Subject: [merged] ocfs2-check-existence-of-old-dentry-in-ocfs2_link.patch removed from -mm tree
To: xuejiufei@xxxxxxxxxx,jlbec@xxxxxxxxxxxx,mfasheh@xxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 11 Feb 2014 11:23:54 -0800
The patch titled
Subject: ocfs2: check existence of old dentry in ocfs2_link()
has been removed from the -mm tree. Its filename was
ocfs2-check-existence-of-old-dentry-in-ocfs2_link.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Xue jiufei <xuejiufei@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Reviewed-by: Mark Fasheh <mfasheh@xxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/namei.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff -puN fs/ocfs2/namei.c~ocfs2-check-existence-of-old-dentry-in-ocfs2_link fs/ocfs2/namei.c
--- a/fs/ocfs2/namei.c~ocfs2-check-existence-of-old-dentry-in-ocfs2_link
+++ a/fs/ocfs2/namei.c
@@ -664,6 +664,7 @@ static int ocfs2_link(struct dentry *old
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,
@@ -685,6 +686,22 @@ static int ocfs2_link(struct dentry *old
err = -ENOENT;
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);
_
Patches currently in -mm which might be from xuejiufei@xxxxxxxxxx are
origin.patch
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