ACK: [T][SRU][PATCH 1/1] Btrfs: send, don't send rmdir for same target multiple times

[Stefan Bader]

On 03.01.19 12:07, Po-Hsu Lin wrote:
> From: Filipe Manana <fdmanana at gmail.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1809868
> 
> When doing an incremental send, if we delete a directory that has N > 1
> hardlinks for the same file and that file has the highest inode number
> inside the directory contents, an incremental send would send N times an
> rmdir operation against the directory. This made the btrfs receive command
> fail on the second rmdir instruction, as the target directory didn't exist
> anymore.
> 
> Steps to reproduce the issue:
> 
>     $ mkfs.btrfs -f /dev/sdb3
>     $ mount /dev/sdb3 /mnt/btrfs
>     $ mkdir -p /mnt/btrfs/a/b/c
>     $ echo 'ola mundo' > /mnt/btrfs/a/b/c/foo.txt
>     $ ln /mnt/btrfs/a/b/c/foo.txt /mnt/btrfs/a/b/c/bar.txt
>     $ btrfs subvolume snapshot -r /mnt/btrfs /mnt/btrfs/snap1
>     $ btrfs send /mnt/btrfs/snap1 -f /tmp/base.send
>     $ rm -f /mnt/btrfs/a/b/c/foo.txt
>     $ rm -f /mnt/btrfs/a/b/c/bar.txt
>     $ rmdir /mnt/btrfs/a/b/c
>     $ btrfs subvolume snapshot -r /mnt/btrfs /mnt/btrfs/snap2
>     $ btrfs send -p /mnt/btrfs/snap1 /mnt/btrfs/snap2 -f /tmp/incremental.send
> 
>     $ umount /mnt/btrfs
>     $ mkfs.btrfs -f /dev/sdb3
>     $ mount /dev/sdb3 /mnt/btrfs
>     $ btrfs receive /mnt/btrfs -f /tmp/base.send
>     $ btrfs receive /mnt/btrfs -f /tmp/incremental.send
> 
> The second btrfs receive command failed with:
> 
>     ERROR: rmdir o259-6-0 failed. No such file or directory
> 
> A test case for xfstests follows.
> 
> Signed-off-by: Filipe David Borba Manana <fdmanana at gmail.com>
> Signed-off-by: Josef Bacik <jbacik at fb.com>
> (backported from commit 29d6d30f5c8aa58b04f40a58442df3bcaae5a1d5)
> Signed-off-by: Po-Hsu Lin <po-hsu.lin at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>
> ---
>  fs/btrfs/send.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> index d553752..9cc2ef0 100644
> --- a/fs/btrfs/send.c
> +++ b/fs/btrfs/send.c
> @@ -2686,6 +2686,7 @@ static int process_recorded_refs(struct send_ctx *sctx)
>  	u64 ow_gen;
>  	int did_overwrite = 0;
>  	int is_orphan = 0;
> +	u64 last_dir_ino_rm = 0;
>  
>  verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
>  
> @@ -2941,7 +2942,8 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
>  			ret = send_utimes(sctx, cur->dir, cur->dir_gen);
>  			if (ret < 0)
>  				goto out;
> -		} else if (ret == inode_state_did_delete) {
> +		} else if (ret == inode_state_did_delete &&
> +			   cur->dir != last_dir_ino_rm) {
>  			ret = can_rmdir(sctx, cur->dir, sctx->cur_ino);
>  			if (ret < 0)
>  				goto out;
> @@ -2953,6 +2955,7 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino);
>  				ret = send_rmdir(sctx, valid_path);
>  				if (ret < 0)
>  					goto out;
> +				last_dir_ino_rm = cur->dir;
>  			}
>  		}
>  	}
> 


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