udf: Fix deadlock in udf_release_file()

udf_release_file() can be called from munmap() path with mmap_sem held.  Thus
we cannot take i_mutex there because that ranks above mmap_sem. Luckily,
i_mutex is not needed in udf_release_file() anymore since protection by
i_data_sem is enough to protect from races with write and truncate.

CC: stable@vger.kernel.org (2.6.38 & later)
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2012-02-20 17:49:56 +01:00
parent b2527bfa53
commit a0391a3ae9
1 changed files with 0 additions and 2 deletions

View File

@ -201,12 +201,10 @@ out:
static int udf_release_file(struct inode *inode, struct file *filp)
{
if (filp->f_mode & FMODE_WRITE) {
mutex_lock(&inode->i_mutex);
down_write(&UDF_I(inode)->i_data_sem);
udf_discard_prealloc(inode);
udf_truncate_tail_extent(inode);
up_write(&UDF_I(inode)->i_data_sem);
mutex_unlock(&inode->i_mutex);
}
return 0;
}