linux/fs/nfs/file.c
Chuck Lever 3d509e5454 NFS: nfs_write_end clean up
Clean up: commit 4899f9c8 added nfs_write_end(), which introduces a
conditional expression that returns an unsigned integer in one arm and
a signed integer in the other.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-01-30 02:06:02 -05:00

662 lines
17 KiB
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 <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,
.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,
.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)
{
/* 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;
}
return remote_llseek(filp, offset, origin);
}
/*
* 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);
#ifdef CONFIG_NFS_DIRECTIO
if (iocb->ki_filp->f_flags & O_DIRECT)
return nfs_file_direct_read(iocb, iov, nr_segs, 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_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,
#ifdef CONFIG_NFS_DIRECTIO
.direct_IO = nfs_direct_IO,
#endif
.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);
#ifdef CONFIG_NFS_DIRECTIO
if (iocb->ki_filp->f_flags & O_DIRECT)
return nfs_file_direct_write(iocb, iov, nr_segs, pos);
#endif
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",
__FUNCTION__, 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);
/* 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.
*/
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;
}