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| author | Jeff Mahoney <jeffm@suse.com> | 2016-08-15 12:10:33 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-07 08:34:53 +0200 |
| commit | 64563a38fde57a26f4d68d488d0d4918f843547c (patch) | |
| tree | 57dccff8ae2829459c70bb3c4bf59f86455ad4bd | |
| parent | 69b69167965e108a775ef20decabcc76fbe4fc08 (diff) | |
| download | lwn-64563a38fde57a26f4d68d488d0d4918f843547c.tar.gz lwn-64563a38fde57a26f4d68d488d0d4918f843547c.zip | |
btrfs: properly track when rescan worker is running
commit d2c609b834d62f1e91f1635a27dca29f7806d3d6 upstream.
The qgroup_flags field is overloaded such that it reflects the on-disk
status of qgroups and the runtime state. The BTRFS_QGROUP_STATUS_FLAG_RESCAN
flag is used to indicate that a rescan operation is in progress, but if
the file system is unmounted while a rescan is running, the rescan
operation is paused. If the file system is then mounted read-only,
the flag will still be present but the rescan operation will not have
been resumed. When we go to umount, btrfs_qgroup_wait_for_completion
will see the flag and interpret it to mean that the rescan worker is
still running and will wait for a completion that will never come.
This patch uses a separate flag to indicate when the worker is
running. The locking and state surrounding the qgroup rescan worker
needs a lot of attention beyond this patch but this is enough to
avoid a hung umount.
Signed-off-by; Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chris Mason <clm@fb.com>
| -rw-r--r-- | fs/btrfs/ctree.h | 1 | ||||
| -rw-r--r-- | fs/btrfs/disk-io.c | 1 | ||||
| -rw-r--r-- | fs/btrfs/qgroup.c | 9 |
3 files changed, 10 insertions, 1 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 4274a7bfdaed..72f50480eee7 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1040,6 +1040,7 @@ struct btrfs_fs_info { struct btrfs_workqueue *qgroup_rescan_workers; struct completion qgroup_rescan_completion; struct btrfs_work qgroup_rescan_work; + bool qgroup_rescan_running; /* protected by qgroup_rescan_lock */ /* filesystem state */ unsigned long fs_state; diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index a2c18b43717e..7cfa2bd75b0d 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2306,6 +2306,7 @@ static void btrfs_init_qgroup(struct btrfs_fs_info *fs_info) fs_info->quota_enabled = 0; fs_info->pending_quota_state = 0; fs_info->qgroup_ulist = NULL; + fs_info->qgroup_rescan_running = false; mutex_init(&fs_info->qgroup_rescan_lock); } diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 1a8a239a636a..4904ebee449b 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -2302,6 +2302,10 @@ static void btrfs_qgroup_rescan_worker(struct btrfs_work *work) int err = -ENOMEM; int ret = 0; + mutex_lock(&fs_info->qgroup_rescan_lock); + fs_info->qgroup_rescan_running = true; + mutex_unlock(&fs_info->qgroup_rescan_lock); + path = btrfs_alloc_path(); if (!path) goto out; @@ -2368,6 +2372,9 @@ out: } done: + mutex_lock(&fs_info->qgroup_rescan_lock); + fs_info->qgroup_rescan_running = false; + mutex_unlock(&fs_info->qgroup_rescan_lock); complete_all(&fs_info->qgroup_rescan_completion); } @@ -2494,7 +2501,7 @@ int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info, mutex_lock(&fs_info->qgroup_rescan_lock); spin_lock(&fs_info->qgroup_lock); - running = fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN; + running = fs_info->qgroup_rescan_running; spin_unlock(&fs_info->qgroup_lock); mutex_unlock(&fs_info->qgroup_rescan_lock); |