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cifs: use workqueue instead of slow-work 

Workqueue can now handle high concurrency.  Use system_nrt_wq
instead of slow-work.

* Updated is_valid_oplock_break() to not call cifs_oplock_break_put()
  as advised by Steve French.  It might cause deadlock.  Instead,
  reference is increased after queueing succeeded and
  cifs_oplock_break() briefly grabs GlobalSMBSeslock before putting
  the cfile to make sure it doesn't put before the matching get is
  finished.

* Anton Blanchard reported that cifs conversion was using now gone
  system_single_wq.  Use system_nrt_wq which provides non-reentrance
  guarantee which is enough and much better.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Steve French <sfrench@samba.org>
Cc: Anton Blanchard <anton@samba.org>
This commit is contained in:
Tejun Heo 2010-07-20 22:09:02 +02:00
parent d098adfb7d
commit 9b64697246
6 changed files with 31 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/cifs/Kconfig
View File

@ -2,7 +2,6 @@ config CIFS
tristate "CIFS support (advanced network filesystem, SMBFS successor)"
depends on INET
select NLS
select SLOW_WORK
help
This is the client VFS module for the Common Internet File System
(CIFS) protocol which is the successor to the Server Message Block

5
fs/cifs/cifsfs.c
View File

@ -917,15 +917,10 @@ init_cifs(void)
if (rc)
goto out_unregister_key_type;
#endif
rc = slow_work_register_user(THIS_MODULE);
if (rc)
goto out_unregister_resolver_key;
return 0;
out_unregister_resolver_key:
#ifdef CONFIG_CIFS_DFS_UPCALL
unregister_key_type(&key_type_dns_resolver);
out_unregister_key_type:
#endif
#ifdef CONFIG_CIFS_UPCALL

8
fs/cifs/cifsglob.h
View File

@ -19,7 +19,7 @@
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/slab.h>
#include <linux/slow-work.h>
#include <linux/workqueue.h>
#include "cifs_fs_sb.h"
#include "cifsacl.h"
/*
@ -363,7 +363,7 @@ struct cifsFileInfo {
atomic_t count; /* reference count */
struct mutex fh_mutex; /* prevents reopen race after dead ses*/
struct cifs_search_info srch_inf;
struct slow_work oplock_break; /* slow_work job for oplock breaks */
struct work_struct oplock_break; /* work for oplock breaks */
};
/* Take a reference on the file private data */
@ -732,4 +732,6 @@ GLOBAL_EXTERN unsigned int cifs_min_rcv; /* min size of big ntwrk buf pool */
GLOBAL_EXTERN unsigned int cifs_min_small; /* min size of small buf pool */
GLOBAL_EXTERN unsigned int cifs_max_pending; /* MAX requests at once to server*/
extern const struct slow_work_ops cifs_oplock_break_ops;
void cifs_oplock_break(struct work_struct *work);
void cifs_oplock_break_get(struct cifsFileInfo *cfile);
void cifs_oplock_break_put(struct cifsFileInfo *cfile);

2
fs/cifs/dir.c
View File

@ -162,7 +162,7 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle,
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);
INIT_WORK(&pCifsFile->oplock_break, cifs_oplock_break);
write_lock(&GlobalSMBSeslock);
list_add(&pCifsFile->tlist, &cifs_sb->tcon->openFileList);

30
fs/cifs/file.c
View File

@ -2295,8 +2295,7 @@ static int cifs_write_begin(struct file *file, struct address_space *mapping,
return rc;
}
static void
cifs_oplock_break(struct slow_work *work)
void cifs_oplock_break(struct work_struct *work)
{
struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
oplock_break);
@ -2333,33 +2332,30 @@ cifs_oplock_break(struct slow_work *work)
LOCKING_ANDX_OPLOCK_RELEASE, false);
cFYI(1, "Oplock release rc = %d", rc);
}
/*
* We might have kicked in before is_valid_oplock_break()
* finished grabbing reference for us. Make sure it's done by
* waiting for GlobalSMSSeslock.
*/
write_lock(&GlobalSMBSeslock);
write_unlock(&GlobalSMBSeslock);
cifs_oplock_break_put(cfile);
}
static int
cifs_oplock_break_get(struct slow_work *work)
void cifs_oplock_break_get(struct cifsFileInfo *cfile)
{
struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
oplock_break);
mntget(cfile->mnt);
cifsFileInfo_get(cfile);
return 0;
}
static void
cifs_oplock_break_put(struct slow_work *work)
void cifs_oplock_break_put(struct cifsFileInfo *cfile)
{
struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
oplock_break);
mntput(cfile->mnt);
cifsFileInfo_put(cfile);
}
const struct slow_work_ops cifs_oplock_break_ops = {
.get_ref = cifs_oplock_break_get,
.put_ref = cifs_oplock_break_put,
.execute = cifs_oplock_break,
};
const struct address_space_operations cifs_addr_ops = {
.readpage = cifs_readpage,
.readpages = cifs_readpages,

20
fs/cifs/misc.c
View File

@ -498,7 +498,6 @@ is_valid_oplock_break(struct smb_hdr *buf, struct TCP_Server_Info *srv)
struct cifsTconInfo *tcon;
struct cifsInodeInfo *pCifsInode;
struct cifsFileInfo *netfile;
int rc;
cFYI(1, "Checking for oplock break or dnotify response");
if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
@ -583,13 +582,18 @@ is_valid_oplock_break(struct smb_hdr *buf, struct TCP_Server_Info *srv)
pCifsInode->clientCanCacheAll = false;
if (pSMB->OplockLevel == 0)
pCifsInode->clientCanCacheRead = false;
rc = slow_work_enqueue(&netfile->oplock_break);
if (rc) {
cERROR(1, "failed to enqueue oplock "
"break: %d\n", rc);
} else {
netfile->oplock_break_cancelled = false;
}
/*
* cifs_oplock_break_put() can't be called
* from here. Get reference after queueing
* succeeded. cifs_oplock_break() will
* synchronize using GlobalSMSSeslock.
*/
if (queue_work(system_nrt_wq,
&netfile->oplock_break))
cifs_oplock_break_get(netfile);
netfile->oplock_break_cancelled = false;
read_unlock(&GlobalSMBSeslock);
read_unlock(&cifs_tcp_ses_lock);
return true;