Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[uclinux-h8/linux.git] / fs / btrfs / volumes.c

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 4b438b4..fbe7c10 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2766,6 +2766,20 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
        root = root->fs_info->chunk_root;
        extent_root = root->fs_info->extent_root;
 
+       /*
+        * Prevent races with automatic removal of unused block groups.
+        * After we relocate and before we remove the chunk with offset
+        * chunk_offset, automatic removal of the block group can kick in,
+        * resulting in a failure when calling btrfs_remove_chunk() below.
+        *
+        * Make sure to acquire this mutex before doing a tree search (dev
+        * or chunk trees) to find chunks. Otherwise the cleaner kthread might
+        * call btrfs_remove_chunk() (through btrfs_delete_unused_bgs()) after
+        * we release the path used to search the chunk/dev tree and before
+        * the current task acquires this mutex and calls us.
+        */
+       ASSERT(mutex_is_locked(&root->fs_info->delete_unused_bgs_mutex));
+
        ret = btrfs_can_relocate(extent_root, chunk_offset);
        if (ret)
                return -ENOSPC;
@@ -2814,13 +2828,18 @@ again:
        key.type = BTRFS_CHUNK_ITEM_KEY;
 
        while (1) {
+               mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
                ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
-               if (ret < 0)
+               if (ret < 0) {
+                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
                        goto error;
+               }
                BUG_ON(ret == 0); /* Corruption */
 
                ret = btrfs_previous_item(chunk_root, path, key.objectid,
                                          key.type);
+               if (ret)
+                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
                if (ret < 0)
                        goto error;
                if (ret > 0)
@@ -2843,6 +2862,7 @@ again:
                        else
                                BUG_ON(ret);
                }
+               mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
 
                if (found_key.offset == 0)
                        break;
@@ -3299,9 +3319,12 @@ again:
                        goto error;
                }
 
+               mutex_lock(&fs_info->delete_unused_bgs_mutex);
                ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
-               if (ret < 0)
+               if (ret < 0) {
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                        goto error;
+               }
 
                /*
                 * this shouldn't happen, it means the last relocate
@@ -3313,6 +3336,7 @@ again:
                ret = btrfs_previous_item(chunk_root, path, 0,
                                          BTRFS_CHUNK_ITEM_KEY);
                if (ret) {
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                        ret = 0;
                        break;
                }
@@ -3321,8 +3345,10 @@ again:
                slot = path->slots[0];
                btrfs_item_key_to_cpu(leaf, &found_key, slot);
 
-               if (found_key.objectid != key.objectid)
+               if (found_key.objectid != key.objectid) {
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                        break;
+               }
 
                chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
 
@@ -3335,10 +3361,13 @@ again:
                ret = should_balance_chunk(chunk_root, leaf, chunk,
                                           found_key.offset);
                btrfs_release_path(path);
-               if (!ret)
+               if (!ret) {
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                        goto loop;
+               }
 
                if (counting) {
+                       mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                        spin_lock(&fs_info->balance_lock);
                        bctl->stat.expected++;
                        spin_unlock(&fs_info->balance_lock);
@@ -3348,6 +3377,7 @@ again:
                ret = btrfs_relocate_chunk(chunk_root,
                                           found_key.objectid,
                                           found_key.offset);
+               mutex_unlock(&fs_info->delete_unused_bgs_mutex);
                if (ret && ret != -ENOSPC)
                        goto error;
                if (ret == -ENOSPC) {
@@ -4087,11 +4117,16 @@ again:
        key.type = BTRFS_DEV_EXTENT_KEY;
 
        do {
+               mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
                ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
-               if (ret < 0)
+               if (ret < 0) {
+                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
                        goto done;
+               }
 
                ret = btrfs_previous_item(root, path, 0, key.type);
+               if (ret)
+                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
                if (ret < 0)
                        goto done;
                if (ret) {
@@ -4105,6 +4140,7 @@ again:
                btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 
                if (key.objectid != device->devid) {
+                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
                        btrfs_release_path(path);
                        break;
                }
@@ -4113,6 +4149,7 @@ again:
                length = btrfs_dev_extent_length(l, dev_extent);
 
                if (key.offset + length <= new_size) {
+                       mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
                        btrfs_release_path(path);
                        break;
                }
@@ -4122,6 +4159,7 @@ again:
                btrfs_release_path(path);
 
                ret = btrfs_relocate_chunk(root, chunk_objectid, chunk_offset);
+               mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
                if (ret && ret != -ENOSPC)
                        goto done;
                if (ret == -ENOSPC)
@@ -5715,7 +5753,6 @@ static inline void btrfs_end_bbio(struct btrfs_bio *bbio, struct bio *bio, int e
 static void btrfs_end_bio(struct bio *bio, int err)
 {
        struct btrfs_bio *bbio = bio->bi_private;
-       struct btrfs_device *dev = bbio->stripes[0].dev;
        int is_orig_bio = 0;
 
        if (err) {
@@ -5723,6 +5760,7 @@ static void btrfs_end_bio(struct bio *bio, int err)
                if (err == -EIO || err == -EREMOTEIO) {
                        unsigned int stripe_index =
                                btrfs_io_bio(bio)->stripe_index;
+                       struct btrfs_device *dev;
 
                        BUG_ON(stripe_index >= bbio->num_stripes);
                        dev = bbio->stripes[stripe_index].dev;