cifs: convert oplock breaks to use slow_work facility (try #4)
This is the fourth respin of the patch to convert oplock breaks to
use the slow_work facility.
A customer of ours was testing a backport of one of the earlier
patchsets, and hit a "Busy inodes after umount..." problem. An oplock
break job had raced with a umount, and the superblock got torn down and
its memory reused. When the oplock break job tried to dereference the
inode->i_sb, the kernel oopsed.
This patchset has the oplock break job hold an inode and vfsmount
reference until the oplock break completes. With this, there should be
no need to take a tcon reference (the vfsmount implicitly holds one
already).
Currently, when an oplock break comes in there's a chance that the
oplock break job won't occur if the allocation of the oplock_q_entry
fails. There are also some rather nasty races in the allocation and
handling these structs.
Rather than allocating oplock queue entries when an oplock break comes
in, add a few extra fields to the cifsFileInfo struct. Get rid of the
dedicated cifs_oplock_thread as well and queue the oplock break job to
the slow_work thread pool.
This approach also has the advantage that the oplock break jobs can
potentially run in parallel rather than be serialized like they are
today.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 3643550..9a5df7a 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -24,6 +24,7 @@
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/namei.h>
+#include <linux/mount.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
@@ -131,11 +132,12 @@
static void
cifs_fill_fileinfo(struct inode *newinode, __u16 fileHandle,
- struct cifsTconInfo *tcon, bool write_only)
+ struct vfsmount *mnt, bool write_only)
{
int oplock = 0;
struct cifsFileInfo *pCifsFile;
struct cifsInodeInfo *pCifsInode;
+ struct cifs_sb_info *cifs_sb = CIFS_SB(mnt->mnt_sb);
pCifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
@@ -148,17 +150,19 @@
pCifsFile->netfid = fileHandle;
pCifsFile->pid = current->tgid;
pCifsFile->pInode = igrab(newinode);
+ pCifsFile->mnt = mnt;
pCifsFile->invalidHandle = false;
pCifsFile->closePend = false;
mutex_init(&pCifsFile->fh_mutex);
mutex_init(&pCifsFile->lock_mutex);
INIT_LIST_HEAD(&pCifsFile->llist);
atomic_set(&pCifsFile->count, 1);
+ slow_work_init(&pCifsFile->oplock_break, &cifs_oplock_break_ops);
/* set the following in open now
pCifsFile->pfile = file; */
write_lock(&GlobalSMBSeslock);
- list_add(&pCifsFile->tlist, &tcon->openFileList);
+ list_add(&pCifsFile->tlist, &cifs_sb->tcon->openFileList);
pCifsInode = CIFS_I(newinode);
if (pCifsInode) {
/* if readable file instance put first in list*/
@@ -179,14 +183,14 @@
}
int cifs_posix_open(char *full_path, struct inode **pinode,
- struct super_block *sb, int mode, int oflags,
+ struct vfsmount *mnt, int mode, int oflags,
__u32 *poplock, __u16 *pnetfid, int xid)
{
int rc;
bool write_only = false;
FILE_UNIX_BASIC_INFO *presp_data;
__u32 posix_flags = 0;
- struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+ struct cifs_sb_info *cifs_sb = CIFS_SB(mnt->mnt_sb);
struct cifs_fattr fattr;
cFYI(1, ("posix open %s", full_path));
@@ -243,7 +247,7 @@
/* get new inode and set it up */
if (*pinode == NULL) {
- *pinode = cifs_iget(sb, &fattr);
+ *pinode = cifs_iget(mnt->mnt_sb, &fattr);
if (!*pinode) {
rc = -ENOMEM;
goto posix_open_ret;
@@ -252,7 +256,7 @@
cifs_fattr_to_inode(*pinode, &fattr);
}
- cifs_fill_fileinfo(*pinode, *pnetfid, cifs_sb->tcon, write_only);
+ cifs_fill_fileinfo(*pinode, *pnetfid, mnt, write_only);
posix_open_ret:
kfree(presp_data);
@@ -322,7 +326,7 @@
if (tcon->unix_ext && (tcon->ses->capabilities & CAP_UNIX) &&
(CIFS_UNIX_POSIX_PATH_OPS_CAP &
le64_to_cpu(tcon->fsUnixInfo.Capability))) {
- rc = cifs_posix_open(full_path, &newinode, inode->i_sb,
+ rc = cifs_posix_open(full_path, &newinode, nd->path.mnt,
mode, oflags, &oplock, &fileHandle, xid);
/* EIO could indicate that (posix open) operation is not
supported, despite what server claimed in capability
@@ -469,8 +473,8 @@
/* mknod case - do not leave file open */
CIFSSMBClose(xid, tcon, fileHandle);
} else if (!(posix_create) && (newinode)) {
- cifs_fill_fileinfo(newinode, fileHandle,
- cifs_sb->tcon, write_only);
+ cifs_fill_fileinfo(newinode, fileHandle, nd->path.mnt,
+ write_only);
}
cifs_create_out:
kfree(buf);
@@ -682,8 +686,7 @@
if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY)) &&
(nd->flags & LOOKUP_OPEN) && !pTcon->broken_posix_open &&
(nd->intent.open.flags & O_CREAT)) {
- rc = cifs_posix_open(full_path, &newInode,
- parent_dir_inode->i_sb,
+ rc = cifs_posix_open(full_path, &newInode, nd->path.mnt,
nd->intent.open.create_mode,
nd->intent.open.flags, &oplock,
&fileHandle, xid);
