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authorJeff Layton <jlayton@redhat.com>2010-10-11 15:07:19 -0400
committerSteve French <sfrench@us.ibm.com>2010-10-12 18:08:01 +0000
commitd7c86ff8cd00abc730fe5d031f43dc9138b6324e (patch)
treea1f264ce2f33e3ac77a459291b9a5e45a63e3bff /fs/cifs/cifsfs.c
parenta5e18bc36e9e05ce0338d370a2ce4290910e43ea (diff)
downloadlinux-d7c86ff8cd00abc730fe5d031f43dc9138b6324e.tar.bz2
cifs: don't use vfsmount to pin superblock for oplock breaks
Filesystems aren't really supposed to do anything with a vfsmount. It's considered a layering violation since vfsmounts are entirely managed at the VFS layer. CIFS currently keeps an active reference to a vfsmount in order to prevent the superblock vanishing before an oplock break has completed. What we really want to do instead is to keep sb->s_active high until the oplock break has completed. This patch borrows the scheme that NFS uses for handling sillyrenames. An atomic_t is added to the cifs_sb_info. When it transitions from 0 to 1, an extra reference to the superblock is taken (by bumping the s_active value). When it transitions from 1 to 0, that reference is dropped and a the superblock teardown may proceed if there are no more references to it. Also, the vfsmount pointer is removed from cifsFileInfo and from cifs_new_fileinfo, and some bogus forward declarations are removed from cifsfs.h. Signed-off-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de> Acked-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs/cifs/cifsfs.c')
-rw-r--r--fs/cifs/cifsfs.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 3258c822328b..cbd468c880c4 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -83,6 +83,24 @@ extern mempool_t *cifs_sm_req_poolp;
extern mempool_t *cifs_req_poolp;
extern mempool_t *cifs_mid_poolp;
+void
+cifs_sb_active(struct super_block *sb)
+{
+ struct cifs_sb_info *server = CIFS_SB(sb);
+
+ if (atomic_inc_return(&server->active) == 1)
+ atomic_inc(&sb->s_active);
+}
+
+void
+cifs_sb_deactive(struct super_block *sb)
+{
+ struct cifs_sb_info *server = CIFS_SB(sb);
+
+ if (atomic_dec_and_test(&server->active))
+ deactivate_super(sb);
+}
+
static int
cifs_read_super(struct super_block *sb, void *data,
const char *devname, int silent)