* [PATCH 2/2] [PATCH 2/2] Btrfs: fix up read_tree_block to return proper error
2015-05-25 9:30 [PATCH 1/2 RESEND] Btrfs: add missing free_extent_buffer Liu Bo
@ 2015-05-25 9:30 ` Liu Bo
2015-05-26 16:34 ` David Sterba
2015-05-26 16:34 ` [PATCH 1/2 RESEND] Btrfs: add missing free_extent_buffer David Sterba
1 sibling, 1 reply; 4+ messages in thread
From: Liu Bo @ 2015-05-25 9:30 UTC (permalink / raw)
To: linux-btrfs
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>
---
This is based on the latest for-linus-4.1.
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 614aaa1..679dc97 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 0f11ebc..54114b4 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 2ef9a4b..7f83778 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 a129254..dfae474 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -7920,9 +7920,12 @@ 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;
}
@@ -8152,7 +8155,9 @@ 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 74b24b0..827951f 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;
}
--
2.1.0
^ permalink raw reply related [flat|nested] 4+ messages in thread