6.15-stable review patch. If anyone has any objections, please let me know.
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From: Filipe Manana fdmanana@suse.com
commit 24e066ded45b8147b79c7455ac43a5bff7b5f378 upstream.
During log replay, at add_inode_ref(), if we have an extref item that contains multiple extrefs and one of them points to a directory that does not exist in the subvolume tree, we are supposed to ignore it and process the remaining extrefs encoded in the extref item, since each extref can point to a different parent inode. However when that happens we just return from the function and ignore the remaining extrefs.
The problem has been around since extrefs were introduced, in commit f186373fef00 ("btrfs: extended inode refs"), but it's hard to hit in practice because getting extref items encoding multiple extref requires getting a hash collision when computing the offset of the extref's key. The offset if computed like this:
key.offset = btrfs_extref_hash(dir_ino, name->name, name->len);
and btrfs_extref_hash() is just a wrapper around crc32c().
Fix this by moving to next iteration of the loop when we don't find the parent directory that an extref points to.
Fixes: f186373fef00 ("btrfs: extended inode refs") CC: stable@vger.kernel.org # 6.1+ Reviewed-by: Boris Burkov boris@bur.io Signed-off-by: Filipe Manana fdmanana@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/tree-log.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
--- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -1397,6 +1397,8 @@ static noinline int add_inode_ref(struct if (log_ref_ver) { ret = extref_get_fields(eb, ref_ptr, &name, &ref_index, &parent_objectid); + if (ret) + goto out; /* * parent object can change from one array * item to another. @@ -1413,16 +1415,23 @@ static noinline int add_inode_ref(struct * the loop when getting the first * parent dir. */ - if (ret == -ENOENT) + if (ret == -ENOENT) { + /* + * The next extref may refer to + * another parent dir that + * exists, so continue. + */ ret = 0; + goto next; + } goto out; } } } else { ret = ref_get_fields(eb, ref_ptr, &name, &ref_index); + if (ret) + goto out; } - if (ret) - goto out;
ret = inode_in_dir(root, path, btrfs_ino(dir), btrfs_ino(inode), ref_index, &name); @@ -1456,10 +1465,11 @@ static noinline int add_inode_ref(struct } /* Else, ret == 1, we already have a perfect match, we're done. */
+next: ref_ptr = (unsigned long)(ref_ptr + ref_struct_size) + name.len; kfree(name.name); name.name = NULL; - if (log_ref_ver) { + if (log_ref_ver && dir) { iput(&dir->vfs_inode); dir = NULL; }