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CIFS: Implement caching mechanism for posix brlocks
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to handle all lock requests on the client in an exclusive oplock case.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
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Pavel Shilovsky authored and Steve French committed Oct 24, 2011
1 parent 85160e0 commit 4f6bcec
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Showing 3 changed files with 147 additions and 15 deletions.
4 changes: 2 additions & 2 deletions fs/cifs/cifsproto.h
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Original file line number Diff line number Diff line change
Expand Up @@ -374,8 +374,8 @@ extern int CIFSSMBLock(const int xid, struct cifs_tcon *tcon,
const __u32 numLock, const __u8 lockType,
const bool waitFlag, const __u8 oplock_level);
extern int CIFSSMBPosixLock(const int xid, struct cifs_tcon *tcon,
const __u16 smb_file_id, const int get_flag,
const __u64 len, struct file_lock *,
const __u16 smb_file_id, const __u32 netpid,
const int get_flag, const __u64 len, struct file_lock *,
const __u16 lock_type, const bool waitFlag);
extern int CIFSSMBTDis(const int xid, struct cifs_tcon *tcon);
extern int CIFSSMBEcho(struct TCP_Server_Info *server);
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8 changes: 4 additions & 4 deletions fs/cifs/cifssmb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2393,9 +2393,9 @@ CIFSSMBLock(const int xid, struct cifs_tcon *tcon,

int
CIFSSMBPosixLock(const int xid, struct cifs_tcon *tcon,
const __u16 smb_file_id, const int get_flag, const __u64 len,
struct file_lock *pLockData, const __u16 lock_type,
const bool waitFlag)
const __u16 smb_file_id, const __u32 netpid, const int get_flag,
const __u64 len, struct file_lock *pLockData,
const __u16 lock_type, const bool waitFlag)
{
struct smb_com_transaction2_sfi_req *pSMB = NULL;
struct smb_com_transaction2_sfi_rsp *pSMBr = NULL;
Expand Down Expand Up @@ -2453,7 +2453,7 @@ CIFSSMBPosixLock(const int xid, struct cifs_tcon *tcon,
} else
pSMB->Timeout = 0;

parm_data->pid = cpu_to_le32(current->tgid);
parm_data->pid = cpu_to_le32(netpid);
parm_data->start = cpu_to_le64(pLockData->fl_start);
parm_data->length = cpu_to_le64(len); /* normalize negative numbers */

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150 changes: 141 additions & 9 deletions fs/cifs/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -788,7 +788,42 @@ cifs_lock_add_if(struct cifsInodeInfo *cinode, __u64 offset, __u64 length,
}

static int
cifs_push_locks(struct cifsFileInfo *cfile)
cifs_posix_lock_test(struct file *file, struct file_lock *flock)
{
int rc = 0;
struct cifsInodeInfo *cinode = CIFS_I(file->f_path.dentry->d_inode);
unsigned char saved_type = flock->fl_type;

mutex_lock(&cinode->lock_mutex);
posix_test_lock(file, flock);

if (flock->fl_type == F_UNLCK && !cinode->can_cache_brlcks) {
flock->fl_type = saved_type;
rc = 1;
}

mutex_unlock(&cinode->lock_mutex);
return rc;
}

static int
cifs_posix_lock_set(struct file *file, struct file_lock *flock)
{
struct cifsInodeInfo *cinode = CIFS_I(file->f_path.dentry->d_inode);
int rc;

mutex_lock(&cinode->lock_mutex);
if (!cinode->can_cache_brlcks) {
mutex_unlock(&cinode->lock_mutex);
return 1;
}
rc = posix_lock_file_wait(file, flock);
mutex_unlock(&cinode->lock_mutex);
return rc;
}

static int
cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
{
int xid, rc = 0, stored_rc;
struct cifsLockInfo *li, *tmp;
Expand Down Expand Up @@ -820,6 +855,91 @@ cifs_push_locks(struct cifsFileInfo *cfile)
return rc;
}

/* copied from fs/locks.c with a name change */
#define cifs_for_each_lock(inode, lockp) \
for (lockp = &inode->i_flock; *lockp != NULL; \
lockp = &(*lockp)->fl_next)

static int
cifs_push_posix_locks(struct cifsFileInfo *cfile)
{
struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
struct file_lock *flock, **before;
struct cifsLockInfo *lck, *tmp;
int rc = 0, xid, type;
__u64 length;
struct list_head locks_to_send;

xid = GetXid();

mutex_lock(&cinode->lock_mutex);
if (!cinode->can_cache_brlcks) {
mutex_unlock(&cinode->lock_mutex);
FreeXid(xid);
return rc;
}

INIT_LIST_HEAD(&locks_to_send);

lock_flocks();
cifs_for_each_lock(cfile->dentry->d_inode, before) {
flock = *before;
length = 1 + flock->fl_end - flock->fl_start;
if (flock->fl_type == F_RDLCK || flock->fl_type == F_SHLCK)
type = CIFS_RDLCK;
else
type = CIFS_WRLCK;

lck = cifs_lock_init(length, flock->fl_start, type,
cfile->netfid);
if (!lck) {
rc = -ENOMEM;
goto send_locks;
}
lck->pid = flock->fl_pid;

list_add_tail(&lck->llist, &locks_to_send);
}

send_locks:
unlock_flocks();

list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
struct file_lock tmp_lock;
int stored_rc;

tmp_lock.fl_start = lck->offset;
stored_rc = CIFSSMBPosixLock(xid, tcon, lck->netfid, lck->pid,
0, lck->length, &tmp_lock,
lck->type, 0);
if (stored_rc)
rc = stored_rc;
list_del(&lck->llist);
kfree(lck);
}

cinode->can_cache_brlcks = false;
mutex_unlock(&cinode->lock_mutex);

FreeXid(xid);
return rc;
}

static int
cifs_push_locks(struct cifsFileInfo *cfile)
{
struct cifs_sb_info *cifs_sb = CIFS_SB(cfile->dentry->d_sb);
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);

if ((tcon->ses->capabilities & CAP_UNIX) &&
(CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
return cifs_push_posix_locks(cfile);

return cifs_push_mandatory_locks(cfile);
}

static void
cifs_read_flock(struct file_lock *flock, __u8 *type, int *lock, int *unlock,
bool *wait_flag)
Expand Down Expand Up @@ -865,24 +985,30 @@ cifs_read_flock(struct file_lock *flock, __u8 *type, int *lock, int *unlock,
}

static int
cifs_getlk(struct cifsFileInfo *cfile, struct file_lock *flock, __u8 type,
cifs_getlk(struct file *file, struct file_lock *flock, __u8 type,
bool wait_flag, bool posix_lck, int xid)
{
int rc = 0;
__u64 length = 1 + flock->fl_end - flock->fl_start;
struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
__u16 netfid = cfile->netfid;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);

if (posix_lck) {
int posix_lock_type;

rc = cifs_posix_lock_test(file, flock);
if (!rc)
return rc;

if (type & LOCKING_ANDX_SHARED_LOCK)
posix_lock_type = CIFS_RDLCK;
else
posix_lock_type = CIFS_WRLCK;
rc = CIFSSMBPosixLock(xid, tcon, netfid, 1 /* get */,
length, flock, posix_lock_type,
wait_flag);
rc = CIFSSMBPosixLock(xid, tcon, netfid, current->tgid,
1 /* get */, length, flock,
posix_lock_type, wait_flag);
return rc;
}

Expand Down Expand Up @@ -944,6 +1070,11 @@ cifs_setlk(struct file *file, struct file_lock *flock, __u8 type,

if (posix_lck) {
int posix_lock_type;

rc = cifs_posix_lock_set(file, flock);
if (!rc || rc < 0)
return rc;

if (type & LOCKING_ANDX_SHARED_LOCK)
posix_lock_type = CIFS_RDLCK;
else
Expand All @@ -952,8 +1083,9 @@ cifs_setlk(struct file *file, struct file_lock *flock, __u8 type,
if (unlock == 1)
posix_lock_type = CIFS_UNLCK;

rc = CIFSSMBPosixLock(xid, tcon, netfid, 0 /* set */, length,
flock, posix_lock_type, wait_flag);
rc = CIFSSMBPosixLock(xid, tcon, netfid, current->tgid,
0 /* set */, length, flock,
posix_lock_type, wait_flag);
goto out;
}

Expand Down Expand Up @@ -1052,7 +1184,7 @@ int cifs_lock(struct file *file, int cmd, struct file_lock *flock)
* negative length which we can not accept over the wire.
*/
if (IS_GETLK(cmd)) {
rc = cifs_getlk(cfile, flock, type, wait_flag, posix_lck, xid);
rc = cifs_getlk(file, flock, type, wait_flag, posix_lck, xid);
FreeXid(xid);
return rc;
}
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