Btrfs: fix a bug in parsing return value in logical resolve

In logical resolve, we parse extent_from_logical()'s 'ret' as a kind of flag.

It is possible to lose our errors because
(-EXXXX & BTRFS_EXTENT_FLAG_TREE_BLOCK) is true.

I'm not sure if it is on purpose, it just looks too hacky if it is.
I'd rather use a real flag and a 'ret' to catch errors.

Acked-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Liu Bo <liub.liubo@gmail.com>

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index e600857..ab286e5 100644 (file)
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1193,7 +1193,8 @@ char *btrfs_iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
  * tree blocks and <0 on error.
  */
 int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
-                       struct btrfs_path *path, struct btrfs_key *found_key)
+                       struct btrfs_path *path, struct btrfs_key *found_key,
+                       u64 *flags_ret)
 {
        int ret;
        u64 flags;
@@ -1237,10 +1238,17 @@ int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
                 (unsigned long long)found_key->objectid,
                 (unsigned long long)found_key->offset,
                 (unsigned long long)flags, item_size);
-       if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
-               return BTRFS_EXTENT_FLAG_TREE_BLOCK;
-       if (flags & BTRFS_EXTENT_FLAG_DATA)
-               return BTRFS_EXTENT_FLAG_DATA;
+
+       WARN_ON(!flags_ret);
+       if (flags_ret) {
+               if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
+                       *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
+               else if (flags & BTRFS_EXTENT_FLAG_DATA)
+                       *flags_ret = BTRFS_EXTENT_FLAG_DATA;
+               else
+                       BUG_ON(1);
+               return 0;
+       }
 
        return -EIO;
 }
@@ -1433,15 +1441,15 @@ int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
 {
        int ret;
        u64 extent_item_pos;
+       u64 flags = 0;
        struct btrfs_key found_key;
        int search_commit_root = path->search_commit_root;
 
-       ret = extent_from_logical(fs_info, logical, path,
-                                       &found_key);
+       ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
        btrfs_release_path(path);
        if (ret < 0)
                return ret;
-       if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK)
+       if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
                return -EINVAL;
 
        extent_item_pos = logical - found_key.objectid;

diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index 032f4dc..4fda5d8 100644 (file)
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -40,7 +40,8 @@ int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
                        struct btrfs_path *path);
 
 int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
-                       struct btrfs_path *path, struct btrfs_key *found_key);
+                       struct btrfs_path *path, struct btrfs_key *found_key,
+                       u64 *flags);
 
 int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
                                struct btrfs_extent_item *ei, u32 item_size,

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index de886ac..48ff3f7 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3211,6 +3211,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
        int ret = 0;
        int size;
        u64 extent_item_pos;
+       u64 flags = 0;
        struct btrfs_ioctl_logical_ino_args *loi;
        struct btrfs_data_container *inodes = NULL;
        struct btrfs_path *path = NULL;
@@ -3240,10 +3241,11 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
                goto out;
        }
 
-       ret = extent_from_logical(root->fs_info, loi->logical, path, &key);
+       ret = extent_from_logical(root->fs_info, loi->logical, path, &key,
+                                 &flags);
        btrfs_release_path(path);
 
-       if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK)
+       if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
                ret = -ENOENT;
        if (ret < 0)
                goto out;

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 4e9eafe..d3bb901 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -352,13 +352,14 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
        struct extent_buffer *eb;
        struct btrfs_extent_item *ei;
        struct scrub_warning swarn;
-       u32 item_size;
-       int ret;
+       unsigned long ptr = 0;
+       u64 extent_item_pos;
+       u64 flags = 0;
        u64 ref_root;
+       u32 item_size;
        u8 ref_level;
-       unsigned long ptr = 0;
        const int bufsize = 4096;
-       u64 extent_item_pos;
+       int ret;
 
        path = btrfs_alloc_path();
 
@@ -375,7 +376,8 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
        if (!path || !swarn.scratch_buf || !swarn.msg_buf)
                goto out;
 
-       ret = extent_from_logical(fs_info, swarn.logical, path, &found_key);
+       ret = extent_from_logical(fs_info, swarn.logical, path, &found_key,
+                                 &flags);
        if (ret < 0)
                goto out;
 
@@ -387,7 +389,7 @@ static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
        item_size = btrfs_item_size_nr(eb, path->slots[0]);
        btrfs_release_path(path);
 
-       if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
+       if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
                do {
                        ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
                                                        &ref_root, &ref_level);

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index e5c8679..c6ef070 100644 (file)
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -1152,6 +1152,7 @@ static int find_extent_clone(struct send_ctx *sctx,
        u64 disk_byte;
        u64 num_bytes;
        u64 extent_item_pos;
+       u64 flags = 0;
        struct btrfs_file_extent_item *fi;
        struct extent_buffer *eb = path->nodes[0];
        struct backref_ctx *backref_ctx = NULL;
@@ -1198,13 +1199,13 @@ static int find_extent_clone(struct send_ctx *sctx,
        }
        logical = disk_byte + btrfs_file_extent_offset(eb, fi);
 
-       ret = extent_from_logical(sctx->send_root->fs_info,
-                       disk_byte, tmp_path, &found_key);
+       ret = extent_from_logical(sctx->send_root->fs_info, disk_byte, tmp_path,
+                                 &found_key, &flags);
        btrfs_release_path(tmp_path);
 
        if (ret < 0)
                goto out;
-       if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
+       if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
                ret = -EIO;
                goto out;
        }