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Commit 53da4939 authored by Mark Fasheh's avatar Mark Fasheh
Browse files

ocfs2: POSIX file locks support 



This is actually pretty easy since fs/dlm already handles the bulk of the
work. The Ocfs2 userspace cluster stack module already uses fs/dlm as the
underlying lock manager, so I only had to add the right calls.

Cluster-aware POSIX locks ("plocks") can be turned off by the same means at
UNIX locks - mount with 'noflocks', or create a local-only Ocfs2 volume.
Internally, the file system uses two sets of file_operations, depending on
whether cluster aware plocks is required. This turns out to be easier than
implementing local-only versions of ->lock.

Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
parent a447c093

fs/ocfs2/file.c

+51 −0
Original line number Diff line number Diff line
@@ -2237,6 +2237,10 @@ const struct inode_operations ocfs2_special_file_iops = { 
	.permission	= ocfs2_permission,

};



/*

 * Other than ->lock, keep ocfs2_fops and ocfs2_dops in sync with

 * ocfs2_fops_no_plocks and ocfs2_dops_no_plocks!

 */

const struct file_operations ocfs2_fops = {

	.llseek		= generic_file_llseek,

	.read		= do_sync_read,
@@ -2251,6 +2255,7 @@ const struct file_operations ocfs2_fops = { 
#ifdef CONFIG_COMPAT

	.compat_ioctl   = ocfs2_compat_ioctl,

#endif

	.lock		= ocfs2_lock,

	.flock		= ocfs2_flock,

	.splice_read	= ocfs2_file_splice_read,

	.splice_write	= ocfs2_file_splice_write,
@@ -2266,6 +2271,52 @@ const struct file_operations ocfs2_dops = { 
	.unlocked_ioctl	= ocfs2_ioctl,

#ifdef CONFIG_COMPAT

	.compat_ioctl   = ocfs2_compat_ioctl,

#endif

	.lock		= ocfs2_lock,

	.flock		= ocfs2_flock,

};



/*

 * POSIX-lockless variants of our file_operations.

 *

 * These will be used if the underlying cluster stack does not support

 * posix file locking, if the user passes the "localflocks" mount

 * option, or if we have a local-only fs.

 *

 * ocfs2_flock is in here because all stacks handle UNIX file locks,

 * so we still want it in the case of no stack support for

 * plocks. Internally, it will do the right thing when asked to ignore

 * the cluster.

 */

const struct file_operations ocfs2_fops_no_plocks = {

	.llseek		= generic_file_llseek,

	.read		= do_sync_read,

	.write		= do_sync_write,

	.mmap		= ocfs2_mmap,

	.fsync		= ocfs2_sync_file,

	.release	= ocfs2_file_release,

	.open		= ocfs2_file_open,

	.aio_read	= ocfs2_file_aio_read,

	.aio_write	= ocfs2_file_aio_write,

	.unlocked_ioctl	= ocfs2_ioctl,

#ifdef CONFIG_COMPAT

	.compat_ioctl   = ocfs2_compat_ioctl,

#endif

	.flock		= ocfs2_flock,

	.splice_read	= ocfs2_file_splice_read,

	.splice_write	= ocfs2_file_splice_write,

};



const struct file_operations ocfs2_dops_no_plocks = {

	.llseek		= generic_file_llseek,

	.read		= generic_read_dir,

	.readdir	= ocfs2_readdir,

	.fsync		= ocfs2_sync_file,

	.release	= ocfs2_dir_release,

	.open		= ocfs2_dir_open,

	.unlocked_ioctl	= ocfs2_ioctl,

#ifdef CONFIG_COMPAT

	.compat_ioctl   = ocfs2_compat_ioctl,

#endif

	.flock		= ocfs2_flock,

};

fs/ocfs2/file.h

+2 −0
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ 


extern const struct file_operations ocfs2_fops;

extern const struct file_operations ocfs2_dops;

extern const struct file_operations ocfs2_fops_no_plocks;

extern const struct file_operations ocfs2_dops_no_plocks;

extern const struct inode_operations ocfs2_file_iops;

extern const struct inode_operations ocfs2_special_file_iops;

struct ocfs2_alloc_context;

fs/ocfs2/inode.c

+13 −2
Original line number Diff line number Diff line
@@ -219,6 +219,7 @@ int ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe, 
	struct super_block *sb;

	struct ocfs2_super *osb;

	int status = -EINVAL;

	int use_plocks = 1;



	mlog_entry("(0x%p, size:%llu)\n", inode,

		   (unsigned long long)le64_to_cpu(fe->i_size));
@@ -226,6 +227,10 @@ int ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe, 
	sb = inode->i_sb;

	osb = OCFS2_SB(sb);



	if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) ||

	    ocfs2_mount_local(osb) || !ocfs2_stack_supports_plocks())

		use_plocks = 0;



	/* this means that read_inode cannot create a superblock inode

	 * today.  change if needed. */

	if (!OCFS2_IS_VALID_DINODE(fe) ||
@@ -295,13 +300,19 @@ int ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe, 


	switch (inode->i_mode & S_IFMT) {

	    case S_IFREG:

		    if (use_plocks)

			    inode->i_fop = &ocfs2_fops;

		    else

			    inode->i_fop = &ocfs2_fops_no_plocks;

		    inode->i_op = &ocfs2_file_iops;

		    i_size_write(inode, le64_to_cpu(fe->i_size));

		    break;

	    case S_IFDIR:

		    inode->i_op = &ocfs2_dir_iops;

		    if (use_plocks)

			    inode->i_fop = &ocfs2_dops;

		    else

			    inode->i_fop = &ocfs2_dops_no_plocks;

		    i_size_write(inode, le64_to_cpu(fe->i_size));

		    break;

	    case S_IFLNK:

fs/ocfs2/locks.c

+15 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
 */



#include <linux/fs.h>

#include <linux/fcntl.h>



#define MLOG_MASK_PREFIX ML_INODE

#include <cluster/masklog.h>
@@ -32,6 +33,7 @@ 


#include "dlmglue.h"

#include "file.h"

#include "inode.h"

#include "locks.h"



static int ocfs2_do_flock(struct file *file, struct inode *inode,
@@ -123,3 +125,16 @@ int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl) 
	else

		return ocfs2_do_flock(file, inode, cmd, fl);

}



int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl)

{

	struct inode *inode = file->f_mapping->host;

	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);



	if (!(fl->fl_flags & FL_POSIX))

		return -ENOLCK;

	if (__mandatory_lock(inode))

		return -ENOLCK;



	return ocfs2_plock(osb->cconn, OCFS2_I(inode)->ip_blkno, file, cmd, fl);

}

fs/ocfs2/locks.h

+1 −0
Original line number Diff line number Diff line
@@ -27,5 +27,6 @@ 
#define OCFS2_LOCKS_H



int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl);

int ocfs2_lock(struct file *file, int cmd, struct file_lock *fl);



#endif /* OCFS2_LOCKS_H */