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cifs: convert oplock breaks to use slow_work facility (try #4)

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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>
This commit is contained in:
Jeff Layton 2009-09-21 06:47:50 -04:00 committed by Steve French
parent 48541bd3dd
commit 3bc303c254
10 changed files with 119 additions and 175 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/cifs/Kconfig
View File

@ -2,6 +2,7 @@ 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

95
fs/cifs/cifsfs.c
View File

@ -64,9 +64,6 @@ unsigned int multiuser_mount = 0;
unsigned int extended_security = CIFSSEC_DEF;
/* unsigned int ntlmv2_support = 0; */
unsigned int sign_CIFS_PDUs = 1;
extern struct task_struct *oplockThread; /* remove sparse warning */
struct task_struct *oplockThread = NULL;
/* extern struct task_struct * dnotifyThread; remove sparse warning */
static const struct super_operations cifs_super_ops;
unsigned int CIFSMaxBufSize = CIFS_MAX_MSGSIZE;
module_param(CIFSMaxBufSize, int, 0);
@ -973,89 +970,12 @@ cifs_destroy_mids(void)
kmem_cache_destroy(cifs_oplock_cachep);
}
static int cifs_oplock_thread(void *dummyarg)
{
struct oplock_q_entry *oplock_item;
struct cifsTconInfo *pTcon;
struct inode *inode;
__u16 netfid;
int rc, waitrc = 0;
set_freezable();
do {
if (try_to_freeze())
continue;
spin_lock(&cifs_oplock_lock);
if (list_empty(&cifs_oplock_list)) {
spin_unlock(&cifs_oplock_lock);
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(39*HZ);
} else {
oplock_item = list_entry(cifs_oplock_list.next,
struct oplock_q_entry, qhead);
cFYI(1, ("found oplock item to write out"));
pTcon = oplock_item->tcon;
inode = oplock_item->pinode;
netfid = oplock_item->netfid;
spin_unlock(&cifs_oplock_lock);
DeleteOplockQEntry(oplock_item);
/* can not grab inode sem here since it would
deadlock when oplock received on delete
since vfs_unlink holds the i_mutex across
the call */
/* mutex_lock(&inode->i_mutex);*/
if (S_ISREG(inode->i_mode)) {
#ifdef CONFIG_CIFS_EXPERIMENTAL
if (CIFS_I(inode)->clientCanCacheAll == 0)
break_lease(inode, FMODE_READ);
else if (CIFS_I(inode)->clientCanCacheRead == 0)
break_lease(inode, FMODE_WRITE);
#endif
rc = filemap_fdatawrite(inode->i_mapping);
if (CIFS_I(inode)->clientCanCacheRead == 0) {
waitrc = filemap_fdatawait(
inode->i_mapping);
invalidate_remote_inode(inode);
}
if (rc == 0)
rc = waitrc;
} else
rc = 0;
/* mutex_unlock(&inode->i_mutex);*/
if (rc)
CIFS_I(inode)->write_behind_rc = rc;
cFYI(1, ("Oplock flush inode %p rc %d",
inode, rc));
/* releasing stale oplock after recent reconnect
of smb session using a now incorrect file
handle is not a data integrity issue but do
not bother sending an oplock release if session
to server still is disconnected since oplock
already released by the server in that case */
if (!pTcon->need_reconnect) {
rc = CIFSSMBLock(0, pTcon, netfid,
0 /* len */ , 0 /* offset */, 0,
0, LOCKING_ANDX_OPLOCK_RELEASE,
false /* wait flag */);
cFYI(1, ("Oplock release rc = %d", rc));
}
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(1); /* yield in case q were corrupt */
}
} while (!kthread_should_stop());
return 0;
}
static int __init
init_cifs(void)
{
int rc = 0;
cifs_proc_init();
INIT_LIST_HEAD(&cifs_tcp_ses_list);
INIT_LIST_HEAD(&cifs_oplock_list);
#ifdef CONFIG_CIFS_EXPERIMENTAL
INIT_LIST_HEAD(&GlobalDnotifyReqList);
INIT_LIST_HEAD(&GlobalDnotifyRsp_Q);
@ -1084,7 +1004,6 @@ init_cifs(void)
rwlock_init(&GlobalSMBSeslock);
rwlock_init(&cifs_tcp_ses_lock);
spin_lock_init(&GlobalMid_Lock);
spin_lock_init(&cifs_oplock_lock);
if (cifs_max_pending < 2) {
cifs_max_pending = 2;
@ -1119,18 +1038,15 @@ init_cifs(void)
if (rc)
goto out_unregister_key_type;
#endif
oplockThread = kthread_run(cifs_oplock_thread, NULL, "cifsoplockd");
if (IS_ERR(oplockThread)) {
rc = PTR_ERR(oplockThread);
cERROR(1, ("error %d create oplock thread", rc));
goto out_unregister_dfs_key_type;
}
rc = slow_work_register_user();
if (rc)
goto out_unregister_resolver_key;
return 0;
out_unregister_dfs_key_type:
#ifdef CONFIG_CIFS_DFS_UPCALL
out_unregister_resolver_key:
unregister_key_type(&key_type_dns_resolver);
#ifdef CONFIG_CIFS_DFS_UPCALL
out_unregister_key_type:
#endif
#ifdef CONFIG_CIFS_UPCALL
@ -1165,7 +1081,6 @@ exit_cifs(void)
cifs_destroy_inodecache();
cifs_destroy_mids();
cifs_destroy_request_bufs();
kthread_stop(oplockThread);
}
MODULE_AUTHOR("Steve French <sfrench@us.ibm.com>");

12
fs/cifs/cifsglob.h
View File

@ -18,6 +18,7 @@
*/
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/slow-work.h>
#include "cifs_fs_sb.h"
#include "cifsacl.h"
/*
@ -346,14 +347,16 @@ struct cifsFileInfo {
/* lock scope id (0 if none) */
struct file *pfile; /* needed for writepage */
struct inode *pInode; /* needed for oplock break */
struct vfsmount *mnt;
struct mutex lock_mutex;
struct list_head llist; /* list of byte range locks we have. */
bool closePend:1; /* file is marked to close */
bool invalidHandle:1; /* file closed via session abend */
bool messageMode:1; /* for pipes: message vs byte mode */
bool oplock_break_cancelled:1;
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 */
};
/* Take a reference on the file private data */
@ -670,12 +673,6 @@ GLOBAL_EXTERN rwlock_t cifs_tcp_ses_lock;
*/
GLOBAL_EXTERN rwlock_t GlobalSMBSeslock;
/* Global list of oplocks */
GLOBAL_EXTERN struct list_head cifs_oplock_list;
/* Protects the cifs_oplock_list */
GLOBAL_EXTERN spinlock_t cifs_oplock_lock;
/* Outstanding dir notify requests */
GLOBAL_EXTERN struct list_head GlobalDnotifyReqList;
/* DirNotify response queue */
@ -726,3 +723,4 @@ 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;

6
fs/cifs/cifsproto.h
View File

@ -86,17 +86,13 @@ extern int CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses,
const int stage,
const struct nls_table *nls_cp);
extern __u16 GetNextMid(struct TCP_Server_Info *server);
extern struct oplock_q_entry *AllocOplockQEntry(struct inode *, u16,
struct cifsTconInfo *);
extern void DeleteOplockQEntry(struct oplock_q_entry *);
extern void DeleteTconOplockQEntries(struct cifsTconInfo *);
extern struct timespec cifs_NTtimeToUnix(__le64 utc_nanoseconds_since_1601);
extern u64 cifs_UnixTimeToNT(struct timespec);
extern struct timespec cnvrtDosUnixTm(__le16 le_date, __le16 le_time,
int offset);
extern 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);
extern void cifs_unix_basic_to_fattr(struct cifs_fattr *fattr,
FILE_UNIX_BASIC_INFO *info,

1
fs/cifs/cifssmb.c
View File

@ -94,6 +94,7 @@ static void mark_open_files_invalid(struct cifsTconInfo *pTcon)
list_for_each_safe(tmp, tmp1, &pTcon->openFileList) {
open_file = list_entry(tmp, struct cifsFileInfo, tlist);
open_file->invalidHandle = true;
open_file->oplock_break_cancelled = true;
}
write_unlock(&GlobalSMBSeslock);
/* BB Add call to invalidate_inodes(sb) for all superblocks mounted

1
fs/cifs/connect.c
View File

@ -1670,7 +1670,6 @@ cifs_put_tcon(struct cifsTconInfo *tcon)
CIFSSMBTDis(xid, tcon);
_FreeXid(xid);
DeleteTconOplockQEntries(tcon);
tconInfoFree(tcon);
cifs_put_smb_ses(ses);
}

25
fs/cifs/dir.c
View File

@ -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 @@ build_path_from_dentry(struct dentry *direntry)
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 @@ cifs_fill_fileinfo(struct inode *newinode, __u16 fileHandle,
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 @@ cifs_fill_fileinfo(struct inode *newinode, __u16 fileHandle,
}
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 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
/* 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 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
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 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
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 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
/* 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 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
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);

74
fs/cifs/file.c
View File

@ -30,6 +30,7 @@
#include <linux/writeback.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/delay.h>
#include <linux/mount.h>
#include <asm/div64.h>
#include "cifsfs.h"
#include "cifspdu.h"
@ -51,11 +52,13 @@ static inline struct cifsFileInfo *cifs_init_private(
INIT_LIST_HEAD(&private_data->llist);
private_data->pfile = file; /* needed for writepage */
private_data->pInode = igrab(inode);
private_data->mnt = file->f_path.mnt;
private_data->invalidHandle = false;
private_data->closePend = false;
/* Initialize reference count to one. The private data is
freed on the release of the last reference */
atomic_set(&private_data->count, 1);
slow_work_init(&private_data->oplock_break, &cifs_oplock_break_ops);
return private_data;
}
@ -327,7 +330,7 @@ int cifs_open(struct inode *inode, struct file *file)
le64_to_cpu(tcon->fsUnixInfo.Capability))) {
int oflags = (int) cifs_posix_convert_flags(file->f_flags);
/* can not refresh inode info since size could be stale */
rc = cifs_posix_open(full_path, &inode, inode->i_sb,
rc = cifs_posix_open(full_path, &inode, file->f_path.mnt,
cifs_sb->mnt_file_mode /* ignored */,
oflags, &oplock, &netfid, xid);
if (rc == 0) {
@ -547,7 +550,7 @@ static int cifs_reopen_file(struct file *file, bool can_flush)
le64_to_cpu(tcon->fsUnixInfo.Capability))) {
int oflags = (int) cifs_posix_convert_flags(file->f_flags);
/* can not refresh inode info since size could be stale */
rc = cifs_posix_open(full_path, NULL, inode->i_sb,
rc = cifs_posix_open(full_path, NULL, file->f_path.mnt,
cifs_sb->mnt_file_mode /* ignored */,
oflags, &oplock, &netfid, xid);
if (rc == 0) {
@ -2312,6 +2315,73 @@ static int cifs_write_begin(struct file *file, struct address_space *mapping,
return rc;
}
static void
cifs_oplock_break(struct slow_work *work)
{
struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
oplock_break);
struct inode *inode = cfile->pInode;
struct cifsInodeInfo *cinode = CIFS_I(inode);
struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->mnt->mnt_sb);
int rc, waitrc = 0;
if (inode && S_ISREG(inode->i_mode)) {
#ifdef CONFIG_CIFS_EXPERIMENTAL
if (cinode->clientCanCacheAll == 0)
break_lease(inode, FMODE_READ);
else if (cinode->clientCanCacheRead == 0)
break_lease(inode, FMODE_WRITE);
#endif
rc = filemap_fdatawrite(inode->i_mapping);
if (cinode->clientCanCacheRead == 0) {
waitrc = filemap_fdatawait(inode->i_mapping);
invalidate_remote_inode(inode);
}
if (!rc)
rc = waitrc;
if (rc)
cinode->write_behind_rc = rc;
cFYI(1, ("Oplock flush inode %p rc %d", inode, rc));
}
/*
* releasing stale oplock after recent reconnect of smb session using
* a now incorrect file handle is not a data integrity issue but do
* not bother sending an oplock release if session to server still is
* disconnected since oplock already released by the server
*/
if (!cfile->closePend && !cfile->oplock_break_cancelled) {
rc = CIFSSMBLock(0, cifs_sb->tcon, cfile->netfid, 0, 0, 0, 0,
LOCKING_ANDX_OPLOCK_RELEASE, false);
cFYI(1, ("Oplock release rc = %d", rc));
}
}
static int
cifs_oplock_break_get(struct slow_work *work)
{
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)
{
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,

29
fs/cifs/misc.c
View File

@ -32,7 +32,6 @@
extern mempool_t *cifs_sm_req_poolp;
extern mempool_t *cifs_req_poolp;
extern struct task_struct *oplockThread;
/* The xid serves as a useful identifier for each incoming vfs request,
in a similar way to the mid which is useful to track each sent smb,
@ -500,6 +499,7 @@ 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) &&
@ -569,19 +569,30 @@ is_valid_oplock_break(struct smb_hdr *buf, struct TCP_Server_Info *srv)
if (pSMB->Fid != netfile->netfid)
continue;
read_unlock(&GlobalSMBSeslock);
read_unlock(&cifs_tcp_ses_lock);
/*
* don't do anything if file is about to be
* closed anyway.
*/
if (netfile->closePend) {
read_unlock(&GlobalSMBSeslock);
read_unlock(&cifs_tcp_ses_lock);
return true;
}
cFYI(1, ("file id match, oplock break"));
pCifsInode = CIFS_I(netfile->pInode);
pCifsInode->clientCanCacheAll = false;
if (pSMB->OplockLevel == 0)
pCifsInode->clientCanCacheRead = false;
AllocOplockQEntry(netfile->pInode,
netfile->netfid, tcon);
cFYI(1, ("about to wake up oplock thread"));
if (oplockThread)
wake_up_process(oplockThread);
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;
}
read_unlock(&GlobalSMBSeslock);
read_unlock(&cifs_tcp_ses_lock);
return true;
}
read_unlock(&GlobalSMBSeslock);

50
fs/cifs/transport.c
View File

@ -103,56 +103,6 @@ DeleteMidQEntry(struct mid_q_entry *midEntry)
mempool_free(midEntry, cifs_mid_poolp);
}
struct oplock_q_entry *
AllocOplockQEntry(struct inode *pinode, __u16 fid, struct cifsTconInfo *tcon)
{
struct oplock_q_entry *temp;
if ((pinode == NULL) || (tcon == NULL)) {
cERROR(1, ("Null parms passed to AllocOplockQEntry"));
return NULL;
}
temp = (struct oplock_q_entry *) kmem_cache_alloc(cifs_oplock_cachep,
GFP_KERNEL);
if (temp == NULL)
return temp;
else {
temp->pinode = pinode;
temp->tcon = tcon;
temp->netfid = fid;
spin_lock(&cifs_oplock_lock);
list_add_tail(&temp->qhead, &cifs_oplock_list);
spin_unlock(&cifs_oplock_lock);
}
return temp;
}
void DeleteOplockQEntry(struct oplock_q_entry *oplockEntry)
{
spin_lock(&cifs_oplock_lock);
/* should we check if list empty first? */
list_del(&oplockEntry->qhead);
spin_unlock(&cifs_oplock_lock);
kmem_cache_free(cifs_oplock_cachep, oplockEntry);
}
void DeleteTconOplockQEntries(struct cifsTconInfo *tcon)
{
struct oplock_q_entry *temp;
if (tcon == NULL)
return;
spin_lock(&cifs_oplock_lock);
list_for_each_entry(temp, &cifs_oplock_list, qhead) {
if ((temp->tcon) && (temp->tcon == tcon)) {
list_del(&temp->qhead);
kmem_cache_free(cifs_oplock_cachep, temp);
}
}
spin_unlock(&cifs_oplock_lock);
}
static int
smb_sendv(struct TCP_Server_Info *server, struct kvec *iov, int n_vec)
{