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path: root/drivers/md/dm.c
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Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c196
1 files changed, 89 insertions, 107 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 54fabbf0667..d487d9deb98 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -55,10 +55,10 @@ union map_info *dm_get_mapinfo(struct bio *bio)
*/
#define DMF_BLOCK_IO 0
#define DMF_SUSPENDED 1
-#define DMF_FS_LOCKED 2
struct mapped_device {
- struct rw_semaphore lock;
+ struct rw_semaphore io_lock;
+ struct semaphore suspend_lock;
rwlock_t map_lock;
atomic_t holders;
@@ -248,16 +248,16 @@ static inline void free_tio(struct mapped_device *md, struct target_io *tio)
*/
static int queue_io(struct mapped_device *md, struct bio *bio)
{
- down_write(&md->lock);
+ down_write(&md->io_lock);
if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
- up_write(&md->lock);
+ up_write(&md->io_lock);
return 1;
}
bio_list_add(&md->deferred, bio);
- up_write(&md->lock);
+ up_write(&md->io_lock);
return 0; /* deferred successfully */
}
@@ -568,14 +568,14 @@ static int dm_request(request_queue_t *q, struct bio *bio)
int r;
struct mapped_device *md = q->queuedata;
- down_read(&md->lock);
+ down_read(&md->io_lock);
/*
* If we're suspended we have to queue
* this io for later.
*/
while (test_bit(DMF_BLOCK_IO, &md->flags)) {
- up_read(&md->lock);
+ up_read(&md->io_lock);
if (bio_rw(bio) == READA) {
bio_io_error(bio, bio->bi_size);
@@ -594,11 +594,11 @@ static int dm_request(request_queue_t *q, struct bio *bio)
* We're in a while loop, because someone could suspend
* before we get to the following read lock.
*/
- down_read(&md->lock);
+ down_read(&md->io_lock);
}
__split_bio(md, bio);
- up_read(&md->lock);
+ up_read(&md->io_lock);
return 0;
}
@@ -610,7 +610,7 @@ static int dm_flush_all(request_queue_t *q, struct gendisk *disk,
int ret = -ENXIO;
if (map) {
- ret = dm_table_flush_all(md->map);
+ ret = dm_table_flush_all(map);
dm_table_put(map);
}
@@ -747,7 +747,8 @@ static struct mapped_device *alloc_dev(unsigned int minor, int persistent)
goto bad1;
memset(md, 0, sizeof(*md));
- init_rwsem(&md->lock);
+ init_rwsem(&md->io_lock);
+ init_MUTEX(&md->suspend_lock);
rwlock_init(&md->map_lock);
atomic_set(&md->holders, 1);
atomic_set(&md->event_nr, 0);
@@ -825,18 +826,13 @@ static void event_callback(void *context)
wake_up(&md->eventq);
}
-static void __set_size(struct gendisk *disk, sector_t size)
+static void __set_size(struct mapped_device *md, sector_t size)
{
- struct block_device *bdev;
-
- set_capacity(disk, size);
- bdev = bdget_disk(disk, 0);
- if (bdev) {
- down(&bdev->bd_inode->i_sem);
- i_size_write(bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
- up(&bdev->bd_inode->i_sem);
- bdput(bdev);
- }
+ set_capacity(md->disk, size);
+
+ down(&md->frozen_bdev->bd_inode->i_sem);
+ i_size_write(md->frozen_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
+ up(&md->frozen_bdev->bd_inode->i_sem);
}
static int __bind(struct mapped_device *md, struct dm_table *t)
@@ -845,17 +841,18 @@ static int __bind(struct mapped_device *md, struct dm_table *t)
sector_t size;
size = dm_table_get_size(t);
- __set_size(md->disk, size);
+ __set_size(md, size);
if (size == 0)
return 0;
+ dm_table_get(t);
+ dm_table_event_callback(t, event_callback, md);
+
write_lock(&md->map_lock);
md->map = t;
+ dm_table_set_restrictions(t, q);
write_unlock(&md->map_lock);
- dm_table_get(t);
- dm_table_event_callback(md->map, event_callback, md);
- dm_table_set_restrictions(t, q);
return 0;
}
@@ -935,7 +932,7 @@ void dm_put(struct mapped_device *md)
struct dm_table *map = dm_get_table(md);
if (atomic_dec_and_test(&md->holders)) {
- if (!test_bit(DMF_SUSPENDED, &md->flags) && map) {
+ if (!dm_suspended(md)) {
dm_table_presuspend_targets(map);
dm_table_postsuspend_targets(map);
}
@@ -968,17 +965,17 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table)
{
int r = -EINVAL;
- down_write(&md->lock);
+ down(&md->suspend_lock);
/* device must be suspended */
- if (!test_bit(DMF_SUSPENDED, &md->flags))
+ if (!dm_suspended(md))
goto out;
__unbind(md);
r = __bind(md, table);
out:
- up_write(&md->lock);
+ up(&md->suspend_lock);
return r;
}
@@ -986,16 +983,13 @@ out:
* Functions to lock and unlock any filesystem running on the
* device.
*/
-static int __lock_fs(struct mapped_device *md)
+static int lock_fs(struct mapped_device *md)
{
- int error = -ENOMEM;
-
- if (test_and_set_bit(DMF_FS_LOCKED, &md->flags))
- return 0;
+ int r = -ENOMEM;
md->frozen_bdev = bdget_disk(md->disk, 0);
if (!md->frozen_bdev) {
- DMWARN("bdget failed in __lock_fs");
+ DMWARN("bdget failed in lock_fs");
goto out;
}
@@ -1003,13 +997,13 @@ static int __lock_fs(struct mapped_device *md)
md->frozen_sb = freeze_bdev(md->frozen_bdev);
if (IS_ERR(md->frozen_sb)) {
- error = PTR_ERR(md->frozen_sb);
+ r = PTR_ERR(md->frozen_sb);
goto out_bdput;
}
/* don't bdput right now, we don't want the bdev
* to go away while it is locked. We'll bdput
- * in __unlock_fs
+ * in unlock_fs
*/
return 0;
@@ -1018,15 +1012,11 @@ out_bdput:
md->frozen_sb = NULL;
md->frozen_bdev = NULL;
out:
- clear_bit(DMF_FS_LOCKED, &md->flags);
- return error;
+ return r;
}
-static void __unlock_fs(struct mapped_device *md)
+static void unlock_fs(struct mapped_device *md)
{
- if (!test_and_clear_bit(DMF_FS_LOCKED, &md->flags))
- return;
-
thaw_bdev(md->frozen_bdev, md->frozen_sb);
bdput(md->frozen_bdev);
@@ -1043,50 +1033,37 @@ static void __unlock_fs(struct mapped_device *md)
*/
int dm_suspend(struct mapped_device *md)
{
- struct dm_table *map;
+ struct dm_table *map = NULL;
DECLARE_WAITQUEUE(wait, current);
- int error = -EINVAL;
+ int r = -EINVAL;
- /* Flush I/O to the device. */
- down_read(&md->lock);
- if (test_bit(DMF_BLOCK_IO, &md->flags))
- goto out_read_unlock;
+ down(&md->suspend_lock);
+
+ if (dm_suspended(md))
+ goto out;
map = dm_get_table(md);
- if (map)
- /* This does not get reverted if there's an error later. */
- dm_table_presuspend_targets(map);
- error = __lock_fs(md);
- if (error) {
- dm_table_put(map);
- goto out_read_unlock;
- }
+ /* This does not get reverted if there's an error later. */
+ dm_table_presuspend_targets(map);
- up_read(&md->lock);
+ /* Flush I/O to the device. */
+ r = lock_fs(md);
+ if (r)
+ goto out;
/*
* First we set the BLOCK_IO flag so no more ios will be mapped.
- *
- * If the flag is already set we know another thread is trying to
- * suspend as well, so we leave the fs locked for this thread.
*/
- error = -EINVAL;
- down_write(&md->lock);
- if (test_and_set_bit(DMF_BLOCK_IO, &md->flags)) {
- if (map)
- dm_table_put(map);
- goto out_write_unlock;
- }
+ down_write(&md->io_lock);
+ set_bit(DMF_BLOCK_IO, &md->flags);
add_wait_queue(&md->wait, &wait);
- up_write(&md->lock);
+ up_write(&md->io_lock);
/* unplug */
- if (map) {
+ if (map)
dm_table_unplug_all(map);
- dm_table_put(map);
- }
/*
* Then we wait for the already mapped ios to
@@ -1102,62 +1079,67 @@ int dm_suspend(struct mapped_device *md)
}
set_current_state(TASK_RUNNING);
- down_write(&md->lock);
+ down_write(&md->io_lock);
remove_wait_queue(&md->wait, &wait);
/* were we interrupted ? */
- error = -EINTR;
- if (atomic_read(&md->pending))
- goto out_unfreeze;
-
- set_bit(DMF_SUSPENDED, &md->flags);
+ r = -EINTR;
+ if (atomic_read(&md->pending)) {
+ up_write(&md->io_lock);
+ unlock_fs(md);
+ clear_bit(DMF_BLOCK_IO, &md->flags);
+ goto out;
+ }
+ up_write(&md->io_lock);
- map = dm_get_table(md);
- if (map)
- dm_table_postsuspend_targets(map);
- dm_table_put(map);
- up_write(&md->lock);
+ dm_table_postsuspend_targets(map);
- return 0;
+ set_bit(DMF_SUSPENDED, &md->flags);
-out_unfreeze:
- __unlock_fs(md);
- clear_bit(DMF_BLOCK_IO, &md->flags);
-out_write_unlock:
- up_write(&md->lock);
- return error;
+ r = 0;
-out_read_unlock:
- up_read(&md->lock);
- return error;
+out:
+ dm_table_put(map);
+ up(&md->suspend_lock);
+ return r;
}
int dm_resume(struct mapped_device *md)
{
+ int r = -EINVAL;
struct bio *def;
- struct dm_table *map = dm_get_table(md);
+ struct dm_table *map = NULL;
- down_write(&md->lock);
- if (!map ||
- !test_bit(DMF_SUSPENDED, &md->flags) ||
- !dm_table_get_size(map)) {
- up_write(&md->lock);
- dm_table_put(map);
- return -EINVAL;
- }
+ down(&md->suspend_lock);
+ if (!dm_suspended(md))
+ goto out;
+
+ map = dm_get_table(md);
+ if (!map || !dm_table_get_size(map))
+ goto out;
dm_table_resume_targets(map);
- clear_bit(DMF_SUSPENDED, &md->flags);
+
+ down_write(&md->io_lock);
clear_bit(DMF_BLOCK_IO, &md->flags);
def = bio_list_get(&md->deferred);
__flush_deferred_io(md, def);
- up_write(&md->lock);
- __unlock_fs(md);
+ up_write(&md->io_lock);
+
+ unlock_fs(md);
+
+ clear_bit(DMF_SUSPENDED, &md->flags);
+
dm_table_unplug_all(map);
+
+ r = 0;
+
+out:
dm_table_put(map);
+ up(&md->suspend_lock);
- return 0;
+ return r;
}
/*-----------------------------------------------------------------