Commit 84210e91 authored by Steve French's avatar Steve French
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[CIFS] improve setlease handling 



fcntl(F_SETLEASE) currently is not exported by cifs (nor by local file
systems) so cifs grants leases based on how other local processes have
opened the file not by whether the file is cacheable (oplocked).  This
adds the check to make sure that the file is cacheable on the client
before checking whether we can grant the lease locally
(generic_setlease).  It also adds a mount option for cifs (locallease)
if the user wants to override this and try to grant leases even
if the server did not grant oplock.

Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent a364bc0b

fs/cifs/CHANGES

+2 −1
Original line number Diff line number Diff line
@@ -3,7 +3,8 @@ Version 1.55 
Various fixes to make delete of open files behavior more predictable

(when delete of an open file fails we mark the file as "delete-on-close"

in a way that more servers accept, but only if we can first rename the

file to a temporary name)

file to a temporary name).  Add experimental support for more safely

handling fcntl(F_SETLEASE).



Version 1.54

------------

fs/cifs/README

+16 −0
Original line number Diff line number Diff line
@@ -491,6 +491,19 @@ A partial list of the supported mount options follows: 
		Note that this differs from the sign mount option in that it

		causes encryption of data sent over this mounted share but other

		shares mounted to the same server are unaffected.

 locallease     This option is rarely needed. Fcntl F_SETLEASE is

		used by some applications such as Samba and NFSv4 server to

		check to see whether a file is cacheable.  CIFS has no way

		to explicitly request a lease, but can check whether a file

		is cacheable (oplocked).  Unfortunately, even if a file

		is not oplocked, it could still be cacheable (ie cifs client

		could grant fcntl leases if no other local processes are using

		the file) for cases for example such as when the server does not

		support oplocks and the user is sure that the only updates to

		the file will be from this client. Specifying this mount option

		will allow the cifs client to check for leases (only) locally

		for files which are not oplocked instead of denying leases

		in that case. (EXPERIMENTAL)

 sec            Security mode.  Allowed values are:

			none	attempt to connection as a null user (no name)

			krb5    Use Kerberos version 5 authentication
@@ -641,6 +654,9 @@ requires enabling CONFIG_CIFS_EXPERIMENTAL 
	cifsacl support needed to retrieve approximated mode bits based on

		the contents on the CIFS ACL.



	lease support: cifs will check the oplock state before calling into

	the vfs to see if we can grant a lease on a file.



	DNOTIFY fcntl: needed for support of directory change 

			    notification and perhaps later for file leases)

fs/cifs/cifsfs.c

+41 −0
Original line number Diff line number Diff line
@@ -618,6 +618,37 @@ static loff_t cifs_llseek(struct file *file, loff_t offset, int origin) 
	return generic_file_llseek_unlocked(file, offset, origin);

}



#ifdef CONFIG_CIFS_EXPERIMENTAL

static int cifs_setlease(struct file *file, long arg, struct file_lock **lease)

{

	/* note that this is called by vfs setlease with the BKL held

	   although I doubt that BKL is needed here in cifs */

	struct inode *inode = file->f_path.dentry->d_inode;



	if (!(S_ISREG(inode->i_mode)))

		return -EINVAL;



	/* check if file is oplocked */

	if (((arg == F_RDLCK) &&

		(CIFS_I(inode)->clientCanCacheRead)) ||

	    ((arg == F_WRLCK) &&

		(CIFS_I(inode)->clientCanCacheAll)))

		return generic_setlease(file, arg, lease);

	else if (CIFS_SB(inode->i_sb)->tcon->local_lease &&

			!CIFS_I(inode)->clientCanCacheRead)

		/* If the server claims to support oplock on this

		   file, then we still need to check oplock even

		   if the local_lease mount option is set, but there

		   are servers which do not support oplock for which

		   this mount option may be useful if the user

		   knows that the file won't be changed on the server

		   by anyone else */

		return generic_setlease(file, arg, lease);

	else

		return -EAGAIN;

}

#endif



struct file_system_type cifs_fs_type = {

	.owner = THIS_MODULE,

	.name = "cifs",
@@ -696,6 +727,7 @@ const struct file_operations cifs_file_ops = { 


#ifdef CONFIG_CIFS_EXPERIMENTAL

	.dir_notify = cifs_dir_notify,

	.setlease = cifs_setlease,

#endif /* CONFIG_CIFS_EXPERIMENTAL */

};
@@ -716,6 +748,7 @@ const struct file_operations cifs_file_direct_ops = { 
	.llseek = cifs_llseek,

#ifdef CONFIG_CIFS_EXPERIMENTAL

	.dir_notify = cifs_dir_notify,

	.setlease = cifs_setlease,

#endif /* CONFIG_CIFS_EXPERIMENTAL */

};

const struct file_operations cifs_file_nobrl_ops = {
@@ -736,6 +769,7 @@ const struct file_operations cifs_file_nobrl_ops = { 


#ifdef CONFIG_CIFS_EXPERIMENTAL

	.dir_notify = cifs_dir_notify,

	.setlease = cifs_setlease,

#endif /* CONFIG_CIFS_EXPERIMENTAL */

};
@@ -755,6 +789,7 @@ const struct file_operations cifs_file_direct_nobrl_ops = { 
	.llseek = cifs_llseek,

#ifdef CONFIG_CIFS_EXPERIMENTAL

	.dir_notify = cifs_dir_notify,

	.setlease = cifs_setlease,

#endif /* CONFIG_CIFS_EXPERIMENTAL */

};
@@ -946,6 +981,12 @@ static int cifs_oplock_thread(void *dummyarg) 
				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(

fs/cifs/cifsglob.h

+1 −0
Original line number Diff line number Diff line
@@ -285,6 +285,7 @@ struct cifsTconInfo { 
	bool seal:1;      /* transport encryption for this mounted share */

	bool unix_ext:1;  /* if false disable Linux extensions to CIFS protocol

				for this mount even if server would support */

	bool local_lease:1; /* check leases (only) on local system not remote */

	/* BB add field for back pointer to sb struct(s)? */

};

fs/cifs/connect.c

+7 −1
Original line number Diff line number Diff line
@@ -90,7 +90,8 @@ struct smb_vol { 
	bool nocase:1;     /* request case insensitive filenames */

	bool nobrl:1;      /* disable sending byte range locks to srv */

	bool seal:1;       /* request transport encryption on share */

	bool nodfs:1;

	bool nodfs:1;      /* Do not request DFS, even if available */

	bool local_lease:1; /* check leases only on local system, not remote */

	unsigned int rsize;

	unsigned int wsize;

	unsigned int sockopt;
@@ -1264,6 +1265,10 @@ cifs_parse_mount_options(char *options, const char *devname, 
			vol->no_psx_acl = 0;

		} else if (strnicmp(data, "noacl", 5) == 0) {

			vol->no_psx_acl = 1;

#ifdef CONFIG_CIFS_EXPERIMENTAL

		} else if (strnicmp(data, "locallease", 6) == 0) {

			vol->local_lease = 1;

#endif

		} else if (strnicmp(data, "sign", 4) == 0) {

			vol->secFlg |= CIFSSEC_MUST_SIGN;

		} else if (strnicmp(data, "seal", 4) == 0) {
@@ -2162,6 +2167,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb, 
			   for the retry flag is used */

			tcon->retry = volume_info.retry;

			tcon->nocase = volume_info.nocase;

			tcon->local_lease = volume_info.local_lease;

			if (tcon->seal != volume_info.seal)

				cERROR(1, ("transport encryption setting "

					   "conflicts with existing tid"));

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