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 Cc: Steve French sfrench@samba.org Cc: Anton Blanchard anton@samba.org --- fs/cifs/Kconfig | 1 - fs/cifs/cifsfs.c | 5 ----- fs/cifs/cifsglob.h | 8 +++++--- fs/cifs/dir.c | 2 +- fs/cifs/file.c | 30 +++++++++++++----------------- fs/cifs/misc.c | 20 ++++++++++++-------- 6 files changed, 31 insertions(+), 35 deletions(-)
diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig index 80f3525..6994a0f 100644 --- a/fs/cifs/Kconfig +++ b/fs/cifs/Kconfig @@ -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 diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 78c02eb..4c07517 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -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 diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index a88479c..f5a1f9b 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -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); diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c index 391816b..b066e73 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -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); diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 75541af..e767bfa 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -2295,8 +2295,7 @@ out: 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, diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c index 1394aa3..3ccadc1 100644 --- a/fs/cifs/misc.c +++ b/fs/cifs/misc.c @@ -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;