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ufs: fix deadlocks introduced by sb mutex merge 

Commit 0244756edc ("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>
This commit is contained in:
Alexey Khoroshilov 2014-09-02 11:40:17 +04:00 committed by Al Viro
parent 81b6b06197
commit 9ef7db7f38
2 changed files with 8 additions and 13 deletions
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7
fs/ufs/inode.c
View File

@ -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);
}

14
fs/ufs/namei.c
View File

@ -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 @@ static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
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;