From 64c043de466d5746e7ca306dab9d418cd871cefc Mon Sep 17 00:00:00 2001 From: Liu Bo <bo.li.liu@oracle.com> Date: Mon, 25 May 2015 17:30:15 +0800 Subject: [PATCH] Btrfs: fix up read_tree_block to return proper error The return value of read_tree_block() can confuse callers as it always returns NULL for either -ENOMEM or -EIO, so it's likely that callers parse it to a wrong error, for instance, in btrfs_read_tree_root(). This fixes the above issue. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com> --- fs/btrfs/backref.c | 9 +++++++-- fs/btrfs/ctree.c | 16 ++++++++++------ fs/btrfs/disk-io.c | 28 +++++++++++++++------------- fs/btrfs/extent-tree.c | 11 ++++++++--- fs/btrfs/relocation.c | 19 ++++++++++++++----- 5 files changed, 54 insertions(+), 29 deletions(-) diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c index 614aaa1969bd..679dc97354be 100644 --- a/fs/btrfs/backref.c +++ b/fs/btrfs/backref.c @@ -491,7 +491,9 @@ 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, 0); - if (!eb || !extent_buffer_uptodate(eb)) { + if (IS_ERR(eb)) { + return PTR_ERR(eb); + } else if (!extent_buffer_uptodate(eb)) { free_extent_buffer(eb); return -EIO; } @@ -1034,7 +1036,10 @@ again: eb = read_tree_block(fs_info->extent_root, ref->parent, 0); - if (!eb || !extent_buffer_uptodate(eb)) { + if (IS_ERR(eb)) { + ret = PTR_ERR(eb); + goto out; + } else if (!extent_buffer_uptodate(eb)) { free_extent_buffer(eb); ret = -EIO; goto out; diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 0f11ebc92f02..54114b4887dd 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1439,8 +1439,9 @@ get_old_root(struct btrfs_root *root, u64 time_seq) btrfs_tree_read_unlock(eb_root); free_extent_buffer(eb_root); old = read_tree_block(root, logical, 0); - if (WARN_ON(!old || !extent_buffer_uptodate(old))) { - free_extent_buffer(old); + if (WARN_ON(IS_ERR(old) || !extent_buffer_uptodate(old))) { + if (!IS_ERR(old)) + free_extent_buffer(old); btrfs_warn(root->fs_info, "failed to read tree block %llu from get_old_root", logical); } else { @@ -1685,7 +1686,9 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, if (!cur || !uptodate) { if (!cur) { cur = read_tree_block(root, blocknr, gen); - if (!cur || !extent_buffer_uptodate(cur)) { + if (IS_ERR(cur)) { + return PTR_ERR(cur); + } else if (!extent_buffer_uptodate(cur)) { free_extent_buffer(cur); return -EIO; } @@ -1864,8 +1867,9 @@ static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root, eb = read_tree_block(root, btrfs_node_blockptr(parent, slot), btrfs_node_ptr_generation(parent, slot)); - if (eb && !extent_buffer_uptodate(eb)) { - free_extent_buffer(eb); + if (IS_ERR(eb) || !extent_buffer_uptodate(eb)) { + if (!IS_ERR(eb)) + free_extent_buffer(eb); eb = NULL; } @@ -2494,7 +2498,7 @@ read_block_for_search(struct btrfs_trans_handle *trans, ret = -EAGAIN; tmp = read_tree_block(root, blocknr, 0); - if (tmp) { + if (!IS_ERR(tmp)) { /* * If the read above didn't mark this buffer up to date, * it will never end up being up to date. Set ret to EIO now diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 2ef9a4b72d06..7f8377871283 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1149,12 +1149,12 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr, buf = btrfs_find_create_tree_block(root, bytenr); if (!buf) - return NULL; + return ERR_PTR(-ENOMEM); ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid); if (ret) { free_extent_buffer(buf); - return NULL; + return ERR_PTR(ret); } return buf; @@ -1509,20 +1509,19 @@ static struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root, generation = btrfs_root_generation(&root->root_item); root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item), generation); - if (!root->node) { - ret = -ENOMEM; + if (IS_ERR(root->node)) { + ret = PTR_ERR(root->node); goto find_fail; } else if (!btrfs_buffer_uptodate(root->node, generation, 0)) { ret = -EIO; - goto read_fail; + free_extent_buffer(root->node); + goto find_fail; } root->commit_root = btrfs_root_node(root); out: btrfs_free_path(path); return root; -read_fail: - free_extent_buffer(root->node); find_fail: kfree(root); alloc_fail: @@ -2320,8 +2319,11 @@ static int btrfs_replay_log(struct btrfs_fs_info *fs_info, log_tree_root->node = read_tree_block(tree_root, bytenr, fs_info->generation + 1); - if (!log_tree_root->node || - !extent_buffer_uptodate(log_tree_root->node)) { + if (IS_ERR(log_tree_root->node)) { + printk(KERN_ERR "BTRFS: failed to read log tree\n"); + kfree(log_tree_root); + return PTR_ERR(log_tree_root->node); + } else if (!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); @@ -2797,8 +2799,8 @@ int open_ctree(struct super_block *sb, chunk_root->node = read_tree_block(chunk_root, btrfs_super_chunk_root(disk_super), generation); - if (!chunk_root->node || - !test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) { + if (IS_ERR(chunk_root->node) || + !extent_buffer_uptodate(chunk_root->node)) { printk(KERN_ERR "BTRFS: failed to read chunk root on %s\n", sb->s_id); goto fail_tree_roots; @@ -2834,8 +2836,8 @@ retry_root_backup: tree_root->node = read_tree_block(tree_root, btrfs_super_root(disk_super), generation); - if (!tree_root->node || - !test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) { + if (IS_ERR(tree_root->node) || + !extent_buffer_uptodate(tree_root->node)) { printk(KERN_WARNING "BTRFS: failed to read tree root on %s\n", sb->s_id); diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 076fd7484a82..f1d1216f7feb 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -7979,9 +7979,12 @@ walk_down: child_gen = btrfs_node_ptr_generation(eb, parent_slot); eb = read_tree_block(root, child_bytenr, child_gen); - if (!eb || !extent_buffer_uptodate(eb)) { - ret = -EIO; + if (IS_ERR(eb)) { + ret = PTR_ERR(eb); + goto out; + } else if (!extent_buffer_uptodate(eb)) { free_extent_buffer(eb); + ret = -EIO; goto out; } @@ -8211,7 +8214,9 @@ 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, generation); - if (!next || !extent_buffer_uptodate(next)) { + if (IS_ERR(next)) { + return PTR_ERR(next); + } else if (!extent_buffer_uptodate(next)) { free_extent_buffer(next); return -EIO; } diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 74b24b01d574..827951fbf7fc 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -1847,8 +1847,10 @@ again: } eb = read_tree_block(dest, old_bytenr, old_ptr_gen); - if (!eb || !extent_buffer_uptodate(eb)) { - ret = (!eb) ? -ENOMEM : -EIO; + if (IS_ERR(eb)) { + ret = PTR_ERR(eb); + } else if (!extent_buffer_uptodate(eb)) { + ret = -EIO; free_extent_buffer(eb); break; } @@ -2002,7 +2004,9 @@ int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path, bytenr = btrfs_node_blockptr(eb, path->slots[i]); eb = read_tree_block(root, bytenr, ptr_gen); - if (!eb || !extent_buffer_uptodate(eb)) { + if (IS_ERR(eb)) { + return PTR_ERR(eb); + } else if (!extent_buffer_uptodate(eb)) { free_extent_buffer(eb); return -EIO; } @@ -2710,7 +2714,10 @@ static int do_relocation(struct btrfs_trans_handle *trans, blocksize = root->nodesize; generation = btrfs_node_ptr_generation(upper->eb, slot); eb = read_tree_block(root, bytenr, generation); - if (!eb || !extent_buffer_uptodate(eb)) { + if (IS_ERR(eb)) { + err = PTR_ERR(eb); + goto next; + } else if (!extent_buffer_uptodate(eb)) { free_extent_buffer(eb); err = -EIO; goto next; @@ -2873,7 +2880,9 @@ 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.offset); - if (!eb || !extent_buffer_uptodate(eb)) { + if (IS_ERR(eb)) { + return PTR_ERR(eb); + } else if (!extent_buffer_uptodate(eb)) { free_extent_buffer(eb); return -EIO; }