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Filipe Manana authored
For an incremental send, fix the process of determining whether the directory inode we're currently processing needs to have its move/rename operation delayed. We were ignoring the fact that if the inode's new immediate ancestor has a higher inode number than ours but wasn't renamed/moved, we might still need to delay our move/rename, because some other ancestor directory higher in the hierarchy might have an inode number higher than ours *and* was renamed/moved too - in this case we have to wait for rename/move of that ancestor to happen before our current directory's rename/move operation. Simple steps to reproduce this issue: $ mkfs.btrfs -f /dev/sdd $ mount /dev/sdd /mnt $ mkdir -p /mnt/a/x1/x2 $ mkdir /mnt/a/Z $ mkdir -p /mnt/a/x1/x2/x3/x4/x5 $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ btrfs send /mnt/snap1 -f /tmp/base.send $ mv /mnt/a/x1/x2/x3 /mnt/a/Z/X33 $ mv /mnt/a/x1/x2 /mnt/a/Z/X33/x4/x5/X22 $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send The incremental send caused the kernel code to enter an infinite loop when building the path string for directory Z after its references are processed. A more complex scenario: $ mkfs.btrfs -f /dev/sdd $ mount /dev/sdd /mnt $ mkdir -p /mnt/a/b/c/d $ mkdir /mnt/a/b/c/d/e $ mkdir /mnt/a/b/c/d/f $ mv /mnt/a/b/c/d/e /mnt/a/b/c/d/f/E2 $ mkdir /mmt/a/b/c/g $ mv /mnt/a/b/c/d /mnt/a/b/D2 $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ btrfs send /mnt/snap1 -f /tmp/base.send $ mkdir /mnt/a/o $ mv /mnt/a/b/c/g /mnt/a/b/D2/f/G2 $ mv /mnt/a/b/D2 /mnt/a/b/dd $ mv /mnt/a/b/c /mnt/a/C2 $ mv /mnt/a/b/dd/f /mnt/a/o/FF $ mv /mnt/a/b /mnt/a/o/FF/E2/BB $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send A test case for xfstests follows. Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by: Chris Mason <clm@fb.com>
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