[net-next-2.6.git] / fs / nfs / file.c

/*
 *  linux/fs/nfs/file.c
 *
 *  Copyright (C) 1992  Rick Sladkey
 *
 *  Changes Copyright (C) 1994 by Florian La Roche
 *   - Do not copy data too often around in the kernel.
 *   - In nfs_file_read the return value of kmalloc wasn't checked.
 *   - Put in a better version of read look-ahead buffering. Original idea
 *     and implementation by Wai S Kok elekokws@ee.nus.sg.
 *
 *  Expire cache on write to a file by Wai S Kok (Oct 1994).
 *
 *  Total rewrite of read side for new NFS buffer cache.. Linus.
 *
 *  nfs regular file handling functions
 */

#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>

#include <asm/uaccess.h>
#include <asm/system.h>

#include "delegation.h"

#define NFSDBG_FACILITY		NFSDBG_FILE

static int nfs_file_open(struct inode *, struct file *);
static int nfs_file_release(struct inode *, struct file *);
static int  nfs_file_mmap(struct file *, struct vm_area_struct *);
static ssize_t nfs_file_sendfile(struct file *, loff_t *, size_t, read_actor_t, void *);
static ssize_t nfs_file_read(struct kiocb *, char __user *, size_t, loff_t);
static ssize_t nfs_file_write(struct kiocb *, const char __user *, size_t, loff_t);
static int  nfs_file_flush(struct file *);
static int  nfs_fsync(struct file *, struct dentry *dentry, int datasync);
static int nfs_check_flags(int flags);
static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);

struct file_operations nfs_file_operations = {
	.llseek		= remote_llseek,
	.read		= do_sync_read,
	.write		= do_sync_write,
	.aio_read		= nfs_file_read,
	.aio_write		= nfs_file_write,
	.mmap		= nfs_file_mmap,
	.open		= nfs_file_open,
	.flush		= nfs_file_flush,
	.release	= nfs_file_release,
	.fsync		= nfs_fsync,
	.lock		= nfs_lock,
	.flock		= nfs_flock,
	.sendfile	= nfs_file_sendfile,
	.check_flags	= nfs_check_flags,
};

struct inode_operations nfs_file_inode_operations = {
	.permission	= nfs_permission,
	.getattr	= nfs_getattr,
	.setattr	= nfs_setattr,
};

/* Hack for future NFS swap support */
#ifndef IS_SWAPFILE
# define IS_SWAPFILE(inode)	(0)
#endif

static int nfs_check_flags(int flags)
{
	if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
		return -EINVAL;

	return 0;
}

/*
 * Open file
 */
static int
nfs_file_open(struct inode *inode, struct file *filp)
{
	struct nfs_server *server = NFS_SERVER(inode);
	int (*open)(struct inode *, struct file *);
	int res;

	res = nfs_check_flags(filp->f_flags);
	if (res)
		return res;

	lock_kernel();
	/* Do NFSv4 open() call */
	if ((open = server->rpc_ops->file_open) != NULL)
		res = open(inode, filp);
	unlock_kernel();
	return res;
}

static int
nfs_file_release(struct inode *inode, struct file *filp)
{
	/* Ensure that dirty pages are flushed out with the right creds */
	if (filp->f_mode & FMODE_WRITE)
		filemap_fdatawrite(filp->f_mapping);
	return NFS_PROTO(inode)->file_release(inode, filp);
}

/*
 * Flush all dirty pages, and check for write errors.
 *
 */
static int
nfs_file_flush(struct file *file)
{
	struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
	struct inode	*inode = file->f_dentry->d_inode;
	int		status;

	dfprintk(VFS, "nfs: flush(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);

	if ((file->f_mode & FMODE_WRITE) == 0)
		return 0;
	lock_kernel();
	/* Ensure that data+attribute caches are up to date after close() */
	status = nfs_wb_all(inode);
	if (!status) {
		status = ctx->error;
		ctx->error = 0;
		if (!status && !nfs_have_delegation(inode, FMODE_READ))
			__nfs_revalidate_inode(NFS_SERVER(inode), inode);
	}
	unlock_kernel();
	return status;
}

static ssize_t
nfs_file_read(struct kiocb *iocb, char __user * buf, size_t count, loff_t pos)
{
	struct dentry * dentry = iocb->ki_filp->f_dentry;
	struct inode * inode = dentry->d_inode;
	ssize_t result;

#ifdef CONFIG_NFS_DIRECTIO
	if (iocb->ki_filp->f_flags & O_DIRECT)
		return nfs_file_direct_read(iocb, buf, count, pos);
#endif

	dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
		dentry->d_parent->d_name.name, dentry->d_name.name,
		(unsigned long) count, (unsigned long) pos);

	result = nfs_revalidate_inode(NFS_SERVER(inode), inode);
	if (!result)
		result = generic_file_aio_read(iocb, buf, count, pos);
	return result;
}

static ssize_t
nfs_file_sendfile(struct file *filp, loff_t *ppos, size_t count,
		read_actor_t actor, void *target)
{
	struct dentry *dentry = filp->f_dentry;
	struct inode *inode = dentry->d_inode;
	ssize_t res;

	dfprintk(VFS, "nfs: sendfile(%s/%s, %lu@%Lu)\n",
		dentry->d_parent->d_name.name, dentry->d_name.name,
		(unsigned long) count, (unsigned long long) *ppos);

	res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
	if (!res)
		res = generic_file_sendfile(filp, ppos, count, actor, target);
	return res;
}

static int
nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
{
	struct dentry *dentry = file->f_dentry;
	struct inode *inode = dentry->d_inode;
	int	status;

	dfprintk(VFS, "nfs: mmap(%s/%s)\n",
		dentry->d_parent->d_name.name, dentry->d_name.name);

	status = nfs_revalidate_inode(NFS_SERVER(inode), inode);
	if (!status)
		status = generic_file_mmap(file, vma);
	return status;
}

/*
 * Flush any dirty pages for this process, and check for write errors.
 * The return status from this call provides a reliable indication of
 * whether any write errors occurred for this process.
 */
static int
nfs_fsync(struct file *file, struct dentry *dentry, int datasync)
{
	struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
	struct inode *inode = dentry->d_inode;
	int status;

	dfprintk(VFS, "nfs: fsync(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);

	lock_kernel();
	status = nfs_wb_all(inode);
	if (!status) {
		status = ctx->error;
		ctx->error = 0;
	}
	unlock_kernel();
	return status;
}

/*
 * This does the "real" work of the write. The generic routine has
 * allocated the page, locked it, done all the page alignment stuff
 * calculations etc. Now we should just copy the data from user
 * space and write it back to the real medium..
 *
 * If the writer ends up delaying the write, the writer needs to
 * increment the page use counts until he is done with the page.
 */
static int nfs_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
{
	return nfs_flush_incompatible(file, page);
}

static int nfs_commit_write(struct file *file, struct page *page, unsigned offset, unsigned to)
{
	long status;

	lock_kernel();
	status = nfs_updatepage(file, page, offset, to-offset);
	unlock_kernel();
	return status;
}

struct address_space_operations nfs_file_aops = {
	.readpage = nfs_readpage,
	.readpages = nfs_readpages,
	.set_page_dirty = __set_page_dirty_nobuffers,
	.writepage = nfs_writepage,
	.writepages = nfs_writepages,
	.prepare_write = nfs_prepare_write,
	.commit_write = nfs_commit_write,
#ifdef CONFIG_NFS_DIRECTIO
	.direct_IO = nfs_direct_IO,
#endif
};

/* 
 * Write to a file (through the page cache).
 */
static ssize_t
nfs_file_write(struct kiocb *iocb, const char __user *buf, size_t count, loff_t pos)
{
	struct dentry * dentry = iocb->ki_filp->f_dentry;
	struct inode * inode = dentry->d_inode;
	ssize_t result;

#ifdef CONFIG_NFS_DIRECTIO
	if (iocb->ki_filp->f_flags & O_DIRECT)
		return nfs_file_direct_write(iocb, buf, count, pos);
#endif

	dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%lu)\n",
		dentry->d_parent->d_name.name, dentry->d_name.name,
		inode->i_ino, (unsigned long) count, (unsigned long) pos);

	result = -EBUSY;
	if (IS_SWAPFILE(inode))
		goto out_swapfile;
	result = nfs_revalidate_inode(NFS_SERVER(inode), inode);
	if (result)
		goto out;

	result = count;
	if (!count)
		goto out;

	result = generic_file_aio_write(iocb, buf, count, pos);
out:
	return result;

out_swapfile:
	printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
	goto out;
}

static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
{
	struct inode *inode = filp->f_mapping->host;
	int status = 0;

	lock_kernel();
	/* Use local locking if mounted with "-onolock" */
	if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
	else {
		struct file_lock *cfl = posix_test_lock(filp, fl);

		fl->fl_type = F_UNLCK;
		if (cfl != NULL)
			memcpy(fl, cfl, sizeof(*fl));
	}
	unlock_kernel();
	return status;
}

static int do_vfs_lock(struct file *file, struct file_lock *fl)
{
	int res = 0;
	switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
		case FL_POSIX:
			res = posix_lock_file_wait(file, fl);
			break;
		case FL_FLOCK:
			res = flock_lock_file_wait(file, fl);
			break;
		default:
			BUG();
	}
	if (res < 0)
		printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
				__FUNCTION__);
	return res;
}

static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
{
	struct inode *inode = filp->f_mapping->host;
	sigset_t oldset;
	int status;

	rpc_clnt_sigmask(NFS_CLIENT(inode), &oldset);
	/*
	 * Flush all pending writes before doing anything
	 * with locks..
	 */
	filemap_fdatawrite(filp->f_mapping);
	down(&inode->i_sem);
	nfs_wb_all(inode);
	up(&inode->i_sem);
	filemap_fdatawait(filp->f_mapping);

	/* NOTE: special case
	 * 	If we're signalled while cleaning up locks on process exit, we
	 * 	still need to complete the unlock.
	 */
	lock_kernel();
	/* Use local locking if mounted with "-onolock" */
	if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
	else
		status = do_vfs_lock(filp, fl);
	unlock_kernel();
	rpc_clnt_sigunmask(NFS_CLIENT(inode), &oldset);
	return status;
}

static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
{
	struct inode *inode = filp->f_mapping->host;
	sigset_t oldset;
	int status;

	rpc_clnt_sigmask(NFS_CLIENT(inode), &oldset);
	/*
	 * Flush all pending writes before doing anything
	 * with locks..
	 */
	status = filemap_fdatawrite(filp->f_mapping);
	if (status == 0) {
		down(&inode->i_sem);
		status = nfs_wb_all(inode);
		up(&inode->i_sem);
		if (status == 0)
			status = filemap_fdatawait(filp->f_mapping);
	}
	if (status < 0)
		goto out;

	lock_kernel();
	/* Use local locking if mounted with "-onolock" */
	if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)) {
		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
		/* If we were signalled we still need to ensure that
		 * we clean up any state on the server. We therefore
		 * record the lock call as having succeeded in order to
		 * ensure that locks_remove_posix() cleans it out when
		 * the process exits.
		 */
		if (status == -EINTR || status == -ERESTARTSYS)
			do_vfs_lock(filp, fl);
	} else
		status = do_vfs_lock(filp, fl);
	unlock_kernel();
	if (status < 0)
		goto out;
	/*
	 * Make sure we clear the cache whenever we try to get the lock.
	 * This makes locking act as a cache coherency point.
	 */
	filemap_fdatawrite(filp->f_mapping);
	down(&inode->i_sem);
	nfs_wb_all(inode);	/* we may have slept */
	up(&inode->i_sem);
	filemap_fdatawait(filp->f_mapping);
	nfs_zap_caches(inode);
out:
	rpc_clnt_sigunmask(NFS_CLIENT(inode), &oldset);
	return status;
}

/*
 * Lock a (portion of) a file
 */
static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
{
	struct inode * inode = filp->f_mapping->host;

	dprintk("NFS: nfs_lock(f=%s/%ld, t=%x, fl=%x, r=%Ld:%Ld)\n",
			inode->i_sb->s_id, inode->i_ino,
			fl->fl_type, fl->fl_flags,
			(long long)fl->fl_start, (long long)fl->fl_end);

	if (!inode)
		return -EINVAL;

	/* No mandatory locks over NFS */
	if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
		return -ENOLCK;

	if (IS_GETLK(cmd))
		return do_getlk(filp, cmd, fl);
	if (fl->fl_type == F_UNLCK)
		return do_unlk(filp, cmd, fl);
	return do_setlk(filp, cmd, fl);
}

/*
 * Lock a (portion of) a file
 */
static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
{
	struct inode * inode = filp->f_mapping->host;

	dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
			inode->i_sb->s_id, inode->i_ino,
			fl->fl_type, fl->fl_flags);

	if (!inode)
		return -EINVAL;

	/*
	 * No BSD flocks over NFS allowed.
	 * Note: we could try to fake a POSIX lock request here by
	 * using ((u32) filp | 0x80000000) or some such as the pid.
	 * Not sure whether that would be unique, though, or whether
	 * that would break in other places.
	 */
	if (!(fl->fl_flags & FL_FLOCK))
		return -ENOLCK;

	/* We're simulating flock() locks using posix locks on the server */
	fl->fl_owner = (fl_owner_t)filp;
	fl->fl_start = 0;
	fl->fl_end = OFFSET_MAX;

	if (fl->fl_type == F_UNLCK)
		return do_unlk(filp, cmd, fl);
	return do_setlk(filp, cmd, fl);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/nfs/file.c
	3	*
	4	* Copyright (C) 1992 Rick Sladkey
	5	*
	6	* Changes Copyright (C) 1994 by Florian La Roche
	7	* - Do not copy data too often around in the kernel.
	8	* - In nfs_file_read the return value of kmalloc wasn't checked.
	9	* - Put in a better version of read look-ahead buffering. Original idea
	10	* and implementation by Wai S Kok elekokws@ee.nus.sg.
	11	*
	12	* Expire cache on write to a file by Wai S Kok (Oct 1994).
	13	*
	14	* Total rewrite of read side for new NFS buffer cache.. Linus.
	15	*
	16	* nfs regular file handling functions
	17	*/
	18
	19	#include <linux/time.h>
	20	#include <linux/kernel.h>
	21	#include <linux/errno.h>
	22	#include <linux/fcntl.h>
	23	#include <linux/stat.h>
	24	#include <linux/nfs_fs.h>
	25	#include <linux/nfs_mount.h>
	26	#include <linux/mm.h>
	27	#include <linux/slab.h>
	28	#include <linux/pagemap.h>
	29	#include <linux/smp_lock.h>
	30
	31	#include <asm/uaccess.h>
	32	#include <asm/system.h>
	33
	34	#include "delegation.h"
	35
	36	#define NFSDBG_FACILITY NFSDBG_FILE
	37
	38	static int nfs_file_open(struct inode , struct file );
	39	static int nfs_file_release(struct inode , struct file );
	40	static int nfs_file_mmap(struct file , struct vm_area_struct );
	41	static ssize_t nfs_file_sendfile(struct file , loff_t , size_t, read_actor_t, void *);
	42	static ssize_t nfs_file_read(struct kiocb , char __user , size_t, loff_t);
	43	static ssize_t nfs_file_write(struct kiocb , const char __user , size_t, loff_t);
	44	static int nfs_file_flush(struct file *);
	45	static int nfs_fsync(struct file , struct dentry dentry, int datasync);
	46	static int nfs_check_flags(int flags);
	47	static int nfs_lock(struct file filp, int cmd, struct file_lock fl);
	48	static int nfs_flock(struct file filp, int cmd, struct file_lock fl);
	49
	50	struct file_operations nfs_file_operations = {
	51	.llseek = remote_llseek,
	52	.read = do_sync_read,
	53	.write = do_sync_write,
	54	.aio_read = nfs_file_read,
	55	.aio_write = nfs_file_write,
	56	.mmap = nfs_file_mmap,
	57	.open = nfs_file_open,
	58	.flush = nfs_file_flush,
	59	.release = nfs_file_release,
	60	.fsync = nfs_fsync,
	61	.lock = nfs_lock,
	62	.flock = nfs_flock,
	63	.sendfile = nfs_file_sendfile,
	64	.check_flags = nfs_check_flags,
65	};
66
67	struct inode_operations nfs_file_inode_operations = {
68	.permission = nfs_permission,
69	.getattr = nfs_getattr,
70	.setattr = nfs_setattr,
71	};
72
73	/* Hack for future NFS swap support */
74	#ifndef IS_SWAPFILE
75	# define IS_SWAPFILE(inode) (0)
76	#endif
77
78	static int nfs_check_flags(int flags)
79	{
80	if ((flags & (O_APPEND \| O_DIRECT)) == (O_APPEND \| O_DIRECT))
81	return -EINVAL;
82
83	return 0;
84	}
85
86	/*
87	* Open file
88	*/
89	static int
90	nfs_file_open(struct inode inode, struct file filp)
91	{
92	struct nfs_server *server = NFS_SERVER(inode);
93	int (open)(struct inode , struct file *);
94	int res;
95
96	res = nfs_check_flags(filp->f_flags);
97	if (res)
98	return res;
99
100	lock_kernel();
101	/* Do NFSv4 open() call */
102	if ((open = server->rpc_ops->file_open) != NULL)
103	res = open(inode, filp);
104	unlock_kernel();
105	return res;
106	}
107
108	static int
109	nfs_file_release(struct inode inode, struct file filp)
110	{
111	/* Ensure that dirty pages are flushed out with the right creds */
112	if (filp->f_mode & FMODE_WRITE)
113	filemap_fdatawrite(filp->f_mapping);
114	return NFS_PROTO(inode)->file_release(inode, filp);
115	}
116
117	/*
118	* Flush all dirty pages, and check for write errors.
119	*
120	*/
121	static int
122	nfs_file_flush(struct file *file)
123	{
124	struct nfs_open_context ctx = (struct nfs_open_context )file->private_data;
125	struct inode *inode = file->f_dentry->d_inode;
126	int status;
127
128	dfprintk(VFS, "nfs: flush(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
129
130	if ((file->f_mode & FMODE_WRITE) == 0)
131	return 0;
132	lock_kernel();
133	/* Ensure that data+attribute caches are up to date after close() */
134	status = nfs_wb_all(inode);
135	if (!status) {
136	status = ctx->error;
137	ctx->error = 0;
138	if (!status && !nfs_have_delegation(inode, FMODE_READ))
139	__nfs_revalidate_inode(NFS_SERVER(inode), inode);
140	}
141	unlock_kernel();
142	return status;
143	}
144
145	static ssize_t
146	nfs_file_read(struct kiocb iocb, char __user buf, size_t count, loff_t pos)
147	{
148	struct dentry * dentry = iocb->ki_filp->f_dentry;
149	struct inode * inode = dentry->d_inode;
150	ssize_t result;
151
152	#ifdef CONFIG_NFS_DIRECTIO
153	if (iocb->ki_filp->f_flags & O_DIRECT)
154	return nfs_file_direct_read(iocb, buf, count, pos);
155	#endif
156
157	dfprintk(VFS, "nfs: read(%s/%s, %lu@%lu)\n",
158	dentry->d_parent->d_name.name, dentry->d_name.name,
159	(unsigned long) count, (unsigned long) pos);
160
161	result = nfs_revalidate_inode(NFS_SERVER(inode), inode);
162	if (!result)
163	result = generic_file_aio_read(iocb, buf, count, pos);
164	return result;
165	}
166
167	static ssize_t
168	nfs_file_sendfile(struct file filp, loff_t ppos, size_t count,
169	read_actor_t actor, void *target)
170	{
171	struct dentry *dentry = filp->f_dentry;
172	struct inode *inode = dentry->d_inode;
173	ssize_t res;
174
175	dfprintk(VFS, "nfs: sendfile(%s/%s, %lu@%Lu)\n",
176	dentry->d_parent->d_name.name, dentry->d_name.name,
177	(unsigned long) count, (unsigned long long) *ppos);
178
179	res = nfs_revalidate_inode(NFS_SERVER(inode), inode);
180	if (!res)
181	res = generic_file_sendfile(filp, ppos, count, actor, target);
182	return res;
183	}
184
185	static int
186	nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
187	{
188	struct dentry *dentry = file->f_dentry;
189	struct inode *inode = dentry->d_inode;
190	int status;
191
192	dfprintk(VFS, "nfs: mmap(%s/%s)\n",
193	dentry->d_parent->d_name.name, dentry->d_name.name);
194
195	status = nfs_revalidate_inode(NFS_SERVER(inode), inode);
196	if (!status)
197	status = generic_file_mmap(file, vma);
198	return status;
199	}
200
201	/*
202	* Flush any dirty pages for this process, and check for write errors.
203	* The return status from this call provides a reliable indication of
204	* whether any write errors occurred for this process.
205	*/
206	static int
207	nfs_fsync(struct file file, struct dentry dentry, int datasync)
208	{
209	struct nfs_open_context ctx = (struct nfs_open_context )file->private_data;
210	struct inode *inode = dentry->d_inode;
211	int status;
212
213	dfprintk(VFS, "nfs: fsync(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);
214
215	lock_kernel();
216	status = nfs_wb_all(inode);
217	if (!status) {
218	status = ctx->error;
219	ctx->error = 0;
220	}
221	unlock_kernel();
222	return status;
223	}
224
225	/*
226	* This does the "real" work of the write. The generic routine has
227	* allocated the page, locked it, done all the page alignment stuff
228	* calculations etc. Now we should just copy the data from user
229	* space and write it back to the real medium..
230	*
231	* If the writer ends up delaying the write, the writer needs to
232	* increment the page use counts until he is done with the page.
233	*/
234	static int nfs_prepare_write(struct file file, struct page page, unsigned offset, unsigned to)
235	{
236	return nfs_flush_incompatible(file, page);
237	}
238
239	static int nfs_commit_write(struct file file, struct page page, unsigned offset, unsigned to)
240	{
241	long status;
242
243	lock_kernel();
244	status = nfs_updatepage(file, page, offset, to-offset);
245	unlock_kernel();
246	return status;
247	}
248
249	struct address_space_operations nfs_file_aops = {
250	.readpage = nfs_readpage,
251	.readpages = nfs_readpages,
252	.set_page_dirty = __set_page_dirty_nobuffers,
253	.writepage = nfs_writepage,
254	.writepages = nfs_writepages,
255	.prepare_write = nfs_prepare_write,
256	.commit_write = nfs_commit_write,
257	#ifdef CONFIG_NFS_DIRECTIO
258	.direct_IO = nfs_direct_IO,
259	#endif
260	};
261
262	/*
263	* Write to a file (through the page cache).
264	*/
265	static ssize_t
266	nfs_file_write(struct kiocb iocb, const char __user buf, size_t count, loff_t pos)
267	{
268	struct dentry * dentry = iocb->ki_filp->f_dentry;
269	struct inode * inode = dentry->d_inode;
270	ssize_t result;
271
272	#ifdef CONFIG_NFS_DIRECTIO
273	if (iocb->ki_filp->f_flags & O_DIRECT)
274	return nfs_file_direct_write(iocb, buf, count, pos);
275	#endif
276
277	dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%lu)\n",
278	dentry->d_parent->d_name.name, dentry->d_name.name,
279	inode->i_ino, (unsigned long) count, (unsigned long) pos);
280
281	result = -EBUSY;
282	if (IS_SWAPFILE(inode))
283	goto out_swapfile;
284	result = nfs_revalidate_inode(NFS_SERVER(inode), inode);
285	if (result)
286	goto out;
287
288	result = count;
289	if (!count)
290	goto out;
291
292	result = generic_file_aio_write(iocb, buf, count, pos);
293	out:
294	return result;
295
296	out_swapfile:
297	printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
298	goto out;
299	}
300
301	static int do_getlk(struct file filp, int cmd, struct file_lock fl)
302	{
303	struct inode *inode = filp->f_mapping->host;
304	int status = 0;
305
306	lock_kernel();
307	/* Use local locking if mounted with "-onolock" */
308	if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
309	status = NFS_PROTO(inode)->lock(filp, cmd, fl);
310	else {
311	struct file_lock *cfl = posix_test_lock(filp, fl);
312
313	fl->fl_type = F_UNLCK;
314	if (cfl != NULL)
315	memcpy(fl, cfl, sizeof(*fl));
316	}
317	unlock_kernel();
318	return status;
319	}
320
321	static int do_vfs_lock(struct file file, struct file_lock fl)
322	{
323	int res = 0;
324	switch (fl->fl_flags & (FL_POSIX\|FL_FLOCK)) {
325	case FL_POSIX:
326	res = posix_lock_file_wait(file, fl);
327	break;
328	case FL_FLOCK:
329	res = flock_lock_file_wait(file, fl);
330	break;
331	default:
332	BUG();
333	}
334	if (res < 0)
335	printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
336	__FUNCTION__);
337	return res;
338	}
339
340	static int do_unlk(struct file filp, int cmd, struct file_lock fl)
341	{
342	struct inode *inode = filp->f_mapping->host;
343	sigset_t oldset;
344	int status;
345
346	rpc_clnt_sigmask(NFS_CLIENT(inode), &oldset);
347	/*
348	* Flush all pending writes before doing anything
349	* with locks..
350	*/
351	filemap_fdatawrite(filp->f_mapping);
352	down(&inode->i_sem);
353	nfs_wb_all(inode);
354	up(&inode->i_sem);
355	filemap_fdatawait(filp->f_mapping);
356
357	/* NOTE: special case
358	* If we're signalled while cleaning up locks on process exit, we
359	* still need to complete the unlock.
360	*/
361	lock_kernel();
362	/* Use local locking if mounted with "-onolock" */
363	if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
364	status = NFS_PROTO(inode)->lock(filp, cmd, fl);
365	else
366	status = do_vfs_lock(filp, fl);
367	unlock_kernel();
368	rpc_clnt_sigunmask(NFS_CLIENT(inode), &oldset);
369	return status;
370	}
371
372	static int do_setlk(struct file filp, int cmd, struct file_lock fl)
373	{
374	struct inode *inode = filp->f_mapping->host;
375	sigset_t oldset;
376	int status;
377
378	rpc_clnt_sigmask(NFS_CLIENT(inode), &oldset);
379	/*
380	* Flush all pending writes before doing anything
381	* with locks..
382	*/
383	status = filemap_fdatawrite(filp->f_mapping);
384	if (status == 0) {
385	down(&inode->i_sem);
386	status = nfs_wb_all(inode);
387	up(&inode->i_sem);
388	if (status == 0)
389	status = filemap_fdatawait(filp->f_mapping);
390	}
391	if (status < 0)
392	goto out;
393
394	lock_kernel();
395	/* Use local locking if mounted with "-onolock" */
396	if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)) {
397	status = NFS_PROTO(inode)->lock(filp, cmd, fl);
398	/* If we were signalled we still need to ensure that
399	* we clean up any state on the server. We therefore
400	* record the lock call as having succeeded in order to
401	* ensure that locks_remove_posix() cleans it out when
402	* the process exits.
403	*/
404	if (status == -EINTR \|\| status == -ERESTARTSYS)
405	do_vfs_lock(filp, fl);
406	} else
407	status = do_vfs_lock(filp, fl);
408	unlock_kernel();
409	if (status < 0)
410	goto out;
411	/*
412	* Make sure we clear the cache whenever we try to get the lock.
413	* This makes locking act as a cache coherency point.
414	*/
415	filemap_fdatawrite(filp->f_mapping);
416	down(&inode->i_sem);
417	nfs_wb_all(inode); /* we may have slept */
418	up(&inode->i_sem);
419	filemap_fdatawait(filp->f_mapping);
420	nfs_zap_caches(inode);
421	out:
422	rpc_clnt_sigunmask(NFS_CLIENT(inode), &oldset);
423	return status;
424	}
425
426	/*
427	* Lock a (portion of) a file
428	*/
429	static int nfs_lock(struct file filp, int cmd, struct file_lock fl)
430	{
431	struct inode * inode = filp->f_mapping->host;
432
433	dprintk("NFS: nfs_lock(f=%s/%ld, t=%x, fl=%x, r=%Ld:%Ld)\n",
434	inode->i_sb->s_id, inode->i_ino,
435	fl->fl_type, fl->fl_flags,
436	(long long)fl->fl_start, (long long)fl->fl_end);
437
438	if (!inode)
439	return -EINVAL;
440
441	/* No mandatory locks over NFS */
442	if ((inode->i_mode & (S_ISGID \| S_IXGRP)) == S_ISGID)
443	return -ENOLCK;
444
445	if (IS_GETLK(cmd))
446	return do_getlk(filp, cmd, fl);
447	if (fl->fl_type == F_UNLCK)
448	return do_unlk(filp, cmd, fl);
449	return do_setlk(filp, cmd, fl);
450	}
451
452	/*
453	* Lock a (portion of) a file
454	*/
455	static int nfs_flock(struct file filp, int cmd, struct file_lock fl)
456	{
457	struct inode * inode = filp->f_mapping->host;
458
459	dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
460	inode->i_sb->s_id, inode->i_ino,
461	fl->fl_type, fl->fl_flags);
462
463	if (!inode)
464	return -EINVAL;
465
466	/*
467	* No BSD flocks over NFS allowed.
468	* Note: we could try to fake a POSIX lock request here by
469	* using ((u32) filp \| 0x80000000) or some such as the pid.
470	* Not sure whether that would be unique, though, or whether
471	* that would break in other places.
472	*/
473	if (!(fl->fl_flags & FL_FLOCK))
474	return -ENOLCK;
475
476	/* We're simulating flock() locks using posix locks on the server */
477	fl->fl_owner = (fl_owner_t)filp;
478	fl->fl_start = 0;
479	fl->fl_end = OFFSET_MAX;
480
481	if (fl->fl_type == F_UNLCK)
482	return do_unlk(filp, cmd, fl);
483	return do_setlk(filp, cmd, fl);
484	}