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cifs: don't use vfsmount to pin superblock for oplock breaks

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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>
This commit is contained in:
Jeff Layton 2010-10-11 15:07:19 -04:00 committed by Steve French
parent a5e18bc36e
commit d7c86ff8cd
7 changed files with 29 additions and 18 deletions
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1
fs/cifs/cifs_fs_sb.h
View File

@ -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;

18
fs/cifs/cifsfs.c
View File

@ -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)

6
fs/cifs/cifsfs.h
View File

@ -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;

1
fs/cifs/cifsglob.h
View File

@ -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. */

2
fs/cifs/cifsproto.h
View File

@ -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,

10
fs/cifs/dir.c
View File

@ -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);

9
fs/cifs/file.c
View File

@ -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 = {