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nilfs2: prevent WARNING in nilfs_dat_commit_end()

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If nilfs2 reads a corrupted disk image and its DAT metadata file contains
invalid lifetime data for a virtual block number, a kernel warning can be
generated by the WARN_ON check in nilfs_dat_commit_end() and can panic if
the kernel is booted with panic_on_warn.

This patch avoids the issue with a sanity check that treats it as an
error.

Since error return is not allowed in the execution phase of
nilfs_dat_commit_end(), this inserts that sanity check in
nilfs_dat_prepare_end(), which prepares for nilfs_dat_commit_end().

As the error code, -EINVAL is returned to notify bmap layer of the
metadata corruption.  When the bmap layer sees this code, it handles the
abnormal situation and replaces the return code with -EIO as it should.

Link: https://lkml.kernel.org/r/000000000000154d2c05e9ec7df6@google.com
Link: https://lkml.kernel.org/r/20230127132202.6083-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: <syzbot+cbff7a52b6f99059e67f@syzkaller.appspotmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Ryusuke Konishi 2023-01-27 22:22:02 +09:00 committed by Andrew Morton
parent e89bd9e7d8
commit 602ce7b8e1
1 changed files with 11 additions and 0 deletions
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11
fs/nilfs2/dat.c
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@ -158,6 +158,7 @@ void nilfs_dat_commit_start(struct inode *dat, struct nilfs_palloc_req *req,
int nilfs_dat_prepare_end(struct inode *dat, struct nilfs_palloc_req *req)
{
struct nilfs_dat_entry *entry;
__u64 start;
sector_t blocknr;
void *kaddr;
int ret;
@ -169,6 +170,7 @@ int nilfs_dat_prepare_end(struct inode *dat, struct nilfs_palloc_req *req)
kaddr = kmap_atomic(req->pr_entry_bh->b_page);
entry = nilfs_palloc_block_get_entry(dat, req->pr_entry_nr,
req->pr_entry_bh, kaddr);
start = le64_to_cpu(entry->de_start);
blocknr = le64_to_cpu(entry->de_blocknr);
kunmap_atomic(kaddr);
@ -179,6 +181,15 @@ int nilfs_dat_prepare_end(struct inode *dat, struct nilfs_palloc_req *req)
return ret;
}
}
if (unlikely(start > nilfs_mdt_cno(dat))) {
nilfs_err(dat->i_sb,
"vblocknr = %llu has abnormal lifetime: start cno (= %llu) > current cno (= %llu)",
(unsigned long long)req->pr_entry_nr,
(unsigned long long)start,
(unsigned long long)nilfs_mdt_cno(dat));
nilfs_dat_abort_entry(dat, req);
return -EINVAL;
}
return 0;
}