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authorLiu Bo <bo.li.liu@oracle.com>2015-08-14 18:33:07 +0800
committerDavid Sterba <dsterba@suse.com>2015-10-01 18:07:59 +0200
commit73416dab235e5ff030e3b3c61da0cd6ced324fc9 (patch)
treeeacb4410f3b1e79be065d826cc7894441fafc3c1 /fs/btrfs/dev-replace.c
parentf190aa471a7a703444f6587ed79c24a04a22d848 (diff)
Btrfs: move kobj stuff out of dev_replace lock range
To avoid deadlock described in commit 084b6e7c7607 ("btrfs: Fix a lockdep warning when running xfstest."), we should move kobj stuff out of dev_replace lock range. "It is because the btrfs_kobj_{add/rm}_device() will call memory allocation with GFP_KERNEL, which may flush fs page cache to free space, waiting for it self to do the commit, causing the deadlock. To solve the problem, move btrfs_kobj_{add/rm}_device() out of the dev_replace lock range, also involing split the btrfs_rm_dev_replace_srcdev() function into remove and free parts. Now only btrfs_rm_dev_replace_remove_srcdev() is called in dev_replace lock range, and kobj_{add/rm} and btrfs_rm_dev_replace_free_srcdev() are called out of the lock range." Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> [added lockup description] Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/dev-replace.c')
-rw-r--r--fs/btrfs/dev-replace.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 02031fc07f7f..0978e52ffa42 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -375,10 +375,6 @@ int btrfs_dev_replace_start(struct btrfs_root *root,
WARN_ON(!tgt_device);
dev_replace->tgtdev = tgt_device;
- ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device);
- if (ret)
- btrfs_err(root->fs_info, "kobj add dev failed %d\n", ret);
-
printk_in_rcu(KERN_INFO
"BTRFS: dev_replace from %s (devid %llu) to %s started\n",
src_device->missing ? "<missing disk>" :
@@ -401,6 +397,10 @@ int btrfs_dev_replace_start(struct btrfs_root *root,
args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
btrfs_dev_replace_unlock(dev_replace);
+ ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device);
+ if (ret)
+ btrfs_err(root->fs_info, "kobj add dev failed %d\n", ret);
+
btrfs_wait_ordered_roots(root->fs_info, -1);
/* force writing the updated state information to disk */