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-rw-r--r--drivers/md/dm-bio-list.h14
-rw-r--r--drivers/md/dm.c105
-rw-r--r--drivers/md/dm.h2
-rw-r--r--include/linux/device-mapper.h3
4 files changed, 114 insertions, 10 deletions
diff --git a/drivers/md/dm-bio-list.h b/drivers/md/dm-bio-list.h
index bbf4615f0e3..da4349649f7 100644
--- a/drivers/md/dm-bio-list.h
+++ b/drivers/md/dm-bio-list.h
@@ -44,6 +44,20 @@ static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
bl->tail = bl2->tail;
}
+static inline void bio_list_merge_head(struct bio_list *bl,
+ struct bio_list *bl2)
+{
+ if (!bl2->head)
+ return;
+
+ if (bl->head)
+ bl2->tail->bi_next = bl->head;
+ else
+ bl->tail = bl2->tail;
+
+ bl->head = bl2->head;
+}
+
static inline struct bio *bio_list_pop(struct bio_list *bl)
{
struct bio *bio = bl->head;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index d8544e1a4c1..fe7c56e1043 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -68,10 +68,12 @@ union map_info *dm_get_mapinfo(struct bio *bio)
#define DMF_FROZEN 2
#define DMF_FREEING 3
#define DMF_DELETING 4
+#define DMF_NOFLUSH_SUSPENDING 5
struct mapped_device {
struct rw_semaphore io_lock;
struct semaphore suspend_lock;
+ spinlock_t pushback_lock;
rwlock_t map_lock;
atomic_t holders;
atomic_t open_count;
@@ -90,6 +92,7 @@ struct mapped_device {
atomic_t pending;
wait_queue_head_t wait;
struct bio_list deferred;
+ struct bio_list pushback;
/*
* The current mapping.
@@ -444,23 +447,50 @@ int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
* you this clearly demarcated crap.
*---------------------------------------------------------------*/
+static int __noflush_suspending(struct mapped_device *md)
+{
+ return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+}
+
/*
* Decrements the number of outstanding ios that a bio has been
* cloned into, completing the original io if necc.
*/
static void dec_pending(struct dm_io *io, int error)
{
- if (error)
+ unsigned long flags;
+
+ /* Push-back supersedes any I/O errors */
+ if (error && !(io->error > 0 && __noflush_suspending(io->md)))
io->error = error;
if (atomic_dec_and_test(&io->io_count)) {
+ if (io->error == DM_ENDIO_REQUEUE) {
+ /*
+ * Target requested pushing back the I/O.
+ * This must be handled before the sleeper on
+ * suspend queue merges the pushback list.
+ */
+ spin_lock_irqsave(&io->md->pushback_lock, flags);
+ if (__noflush_suspending(io->md))
+ bio_list_add(&io->md->pushback, io->bio);
+ else
+ /* noflush suspend was interrupted. */
+ io->error = -EIO;
+ spin_unlock_irqrestore(&io->md->pushback_lock, flags);
+ }
+
if (end_io_acct(io))
/* nudge anyone waiting on suspend queue */
wake_up(&io->md->wait);
- blk_add_trace_bio(io->md->queue, io->bio, BLK_TA_COMPLETE);
+ if (io->error != DM_ENDIO_REQUEUE) {
+ blk_add_trace_bio(io->md->queue, io->bio,
+ BLK_TA_COMPLETE);
+
+ bio_endio(io->bio, io->bio->bi_size, io->error);
+ }
- bio_endio(io->bio, io->bio->bi_size, io->error);
free_io(io->md, io);
}
}
@@ -480,7 +510,11 @@ static int clone_endio(struct bio *bio, unsigned int done, int error)
if (endio) {
r = endio(tio->ti, bio, error, &tio->info);
- if (r < 0)
+ if (r < 0 || r == DM_ENDIO_REQUEUE)
+ /*
+ * error and requeue request are handled
+ * in dec_pending().
+ */
error = r;
else if (r == DM_ENDIO_INCOMPLETE)
/* The target will handle the io */
@@ -554,8 +588,8 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
clone->bi_sector);
generic_make_request(clone);
- } else if (r < 0) {
- /* error the io and bail out */
+ } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
+ /* error the io and bail out, or requeue it if needed */
md = tio->io->md;
dec_pending(tio->io, r);
/*
@@ -952,6 +986,7 @@ static struct mapped_device *alloc_dev(int minor)
memset(md, 0, sizeof(*md));
init_rwsem(&md->io_lock);
init_MUTEX(&md->suspend_lock);
+ spin_lock_init(&md->pushback_lock);
rwlock_init(&md->map_lock);
atomic_set(&md->holders, 1);
atomic_set(&md->open_count, 0);
@@ -1282,10 +1317,12 @@ static void unlock_fs(struct mapped_device *md)
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
+ unsigned long flags;
DECLARE_WAITQUEUE(wait, current);
struct bio *def;
int r = -EINVAL;
int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
+ int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
down(&md->suspend_lock);
@@ -1294,6 +1331,13 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
map = dm_get_table(md);
+ /*
+ * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
+ * This flag is cleared before dm_suspend returns.
+ */
+ if (noflush)
+ set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+
/* This does not get reverted if there's an error later. */
dm_table_presuspend_targets(map);
@@ -1301,11 +1345,14 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
if (!md->suspended_bdev) {
DMWARN("bdget failed in dm_suspend");
r = -ENOMEM;
- goto out;
+ goto flush_and_out;
}
- /* Flush I/O to the device. */
- if (do_lockfs) {
+ /*
+ * Flush I/O to the device.
+ * noflush supersedes do_lockfs, because lock_fs() needs to flush I/Os.
+ */
+ if (do_lockfs && !noflush) {
r = lock_fs(md);
if (r)
goto out;
@@ -1341,6 +1388,14 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
down_write(&md->io_lock);
remove_wait_queue(&md->wait, &wait);
+ if (noflush) {
+ spin_lock_irqsave(&md->pushback_lock, flags);
+ clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+ bio_list_merge_head(&md->deferred, &md->pushback);
+ bio_list_init(&md->pushback);
+ spin_unlock_irqrestore(&md->pushback_lock, flags);
+ }
+
/* were we interrupted ? */
r = -EINTR;
if (atomic_read(&md->pending)) {
@@ -1349,7 +1404,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
__flush_deferred_io(md, def);
up_write(&md->io_lock);
unlock_fs(md);
- goto out;
+ goto out; /* pushback list is already flushed, so skip flush */
}
up_write(&md->io_lock);
@@ -1359,6 +1414,25 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
r = 0;
+flush_and_out:
+ if (r && noflush) {
+ /*
+ * Because there may be already I/Os in the pushback list,
+ * flush them before return.
+ */
+ down_write(&md->io_lock);
+
+ spin_lock_irqsave(&md->pushback_lock, flags);
+ clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
+ bio_list_merge_head(&md->deferred, &md->pushback);
+ bio_list_init(&md->pushback);
+ spin_unlock_irqrestore(&md->pushback_lock, flags);
+
+ def = bio_list_get(&md->deferred);
+ __flush_deferred_io(md, def);
+ up_write(&md->io_lock);
+ }
+
out:
if (r && md->suspended_bdev) {
bdput(md->suspended_bdev);
@@ -1445,6 +1519,17 @@ int dm_suspended(struct mapped_device *md)
return test_bit(DMF_SUSPENDED, &md->flags);
}
+int dm_noflush_suspending(struct dm_target *ti)
+{
+ struct mapped_device *md = dm_table_get_md(ti->table);
+ int r = __noflush_suspending(md);
+
+ dm_put(md);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_noflush_suspending);
+
static struct block_device_operations dm_blk_dops = {
.open = dm_blk_open,
.release = dm_blk_close,
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index c307ca9a4c3..2f796b1436b 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -36,12 +36,14 @@
* Definitions of return values from target end_io function.
*/
#define DM_ENDIO_INCOMPLETE 1
+#define DM_ENDIO_REQUEUE 2
/*
* Definitions of return values from target map function.
*/
#define DM_MAPIO_SUBMITTED 0
#define DM_MAPIO_REMAPPED 1
+#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
/*
* Suspend feature flags
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 2e5c42346c3..499f5373e21 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -40,6 +40,7 @@ typedef void (*dm_dtr_fn) (struct dm_target *ti);
* < 0: error
* = 0: The target will handle the io by resubmitting it later
* = 1: simple remap complete
+ * = 2: The target wants to push back the io
*/
typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
union map_info *map_context);
@@ -50,6 +51,7 @@ typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
* 0 : ended successfully
* 1 : for some reason the io has still not completed (eg,
* multipath target might want to requeue a failed io).
+ * 2 : The target wants to push back the io
*/
typedef int (*dm_endio_fn) (struct dm_target *ti,
struct bio *bio, int error,
@@ -188,6 +190,7 @@ int dm_wait_event(struct mapped_device *md, int event_nr);
const char *dm_device_name(struct mapped_device *md);
struct gendisk *dm_disk(struct mapped_device *md);
int dm_suspended(struct mapped_device *md);
+int dm_noflush_suspending(struct dm_target *ti);
/*
* Geometry functions.
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-28 17:18:43 +0000