /dev/sdd $ mount /dev/sdd /mnt $ mkdir -p /mnt/a/b $ mkdir -p /mnt/a/c/d $ mkdir /mnt/a/b/e $ mkdir /mnt/a/c/d/f $ mv /mnt/a/b /mnt/a/c/d/2b $ mkdir /mnt/a/x $ mkdir /mnt/a/y $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ btrfs send /mnt/snap1 -f /tmp/base.send $ mv /mnt/a/x /mnt/a/y $ mv /mnt/a/c/d/2b/e /mnt/a/c/d/2b/2e $ mv /mnt/a/c/d /mnt/a/h/2d $ mv /mnt/a/c /mnt/a/h/2d/2b/2c $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send Simple reproducer for case 2) $ mkfs.btrfs -f /dev/sdd $ mount /dev/sdd /mnt $ mkdir -p /mnt/a/b $ mkdir /mnt/a/c $ mv /mnt/a/b /mnt/a/c/b2 $ mkdir /mnt/a/e $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ btrfs send /mnt/snap1 -f /tmp/base.send $ mv /mnt/a/c/b2 /mnt/a/e/b3 $ mkdir /mnt/a/e/b3/f $ mkdir /mnt/a/h $ mv /mnt/a/c /mnt/a/e/b3/f/c2 $ mv /mnt/a/e /mnt/a/h/e2 $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send Another simple reproducer for case 2) $ mkfs.btrfs -f /dev/sdd $ mount /dev/sdd /mnt $ mkdir -p /mnt/a/b $ mkdir /mnt/a/c $ mkdir /mnt/a/b/d $ mkdir /mnt/a/c/e $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ btrfs send /mnt/snap1 -f /tmp/base.send $ mkdir /mnt/a/b/d/f $ mkdir /mnt/a/b/g $ mv /mnt/a/c/e /mnt/a/b/g/e2 $ mv /mnt/a/c /mnt/a/b/d/f/c2 $ mv /mnt/a/b/d/f /mnt/a/b/g/e2/f2 $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send More complex reproducer for case 2) $ mkfs.btrfs -f /dev/sdd $ mount /dev/sdd /mnt $ mkdir -p /mnt/a/b $ mkdir -p /mnt/a/c/d $ mkdir /mnt/a/b/e $ mkdir /mnt/a/c/d/f $ mv /mnt/a/b /mnt/a/c/d/2b $ mkdir /mnt/a/x $ mkdir /mnt/a/y $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ btrfs send /mnt/snap1 -f /tmp/base.send $ mv /mnt/a/x /mnt/a/y $ mv /mnt/a/c/d/2b/e /mnt/a/c/d/2b/2e $ mv /mnt/a/c/d /mnt/a/h/2d $ mv /mnt/a/c /mnt/a/h/2d/2b/2c $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send For both cases the incremental send would enter an infinite loop when building path strings. While solving these cases, this change also re-implements the code to detect when directory moves/renames should be delayed. Instead of dealing with several specific cases separately, it's now more generic handling all cases with a simple detection algorithm and if when applying a delayed move/rename there's a path loop detected, it further delays the move/rename registering a new ancestor inode as the dependency inode (so our rename happens after that ancestor is renamed). Tests for these cases is being added to xfstests too. Signed-off-by:Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by:
Chris Mason <clm@fb.com>
parent
a10c4076
Please register or sign in to comment