path: root/fs/cifs/cifsfs.h
diff options
authorJeff Layton <jlayton@poochiereds.net>2014-04-30 09:31:47 -0400
committerSteve French <smfrench@gmail.com>2014-05-21 10:18:05 -0700
commit4f73c7d342d57d065bdbc0995cb56d8d1701b0c0 (patch)
tree6933002e316475c879d702ffbb733a24ba4f0561 /fs/cifs/cifsfs.h
parentcifs: new helper function: cifs_revalidate_mapping (diff)
cifs: fix potential races in cifs_revalidate_mapping
The handling of the CIFS_INO_INVALID_MAPPING flag is racy. It's possible for two tasks to attempt to revalidate the mapping at the same time. The first sees that CIFS_INO_INVALID_MAPPING is set. It clears the flag and then calls invalidate_inode_pages2 to start shooting down the pagecache. While that's going on, another task checks the flag and sees that it's clear. It then ends up trusting the pagecache to satisfy a read when it shouldn't. Fix this by adding a bitlock to ensure that the clearing of the flag is atomic with respect to the actual cache invalidation. Also, move the other existing users of cifs_invalidate_mapping to use a new cifs_zap_mapping() function that just sets the INVALID_MAPPING bit and then uses the standard codepath to handle the invalidation. Signed-off-by: Jeff Layton <jlayton@poochiereds.net> Signed-off-by: Steve French <smfrench@gmail.com>
Diffstat (limited to 'fs/cifs/cifsfs.h')
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 63d51274dfbf..1bbe97c2a632 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -76,6 +76,7 @@ extern int cifs_revalidate_file(struct file *filp);
extern int cifs_revalidate_dentry(struct dentry *);
extern int cifs_invalidate_mapping(struct inode *inode);
extern int cifs_revalidate_mapping(struct inode *inode);
+extern int cifs_zap_mapping(struct inode *inode);
extern int cifs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
extern int cifs_setattr(struct dentry *, struct iattr *);