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authorAlexey Khoroshilov <khoroshilov@ispras.ru>2014-09-02 11:40:17 +0400
committerAl Viro <viro@zeniv.linux.org.uk>2014-09-07 13:26:39 -0400
commit9ef7db7f38d0472dd9c444e42d5c5175ccbe5451 (patch)
tree38098751b8e07a868788fda862f96763b55d0763
parent81b6b06197606b4bef4e427a197aeb808e8d89e1 (diff)
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>
-rw-r--r--fs/ufs/inode.c7
-rw-r--r--fs/ufs/namei.c14
2 files changed, 8 insertions, 13 deletions
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 @@ void ufs_evict_inode(struct inode * inode)
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 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,
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 @@ static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
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 @@ static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
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 @@ out_fail:
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;