1 files changed, 72 insertions, 12 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 9ac2eca681eb..3d551231caba 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -257,7 +257,8 @@ static int exclude_super_stripes(struct btrfs_root *root,
                 cache->bytes_super += stripe_len;
                 ret = add_excluded_extent(root, cache->key.objectid,
                                           stripe_len);
-                BUG_ON(ret); /* -ENOMEM */
+                if (ret)
+                        return ret;
         }
 
         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
@@ -265,13 +266,17 @@ static int exclude_super_stripes(struct btrfs_root *root,
                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
                                        cache->key.objectid, bytenr,
                                        0, &logical, &nr, &stripe_len);
-                BUG_ON(ret); /* -ENOMEM */
+                if (ret)
+                        return ret;
 
                 while (nr--) {
                         cache->bytes_super += stripe_len;
                         ret = add_excluded_extent(root, logical[nr],
                                                   stripe_len);
-                        BUG_ON(ret); /* -ENOMEM */
+                        if (ret) {
+                                kfree(logical);
+                                return ret;
+                        }
                 }
 
                 kfree(logical);
@@ -4438,7 +4443,7 @@ static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
         spin_lock(&sinfo->lock);
         spin_lock(&block_rsv->lock);
 
-        block_rsv->size = num_bytes;
+        block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
 
         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
                     sinfo->bytes_reserved + sinfo->bytes_readonly +
@@ -4793,14 +4798,49 @@ out_fail:
          * If the inodes csum_bytes is the same as the original
          * csum_bytes then we know we haven't raced with any free()ers
          * so we can just reduce our inodes csum bytes and carry on.
-         * Otherwise we have to do the normal free thing to account for
-         * the case that the free side didn't free up its reserve
-         * because of this outstanding reservation.
          */
-        if (BTRFS_I(inode)->csum_bytes == csum_bytes)
+        if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
                 calc_csum_metadata_size(inode, num_bytes, 0);
-        else
-                to_free = calc_csum_metadata_size(inode, num_bytes, 0);
+        } else {
+                u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
+                u64 bytes;
+
+                /*
+                 * This is tricky, but first we need to figure out how much we
+                 * free'd from any free-ers that occured during this
+                 * reservation, so we reset ->csum_bytes to the csum_bytes
+                 * before we dropped our lock, and then call the free for the
+                 * number of bytes that were freed while we were trying our
+                 * reservation.
+                 */
+                bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
+                BTRFS_I(inode)->csum_bytes = csum_bytes;
+                to_free = calc_csum_metadata_size(inode, bytes, 0);
+
+
+                /*
+                 * Now we need to see how much we would have freed had we not
+                 * been making this reservation and our ->csum_bytes were not
+                 * artificially inflated.
+                 */
+                BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
+                bytes = csum_bytes - orig_csum_bytes;
+                bytes = calc_csum_metadata_size(inode, bytes, 0);
+
+                /*
+                 * Now reset ->csum_bytes to what it should be.  If bytes is
+                 * more than to_free then we would have free'd more space had we
+                 * not had an artificially high ->csum_bytes, so we need to free
+                 * the remainder.  If bytes is the same or less then we don't
+                 * need to do anything, the other free-ers did the correct
+                 * thing.
+                 */
+                BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
+                if (bytes > to_free)
+                        to_free = bytes - to_free;
+                else
+                        to_free = 0;
+        }
         spin_unlock(&BTRFS_I(inode)->lock);
         if (dropped)
                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
@@ -7947,7 +7987,17 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                  * info has super bytes accounted for, otherwise we'll think
                  * we have more space than we actually do.
                  */
-                exclude_super_stripes(root, cache);
+                ret = exclude_super_stripes(root, cache);
+                if (ret) {
+                        /*
+                         * We may have excluded something, so call this just in
+                         * case.
+                         */
+                        free_excluded_extents(root, cache);
+                        kfree(cache->free_space_ctl);
+                        kfree(cache);
+                        goto error;
+                }
 
                 /*
                  * check for two cases, either we are full, and therefore
@@ -8089,7 +8139,17 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans,
 
         cache->last_byte_to_unpin = (u64)-1;
         cache->cached = BTRFS_CACHE_FINISHED;
-        exclude_super_stripes(root, cache);
+        ret = exclude_super_stripes(root, cache);
+        if (ret) {
+                /*
+                 * We may have excluded something, so call this just in
+                 * case.
+                 */
+                free_excluded_extents(root, cache);
+                kfree(cache->free_space_ctl);
+                kfree(cache);
+                return ret;
+        }
 
         add_new_free_space(cache, root->fs_info, chunk_offset,
                            chunk_offset + size);