Hello, It seems that this commit is applied two times. Furthermore, as indicated in the commit message, dm_internal_suspend_fast and dm_internal_resume_fast need to be replaced by dm_internal_suspend and dm_internal_resume instead in kernel 3.18. Doing this trival replacements solves the compiles error.
Sincerely yours, François Valenduc Le 16/04/15 19:10, Sasha Levin a écrit : > From: Mikulas Patocka <[email protected]> > > [ Upstream commit 09ee96b21456883e108c3b00597bb37ec512151b > b735fede8d957d9d255e9c5cf3964cfa59799637 ] > > The "dm snapshot: suspend origin when doing exception handover" commit > fixed a exception store handover bug associated with pending exceptions > to the "snapshot-origin" target. > > However, a similar problem exists in snapshot merging. When snapshot > merging is in progress, we use the target "snapshot-merge" instead of > "snapshot-origin". Consequently, during exception store handover, we > must find the snapshot-merge target and suspend its associated > mapped_device. > > To avoid lockdep warnings, the target must be suspended and resumed > without holding _origins_lock. > > Introduce a dm_hold() function that grabs a reference on a > mapped_device, but unlike dm_get(), it doesn't crash if the device has > the DMF_FREEING flag set, it returns an error in this case. > > In snapshot_resume() we grab the reference to the origin device using > dm_hold() while holding _origins_lock (_origins_lock guarantees that the > device won't disappear). Then we release _origins_lock, suspend the > device and grab _origins_lock again. > > NOTE to stable@ people: > When backporting to kernels 3.18 and older, use dm_internal_suspend and > dm_internal_resume instead of dm_internal_suspend_fast and > dm_internal_resume_fast. > > Signed-off-by: Mikulas Patocka <[email protected]> > Signed-off-by: Mike Snitzer <[email protected]> > Cc: [email protected] > > dm snapshot: suspend origin when doing exception handover > > [ Upstream commit 09ee96b21456883e108c3b00597bb37ec512151b > b735fede8d957d9d255e9c5cf3964cfa59799637 ] > > In the function snapshot_resume we perform exception store handover. If > there is another active snapshot target, the exception store is moved > from this target to the target that is being resumed. > > The problem is that if there is some pending exception, it will point to > an incorrect exception store after that handover, causing a crash due to > dm-snap-persistent.c:get_exception()'s BUG_ON. > > This bug can be triggered by repeatedly changing snapshot permissions > with "lvchange -p r" and "lvchange -p rw" while there are writes on the > associated origin device. > > To fix this bug, we must suspend the origin device when doing the > exception store handover to make sure that there are no pending > exceptions: > - introduce _origin_hash that keeps track of dm_origin structures. > - introduce functions __lookup_dm_origin, __insert_dm_origin and > __remove_dm_origin that manipulate the origin hash. > - modify snapshot_resume so that it calls dm_internal_suspend_fast() and > dm_internal_resume_fast() on the origin device. > > NOTE to stable@ people: > > When backporting to kernels 3.12-3.18, use dm_internal_suspend and > dm_internal_resume instead of dm_internal_suspend_fast and > dm_internal_resume_fast. > > When backporting to kernels older than 3.12, you need to pick functions > dm_internal_suspend and dm_internal_resume from the commit > fd2ed4d252701d3bbed4cd3e3d267ad469bb832a. > > Signed-off-by: Mikulas Patocka <[email protected]> > Signed-off-by: Mike Snitzer <[email protected]> > Cc: [email protected] > Signed-off-by: Sasha Levin <[email protected]> > --- > drivers/md/dm-snap.c | 93 > +++++++++++++++++++++++++++++++++++++++++++++++----- > drivers/md/dm.c | 2 ++ > 2 files changed, 86 insertions(+), 9 deletions(-) > > diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c > index 8b204ae2..c2bf822 100644 > --- a/drivers/md/dm-snap.c > +++ b/drivers/md/dm-snap.c > @@ -20,6 +20,8 @@ > #include <linux/log2.h> > #include <linux/dm-kcopyd.h> > > +#include "dm.h" > + > #include "dm-exception-store.h" > > #define DM_MSG_PREFIX "snapshots" > @@ -291,12 +293,23 @@ struct origin { > }; > > /* > + * This structure is allocated for each origin target > + */ > +struct dm_origin { > + struct dm_dev *dev; > + struct dm_target *ti; > + unsigned split_boundary; > + struct list_head hash_list; > +}; > + > +/* > * Size of the hash table for origin volumes. If we make this > * the size of the minors list then it should be nearly perfect > */ > #define ORIGIN_HASH_SIZE 256 > #define ORIGIN_MASK 0xFF > static struct list_head *_origins; > +static struct list_head *_dm_origins; > static struct rw_semaphore _origins_lock; > > static DECLARE_WAIT_QUEUE_HEAD(_pending_exceptions_done); > @@ -310,12 +323,22 @@ static int init_origin_hash(void) > _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), > GFP_KERNEL); > if (!_origins) { > - DMERR("unable to allocate memory"); > + DMERR("unable to allocate memory for _origins"); > return -ENOMEM; > } > - > for (i = 0; i < ORIGIN_HASH_SIZE; i++) > INIT_LIST_HEAD(_origins + i); > + > + _dm_origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head), > + GFP_KERNEL); > + if (!_dm_origins) { > + DMERR("unable to allocate memory for _dm_origins"); > + kfree(_origins); > + return -ENOMEM; > + } > + for (i = 0; i < ORIGIN_HASH_SIZE; i++) > + INIT_LIST_HEAD(_dm_origins + i); > + > init_rwsem(&_origins_lock); > > return 0; > @@ -324,6 +347,7 @@ static int init_origin_hash(void) > static void exit_origin_hash(void) > { > kfree(_origins); > + kfree(_dm_origins); > } > > static unsigned origin_hash(struct block_device *bdev) > @@ -350,6 +374,30 @@ static void __insert_origin(struct origin *o) > list_add_tail(&o->hash_list, sl); > } > > +static struct dm_origin *__lookup_dm_origin(struct block_device *origin) > +{ > + struct list_head *ol; > + struct dm_origin *o; > + > + ol = &_dm_origins[origin_hash(origin)]; > + list_for_each_entry (o, ol, hash_list) > + if (bdev_equal(o->dev->bdev, origin)) > + return o; > + > + return NULL; > +} > + > +static void __insert_dm_origin(struct dm_origin *o) > +{ > + struct list_head *sl = &_dm_origins[origin_hash(o->dev->bdev)]; > + list_add_tail(&o->hash_list, sl); > +} > + > +static void __remove_dm_origin(struct dm_origin *o) > +{ > + list_del(&o->hash_list); > +} > + > /* > * _origins_lock must be held when calling this function. > * Returns number of snapshots registered using the supplied cow device, > plus: > @@ -1841,8 +1889,20 @@ static void snapshot_resume(struct dm_target *ti) > { > struct dm_snapshot *s = ti->private; > struct dm_snapshot *snap_src = NULL, *snap_dest = NULL; > + struct dm_origin *o; > + struct mapped_device *origin_md = NULL; > > down_read(&_origins_lock); > + > + o = __lookup_dm_origin(s->origin->bdev); > + if (o) > + origin_md = dm_table_get_md(o->ti->table); > + if (origin_md == dm_table_get_md(ti->table)) > + origin_md = NULL; > + > + if (origin_md) > + dm_internal_suspend_fast(origin_md); > + > (void) __find_snapshots_sharing_cow(s, &snap_src, &snap_dest, NULL); > if (snap_src && snap_dest) { > down_write(&snap_src->lock); > @@ -1851,6 +1911,10 @@ static void snapshot_resume(struct dm_target *ti) > up_write(&snap_dest->lock); > up_write(&snap_src->lock); > } > + > + if (origin_md) > + dm_internal_resume_fast(origin_md); > + > up_read(&_origins_lock); > > /* Now we have correct chunk size, reregister */ > @@ -2133,11 +2197,6 @@ static int origin_write_extent(struct dm_snapshot > *merging_snap, > * Origin: maps a linear range of a device, with hooks for snapshotting. > */ > > -struct dm_origin { > - struct dm_dev *dev; > - unsigned split_boundary; > -}; > - > /* > * Construct an origin mapping: <dev_path> > * The context for an origin is merely a 'struct dm_dev *' > @@ -2166,6 +2225,7 @@ static int origin_ctr(struct dm_target *ti, unsigned > int argc, char **argv) > goto bad_open; > } > > + o->ti = ti; > ti->private = o; > ti->num_flush_bios = 1; > > @@ -2180,6 +2240,7 @@ bad_alloc: > static void origin_dtr(struct dm_target *ti) > { > struct dm_origin *o = ti->private; > + > dm_put_device(ti, o->dev); > kfree(o); > } > @@ -2216,6 +2277,19 @@ static void origin_resume(struct dm_target *ti) > struct dm_origin *o = ti->private; > > o->split_boundary = get_origin_minimum_chunksize(o->dev->bdev); > + > + down_write(&_origins_lock); > + __insert_dm_origin(o); > + up_write(&_origins_lock); > +} > + > +static void origin_postsuspend(struct dm_target *ti) > +{ > + struct dm_origin *o = ti->private; > + > + down_write(&_origins_lock); > + __remove_dm_origin(o); > + up_write(&_origins_lock); > } > > static void origin_status(struct dm_target *ti, status_type_t type, > @@ -2258,12 +2332,13 @@ static int origin_iterate_devices(struct dm_target > *ti, > > static struct target_type origin_target = { > .name = "snapshot-origin", > - .version = {1, 8, 1}, > + .version = {1, 9, 0}, > .module = THIS_MODULE, > .ctr = origin_ctr, > .dtr = origin_dtr, > .map = origin_map, > .resume = origin_resume, > + .postsuspend = origin_postsuspend, > .status = origin_status, > .merge = origin_merge, > .iterate_devices = origin_iterate_devices, > @@ -2271,7 +2346,7 @@ static struct target_type origin_target = { > > static struct target_type snapshot_target = { > .name = "snapshot", > - .version = {1, 12, 0}, > + .version = {1, 13, 0}, > .module = THIS_MODULE, > .ctr = snapshot_ctr, > .dtr = snapshot_dtr, > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index f743f47..83aa36f 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -2887,6 +2887,7 @@ void dm_internal_suspend(struct mapped_device *md) > flush_workqueue(md->wq); > dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE); > } > +EXPORT_SYMBOL_GPL(dm_internal_suspend_fast); > > void dm_internal_resume(struct mapped_device *md) > { > @@ -2898,6 +2899,7 @@ void dm_internal_resume(struct mapped_device *md) > done: > mutex_unlock(&md->suspend_lock); > } > +EXPORT_SYMBOL_GPL(dm_internal_resume_fast); > > /*----------------------------------------------------------------- > * Event notification. > -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
