gfs2: Change inode qa_data to allow multiple users

Before this patch, multiple users called gfs2_qa_alloc which allocated
a qadata structure to the inode, if quotas are turned on. Later, in
file close or evict, the structure was deleted with gfs2_qa_delete.
But there can be several competing processes who need access to the
structure. There were races between file close (release) and the others.
Thus, a release could delete the structure out from under a process
that relied upon its existence. For example, chown.

This patch changes the management of the qadata structures to be
a get/put scheme. Function gfs2_qa_alloc has been changed to gfs2_qa_get
and if the structure is allocated, the count essentially starts out at
1. Function gfs2_qa_delete has been renamed to gfs2_qa_put, and the
last guy to decrement the count to 0 frees the memory.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/gfs2/quota.h b/fs/gfs2/quota.h
index 765627d9a91e..7f9ca8ef40fc 100644
--- a/fs/gfs2/quota.h
+++ b/fs/gfs2/quota.h
@@ -15,8 +15,8 @@ struct gfs2_sbd;
 #define NO_UID_QUOTA_CHANGE INVALID_UID
 #define NO_GID_QUOTA_CHANGE INVALID_GID
 
-extern int gfs2_qa_alloc(struct gfs2_inode *ip);
-extern void gfs2_qa_delete(struct gfs2_inode *ip, atomic_t *wcount);
+extern int gfs2_qa_get(struct gfs2_inode *ip);
+extern void gfs2_qa_put(struct gfs2_inode *ip);
 extern int gfs2_quota_hold(struct gfs2_inode *ip, kuid_t uid, kgid_t gid);
 extern void gfs2_quota_unhold(struct gfs2_inode *ip);