From d7c86ff8cd00abc730fe5d031f43dc9138b6324e Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Mon, 11 Oct 2010 15:07:19 -0400 Subject: 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 Reviewed-by: Suresh Jayaraman Acked-by: Dave Kleikamp Signed-off-by: Steve French --- fs/cifs/cifsfs.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'fs/cifs/cifsfs.c') 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) -- cgit