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authorXue jiufei <xuejiufei@huawei.com>2014-02-10 14:25:54 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-02-10 16:01:43 -0800
commit0e048316ff577e12c748e2d0a2e4f0f7b006654d (patch)
treef37ad130de45bf55b3cb43fcb8e5e06a924a41d8 /fs/ocfs2/namei.c
parentc7d2cbc364b2a237b0ed1bdd7cbf8a24c8a89dfd (diff)
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>
Diffstat (limited to 'fs/ocfs2/namei.c')
-rw-r--r--fs/ocfs2/namei.c17
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)