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author | Xue jiufei <xuejiufei@huawei.com> | 2014-02-10 14:25:54 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-02-10 16:01:43 -0800 |
commit | 0e048316ff577e12c748e2d0a2e4f0f7b006654d (patch) | |
tree | f37ad130de45bf55b3cb43fcb8e5e06a924a41d8 | |
parent | c7d2cbc364b2a237b0ed1bdd7cbf8a24c8a89dfd (diff) | |
download | linux-0e048316ff577e12c748e2d0a2e4f0f7b006654d.tar.bz2 |
ocfs2: check existence of old dentry in ocfs2_link()
System call linkat first calls user_path_at(), check the existence of
old dentry, and then calls vfs_link()->ocfs2_link() to do the actual
work. There may exist a race when Node A create a hard link for file
while node B rm it.
Node A Node B
user_path_at()
->ocfs2_lookup(),
find old dentry exist
rm file, add inode say inodeA
to orphan_dir
call ocfs2_link(),create a
hard link for inodeA.
rm the link, add inodeA to orphan_dir
again
When orphan_scan work start, it calls ocfs2_queue_orphans() to do the
main work. It first tranverses entrys in orphan_dir, linking all inodes
in this orphan_dir to a list look like this:
inodeA->inodeB->...->inodeA
When tranvering this list, it will fall into loop, calling iput() again
and again. And finally trigger BUG_ON(inode->i_state & I_CLEAR).
Signed-off-by: joyce <xuejiufei@huawei.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | fs/ocfs2/namei.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c index f4d609be9400..3683643f3f0e 100644 --- a/fs/ocfs2/namei.c +++ b/fs/ocfs2/namei.c @@ -664,6 +664,7 @@ static int ocfs2_link(struct dentry *old_dentry, struct ocfs2_super *osb = OCFS2_SB(dir->i_sb); struct ocfs2_dir_lookup_result lookup = { NULL, }; sigset_t oldset; + u64 old_de_ino; trace_ocfs2_link((unsigned long long)OCFS2_I(inode)->ip_blkno, old_dentry->d_name.len, old_dentry->d_name.name, @@ -686,6 +687,22 @@ static int ocfs2_link(struct dentry *old_dentry, goto out; } + err = ocfs2_lookup_ino_from_name(dir, old_dentry->d_name.name, + old_dentry->d_name.len, &old_de_ino); + if (err) { + err = -ENOENT; + goto out; + } + + /* + * Check whether another node removed the source inode while we + * were in the vfs. + */ + if (old_de_ino != OCFS2_I(inode)->ip_blkno) { + err = -ENOENT; + goto out; + } + err = ocfs2_check_dir_for_entry(dir, dentry->d_name.name, dentry->d_name.len); if (err) |