[PATCH 5.4 08/84] nilfs2: replace WARN_ONs for invalid DAT metadata block requests

Greg Kroah-Hartman
2024-02-27T14:23:35Z

From: Ryusuke Konishi <konishi.ryusuke@gmail.com>

commit 5124a0a549857c4b87173280e192eea24dea72ad upstream.

If DAT metadata file block access fails due to corruption of the DAT file
or abnormal virtual block numbers held by b-trees or inodes, a kernel
warning is generated.

This replaces the WARN_ONs by error output, so that a kernel, booted with
panic_on_warn, does not panic. This patch also replaces the detected
return code -ENOENT with another internal code -EINVAL to notify the bmap
layer of metadata corruption. When the bmap layer sees -EINVAL, it
handles the abnormal situation with nilfs_bmap_convert_error() and finally
returns code -EIO as it should.

Link: https://lkml.kernel.org/r/0000000000005cc3d205ea23ddcf@google.com
Link: https://lkml.kernel.org/r/20230126164114.6911-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: <syzbot+5d5d25f90f195a3cfcb4@syzkaller.appspotmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/nilfs2/dat.c | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)

--- a/fs/nilfs2/dat.c
+++ b/fs/nilfs2/dat.c
@@ -40,8 +40,21 @@ static inline struct nilfs_dat_info *NIL
static int nilfs_dat_prepare_entry(struct inode *dat,
struct nilfs_palloc_req *req, int create)
{
- return nilfs_palloc_get_entry_block(dat, req->pr_entry_nr,
- create, &req->pr_entry_bh);
+ int ret;
+
+ ret = nilfs_palloc_get_entry_block(dat, req->pr_entry_nr,
+ create, &req->pr_entry_bh);
+ if (unlikely(ret == -ENOENT)) {
+ nilfs_msg(dat->i_sb, KERN_ERR,
+ "DAT doesn't have a block to manage vblocknr = %llu",
+ (unsigned long long)req->pr_entry_nr);
+ /*
+ * Return internal code -EINVAL to notify bmap layer of
+ * metadata corruption.
+ */
+ ret = -EINVAL;
+ }
+ return ret;
}

static void nilfs_dat_commit_entry(struct inode *dat,
@@ -123,11 +136,7 @@ static void nilfs_dat_commit_free(struct

int nilfs_dat_prepare_start(struct inode *dat, struct nilfs_palloc_req *req)
{
- int ret;
-
- ret = nilfs_dat_prepare_entry(dat, req, 0);
- WARN_ON(ret == -ENOENT);
- return ret;
+ return nilfs_dat_prepare_entry(dat, req, 0);
}

void nilfs_dat_commit_start(struct inode *dat, struct nilfs_palloc_req *req,
@@ -154,10 +163,8 @@ int nilfs_dat_prepare_end(struct inode *
int ret;

ret = nilfs_dat_prepare_entry(dat, req, 0);
- if (ret < 0) {
- WARN_ON(ret == -ENOENT);
+ if (ret < 0)
return ret;
- }

kaddr = kmap_atomic(req->pr_entry_bh->b_page);
entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,