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48b3b9d401
Move scratch super outside of the chunk lock to avoid below lockdep warning. The better place to scratch super is in the function btrfs_rm_dev_replace_free_srcdev() just before free_device, which is outside of the chunk lock as well. To reproduce: (fresh boot) mkfs.btrfs -f -draid5 -mraid5 /dev/sdc /dev/sdd /dev/sde mount /dev/sdc /btrfs dd if=/dev/zero of=/btrfs/tf1 bs=4096 count=100 (get devmgt from https://github.com/asj/devmgt.git) devmgt detach /dev/sde dd if=/dev/zero of=/btrfs/tf1 bs=4096 count=100 sync btrfs replace start -Brf 3 /dev/sdf /btrfs <-- devmgt attach host7 ====================================================== [ INFO: possible circular locking dependency detected ] 4.6.0-rc2asj+ #1 Not tainted --------------------------------------------------- btrfs/2174 is trying to acquire lock: (sb_writers){.+.+.+}, at: [<ffffffff812449b4>] __sb_start_write+0xb4/0xf0 but task is already holding lock: (&fs_info->chunk_mutex){+.+.+.}, at: [<ffffffffa05c5f55>] btrfs_dev_replace_finishing+0x145/0x980 [btrfs] which lock already depends on the new lock. Chain exists of: sb_writers --> &fs_devs->device_list_mutex --> &fs_info->chunk_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fs_info->chunk_mutex); lock(&fs_devs->device_list_mutex); lock(&fs_info->chunk_mutex); lock(sb_writers); *** DEADLOCK *** -> #0 (sb_writers){.+.+.+}: [<ffffffff810e6415>] __lock_acquire+0x1bc5/0x1ee0 [<ffffffff810e707e>] lock_acquire+0xbe/0x210 [<ffffffff810df49a>] percpu_down_read+0x4a/0xa0 [<ffffffff812449b4>] __sb_start_write+0xb4/0xf0 [<ffffffff81265534>] mnt_want_write+0x24/0x50 [<ffffffff812508a2>] path_openat+0x952/0x1190 [<ffffffff81252451>] do_filp_open+0x91/0x100 [<ffffffff8123f5cc>] file_open_name+0xfc/0x140 [<ffffffff8123f643>] filp_open+0x33/0x60 [<ffffffffa0572bb6>] update_dev_time+0x16/0x40 [btrfs] [<ffffffffa057f60d>] btrfs_scratch_superblocks+0x5d/0xb0 [btrfs] [<ffffffffa057f70e>] btrfs_rm_dev_replace_remove_srcdev+0xae/0xd0 [btrfs] [<ffffffffa05c62c5>] btrfs_dev_replace_finishing+0x4b5/0x980 [btrfs] [<ffffffffa05c6ae8>] btrfs_dev_replace_start+0x358/0x530 [btrfs] Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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| .. | ||
| tests | ||
| acl.c | ||
| async-thread.c | ||
| async-thread.h | ||
| backref.c | ||
| backref.h | ||
| btrfs_inode.h | ||
| check-integrity.c | ||
| check-integrity.h | ||
| compression.c | ||
| compression.h | ||
| ctree.c | ||
| ctree.h | ||
| delayed-inode.c | ||
| delayed-inode.h | ||
| delayed-ref.c | ||
| delayed-ref.h | ||
| dev-replace.c | ||
| dev-replace.h | ||
| dir-item.c | ||
| disk-io.c | ||
| disk-io.h | ||
| export.c | ||
| export.h | ||
| extent-tree.c | ||
| extent_io.c | ||
| extent_io.h | ||
| extent_map.c | ||
| extent_map.h | ||
| file-item.c | ||
| file.c | ||
| free-space-cache.c | ||
| free-space-cache.h | ||
| free-space-tree.c | ||
| free-space-tree.h | ||
| hash.c | ||
| hash.h | ||
| inode-item.c | ||
| inode-map.c | ||
| inode-map.h | ||
| inode.c | ||
| ioctl.c | ||
| Kconfig | ||
| locking.c | ||
| locking.h | ||
| lzo.c | ||
| Makefile | ||
| math.h | ||
| ordered-data.c | ||
| ordered-data.h | ||
| orphan.c | ||
| print-tree.c | ||
| print-tree.h | ||
| props.c | ||
| props.h | ||
| qgroup.c | ||
| qgroup.h | ||
| raid56.c | ||
| raid56.h | ||
| rcu-string.h | ||
| reada.c | ||
| relocation.c | ||
| root-tree.c | ||
| scrub.c | ||
| send.c | ||
| send.h | ||
| struct-funcs.c | ||
| super.c | ||
| sysfs.c | ||
| sysfs.h | ||
| transaction.c | ||
| transaction.h | ||
| tree-defrag.c | ||
| tree-log.c | ||
| tree-log.h | ||
| ulist.c | ||
| ulist.h | ||
| uuid-tree.c | ||
| volumes.c | ||
| volumes.h | ||
| xattr.c | ||
| xattr.h | ||
| zlib.c | ||