ufs: fix deadlocks introduced by sb mutex merge
Commit 0244756edc4b ("ufs: sb mutex merge + mutex_destroy") introduces
deadlocks in ufs_new_inode() and ufs_free_inode().
Most callers of that functions acqure the mutex by themselves and
ufs_{new,free}_inode() do that via lock_ufs(),
i.e we have an unavoidable double lock.
The patch proposes to resolve the issue by making sure that
ufs_{new,free}_inode() are not called with the mutex held.
Found by Linux Driver Verification project (linuxtesting.org).
Cc: stable@vger.kernel.org # 3.16
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c
index 7c580c9..be7d42c 100644
--- a/fs/ufs/inode.c
+++ b/fs/ufs/inode.c
@@ -902,9 +902,6 @@
invalidate_inode_buffers(inode);
clear_inode(inode);
- if (want_delete) {
- lock_ufs(inode->i_sb);
- ufs_free_inode (inode);
- unlock_ufs(inode->i_sb);
- }
+ if (want_delete)
+ ufs_free_inode(inode);
}
diff --git a/fs/ufs/namei.c b/fs/ufs/namei.c
index 90d74b8..2df62a7 100644
--- a/fs/ufs/namei.c
+++ b/fs/ufs/namei.c
@@ -126,12 +126,12 @@
if (l > sb->s_blocksize)
goto out_notlocked;
- lock_ufs(dir->i_sb);
inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
err = PTR_ERR(inode);
if (IS_ERR(inode))
- goto out;
+ goto out_notlocked;
+ lock_ufs(dir->i_sb);
if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
/* slow symlink */
inode->i_op = &ufs_symlink_inode_operations;
@@ -181,13 +181,9 @@
struct inode * inode;
int err;
- lock_ufs(dir->i_sb);
- inode_inc_link_count(dir);
-
inode = ufs_new_inode(dir, S_IFDIR|mode);
- err = PTR_ERR(inode);
if (IS_ERR(inode))
- goto out_dir;
+ return PTR_ERR(inode);
inode->i_op = &ufs_dir_inode_operations;
inode->i_fop = &ufs_dir_operations;
@@ -195,6 +191,9 @@
inode_inc_link_count(inode);
+ lock_ufs(dir->i_sb);
+ inode_inc_link_count(dir);
+
err = ufs_make_empty(inode, dir);
if (err)
goto out_fail;
@@ -212,7 +211,6 @@
inode_dec_link_count(inode);
inode_dec_link_count(inode);
iput (inode);
-out_dir:
inode_dec_link_count(dir);
unlock_ufs(dir->i_sb);
goto out;