Btrfs: fix all callers of read_tree_block

We kept leaking extent buffers when mounting a broken file system and it turns
out it's because not everybody uses read_tree_block properly.  You need to check
and make sure the extent_buffer is uptodate before you use it.  This patch fixes
everybody who calls read_tree_block directly to make sure they check that it is
uptodate and free it and return an error if it is not.  With this we no longer
leak EB's when things go horribly wrong.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>

5 files changed, 59 insertions, 13 deletions

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 23e927b191c9..04b5b3093893 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -423,7 +423,10 @@ static int __add_missing_keys(struct btrfs_fs_info *fs_info,
                 BUG_ON(!ref->wanted_disk_byte);
                 eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
                                      fs_info->tree_root->leafsize, 0);
-                BUG_ON(!eb);
+                if (!eb || !extent_buffer_uptodate(eb)) {
+                        free_extent_buffer(eb);
+                        return -EIO;
+                }
                 btrfs_tree_read_lock(eb);
                 if (btrfs_header_level(eb) == 0)
                         btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
@@ -913,7 +916,10 @@ again:
                                                         info_level);
                                 eb = read_tree_block(fs_info->extent_root,
                                                            ref->parent, bsz, 0);
-                                BUG_ON(!eb);
+                                if (!eb || !extent_buffer_uptodate(eb)) {
+                                        free_extent_buffer(eb);
+                                        return -EIO;
+                                }
                                 ret = find_extent_in_eb(eb, bytenr,
                                                         *extent_item_pos, &eie);
                                 ref->inode_list = eie;
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 566d99b51bef..2bc34408872d 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1281,7 +1281,8 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
                 free_extent_buffer(eb_root);
                 blocksize = btrfs_level_size(root, old_root->level);
                 old = read_tree_block(root, logical, blocksize, 0);
-                if (!old) {
+                if (!old || !extent_buffer_uptodate(old)) {
+                        free_extent_buffer(old);
                         pr_warn("btrfs: failed to read tree block %llu from get_old_root\n",
                                 logical);
                         WARN_ON(1);
@@ -1526,8 +1527,10 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                         if (!cur) {
                                 cur = read_tree_block(root, blocknr,
                                                          blocksize, gen);
-                                if (!cur)
+                                if (!cur || !extent_buffer_uptodate(cur)) {
+                                        free_extent_buffer(cur);
                                         return -EIO;
+                                }
                         } else if (!uptodate) {
                                 err = btrfs_read_buffer(cur, gen);
                                 if (err) {
@@ -1692,6 +1695,8 @@ static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
                                    struct extent_buffer *parent, int slot)
 {
         int level = btrfs_header_level(parent);
+        struct extent_buffer *eb;
+
         if (slot < 0)
                 return NULL;
         if (slot >= btrfs_header_nritems(parent))
@@ -1699,9 +1704,15 @@ static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
 
         BUG_ON(level == 0);
 
-        return read_tree_block(root, btrfs_node_blockptr(parent, slot),
-                       btrfs_level_size(root, level - 1),
-                       btrfs_node_ptr_generation(parent, slot));
+        eb = read_tree_block(root, btrfs_node_blockptr(parent, slot),
+                             btrfs_level_size(root, level - 1),
+                             btrfs_node_ptr_generation(parent, slot));
+        if (eb && !extent_buffer_uptodate(eb)) {
+                free_extent_buffer(eb);
+                eb = NULL;
+        }
+
+        return eb;
 }
 
 /*
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index c7d8fb0dbff6..deb6e3d07281 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1496,6 +1496,14 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
                                      blocksize, generation);
+        if (!root->node || !extent_buffer_uptodate(root->node)) {
+                ret = (!root->node) ? -ENOMEM : -EIO;
+
+                free_extent_buffer(root->node);
+                kfree(root);
+                return ERR_PTR(ret);
+        }
+
         root->commit_root = btrfs_root_node(root);
         BUG_ON(!root->node); /* -ENOMEM */
 out:
@@ -2515,8 +2523,8 @@ int open_ctree(struct super_block *sb,
         chunk_root->node = read_tree_block(chunk_root,
                                            btrfs_super_chunk_root(disk_super),
                                            blocksize, generation);
-        BUG_ON(!chunk_root->node); /* -ENOMEM */
-        if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
+        if (!chunk_root->node ||
+            !test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
                 printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
                        sb->s_id);
                 goto fail_tree_roots;
@@ -2701,6 +2709,13 @@ retry_root_backup:
                 log_tree_root->node = read_tree_block(tree_root, bytenr,
                                                       blocksize,
                                                       generation + 1);
+                if (!log_tree_root->node ||
+                    !extent_buffer_uptodate(log_tree_root->node)) {
+                        printk(KERN_ERR "btrfs: failed to read log tree\n");
+                        free_extent_buffer(log_tree_root->node);
+                        kfree(log_tree_root);
+                        goto fail_trans_kthread;
+                }
                 /* returns with log_tree_root freed on success */
                 ret = btrfs_recover_log_trees(log_tree_root);
                 if (ret) {
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 94bed61b799f..6526f1faf6c2 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7087,8 +7087,10 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
                 if (reada && level == 1)
                         reada_walk_down(trans, root, wc, path);
                 next = read_tree_block(root, bytenr, blocksize, generation);
-                if (!next)
+                if (!next || !extent_buffer_uptodate(next)) {
+                        free_extent_buffer(next);
                         return -EIO;
+                }
                 btrfs_tree_lock(next);
                 btrfs_set_lock_blocking(next);
         }
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 208154986c4c..63cdd9246c70 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1771,7 +1771,11 @@ again:
 
                         eb = read_tree_block(dest, old_bytenr, blocksize,
                                              old_ptr_gen);
-                        BUG_ON(!eb);
+                        if (!eb || !extent_buffer_uptodate(eb)) {
+                                ret = (!eb) ? -ENOMEM : -EIO;
+                                free_extent_buffer(eb);
+                                return ret;
+                        }
                         btrfs_tree_lock(eb);
                         if (cow) {
                                 ret = btrfs_cow_block(trans, dest, eb, parent,
@@ -1924,6 +1928,10 @@ int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
                 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
                 blocksize = btrfs_level_size(root, i - 1);
                 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
+                if (!eb || !extent_buffer_uptodate(eb)) {
+                        free_extent_buffer(eb);
+                        return -EIO;
+                }
                 BUG_ON(btrfs_header_level(eb) != i - 1);
                 path->nodes[i - 1] = eb;
                 path->slots[i - 1] = 0;
@@ -2601,7 +2609,8 @@ static int do_relocation(struct btrfs_trans_handle *trans,
                 blocksize = btrfs_level_size(root, node->level);
                 generation = btrfs_node_ptr_generation(upper->eb, slot);
                 eb = read_tree_block(root, bytenr, blocksize, generation);
-                if (!eb) {
+                if (!eb || !extent_buffer_uptodate(eb)) {
+                        free_extent_buffer(eb);
                         err = -EIO;
                         goto next;
                 }
@@ -2762,7 +2771,10 @@ static int get_tree_block_key(struct reloc_control *rc,
         BUG_ON(block->key_ready);
         eb = read_tree_block(rc->extent_root, block->bytenr,
                              block->key.objectid, block->key.offset);
-        BUG_ON(!eb);
+        if (!eb || !extent_buffer_uptodate(eb)) {
+                free_extent_buffer(eb);
+                return -EIO;
+        }
         WARN_ON(btrfs_header_level(eb) != block->level);
         if (block->level == 0)
                 btrfs_item_key_to_cpu(eb, &block->key, 0);