fs/nfs/file.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  *  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 <linux/aio.h>

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

 #include "delegation.h"
 #include "internal.h"
 #include "iostat.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 loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
 static int  nfs_file_mmap(struct file *, struct vm_area_struct *);
 static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos,
 					struct pipe_inode_info *pipe,
 					size_t count, unsigned int flags);
 static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
 				unsigned long nr_segs, loff_t pos);
 static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
 				unsigned long nr_segs, loff_t pos);
 static int  nfs_file_flush(struct file *, fl_owner_t id);
 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);
 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);

 static struct vm_operations_struct nfs_file_vm_ops;

 const struct file_operations nfs_file_operations = {
 	.llseek		= nfs_file_llseek,
 	.read		= do_sync_read,
 	.write		= do_sync_write,
 	.aio_read	= nfs_file_read,
 	.aio_write	= nfs_file_write,
 #ifdef CONFIG_MMU
 	.mmap		= nfs_file_mmap,
 #else
 	.mmap		= generic_file_mmap,
 #endif
 	.open		= nfs_file_open,
 	.flush		= nfs_file_flush,
 	.release	= nfs_file_release,
 	.fsync		= nfs_fsync,
 	.lock		= nfs_lock,
 	.flock		= nfs_flock,
 	.splice_read	= nfs_file_splice_read,
 	.check_flags	= nfs_check_flags,
 	.setlease	= nfs_setlease,
 };

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

 #ifdef CONFIG_NFS_V3
 const struct inode_operations nfs3_file_inode_operations = {
 	.permission	= nfs_permission,
 	.getattr	= nfs_getattr,
 	.setattr	= nfs_setattr,
 	.listxattr	= nfs3_listxattr,
 	.getxattr	= nfs3_getxattr,
 	.setxattr	= nfs3_setxattr,
 	.removexattr	= nfs3_removexattr,
 };
 #endif  /* CONFIG_NFS_v3 */

 /* 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)
 {
 	int res;

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

 	nfs_inc_stats(inode, NFSIOS_VFSOPEN);
 	lock_kernel();
 	res = NFS_PROTO(inode)->file_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)
 		nfs_wb_all(filp->f_path.dentry->d_inode);
 	nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
 	return NFS_PROTO(inode)->file_release(inode, filp);
 }

 /**
  * nfs_revalidate_size - Revalidate the file size
  * @inode - pointer to inode struct
  * @file - pointer to struct file
  *
  * Revalidates the file length. This is basically a wrapper around
  * nfs_revalidate_inode() that takes into account the fact that we may
  * have cached writes (in which case we don't care about the server's
  * idea of what the file length is), or O_DIRECT (in which case we
  * shouldn't trust the cache).
  */
 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
 {
 	struct nfs_server *server = NFS_SERVER(inode);
 	struct nfs_inode *nfsi = NFS_I(inode);

 	if (server->flags & NFS_MOUNT_NOAC)
 		goto force_reval;
 	if (filp->f_flags & O_DIRECT)
 		goto force_reval;
 	if (nfsi->npages != 0)
 		return 0;
 	if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
 		return 0;
 force_reval:
 	return __nfs_revalidate_inode(server, inode);
 }

 static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
 {
 	loff_t loff;
 	/* origin == SEEK_END => we must revalidate the cached file length */
 	if (origin == SEEK_END) {
 		struct inode *inode = filp->f_mapping->host;
 		int retval = nfs_revalidate_file_size(inode, filp);
 		if (retval < 0)
 			return (loff_t)retval;
 	}
 	lock_kernel();	/* BKL needed? */
 	loff = generic_file_llseek_unlocked(filp, offset, origin);
 	unlock_kernel();
 	return loff;
 }

 /*
  * Helper for nfs_file_flush() and nfs_fsync()
  *
  * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
  * disk, but it retrieves and clears ctx->error after synching, despite
  * the two being set at the same time in nfs_context_set_write_error().
  * This is because the former is used to notify the _next_ call to
  * nfs_file_write() that a write error occured, and hence cause it to
  * fall back to doing a synchronous write.
  */
 static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
 {
 	int have_error, status;
 	int ret = 0;

 	have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 	status = nfs_wb_all(inode);
 	have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 	if (have_error)
 		ret = xchg(&ctx->error, 0);
 	if (!ret)
 		ret = status;
 	return ret;
 }

 /*
  * Flush all dirty pages, and check for write errors.
  *
  */
 static int
 nfs_file_flush(struct file *file, fl_owner_t id)
 {
 	struct nfs_open_context *ctx = nfs_file_open_context(file);
 	struct inode	*inode = file->f_path.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;
 	nfs_inc_stats(inode, NFSIOS_VFSFLUSH);

 	/* Ensure that data+attribute caches are up to date after close() */
 	status = nfs_do_fsync(ctx, inode);
 	if (!status)
 		nfs_revalidate_inode(NFS_SERVER(inode), inode);
 	return status;
 }

 static ssize_t
 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
 		unsigned long nr_segs, loff_t pos)
 {
 	struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 	struct inode * inode = dentry->d_inode;
 	ssize_t result;
 	size_t count = iov_length(iov, nr_segs);

 	if (iocb->ki_filp->f_flags & O_DIRECT)
 		return nfs_file_direct_read(iocb, iov, nr_segs, pos);

 	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_mapping(inode, iocb->ki_filp->f_mapping);
 	nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
 	if (!result)
 		result = generic_file_aio_read(iocb, iov, nr_segs, pos);
 	return result;
 }

 static ssize_t
 nfs_file_splice_read(struct file *filp, loff_t *ppos,
 		     struct pipe_inode_info *pipe, size_t count,
 		     unsigned int flags)
 {
 	struct dentry *dentry = filp->f_path.dentry;
 	struct inode *inode = dentry->d_inode;
 	ssize_t res;

 	dfprintk(VFS, "nfs: splice_read(%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_mapping(inode, filp->f_mapping);
 	if (!res)
 		res = generic_file_splice_read(filp, ppos, pipe, count, flags);
 	return res;
 }

 static int
 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
 {
 	struct dentry *dentry = file->f_path.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_mapping(inode, file->f_mapping);
 	if (!status) {
 		vma->vm_ops = &nfs_file_vm_ops;
 		vma->vm_flags |= VM_CAN_NONLINEAR;
 		file_accessed(file);
 	}
 	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 = nfs_file_open_context(file);
 	struct inode *inode = dentry->d_inode;

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

 	nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
 	return nfs_do_fsync(ctx, inode);
 }

 /*
  * This does the "real" work of the write. We must allocate and lock the
  * page to be sent back to the generic routine, which then copies the
  * data from user space.
  *
  * 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_write_begin(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
 	int ret;
 	pgoff_t index;
 	struct page *page;
 	index = pos >> PAGE_CACHE_SHIFT;

 	page = __grab_cache_page(mapping, index);
 	if (!page)
 		return -ENOMEM;
 	*pagep = page;

 	ret = nfs_flush_incompatible(file, page);
 	if (ret) {
 		unlock_page(page);
 		page_cache_release(page);
 	}
 	return ret;
 }

 static int nfs_write_end(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned copied,
 			struct page *page, void *fsdata)
 {
 	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 	int status;

 	lock_kernel();
 	status = nfs_updatepage(file, page, offset, copied);
 	unlock_kernel();

 	unlock_page(page);
 	page_cache_release(page);

 	if (status < 0)
 		return status;
 	return copied;
 }

 static void nfs_invalidate_page(struct page *page, unsigned long offset)
 {
 	if (offset != 0)
 		return;
 	/* Cancel any unstarted writes on this page */
 	nfs_wb_page_cancel(page->mapping->host, page);
 }

 static int nfs_release_page(struct page *page, gfp_t gfp)
 {
 	/* If PagePrivate() is set, then the page is not freeable */
 	return 0;
 }

 static int nfs_launder_page(struct page *page)
 {
 	return nfs_wb_page(page->mapping->host, page);
 }

 const 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,
 	.write_begin = nfs_write_begin,
 	.write_end = nfs_write_end,
 	.invalidatepage = nfs_invalidate_page,
 	.releasepage = nfs_release_page,
 	.direct_IO = nfs_direct_IO,
 	.launder_page = nfs_launder_page,
 };

 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
 {
 	struct file *filp = vma->vm_file;
 	unsigned pagelen;
 	int ret = -EINVAL;
 	struct address_space *mapping;

 	lock_page(page);
 	mapping = page->mapping;
 	if (mapping != vma->vm_file->f_path.dentry->d_inode->i_mapping)
 		goto out_unlock;

 	ret = 0;
 	pagelen = nfs_page_length(page);
 	if (pagelen == 0)
 		goto out_unlock;

 	ret = nfs_flush_incompatible(filp, page);
 	if (ret != 0)
 		goto out_unlock;

 	ret = nfs_updatepage(filp, page, 0, pagelen);
 	if (ret == 0)
 		ret = pagelen;
 out_unlock:
 	unlock_page(page);
 	return ret;
 }

 static struct vm_operations_struct nfs_file_vm_ops = {
 	.fault = filemap_fault,
 	.page_mkwrite = nfs_vm_page_mkwrite,
 };

 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
 {
 	struct nfs_open_context *ctx;

 	if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
 		return 1;
 	ctx = nfs_file_open_context(filp);
 	if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
 		return 1;
 	return 0;
 }

 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
 				unsigned long nr_segs, loff_t pos)
 {
 	struct dentry * dentry = iocb->ki_filp->f_path.dentry;
 	struct inode * inode = dentry->d_inode;
 	ssize_t result;
 	size_t count = iov_length(iov, nr_segs);

 	if (iocb->ki_filp->f_flags & O_DIRECT)
 		return nfs_file_direct_write(iocb, iov, nr_segs, pos);

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

 	result = -EBUSY;
 	if (IS_SWAPFILE(inode))
 		goto out_swapfile;
 	/*
 	 * O_APPEND implies that we must revalidate the file length.
 	 */
 	if (iocb->ki_filp->f_flags & O_APPEND) {
 		result = nfs_revalidate_file_size(inode, iocb->ki_filp);
 		if (result)
 			goto out;
 	}

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

 	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
 	result = generic_file_aio_write(iocb, iov, nr_segs, pos);
 	/* Return error values for O_SYNC and IS_SYNC() */
 	if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
 		int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
 		if (err < 0)
 			result = err;
 	}
 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();
 	/* Try local locking first */
 	posix_test_lock(filp, fl);
 	if (fl->fl_type != F_UNLCK) {
 		/* found a conflict */
 		goto out;
 	}

 	if (nfs_have_delegation(inode, FMODE_READ))
 		goto out_noconflict;

 	if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
 		goto out_noconflict;

 	status = NFS_PROTO(inode)->lock(filp, cmd, fl);
 out:
 	unlock_kernel();
 	return status;
 out_noconflict:
 	fl->fl_type = F_UNLCK;
 	goto out;
 }

 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)
 		dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
 			" - error %d!\n",
 				__func__, res);
 	return res;
 }

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

 	/*
 	 * Flush all pending writes before doing anything
 	 * with locks..
 	 */
 	nfs_sync_mapping(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();
 	return status;
 }

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

 	/*
 	 * Flush all pending writes before doing anything
 	 * with locks..
 	 */
 	status = nfs_sync_mapping(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);
 	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.
 	 */
 	nfs_sync_mapping(filp->f_mapping);
 	nfs_zap_caches(inode);
 out:
 	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);
 	nfs_inc_stats(inode, NFSIOS_VFSLOCK);

 	/* No mandatory locks over NFS */
 	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
 		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)
 {
 	dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
 			filp->f_path.dentry->d_inode->i_sb->s_id,
 			filp->f_path.dentry->d_inode->i_ino,
 			fl->fl_type, fl->fl_flags);

 	/*
 	 * 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);
 }

 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
 {
 	/*
 	 * There is no protocol support for leases, so we have no way
 	 * to implement them correctly in the face of opens by other
 	 * clients.
 	 */
 	return -EINVAL;
 }
	/*
	* 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 <linux/aio.h>

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

	#include "delegation.h"
	#include "internal.h"
	#include "iostat.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 loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
	static int nfs_file_mmap(struct file , struct vm_area_struct );
	static ssize_t nfs_file_splice_read(struct file filp, loff_t ppos,
	struct pipe_inode_info *pipe,
	size_t count, unsigned int flags);
	static ssize_t nfs_file_read(struct kiocb , const struct iovec iov,
	unsigned long nr_segs, loff_t pos);
	static ssize_t nfs_file_write(struct kiocb , const struct iovec iov,
	unsigned long nr_segs, loff_t pos);
	static int nfs_file_flush(struct file *, fl_owner_t id);
	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);
	static int nfs_setlease(struct file file, long arg, struct file_lock *fl);

	static struct vm_operations_struct nfs_file_vm_ops;

	const struct file_operations nfs_file_operations = {
	.llseek = nfs_file_llseek,
	.read = do_sync_read,
	.write = do_sync_write,
	.aio_read = nfs_file_read,
	.aio_write = nfs_file_write,
	#ifdef CONFIG_MMU
	.mmap = nfs_file_mmap,
	#else
	.mmap = generic_file_mmap,
	#endif
	.open = nfs_file_open,
	.flush = nfs_file_flush,
	.release = nfs_file_release,
	.fsync = nfs_fsync,
	.lock = nfs_lock,
	.flock = nfs_flock,
	.splice_read = nfs_file_splice_read,
	.check_flags = nfs_check_flags,
	.setlease = nfs_setlease,
	};

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

	#ifdef CONFIG_NFS_V3
	const struct inode_operations nfs3_file_inode_operations = {
	.permission = nfs_permission,
	.getattr = nfs_getattr,
	.setattr = nfs_setattr,
	.listxattr = nfs3_listxattr,
	.getxattr = nfs3_getxattr,
	.setxattr = nfs3_setxattr,
	.removexattr = nfs3_removexattr,
	};
	#endif /* CONFIG_NFS_v3 */

	/* 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)
	{
	int res;

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

	nfs_inc_stats(inode, NFSIOS_VFSOPEN);
	lock_kernel();
	res = NFS_PROTO(inode)->file_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)
	nfs_wb_all(filp->f_path.dentry->d_inode);
	nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
	return NFS_PROTO(inode)->file_release(inode, filp);
	}

	/**
	* nfs_revalidate_size - Revalidate the file size
	* @inode - pointer to inode struct
	* @file - pointer to struct file
	*
	* Revalidates the file length. This is basically a wrapper around
	* nfs_revalidate_inode() that takes into account the fact that we may
	* have cached writes (in which case we don't care about the server's
	* idea of what the file length is), or O_DIRECT (in which case we
	* shouldn't trust the cache).
	*/
	static int nfs_revalidate_file_size(struct inode inode, struct file filp)
	{
	struct nfs_server *server = NFS_SERVER(inode);
	struct nfs_inode *nfsi = NFS_I(inode);

	if (server->flags & NFS_MOUNT_NOAC)
	goto force_reval;
	if (filp->f_flags & O_DIRECT)
	goto force_reval;
	if (nfsi->npages != 0)
	return 0;
	if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
	return 0;
	force_reval:
	return __nfs_revalidate_inode(server, inode);
	}

	static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
	{
	loff_t loff;
	/* origin == SEEK_END => we must revalidate the cached file length */
	if (origin == SEEK_END) {
	struct inode *inode = filp->f_mapping->host;
	int retval = nfs_revalidate_file_size(inode, filp);
	if (retval < 0)
	return (loff_t)retval;
	}
	lock_kernel(); /* BKL needed? */
	loff = generic_file_llseek_unlocked(filp, offset, origin);
	unlock_kernel();
	return loff;
	}

	/*
	* Helper for nfs_file_flush() and nfs_fsync()
	*
	* Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
	* disk, but it retrieves and clears ctx->error after synching, despite
	* the two being set at the same time in nfs_context_set_write_error().
	* This is because the former is used to notify the _next_ call to
	* nfs_file_write() that a write error occured, and hence cause it to
	* fall back to doing a synchronous write.
	*/
	static int nfs_do_fsync(struct nfs_open_context ctx, struct inode inode)
	{
	int have_error, status;
	int ret = 0;

	have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
	status = nfs_wb_all(inode);
	have_error \|= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
	if (have_error)
	ret = xchg(&ctx->error, 0);
	if (!ret)
	ret = status;
	return ret;
	}

	/*
	* Flush all dirty pages, and check for write errors.
	*
	*/
	static int
	nfs_file_flush(struct file *file, fl_owner_t id)
	{
	struct nfs_open_context *ctx = nfs_file_open_context(file);
	struct inode *inode = file->f_path.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;
	nfs_inc_stats(inode, NFSIOS_VFSFLUSH);

	/* Ensure that data+attribute caches are up to date after close() */
	status = nfs_do_fsync(ctx, inode);
	if (!status)
	nfs_revalidate_inode(NFS_SERVER(inode), inode);
	return status;
	}

	static ssize_t
	nfs_file_read(struct kiocb iocb, const struct iovec iov,
	unsigned long nr_segs, loff_t pos)
	{
	struct dentry * dentry = iocb->ki_filp->f_path.dentry;
	struct inode * inode = dentry->d_inode;
	ssize_t result;
	size_t count = iov_length(iov, nr_segs);

	if (iocb->ki_filp->f_flags & O_DIRECT)
	return nfs_file_direct_read(iocb, iov, nr_segs, pos);

	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_mapping(inode, iocb->ki_filp->f_mapping);
	nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
	if (!result)
	result = generic_file_aio_read(iocb, iov, nr_segs, pos);
	return result;
	}

	static ssize_t
	nfs_file_splice_read(struct file filp, loff_t ppos,
	struct pipe_inode_info *pipe, size_t count,
	unsigned int flags)
	{
	struct dentry *dentry = filp->f_path.dentry;
	struct inode *inode = dentry->d_inode;
	ssize_t res;

	dfprintk(VFS, "nfs: splice_read(%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_mapping(inode, filp->f_mapping);
	if (!res)
	res = generic_file_splice_read(filp, ppos, pipe, count, flags);
	return res;
	}

	static int
	nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
	{
	struct dentry *dentry = file->f_path.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_mapping(inode, file->f_mapping);
	if (!status) {
	vma->vm_ops = &nfs_file_vm_ops;
	vma->vm_flags \|= VM_CAN_NONLINEAR;
	file_accessed(file);
	}
	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 = nfs_file_open_context(file);
	struct inode *inode = dentry->d_inode;

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

	nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
	return nfs_do_fsync(ctx, inode);
	}

	/*
	* This does the "real" work of the write. We must allocate and lock the
	* page to be sent back to the generic routine, which then copies the
	* data from user space.
	*
	* 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_write_begin(struct file file, struct address_space mapping,
	loff_t pos, unsigned len, unsigned flags,
	struct page pagep, void fsdata)
	{
	int ret;
	pgoff_t index;
	struct page *page;
	index = pos >> PAGE_CACHE_SHIFT;

	page = __grab_cache_page(mapping, index);
	if (!page)
	return -ENOMEM;
	*pagep = page;

	ret = nfs_flush_incompatible(file, page);
	if (ret) {
	unlock_page(page);
	page_cache_release(page);
	}
	return ret;
	}

	static int nfs_write_end(struct file file, struct address_space mapping,
	loff_t pos, unsigned len, unsigned copied,
	struct page page, void fsdata)
	{
	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
	int status;

	lock_kernel();
	status = nfs_updatepage(file, page, offset, copied);
	unlock_kernel();

	unlock_page(page);
	page_cache_release(page);

	if (status < 0)
	return status;
	return copied;
	}

	static void nfs_invalidate_page(struct page *page, unsigned long offset)
	{
	if (offset != 0)
	return;
	/* Cancel any unstarted writes on this page */
	nfs_wb_page_cancel(page->mapping->host, page);
	}

	static int nfs_release_page(struct page *page, gfp_t gfp)
	{
	/* If PagePrivate() is set, then the page is not freeable */
	return 0;
	}

	static int nfs_launder_page(struct page *page)
	{
	return nfs_wb_page(page->mapping->host, page);
	}

	const 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,
	.write_begin = nfs_write_begin,
	.write_end = nfs_write_end,
	.invalidatepage = nfs_invalidate_page,
	.releasepage = nfs_release_page,
	.direct_IO = nfs_direct_IO,
	.launder_page = nfs_launder_page,
	};

	static int nfs_vm_page_mkwrite(struct vm_area_struct vma, struct page page)
	{
	struct file *filp = vma->vm_file;
	unsigned pagelen;
	int ret = -EINVAL;
	struct address_space *mapping;

	lock_page(page);
	mapping = page->mapping;
	if (mapping != vma->vm_file->f_path.dentry->d_inode->i_mapping)
	goto out_unlock;

	ret = 0;
	pagelen = nfs_page_length(page);
	if (pagelen == 0)
	goto out_unlock;

	ret = nfs_flush_incompatible(filp, page);
	if (ret != 0)
	goto out_unlock;

	ret = nfs_updatepage(filp, page, 0, pagelen);
	if (ret == 0)
	ret = pagelen;
	out_unlock:
	unlock_page(page);
	return ret;
	}

	static struct vm_operations_struct nfs_file_vm_ops = {
	.fault = filemap_fault,
	.page_mkwrite = nfs_vm_page_mkwrite,
	};

	static int nfs_need_sync_write(struct file filp, struct inode inode)
	{
	struct nfs_open_context *ctx;

	if (IS_SYNC(inode) \|\| (filp->f_flags & O_SYNC))
	return 1;
	ctx = nfs_file_open_context(filp);
	if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
	return 1;
	return 0;
	}

	static ssize_t nfs_file_write(struct kiocb iocb, const struct iovec iov,
	unsigned long nr_segs, loff_t pos)
	{
	struct dentry * dentry = iocb->ki_filp->f_path.dentry;
	struct inode * inode = dentry->d_inode;
	ssize_t result;
	size_t count = iov_length(iov, nr_segs);

	if (iocb->ki_filp->f_flags & O_DIRECT)
	return nfs_file_direct_write(iocb, iov, nr_segs, pos);

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

	result = -EBUSY;
	if (IS_SWAPFILE(inode))
	goto out_swapfile;
	/*
	* O_APPEND implies that we must revalidate the file length.
	*/
	if (iocb->ki_filp->f_flags & O_APPEND) {
	result = nfs_revalidate_file_size(inode, iocb->ki_filp);
	if (result)
	goto out;
	}

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

	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
	result = generic_file_aio_write(iocb, iov, nr_segs, pos);
	/* Return error values for O_SYNC and IS_SYNC() */
	if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
	int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
	if (err < 0)
	result = err;
	}
	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();
	/* Try local locking first */
	posix_test_lock(filp, fl);
	if (fl->fl_type != F_UNLCK) {
	/* found a conflict */
	goto out;
	}

	if (nfs_have_delegation(inode, FMODE_READ))
	goto out_noconflict;

	if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
	goto out_noconflict;

	status = NFS_PROTO(inode)->lock(filp, cmd, fl);
	out:
	unlock_kernel();
	return status;
	out_noconflict:
	fl->fl_type = F_UNLCK;
	goto out;
	}

	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)
	dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
	" - error %d!\n",
	__func__, res);
	return res;
	}

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

	/*
	* Flush all pending writes before doing anything
	* with locks..
	*/
	nfs_sync_mapping(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();
	return status;
	}

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

	/*
	* Flush all pending writes before doing anything
	* with locks..
	*/
	status = nfs_sync_mapping(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);
	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.
	*/
	nfs_sync_mapping(filp->f_mapping);
	nfs_zap_caches(inode);
	out:
	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);
	nfs_inc_stats(inode, NFSIOS_VFSLOCK);

	/* No mandatory locks over NFS */
	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
	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)
	{
	dprintk("NFS: nfs_flock(f=%s/%ld, t=%x, fl=%x)\n",
	filp->f_path.dentry->d_inode->i_sb->s_id,
	filp->f_path.dentry->d_inode->i_ino,
	fl->fl_type, fl->fl_flags);

	/*
	* 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);
	}

	static int nfs_setlease(struct file file, long arg, struct file_lock *fl)
	{
	/*
	* There is no protocol support for leases, so we have no way
	* to implement them correctly in the face of opens by other
	* clients.
	*/
	return -EINVAL;
	}