[PATCH] make dm-mirror not issue invalid resync requests

[pandora-kernel.git] / drivers / md / dm.c

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index d487d9d..0e48151 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -55,6 +55,7 @@ union map_info *dm_get_mapinfo(struct bio *bio)
  */
 #define DMF_BLOCK_IO 0
 #define DMF_SUSPENDED 1
+#define DMF_FROZEN 2
 
 struct mapped_device {
        struct rw_semaphore io_lock;
@@ -97,7 +98,7 @@ struct mapped_device {
         * freeze/thaw support require holding onto a super block
         */
        struct super_block *frozen_sb;
-       struct block_device *frozen_bdev;
+       struct block_device *suspended_bdev;
 };
 
 #define MIN_IOS 256
@@ -399,6 +400,11 @@ struct clone_info {
        unsigned short idx;
 };
 
+static void dm_bio_destructor(struct bio *bio)
+{
+       bio_free(bio, dm_set);
+}
+
 /*
  * Creates a little bio that is just does part of a bvec.
  */
@@ -410,6 +416,7 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector,
        struct bio_vec *bv = bio->bi_io_vec + idx;
 
        clone = bio_alloc_bioset(GFP_NOIO, 1, dm_set);
+       clone->bi_destructor = dm_bio_destructor;
        *clone->bi_io_vec = *bv;
 
        clone->bi_sector = sector;
@@ -830,9 +837,9 @@ static void __set_size(struct mapped_device *md, sector_t size)
 {
        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);
+       down(&md->suspended_bdev->bd_inode->i_sem);
+       i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
+       up(&md->suspended_bdev->bd_inode->i_sem);
 }
 
 static int __bind(struct mapped_device *md, struct dm_table *t)
@@ -896,10 +903,9 @@ int dm_create_with_minor(unsigned int minor, struct mapped_device **result)
        return create_aux(minor, 1, result);
 }
 
-void *dm_get_mdptr(dev_t dev)
+static struct mapped_device *dm_find_md(dev_t dev)
 {
        struct mapped_device *md;
-       void *mdptr = NULL;
        unsigned minor = MINOR(dev);
 
        if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
@@ -908,12 +914,32 @@ void *dm_get_mdptr(dev_t dev)
        down(&_minor_lock);
 
        md = idr_find(&_minor_idr, minor);
-
-       if (md && (dm_disk(md)->first_minor == minor))
-               mdptr = md->interface_ptr;
+       if (!md || (dm_disk(md)->first_minor != minor))
+               md = NULL;
 
        up(&_minor_lock);
 
+       return md;
+}
+
+struct mapped_device *dm_get_md(dev_t dev)
+{
+       struct mapped_device *md = dm_find_md(dev);
+
+       if (md)
+               dm_get(md);
+
+       return md;
+}
+
+void *dm_get_mdptr(dev_t dev)
+{
+       struct mapped_device *md;
+       void *mdptr = NULL;
+
+       md = dm_find_md(dev);
+       if (md)
+               mdptr = md->interface_ptr;
        return mdptr;
 }
 
@@ -985,43 +1011,33 @@ out:
  */
 static int lock_fs(struct mapped_device *md)
 {
-       int r = -ENOMEM;
-
-       md->frozen_bdev = bdget_disk(md->disk, 0);
-       if (!md->frozen_bdev) {
-               DMWARN("bdget failed in lock_fs");
-               goto out;
-       }
+       int r;
 
        WARN_ON(md->frozen_sb);
 
-       md->frozen_sb = freeze_bdev(md->frozen_bdev);
+       md->frozen_sb = freeze_bdev(md->suspended_bdev);
        if (IS_ERR(md->frozen_sb)) {
                r = PTR_ERR(md->frozen_sb);
-               goto out_bdput;
+               md->frozen_sb = NULL;
+               return r;
        }
 
+       set_bit(DMF_FROZEN, &md->flags);
+
        /* don't bdput right now, we don't want the bdev
-        * to go away while it is locked.  We'll bdput
-        * in unlock_fs
+        * to go away while it is locked.
         */
        return 0;
-
-out_bdput:
-       bdput(md->frozen_bdev);
-       md->frozen_sb = NULL;
-       md->frozen_bdev = NULL;
-out:
-       return r;
 }
 
 static void unlock_fs(struct mapped_device *md)
 {
-       thaw_bdev(md->frozen_bdev, md->frozen_sb);
-       bdput(md->frozen_bdev);
+       if (!test_bit(DMF_FROZEN, &md->flags))
+               return;
 
+       thaw_bdev(md->suspended_bdev, md->frozen_sb);
        md->frozen_sb = NULL;
-       md->frozen_bdev = NULL;
+       clear_bit(DMF_FROZEN, &md->flags);
 }
 
 /*
@@ -1031,7 +1047,7 @@ static void unlock_fs(struct mapped_device *md)
  * dm_bind_table, dm_suspend must be called to flush any in
  * flight bios and ensure that any further io gets deferred.
  */
-int dm_suspend(struct mapped_device *md)
+int dm_suspend(struct mapped_device *md, int do_lockfs)
 {
        struct dm_table *map = NULL;
        DECLARE_WAITQUEUE(wait, current);
@@ -1047,10 +1063,19 @@ int dm_suspend(struct mapped_device *md)
        /* This does not get reverted if there's an error later. */
        dm_table_presuspend_targets(map);
 
-       /* Flush I/O to the device. */
-       r = lock_fs(md);
-       if (r)
+       md->suspended_bdev = bdget_disk(md->disk, 0);
+       if (!md->suspended_bdev) {
+               DMWARN("bdget failed in dm_suspend");
+               r = -ENOMEM;
                goto out;
+       }
+
+       /* Flush I/O to the device. */
+       if (do_lockfs) {
+               r = lock_fs(md);
+               if (r)
+                       goto out;
+       }
 
        /*
         * First we set the BLOCK_IO flag so no more ios will be mapped.
@@ -1099,6 +1124,11 @@ int dm_suspend(struct mapped_device *md)
        r = 0;
 
 out:
+       if (r && md->suspended_bdev) {
+               bdput(md->suspended_bdev);
+               md->suspended_bdev = NULL;
+       }
+
        dm_table_put(map);
        up(&md->suspend_lock);
        return r;
@@ -1129,6 +1159,9 @@ int dm_resume(struct mapped_device *md)
 
        unlock_fs(md);
 
+       bdput(md->suspended_bdev);
+       md->suspended_bdev = NULL;
+
        clear_bit(DMF_SUSPENDED, &md->flags);
 
        dm_table_unplug_all(map);