Btrfs: fix an oops when deleting snapshots
We can reproduce this oops via the following steps: $ mkfs.btrfs /dev/sdb7 $ mount /dev/sdb7 /mnt/btrfs $ for ((i=0; i<3; i++)); do btrfs sub snap /mnt/btrfs /mnt/btrfs/s_$i; done $ rm -fr /mnt/btrfs/* $ rm -fr /mnt/btrfs/* then we'll get ------------[ cut here ]------------ kernel BUG at fs/btrfs/inode.c:2264! [...] Call Trace: [<ffffffffa05578c7>] btrfs_rmdir+0xf7/0x1b0 [btrfs] [<ffffffff81150b95>] vfs_rmdir+0xa5/0xf0 [<ffffffff81153cc3>] do_rmdir+0x123/0x140 [<ffffffff81145ac7>] ? fput+0x197/0x260 [<ffffffff810aecff>] ? audit_syscall_entry+0x1bf/0x1f0 [<ffffffff81153d0d>] sys_unlinkat+0x2d/0x40 [<ffffffff8147896b>] system_call_fastpath+0x16/0x1b RIP [<ffffffffa054f7b9>] btrfs_orphan_add+0x179/0x1a0 [btrfs] When it comes to btrfs_lookup_dentry, we may set a snapshot's inode->i_ino to BTRFS_EMPTY_SUBVOL_DIR_OBJECTID instead of BTRFS_FIRST_FREE_OBJECTID, while the snapshot's location.objectid remains unchanged. However, btrfs_ino() does not take this into account, and returns a wrong ino, and causes the oops. Signed-off-by:Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by:
Chris Mason <chris.mason@oracle.com>
parent
f1e490a7
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