vserver 2.0 rc7

[linux-2.6.git] / drivers / md / dm.c

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7f1af52..f6b0395 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -43,6 +43,13 @@ struct target_io {
        union map_info info;
 };
 
+union map_info *dm_get_mapinfo(struct bio *bio)
+{
+        if (bio && bio->bi_private)
+                return &((struct target_io *)bio->bi_private)->info;
+        return NULL;
+}
+
 /*
  * Bits for the md->flags field.
  */
@@ -90,16 +97,23 @@ struct mapped_device {
         * freeze/thaw support require holding onto a super block
         */
        struct super_block *frozen_sb;
+       struct block_device *frozen_bdev;
 };
 
 #define MIN_IOS 256
 static kmem_cache_t *_io_cache;
 static kmem_cache_t *_tio_cache;
 
+static struct bio_set *dm_set;
+
 static int __init local_init(void)
 {
        int r;
 
+       dm_set = bioset_create(16, 16, 4);
+       if (!dm_set)
+               return -ENOMEM;
+
        /* allocate a slab for the dm_ios */
        _io_cache = kmem_cache_create("dm_io",
                                      sizeof(struct dm_io), 0, 0, NULL, NULL);
@@ -133,6 +147,8 @@ static void local_exit(void)
        kmem_cache_destroy(_tio_cache);
        kmem_cache_destroy(_io_cache);
 
+       bioset_free(dm_set);
+
        if (unregister_blkdev(_major, _name) < 0)
                DMERR("devfs_unregister_blkdev failed");
 
@@ -393,7 +409,7 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector,
        struct bio *clone;
        struct bio_vec *bv = bio->bi_io_vec + idx;
 
-       clone = bio_alloc(GFP_NOIO, 1);
+       clone = bio_alloc_bioset(GFP_NOIO, 1, dm_set);
        *clone->bi_io_vec = *bv;
 
        clone->bi_sector = sector;
@@ -975,44 +991,50 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table)
  */
 static int __lock_fs(struct mapped_device *md)
 {
-       struct block_device *bdev;
+       int error = -ENOMEM;
 
        if (test_and_set_bit(DMF_FS_LOCKED, &md->flags))
                return 0;
 
-       bdev = bdget_disk(md->disk, 0);
-       if (!bdev) {
+       md->frozen_bdev = bdget_disk(md->disk, 0);
+       if (!md->frozen_bdev) {
                DMWARN("bdget failed in __lock_fs");
-               return -ENOMEM;
+               goto out;
        }
 
        WARN_ON(md->frozen_sb);
-       md->frozen_sb = freeze_bdev(bdev);
+
+       md->frozen_sb = freeze_bdev(md->frozen_bdev);
+       if (IS_ERR(md->frozen_sb)) {
+               error = 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
         */
        return 0;
+
+out_bdput:
+       bdput(md->frozen_bdev);
+       md->frozen_sb = NULL;
+       md->frozen_bdev = NULL;
+out:
+       clear_bit(DMF_FS_LOCKED, &md->flags);
+       return error;
 }
 
-static int __unlock_fs(struct mapped_device *md)
+static void __unlock_fs(struct mapped_device *md)
 {
-       struct block_device *bdev;
-
        if (!test_and_clear_bit(DMF_FS_LOCKED, &md->flags))
-               return 0;
+               return;
 
-       bdev = bdget_disk(md->disk, 0);
-       if (!bdev) {
-               DMWARN("bdget failed in __unlock_fs");
-               return -ENOMEM;
-       }
+       thaw_bdev(md->frozen_bdev, md->frozen_sb);
+       bdput(md->frozen_bdev);
 
-       thaw_bdev(bdev, md->frozen_sb);
        md->frozen_sb = NULL;
-       bdput(bdev);
-       bdput(bdev);
-       return 0;
+       md->frozen_bdev = NULL;
 }
 
 /*
@@ -1026,37 +1048,37 @@ int dm_suspend(struct mapped_device *md)
 {
        struct dm_table *map;
        DECLARE_WAITQUEUE(wait, current);
+       int error = -EINVAL;
 
        /* Flush I/O to the device. */
        down_read(&md->lock);
-       if (test_bit(DMF_BLOCK_IO, &md->flags)) {
-               up_read(&md->lock);
-               return -EINVAL;
-       }
+       if (test_bit(DMF_BLOCK_IO, &md->flags))
+               goto out_read_unlock;
+
+       error = __lock_fs(md);
+       if (error)
+               goto out_read_unlock;
 
        map = dm_get_table(md);
        if (map)
                dm_table_presuspend_targets(map);
-       __lock_fs(md);
 
        up_read(&md->lock);
 
        /*
-        * First we set the BLOCK_IO flag so no more ios will be
-        * mapped.
+        * 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_bit(DMF_BLOCK_IO, &md->flags)) {
-               /*
-                * If we get here we know another thread is
-                * trying to suspend as well, so we leave the fs
-                * locked for this thread.
-                */
-               up_write(&md->lock);
-               return -EINVAL;
+       if (test_and_set_bit(DMF_BLOCK_IO, &md->flags)) {
+               if (map)
+                       dm_table_put(map);
+               goto out_write_unlock;
        }
 
-       set_bit(DMF_BLOCK_IO, &md->flags);
        add_wait_queue(&md->wait, &wait);
        up_write(&md->lock);
 
@@ -1084,12 +1106,9 @@ int dm_suspend(struct mapped_device *md)
        remove_wait_queue(&md->wait, &wait);
 
        /* were we interrupted ? */
-       if (atomic_read(&md->pending)) {
-               __unlock_fs(md);
-               clear_bit(DMF_BLOCK_IO, &md->flags);
-               up_write(&md->lock);
-               return -EINTR;
-       }
+       error = -EINTR;
+       if (atomic_read(&md->pending))
+               goto out_unfreeze;
 
        set_bit(DMF_SUSPENDED, &md->flags);
 
@@ -1100,6 +1119,18 @@ int dm_suspend(struct mapped_device *md)
        up_write(&md->lock);
 
        return 0;
+
+out_unfreeze:
+       /* FIXME Undo dm_table_presuspend_targets */
+       __unlock_fs(md);
+       clear_bit(DMF_BLOCK_IO, &md->flags);
+out_write_unlock:
+       up_write(&md->lock);
+       return error;
+
+out_read_unlock:
+       up_read(&md->lock);
+       return error;
 }
 
 int dm_resume(struct mapped_device *md)
@@ -1164,6 +1195,8 @@ static struct block_device_operations dm_blk_dops = {
        .owner = THIS_MODULE
 };
 
+EXPORT_SYMBOL(dm_get_mapinfo);
+
 /*
  * module hooks
  */