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authorJeff Layton <jlayton@redhat.com>2014-03-10 09:54:15 -0400
committerJeff Layton <jlayton@redhat.com>2014-03-31 08:24:43 -0400
commitd7a06983a01a33605191c0766857b832ac32a2b6 (patch)
treed6a0f83579e0d7a20a235ddb568d935fe54b24fb /fs
parent90478939dce096ed5b239cad16237dca0a59d66f (diff)
downloadlinux-d7a06983a01a33605191c0766857b832ac32a2b6.tar.bz2
locks: fix locks_mandatory_locked to respect file-private locks
As Trond pointed out, you can currently deadlock yourself by setting a file-private lock on a file that requires mandatory locking and then trying to do I/O on it. Avoid this problem by plumbing some knowledge of file-private locks into the mandatory locking code. In order to do this, we must pass down information about the struct file that's being used to locks_verify_locked. Reported-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Acked-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/locks.c7
-rw-r--r--fs/namei.c2
2 files changed, 5 insertions, 4 deletions
diff --git a/fs/locks.c b/fs/locks.c
index 09d6c8c33c81..d82c51c4fcd2 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1155,13 +1155,14 @@ EXPORT_SYMBOL(posix_lock_file_wait);
/**
* locks_mandatory_locked - Check for an active lock
- * @inode: the file to check
+ * @file: the file to check
*
* Searches the inode's list of locks to find any POSIX locks which conflict.
* This function is called from locks_verify_locked() only.
*/
-int locks_mandatory_locked(struct inode *inode)
+int locks_mandatory_locked(struct file *file)
{
+ struct inode *inode = file_inode(file);
fl_owner_t owner = current->files;
struct file_lock *fl;
@@ -1172,7 +1173,7 @@ int locks_mandatory_locked(struct inode *inode)
for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
if (!IS_POSIX(fl))
continue;
- if (fl->fl_owner != owner)
+ if (fl->fl_owner != owner && fl->fl_owner != (fl_owner_t)file)
break;
}
spin_unlock(&inode->i_lock);
diff --git a/fs/namei.c b/fs/namei.c
index d580df2e6804..dc51bac037c9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2542,7 +2542,7 @@ static int handle_truncate(struct file *filp)
/*
* Refuse to truncate files with mandatory locks held on them.
*/
- error = locks_verify_locked(inode);
+ error = locks_verify_locked(filp);
if (!error)
error = security_path_truncate(path);
if (!error) {