* [PATCH] btrfs: switch uuid tree semaphore to mutex
@ 2017-11-06 18:24 David Sterba
2017-11-06 18:49 ` Nikolay Borisov
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: David Sterba @ 2017-11-06 18:24 UTC (permalink / raw)
To: linux-btrfs; +Cc: David Sterba
The uuid_tree_rescan_sem is used as a mutex (initialized with value 1
and with at most one active user), no reason to obscure that as a
semaphore.
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/ctree.h | 6 +++++-
fs/btrfs/disk-io.c | 6 +++---
fs/btrfs/super.c | 4 ++--
fs/btrfs/volumes.c | 12 ++++++------
4 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index cab2f3607040..a643ff0fa0f0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1073,7 +1073,11 @@ struct btrfs_fs_info {
struct percpu_counter bio_counter;
wait_queue_head_t replace_wait;
- struct semaphore uuid_tree_rescan_sem;
+ /*
+ * Protect updating of uuid_tree, can be used to wait for the task
+ * completion
+ */
+ struct mutex uuid_tree_mutex;
/* Used to reclaim the metadata space in the background. */
struct work_struct async_reclaim_work;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 53c9145a56e9..8330226234f2 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2542,10 +2542,10 @@ int open_ctree(struct super_block *sb,
mutex_init(&fs_info->cleaner_mutex);
mutex_init(&fs_info->volume_mutex);
mutex_init(&fs_info->ro_block_group_mutex);
+ mutex_init(&fs_info->uuid_tree_mutex);
init_rwsem(&fs_info->commit_root_sem);
init_rwsem(&fs_info->cleanup_work_sem);
init_rwsem(&fs_info->subvol_sem);
- sema_init(&fs_info->uuid_tree_rescan_sem, 1);
btrfs_init_dev_replace_locks(fs_info);
btrfs_init_qgroup(fs_info);
@@ -3696,9 +3696,9 @@ void close_ctree(struct btrfs_fs_info *fs_info)
btrfs_qgroup_wait_for_completion(fs_info, false);
/* wait for the uuid_scan task to finish */
- down(&fs_info->uuid_tree_rescan_sem);
+ mutex_lock(&fs_info->uuid_tree_mutex);
/* avoid complains from lockdep et al., set sem back to initial state */
- up(&fs_info->uuid_tree_rescan_sem);
+ mutex_unlock(&fs_info->uuid_tree_mutex);
/* pause restriper - we want to resume on mount */
btrfs_pause_balance(fs_info);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 713f899bae81..5d0686c18bad 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1777,9 +1777,9 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
cancel_work_sync(&fs_info->async_reclaim_work);
/* wait for the uuid_scan task to finish */
- down(&fs_info->uuid_tree_rescan_sem);
+ mutex_lock(&fs_info->uuid_tree_mutex);
/* avoid complains from lockdep et al. */
- up(&fs_info->uuid_tree_rescan_sem);
+ mutex_unlock(&fs_info->uuid_tree_mutex);
sb->s_flags |= MS_RDONLY;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 1b43f762906f..b2949232ba52 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4202,7 +4202,7 @@ static int btrfs_uuid_scan_kthread(void *data)
btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
else
set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags);
- up(&fs_info->uuid_tree_rescan_sem);
+ mutex_unlock(&fs_info->uuid_tree_mutex);
return 0;
}
@@ -4264,7 +4264,7 @@ static int btrfs_uuid_rescan_kthread(void *data)
ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
if (ret < 0) {
btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
- up(&fs_info->uuid_tree_rescan_sem);
+ mutex_unlock(&fs_info->uuid_tree_mutex);
return ret;
}
return btrfs_uuid_scan_kthread(data);
@@ -4301,12 +4301,12 @@ int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
if (ret)
return ret;
- down(&fs_info->uuid_tree_rescan_sem);
+ mutex_lock(&fs_info->uuid_tree_mutex);
task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
if (IS_ERR(task)) {
/* fs_info->update_uuid_tree_gen remains 0 in all error case */
btrfs_warn(fs_info, "failed to start uuid_scan task");
- up(&fs_info->uuid_tree_rescan_sem);
+ mutex_unlock(&fs_info->uuid_tree_mutex);
return PTR_ERR(task);
}
@@ -4317,12 +4317,12 @@ int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
{
struct task_struct *task;
- down(&fs_info->uuid_tree_rescan_sem);
+ mutex_lock(&fs_info->uuid_tree_mutex);
task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
if (IS_ERR(task)) {
/* fs_info->update_uuid_tree_gen remains 0 in all error case */
btrfs_warn(fs_info, "failed to start uuid_rescan task");
- up(&fs_info->uuid_tree_rescan_sem);
+ mutex_unlock(&fs_info->uuid_tree_mutex);
return PTR_ERR(task);
}
--
2.14.3
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] btrfs: switch uuid tree semaphore to mutex
2017-11-06 18:24 [PATCH] btrfs: switch uuid tree semaphore to mutex David Sterba
@ 2017-11-06 18:49 ` Nikolay Borisov
2017-11-07 13:58 ` Filipe Manana
2017-11-22 19:20 ` David Sterba
2 siblings, 0 replies; 5+ messages in thread
From: Nikolay Borisov @ 2017-11-06 18:49 UTC (permalink / raw)
To: David Sterba, linux-btrfs
On 6.11.2017 20:24, David Sterba wrote:
> The uuid_tree_rescan_sem is used as a mutex (initialized with value 1
> and with at most one active user), no reason to obscure that as a
> semaphore.
>
> Signed-off-by: David Sterba <dsterba@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
> ---
> fs/btrfs/ctree.h | 6 +++++-
> fs/btrfs/disk-io.c | 6 +++---
> fs/btrfs/super.c | 4 ++--
> fs/btrfs/volumes.c | 12 ++++++------
> 4 files changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index cab2f3607040..a643ff0fa0f0 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -1073,7 +1073,11 @@ struct btrfs_fs_info {
> struct percpu_counter bio_counter;
> wait_queue_head_t replace_wait;
>
> - struct semaphore uuid_tree_rescan_sem;
> + /*
> + * Protect updating of uuid_tree, can be used to wait for the task
> + * completion
> + */
> + struct mutex uuid_tree_mutex;
>
> /* Used to reclaim the metadata space in the background. */
> struct work_struct async_reclaim_work;
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 53c9145a56e9..8330226234f2 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -2542,10 +2542,10 @@ int open_ctree(struct super_block *sb,
> mutex_init(&fs_info->cleaner_mutex);
> mutex_init(&fs_info->volume_mutex);
> mutex_init(&fs_info->ro_block_group_mutex);
> + mutex_init(&fs_info->uuid_tree_mutex);
> init_rwsem(&fs_info->commit_root_sem);
> init_rwsem(&fs_info->cleanup_work_sem);
> init_rwsem(&fs_info->subvol_sem);
> - sema_init(&fs_info->uuid_tree_rescan_sem, 1);
>
> btrfs_init_dev_replace_locks(fs_info);
> btrfs_init_qgroup(fs_info);
> @@ -3696,9 +3696,9 @@ void close_ctree(struct btrfs_fs_info *fs_info)
> btrfs_qgroup_wait_for_completion(fs_info, false);
>
> /* wait for the uuid_scan task to finish */
> - down(&fs_info->uuid_tree_rescan_sem);
> + mutex_lock(&fs_info->uuid_tree_mutex);
> /* avoid complains from lockdep et al., set sem back to initial state */
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
>
> /* pause restriper - we want to resume on mount */
> btrfs_pause_balance(fs_info);
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index 713f899bae81..5d0686c18bad 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -1777,9 +1777,9 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
> cancel_work_sync(&fs_info->async_reclaim_work);
>
> /* wait for the uuid_scan task to finish */
> - down(&fs_info->uuid_tree_rescan_sem);
> + mutex_lock(&fs_info->uuid_tree_mutex);
> /* avoid complains from lockdep et al. */
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
>
> sb->s_flags |= MS_RDONLY;
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 1b43f762906f..b2949232ba52 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -4202,7 +4202,7 @@ static int btrfs_uuid_scan_kthread(void *data)
> btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
> else
> set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags);
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
> return 0;
> }
>
> @@ -4264,7 +4264,7 @@ static int btrfs_uuid_rescan_kthread(void *data)
> ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
> if (ret < 0) {
> btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
> return ret;
> }
> return btrfs_uuid_scan_kthread(data);
> @@ -4301,12 +4301,12 @@ int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
> if (ret)
> return ret;
>
> - down(&fs_info->uuid_tree_rescan_sem);
> + mutex_lock(&fs_info->uuid_tree_mutex);
> task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
> if (IS_ERR(task)) {
> /* fs_info->update_uuid_tree_gen remains 0 in all error case */
> btrfs_warn(fs_info, "failed to start uuid_scan task");
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
> return PTR_ERR(task);
> }
>
> @@ -4317,12 +4317,12 @@ int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
> {
> struct task_struct *task;
>
> - down(&fs_info->uuid_tree_rescan_sem);
> + mutex_lock(&fs_info->uuid_tree_mutex);
> task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
> if (IS_ERR(task)) {
> /* fs_info->update_uuid_tree_gen remains 0 in all error case */
> btrfs_warn(fs_info, "failed to start uuid_rescan task");
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
> return PTR_ERR(task);
> }
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] btrfs: switch uuid tree semaphore to mutex
2017-11-06 18:24 [PATCH] btrfs: switch uuid tree semaphore to mutex David Sterba
2017-11-06 18:49 ` Nikolay Borisov
@ 2017-11-07 13:58 ` Filipe Manana
2017-11-07 14:20 ` David Sterba
2017-11-22 19:20 ` David Sterba
2 siblings, 1 reply; 5+ messages in thread
From: Filipe Manana @ 2017-11-07 13:58 UTC (permalink / raw)
To: David Sterba; +Cc: linux-btrfs
On Mon, Nov 6, 2017 at 6:24 PM, David Sterba <dsterba@suse.com> wrote:
> The uuid_tree_rescan_sem is used as a mutex (initialized with value 1
> and with at most one active user), no reason to obscure that as a
> semaphore.
>
> Signed-off-by: David Sterba <dsterba@suse.com>
> ---
> fs/btrfs/ctree.h | 6 +++++-
> fs/btrfs/disk-io.c | 6 +++---
> fs/btrfs/super.c | 4 ++--
> fs/btrfs/volumes.c | 12 ++++++------
> 4 files changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index cab2f3607040..a643ff0fa0f0 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -1073,7 +1073,11 @@ struct btrfs_fs_info {
> struct percpu_counter bio_counter;
> wait_queue_head_t replace_wait;
>
> - struct semaphore uuid_tree_rescan_sem;
> + /*
> + * Protect updating of uuid_tree, can be used to wait for the task
> + * completion
> + */
> + struct mutex uuid_tree_mutex;
>
> /* Used to reclaim the metadata space in the background. */
> struct work_struct async_reclaim_work;
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 53c9145a56e9..8330226234f2 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -2542,10 +2542,10 @@ int open_ctree(struct super_block *sb,
> mutex_init(&fs_info->cleaner_mutex);
> mutex_init(&fs_info->volume_mutex);
> mutex_init(&fs_info->ro_block_group_mutex);
> + mutex_init(&fs_info->uuid_tree_mutex);
> init_rwsem(&fs_info->commit_root_sem);
> init_rwsem(&fs_info->cleanup_work_sem);
> init_rwsem(&fs_info->subvol_sem);
> - sema_init(&fs_info->uuid_tree_rescan_sem, 1);
>
> btrfs_init_dev_replace_locks(fs_info);
> btrfs_init_qgroup(fs_info);
> @@ -3696,9 +3696,9 @@ void close_ctree(struct btrfs_fs_info *fs_info)
> btrfs_qgroup_wait_for_completion(fs_info, false);
>
> /* wait for the uuid_scan task to finish */
> - down(&fs_info->uuid_tree_rescan_sem);
> + mutex_lock(&fs_info->uuid_tree_mutex);
> /* avoid complains from lockdep et al., set sem back to initial state */
This comment should go away too.
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
>
> /* pause restriper - we want to resume on mount */
> btrfs_pause_balance(fs_info);
> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> index 713f899bae81..5d0686c18bad 100644
> --- a/fs/btrfs/super.c
> +++ b/fs/btrfs/super.c
> @@ -1777,9 +1777,9 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
> cancel_work_sync(&fs_info->async_reclaim_work);
>
> /* wait for the uuid_scan task to finish */
> - down(&fs_info->uuid_tree_rescan_sem);
> + mutex_lock(&fs_info->uuid_tree_mutex);
> /* avoid complains from lockdep et al. */
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
>
> sb->s_flags |= MS_RDONLY;
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 1b43f762906f..b2949232ba52 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -4202,7 +4202,7 @@ static int btrfs_uuid_scan_kthread(void *data)
> btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
> else
> set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags);
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
> return 0;
> }
>
> @@ -4264,7 +4264,7 @@ static int btrfs_uuid_rescan_kthread(void *data)
> ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
> if (ret < 0) {
> btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
> return ret;
> }
> return btrfs_uuid_scan_kthread(data);
> @@ -4301,12 +4301,12 @@ int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
> if (ret)
> return ret;
>
> - down(&fs_info->uuid_tree_rescan_sem);
> + mutex_lock(&fs_info->uuid_tree_mutex);
> task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
> if (IS_ERR(task)) {
> /* fs_info->update_uuid_tree_gen remains 0 in all error case */
> btrfs_warn(fs_info, "failed to start uuid_scan task");
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
> return PTR_ERR(task);
> }
>
> @@ -4317,12 +4317,12 @@ int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
> {
> struct task_struct *task;
>
> - down(&fs_info->uuid_tree_rescan_sem);
> + mutex_lock(&fs_info->uuid_tree_mutex);
> task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
> if (IS_ERR(task)) {
> /* fs_info->update_uuid_tree_gen remains 0 in all error case */
> btrfs_warn(fs_info, "failed to start uuid_rescan task");
> - up(&fs_info->uuid_tree_rescan_sem);
> + mutex_unlock(&fs_info->uuid_tree_mutex);
> return PTR_ERR(task);
> }
>
> --
> 2.14.3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Filipe David Manana,
“Whether you think you can, or you think you can't — you're right.”
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] btrfs: switch uuid tree semaphore to mutex
2017-11-07 13:58 ` Filipe Manana
@ 2017-11-07 14:20 ` David Sterba
0 siblings, 0 replies; 5+ messages in thread
From: David Sterba @ 2017-11-07 14:20 UTC (permalink / raw)
To: Filipe Manana; +Cc: linux-btrfs
On Tue, Nov 07, 2017 at 01:58:12PM +0000, Filipe Manana wrote:
> On Mon, Nov 6, 2017 at 6:24 PM, David Sterba <dsterba@suse.com> wrote:
> > @@ -3696,9 +3696,9 @@ void close_ctree(struct btrfs_fs_info *fs_info)
> > btrfs_qgroup_wait_for_completion(fs_info, false);
> >
> > /* wait for the uuid_scan task to finish */
> > - down(&fs_info->uuid_tree_rescan_sem);
> > + mutex_lock(&fs_info->uuid_tree_mutex);
> > /* avoid complains from lockdep et al., set sem back to initial state */
>
> This comment should go away too.
Agreed, removed in v2.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] btrfs: switch uuid tree semaphore to mutex
2017-11-06 18:24 [PATCH] btrfs: switch uuid tree semaphore to mutex David Sterba
2017-11-06 18:49 ` Nikolay Borisov
2017-11-07 13:58 ` Filipe Manana
@ 2017-11-22 19:20 ` David Sterba
2 siblings, 0 replies; 5+ messages in thread
From: David Sterba @ 2017-11-22 19:20 UTC (permalink / raw)
To: David Sterba; +Cc: linux-btrfs, nborisov
On Mon, Nov 06, 2017 at 07:24:02PM +0100, David Sterba wrote:
> The uuid_tree_rescan_sem is used as a mutex (initialized with value 1
> and with at most one active user), no reason to obscure that as a
> semaphore.
>
> Signed-off-by: David Sterba <dsterba@suse.com>
[ 136.287143] ------------[ cut here ]------------
[ 136.291962] DEBUG_LOCKS_WARN_ON(depth <= 0)
[ 136.292033] WARNING: CPU: 0 PID: 1762 at kernel/locking/lockdep.c:3766 lock_release+0x253/0x3a0
[ 136.305245] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace sunrpc fscache af_packet br_netfilter bridge stp llc iscsi_ibft iscsi_boot_sysfs btrfs xor zstd_decompress zstd_c
ompress xxhash zlib_deflate i2c_algo_bit raid6_pq drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops dm_mod ttm dax drm tg3 kvm_amd ptp pps_core tpm_infineon libphy kvm mptctl shpchp tpm_tis tpm_tis_c
ore i2c_piix4 tpm acpi_cpufreq irqbypass k10temp pcspkr button ext4 mbcache jbd2 sr_mod cdrom ohci_pci ehci_pci ohci_hcd ehci_hcd mptsas scsi_transport_sas mptscsih serio_raw ata_generic mptbase sata_svw usbcor
e pata_serverworks sg scsi_dh_rdac scsi_dh_emc scsi_dh_alua
[ 136.366011] CPU: 0 PID: 1762 Comm: btrfs-uuid Not tainted 4.14.0-1.ge195904-vanilla+ #91
[ 136.374300] Hardware name: empty empty/S3993, BIOS PAQEX0-3 02/24/2008
[ 136.380954] task: ffff895de4e45140 task.stack: ffffabc901ea8000
[ 136.387005] RIP: 0010:lock_release+0x253/0x3a0
[ 136.391574] RSP: 0018:ffffabc901eabc80 EFLAGS: 00010082
[ 136.396932] RAX: 000000000000001f RBX: ffff895de4e45140 RCX: ffff895de4e45140
[ 136.404189] RDX: ffff895de4e45140 RSI: 0000000000000001 RDI: ffffffff8b0edca0
[ 136.411473] RBP: ffff895dd4723470 R08: 0000000000000000 R09: 0000000000000000
[ 136.418725] R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000282
[ 136.425987] R13: ffffffffc103b852 R14: 0000000000000000 R15: 0000000000000000
[ 136.433259] FS: 0000000000000000(0000) GS:ffff895defc00000(0000) knlGS:0000000000000000
[ 136.441543] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 136.447408] CR2: 00007f0f708bf000 CR3: 000000022290f000 CR4: 00000000000006f0
[ 136.454682] Call Trace:
[ 136.457320] ? btrfs_search_forward+0x168/0x320 [btrfs]
[ 136.462682] __mutex_unlock_slowpath+0x3b/0x260
[ 136.467368] btrfs_uuid_scan_kthread+0x242/0x350 [btrfs]
[ 136.472849] kthread+0x13e/0x170
[ 136.476241] ? get_chunk_map+0xc0/0xc0 [btrfs]
[ 136.480821] ? kthread_stop+0x300/0x300
[ 136.484786] ret_from_fork+0x24/0x30
[ 136.507678] ---[ end trace cd10910755287819 ]---
this apparently relies on the semantics of a semaphore where up and down do not
pair the same way as is required for a mutex. I'm going to drop this
patch and eventually replace it with a clearer waiting logic.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2017-11-22 19:22 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-11-06 18:24 [PATCH] btrfs: switch uuid tree semaphore to mutex David Sterba
2017-11-06 18:49 ` Nikolay Borisov
2017-11-07 13:58 ` Filipe Manana
2017-11-07 14:20 ` David Sterba
2017-11-22 19:20 ` David Sterba
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