diff options
| -rw-r--r-- | drivers/md/dm-ioctl.c | 5 | ||||
| -rw-r--r-- | drivers/md/dm-stats.c | 2 | ||||
| -rw-r--r-- | drivers/md/dm.c | 229 | ||||
| -rw-r--r-- | drivers/md/dm.h | 9 | ||||
| -rw-r--r-- | include/uapi/linux/dm-ioctl.h | 5 |
5 files changed, 192 insertions, 58 deletions
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 0be9381365d7..73f791bb9ea4 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -684,11 +684,14 @@ static void __dev_status(struct mapped_device *md, struct dm_ioctl *param) int srcu_idx; param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG | - DM_ACTIVE_PRESENT_FLAG); + DM_ACTIVE_PRESENT_FLAG | DM_INTERNAL_SUSPEND_FLAG); if (dm_suspended_md(md)) param->flags |= DM_SUSPEND_FLAG; + if (dm_suspended_internally_md(md)) + param->flags |= DM_INTERNAL_SUSPEND_FLAG; + if (dm_test_deferred_remove_flag(md)) param->flags |= DM_DEFERRED_REMOVE; diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c index 28a90122a5a8..42a057aa3811 100644 --- a/drivers/md/dm-stats.c +++ b/drivers/md/dm-stats.c @@ -824,7 +824,7 @@ static int message_stats_create(struct mapped_device *md, return 1; id = dm_stats_create(dm_get_stats(md), start, end, step, program_id, aux_data, - dm_internal_suspend, dm_internal_resume, md); + dm_internal_suspend_fast, dm_internal_resume_fast, md); if (id < 0) return id; diff --git a/drivers/md/dm.c b/drivers/md/dm.c index f84de3215982..a0ece87ad426 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -19,6 +19,7 @@ #include <linux/idr.h> #include <linux/hdreg.h> #include <linux/delay.h> +#include <linux/wait.h> #include <trace/events/block.h> @@ -117,6 +118,7 @@ EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo); #define DMF_NOFLUSH_SUSPENDING 5 #define DMF_MERGE_IS_OPTIONAL 6 #define DMF_DEFERRED_REMOVE 7 +#define DMF_SUSPENDED_INTERNALLY 8 /* * A dummy definition to make RCU happy. @@ -2718,36 +2720,18 @@ static void unlock_fs(struct mapped_device *md) } /* - * We need to be able to change a mapping table under a mounted - * filesystem. For example we might want to move some data in - * the background. Before the table can be swapped with - * dm_bind_table, dm_suspend must be called to flush any in - * flight bios and ensure that any further io gets deferred. - */ -/* - * Suspend mechanism in request-based dm. - * - * 1. Flush all I/Os by lock_fs() if needed. - * 2. Stop dispatching any I/O by stopping the request_queue. - * 3. Wait for all in-flight I/Os to be completed or requeued. + * If __dm_suspend returns 0, the device is completely quiescent + * now. There is no request-processing activity. All new requests + * are being added to md->deferred list. * - * To abort suspend, start the request_queue. + * Caller must hold md->suspend_lock */ -int dm_suspend(struct mapped_device *md, unsigned suspend_flags) +static int __dm_suspend(struct mapped_device *md, struct dm_table *map, + unsigned suspend_flags, int interruptible) { - struct dm_table *map = NULL; - int r = 0; - int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0; - int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0; - - mutex_lock(&md->suspend_lock); - - if (dm_suspended_md(md)) { - r = -EINVAL; - goto out_unlock; - } - - map = rcu_dereference(md->map); + bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG; + bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG; + int r; /* * DMF_NOFLUSH_SUSPENDING must be set before presuspend. @@ -2772,7 +2756,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) r = lock_fs(md); if (r) { dm_table_presuspend_undo_targets(map); - goto out_unlock; + return r; } } @@ -2806,7 +2790,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) * We call dm_wait_for_completion to wait for all existing requests * to finish. */ - r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE); + r = dm_wait_for_completion(md, interruptible); if (noflush) clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); @@ -2822,14 +2806,55 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) unlock_fs(md); dm_table_presuspend_undo_targets(map); - goto out_unlock; /* pushback list is already flushed, so skip flush */ + /* pushback list is already flushed, so skip flush */ } - /* - * If dm_wait_for_completion returned 0, the device is completely - * quiescent now. There is no request-processing activity. All new - * requests are being added to md->deferred list. - */ + return r; +} + +/* + * We need to be able to change a mapping table under a mounted + * filesystem. For example we might want to move some data in + * the background. Before the table can be swapped with + * dm_bind_table, dm_suspend must be called to flush any in + * flight bios and ensure that any further io gets deferred. + */ +/* + * Suspend mechanism in request-based dm. + * + * 1. Flush all I/Os by lock_fs() if needed. + * 2. Stop dispatching any I/O by stopping the request_queue. + * 3. Wait for all in-flight I/Os to be completed or requeued. + * + * To abort suspend, start the request_queue. + */ +int dm_suspend(struct mapped_device *md, unsigned suspend_flags) +{ + struct dm_table *map = NULL; + int r = 0; + +retry: + mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING); + + if (dm_suspended_md(md)) { + r = -EINVAL; + goto out_unlock; + } + + if (dm_suspended_internally_md(md)) { + /* already internally suspended, wait for internal resume */ + mutex_unlock(&md->suspend_lock); + r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE); + if (r) + return r; + goto retry; + } + + map = rcu_dereference(md->map); + + r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE); + if (r) + goto out_unlock; set_bit(DMF_SUSPENDED, &md->flags); @@ -2840,35 +2865,57 @@ out_unlock: return r; } +static int __dm_resume(struct mapped_device *md, struct dm_table *map) +{ + if (map) { + int r = dm_table_resume_targets(map); + if (r) + return r; + } + + dm_queue_flush(md); + + /* + * Flushing deferred I/Os must be done after targets are resumed + * so that mapping of targets can work correctly. + * Request-based dm is queueing the deferred I/Os in its request_queue. + */ + if (dm_request_based(md)) + start_queue(md->queue); + + unlock_fs(md); + + return 0; +} + int dm_resume(struct mapped_device *md) { int r = -EINVAL; struct dm_table *map = NULL; - mutex_lock(&md->suspend_lock); +retry: + mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING); + if (!dm_suspended_md(md)) goto out; + if (dm_suspended_internally_md(md)) { + /* already internally suspended, wait for internal resume */ + mutex_unlock(&md->suspend_lock); + r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE); + if (r) + return r; + goto retry; + } + map = rcu_dereference(md->map); if (!map || !dm_table_get_size(map)) goto out; - r = dm_table_resume_targets(map); + r = __dm_resume(md, map); if (r) goto out; - dm_queue_flush(md); - - /* - * Flushing deferred I/Os must be done after targets are resumed - * so that mapping of targets can work correctly. - * Request-based dm is queueing the deferred I/Os in its request_queue. - */ - if (dm_request_based(md)) - start_queue(md->queue); - - unlock_fs(md); - clear_bit(DMF_SUSPENDED, &md->flags); r = 0; @@ -2882,15 +2929,80 @@ out: * Internal suspend/resume works like userspace-driven suspend. It waits * until all bios finish and prevents issuing new bios to the target drivers. * It may be used only from the kernel. - * - * Internal suspend holds md->suspend_lock, which prevents interaction with - * userspace-driven suspend. */ -void dm_internal_suspend(struct mapped_device *md) +static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_flags) { - mutex_lock(&md->suspend_lock); + struct dm_table *map = NULL; + + if (dm_suspended_internally_md(md)) + return; /* nested internal suspend */ + + if (dm_suspended_md(md)) { + set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags); + return; /* nest suspend */ + } + + map = rcu_dereference(md->map); + + /* + * Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is + * supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend + * would require changing .presuspend to return an error -- avoid this + * until there is a need for more elaborate variants of internal suspend. + */ + (void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE); + + set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags); + + dm_table_postsuspend_targets(map); +} + +static void __dm_internal_resume(struct mapped_device *md) +{ + if (!dm_suspended_internally_md(md)) + return; /* resume from nested internal suspend */ + if (dm_suspended_md(md)) + goto done; /* resume from nested suspend */ + + /* + * NOTE: existing callers don't need to call dm_table_resume_targets + * (which may fail -- so best to avoid it for now by passing NULL map) + */ + (void) __dm_resume(md, NULL); + +done: + clear_bit(DMF_SUSPENDED_INTERNALLY, &md->flags); + smp_mb__after_atomic(); + wake_up_bit(&md->flags, DMF_SUSPENDED_INTERNALLY); +} + +void dm_internal_suspend_noflush(struct mapped_device *md) +{ + mutex_lock(&md->suspend_lock); + __dm_internal_suspend(md, DM_SUSPEND_NOFLUSH_FLAG); + mutex_unlock(&md->suspend_lock); +} +EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush); + +void dm_internal_resume(struct mapped_device *md) +{ + mutex_lock(&md->suspend_lock); + __dm_internal_resume(md); + mutex_unlock(&md->suspend_lock); +} +EXPORT_SYMBOL_GPL(dm_internal_resume); + +/* + * Fast variants of internal suspend/resume hold md->suspend_lock, + * which prevents interaction with userspace-driven suspend. + */ + +void dm_internal_suspend_fast(struct mapped_device *md) +{ + mutex_lock(&md->suspend_lock); + if (dm_suspended_md(md) || dm_suspended_internally_md(md)) return; set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags); @@ -2899,9 +3011,9 @@ void dm_internal_suspend(struct mapped_device *md) dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE); } -void dm_internal_resume(struct mapped_device *md) +void dm_internal_resume_fast(struct mapped_device *md) { - if (dm_suspended_md(md)) + if (dm_suspended_md(md) || dm_suspended_internally_md(md)) goto done; dm_queue_flush(md); @@ -2987,6 +3099,11 @@ int dm_suspended_md(struct mapped_device *md) return test_bit(DMF_SUSPENDED, &md->flags); } +int dm_suspended_internally_md(struct mapped_device *md) +{ + return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags); +} + int dm_test_deferred_remove_flag(struct mapped_device *md) { return test_bit(DMF_DEFERRED_REMOVE, &md->flags); diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 781994093bf5..84b0f9e4ba6c 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -130,6 +130,15 @@ int dm_deleting_md(struct mapped_device *md); int dm_suspended_md(struct mapped_device *md); /* + * Internal suspend and resume methods. + */ +int dm_suspended_internally_md(struct mapped_device *md); +void dm_internal_suspend_fast(struct mapped_device *md); +void dm_internal_resume_fast(struct mapped_device *md); +void dm_internal_suspend_noflush(struct mapped_device *md); +void dm_internal_resume(struct mapped_device *md); + +/* * Test if the device is scheduled for deferred remove. */ int dm_test_deferred_remove_flag(struct mapped_device *md); diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h index 2be66f4be2f9..a570d7b5796c 100644 --- a/include/uapi/linux/dm-ioctl.h +++ b/include/uapi/linux/dm-ioctl.h @@ -352,4 +352,9 @@ enum { */ #define DM_DEFERRED_REMOVE (1 << 17) /* In/Out */ +/* + * If set, the device is suspended internally. + */ +#define DM_INTERNAL_SUSPEND_FLAG (1 << 18) /* Out */ + #endif /* _LINUX_DM_IOCTL_H */ |