From d7c86ff8cd00abc730fe5d031f43dc9138b6324e Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Mon, 11 Oct 2010 15:07:19 -0400 Subject: [PATCH] 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/cifs_fs_sb.h | 1 + fs/cifs/cifsfs.c | 18 ++++++++++++++++++ fs/cifs/cifsfs.h | 6 ++---- fs/cifs/cifsglob.h | 1 - fs/cifs/cifsproto.h | 2 +- fs/cifs/dir.c | 10 +++------- fs/cifs/file.c | 9 ++++----- 7 files changed, 29 insertions(+), 18 deletions(-) diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h index 586ee3d527d2..525ba59a4105 100644 --- a/fs/cifs/cifs_fs_sb.h +++ b/fs/cifs/cifs_fs_sb.h @@ -48,6 +48,7 @@ struct cifs_sb_info { struct nls_table *local_nls; unsigned int rsize; unsigned int wsize; + atomic_t active; uid_t mnt_uid; gid_t mnt_gid; mode_t mnt_file_mode; 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) diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h index 786bdf36aebf..85544bcab517 100644 --- a/fs/cifs/cifsfs.h +++ b/fs/cifs/cifsfs.h @@ -42,10 +42,8 @@ extern const struct address_space_operations cifs_addr_ops; extern const struct address_space_operations cifs_addr_ops_smallbuf; /* Functions related to super block operations */ -/* extern const struct super_operations cifs_super_ops;*/ -extern void cifs_read_inode(struct inode *); -/*extern void cifs_delete_inode(struct inode *);*/ /* BB not needed yet */ -/* extern void cifs_write_inode(struct inode *); */ /* BB not needed yet */ +extern void cifs_sb_active(struct super_block *sb); +extern void cifs_sb_deactive(struct super_block *sb); /* Functions related to inodes */ extern const struct inode_operations cifs_dir_inode_ops; diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index 8289e61937a2..e2b760ef22ff 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -388,7 +388,6 @@ struct cifsFileInfo { /* lock scope id (0 if none) */ struct file *pfile; /* needed for writepage */ struct dentry *dentry; - struct vfsmount *mnt; struct tcon_link *tlink; struct mutex lock_mutex; struct list_head llist; /* list of byte range locks we have. */ diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index 29a2ee8ae51f..7f416abd34cf 100644 --- a/fs/cifs/cifsproto.h +++ b/fs/cifs/cifsproto.h @@ -107,7 +107,7 @@ extern struct timespec cnvrtDosUnixTm(__le16 le_date, __le16 le_time, extern struct cifsFileInfo *cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle, struct file *file, - struct vfsmount *mnt, struct tcon_link *tlink, + struct tcon_link *tlink, unsigned int oflags, __u32 oplock); extern int cifs_posix_open(char *full_path, struct inode **pinode, struct super_block *sb, diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c index 6887c412c61a..c205ec9293ea 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -132,8 +132,7 @@ build_path_from_dentry(struct dentry *direntry) struct cifsFileInfo * cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle, struct file *file, - struct vfsmount *mnt, struct tcon_link *tlink, - unsigned int oflags, __u32 oplock) + struct tcon_link *tlink, unsigned int oflags, __u32 oplock) { struct dentry *dentry = file->f_path.dentry; struct cifsFileInfo *pCifsFile; @@ -147,7 +146,6 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle, struct file *file, pCifsFile->pid = current->tgid; pCifsFile->uid = current_fsuid(); pCifsFile->dentry = dget(dentry); - pCifsFile->mnt = mnt; pCifsFile->pfile = file; pCifsFile->invalidHandle = false; pCifsFile->closePend = false; @@ -485,8 +483,7 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode, } pfile_info = cifs_new_fileinfo(newinode, fileHandle, filp, - nd->path.mnt, tlink, oflags, - oplock); + tlink, oflags, oplock); if (pfile_info == NULL) { fput(filp); CIFSSMBClose(xid, tcon, fileHandle); @@ -760,8 +757,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, } cfile = cifs_new_fileinfo(newInode, fileHandle, filp, - nd->path.mnt, tlink, - nd->intent.open.flags, + tlink, nd->intent.open.flags, oplock); if (cfile == NULL) { fput(filp); diff --git a/fs/cifs/file.c b/fs/cifs/file.c index c302b9c52644..fd78a355f634 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -282,7 +282,6 @@ int cifs_open(struct inode *inode, struct file *file) } pCifsFile = cifs_new_fileinfo(inode, netfid, file, - file->f_path.mnt, tlink, oflags, oplock); if (pCifsFile == NULL) { CIFSSMBClose(xid, tcon, netfid); @@ -375,8 +374,8 @@ int cifs_open(struct inode *inode, struct file *file) if (rc != 0) goto out; - pCifsFile = cifs_new_fileinfo(inode, netfid, file, file->f_path.mnt, - tlink, file->f_flags, oplock); + pCifsFile = cifs_new_fileinfo(inode, netfid, file, tlink, + file->f_flags, oplock); if (pCifsFile == NULL) { rc = -ENOMEM; goto out; @@ -2381,14 +2380,14 @@ void cifs_oplock_break(struct work_struct *work) void cifs_oplock_break_get(struct cifsFileInfo *cfile) { - mntget(cfile->mnt); + cifs_sb_active(cfile->dentry->d_sb); cifsFileInfo_get(cfile); } void cifs_oplock_break_put(struct cifsFileInfo *cfile) { - mntput(cfile->mnt); cifsFileInfo_put(cfile); + cifs_sb_deactive(cfile->dentry->d_sb); } const struct address_space_operations cifs_addr_ops = {