- 根目录:
- fs
- 9p
- vfs_file.c
/*
* linux/fs/9p/vfs_file.c
*
* This file contians vfs file ops for 9P2000.
*
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/list.h>
#include <linux/pagemap.h>
#include <linux/utsname.h>
#include <asm/uaccess.h>
#include <linux/idr.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
#include "cache.h"
static const struct vm_operations_struct v9fs_file_vm_ops;
/**
* v9fs_file_open - open a file (or directory)
* @inode: inode to be opened
* @file: file being opened
*
*/
int v9fs_file_open(struct inode *inode, struct file *file)
{
int err;
struct v9fs_inode *v9inode;
struct v9fs_session_info *v9ses;
struct p9_fid *fid;
int omode;
p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
v9inode = V9FS_I(inode);
v9ses = v9fs_inode2v9ses(inode);
if (v9fs_proto_dotl(v9ses))
omode = v9fs_open_to_dotl_flags(file->f_flags);
else
omode = v9fs_uflags2omode(file->f_flags,
v9fs_proto_dotu(v9ses));
fid = file->private_data;
if (!fid) {
fid = v9fs_fid_clone(file->f_path.dentry);
if (IS_ERR(fid))
return PTR_ERR(fid);
err = p9_client_open(fid, omode);
if (err < 0) {
p9_client_clunk(fid);
return err;
}
if ((file->f_flags & O_APPEND) &&
(!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
generic_file_llseek(file, 0, SEEK_END);
}
file->private_data = fid;
mutex_lock(&v9inode->v_mutex);
if (v9ses->cache && !v9inode->writeback_fid &&
((file->f_flags & O_ACCMODE) != O_RDONLY)) {
/*
* clone a fid and add it to writeback_fid
* we do it during open time instead of
* page dirty time via write_begin/page_mkwrite
* because we want write after unlink usecase
* to work.
*/
fid = v9fs_writeback_fid(file->f_path.dentry);
if (IS_ERR(fid)) {
err = PTR_ERR(fid);
mutex_unlock(&v9inode->v_mutex);
goto out_error;
}
v9inode->writeback_fid = (void *) fid;
}
mutex_unlock(&v9inode->v_mutex);
#ifdef CONFIG_9P_FSCACHE
if (v9ses->cache)
v9fs_cache_inode_set_cookie(inode, file);
#endif
return 0;
out_error:
p9_client_clunk(file->private_data);
file->private_data = NULL;
return err;
}
/**
* v9fs_file_lock - lock a file (or directory)
* @filp: file to be locked
* @cmd: lock command
* @fl: file lock structure
*
* Bugs: this looks like a local only lock, we should extend into 9P
* by using open exclusive
*/
static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
{
int res = 0;
struct inode *inode = file_inode(filp);
p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
/* No mandatory locks */
if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
return -ENOLCK;
if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
filemap_write_and_wait(inode->i_mapping);
invalidate_mapping_pages(&inode->i_data, 0, -1);
}
return res;
}
static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
{
struct p9_flock flock;
struct p9_fid *fid;
uint8_t status;
int res = 0;
unsigned char fl_type;
fid = filp->private_data;
BUG_ON(fid == NULL);
if ((fl->fl_flags & FL_POSIX) != FL_POSIX)
BUG();
res = posix_lock_file_wait(filp, fl);
if (res < 0)
goto out;
/* convert posix lock to p9 tlock args */
memset(&flock, 0, sizeof(flock));
/* map the lock type */
switch (fl->fl_type) {
case F_RDLCK:
flock.type = P9_LOCK_TYPE_RDLCK;
break;
case F_WRLCK:
flock.type = P9_LOCK_TYPE_WRLCK;
break;
case F_UNLCK:
flock.type = P9_LOCK_TYPE_UNLCK;
break;
}
flock.start = fl->fl_start;
if (fl->fl_end == OFFSET_MAX)
flock.length = 0;
else
flock.length = fl->fl_end - fl->fl_start + 1;
flock.proc_id = fl->fl_pid;
flock.client_id = utsname()->nodename;
if (IS_SETLKW(cmd))
flock.flags = P9_LOCK_FLAGS_BLOCK;
/*
* if its a blocked request and we get P9_LOCK_BLOCKED as the status
* for lock request, keep on trying
*/
for (;;) {
res = p9_client_lock_dotl(fid, &flock, &status);
if (res < 0)
break;
if (status != P9_LOCK_BLOCKED)
break;
if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
break;
if (schedule_timeout_interruptible(P9_LOCK_TIMEOUT) != 0)
break;
}
/* map 9p status to VFS status */
switch (status) {
case P9_LOCK_SUCCESS:
res = 0;
break;
case P9_LOCK_BLOCKED:
res = -EAGAIN;
break;
case P9_LOCK_ERROR:
case P9_LOCK_GRACE:
res = -ENOLCK;
break;
default:
BUG();
}
/*
* incase server returned error for lock request, revert
* it locally
*/
if (res < 0 && fl->fl_type != F_UNLCK) {
fl_type = fl->fl_type;
fl->fl_type = F_UNLCK;
res = posix_lock_file_wait(filp, fl);
fl->fl_type = fl_type;
}
out:
return res;
}
static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
{
struct p9_getlock glock;
struct p9_fid *fid;
int res = 0;
fid = filp->private_data;
BUG_ON(fid == NULL);
posix_test_lock(filp, fl);
/*
* if we have a conflicting lock locally, no need to validate
* with server
*/
if (fl->fl_type != F_UNLCK)
return res;
/* convert posix lock to p9 tgetlock args */
memset(&glock, 0, sizeof(glock));
glock.type = P9_LOCK_TYPE_UNLCK;
glock.start = fl->fl_start;
if (fl->fl_end == OFFSET_MAX)
glock.length = 0;
else
glock.length = fl->fl_end - fl->fl_start + 1;
glock.proc_id = fl->fl_pid;
glock.client_id = utsname()->nodename;
res = p9_client_getlock_dotl(fid, &glock);
if (res < 0)
return res;
/* map 9p lock type to os lock type */
switch (glock.type) {
case P9_LOCK_TYPE_RDLCK:
fl->fl_type = F_RDLCK;
break;
case P9_LOCK_TYPE_WRLCK:
fl->fl_type = F_WRLCK;
break;
case P9_LOCK_TYPE_UNLCK:
fl->fl_type = F_UNLCK;
break;
}
if (glock.type != P9_LOCK_TYPE_UNLCK) {
fl->fl_start = glock.start;
if (glock.length == 0)
fl->fl_end = OFFSET_MAX;
else
fl->fl_end = glock.start + glock.length - 1;
fl->fl_pid = glock.proc_id;
}
return res;
}
/**
* v9fs_file_lock_dotl - lock a file (or directory)
* @filp: file to be locked
* @cmd: lock command
* @fl: file lock structure
*
*/
static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
{
struct inode *inode = file_inode(filp);
int ret = -ENOLCK;
p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n",
filp, cmd, fl, filp->f_path.dentry->d_name.name);
/* No mandatory locks */
if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
goto out_err;
if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
filemap_write_and_wait(inode->i_mapping);
invalidate_mapping_pages(&inode->i_data, 0, -1);
}
if (IS_SETLK(cmd) || IS_SETLKW(cmd))
ret = v9fs_file_do_lock(filp, cmd, fl);
else if (IS_GETLK(cmd))
ret = v9fs_file_getlock(filp, fl);
else
ret = -EINVAL;
out_err:
return ret;
}
/**
* v9fs_file_flock_dotl - lock a file
* @filp: file to be locked
* @cmd: lock command
* @fl: file lock structure
*
*/
static int v9fs_file_flock_dotl(struct file *filp, int cmd,
struct file_lock *fl)
{
struct inode *inode = file_inode(filp);
int ret = -ENOLCK;
p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n",
filp, cmd, fl, filp->f_path.dentry->d_name.name);
/* No mandatory locks */
if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
goto out_err;
if (!(fl->fl_flags & FL_FLOCK))
goto out_err;
if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
filemap_write_and_wait(inode->i_mapping);
invalidate_mapping_pages(&inode->i_data, 0, -1);
}
/* Convert flock to posix lock */
fl->fl_owner = (fl_owner_t)filp;
fl->fl_start = 0;
fl->fl_end = OFFSET_MAX;
fl->fl_flags |= FL_POSIX;
fl->fl_flags ^= FL_FLOCK;
if (IS_SETLK(cmd) | IS_SETLKW(cmd))
ret = v9fs_file_do_lock(filp, cmd, fl);
else
ret = -EINVAL;
out_err:
return ret;
}
/**
* v9fs_fid_readn - read from a fid
* @fid: fid to read
* @data: data buffer to read data into
* @udata: user data buffer to read data into
* @count: size of buffer
* @offset: offset at which to read data
*
*/
ssize_t
v9fs_fid_readn(struct p9_fid *fid, char *data, char __user *udata, u32 count,
u64 offset)
{
int n, total, size;
p9_debug(P9_DEBUG_VFS, "fid %d offset %llu count %d\n",
fid->fid, (long long unsigned)offset, count);
n = 0;
total = 0;
size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
do {
n = p9_client_read(fid, data, udata, offset, count);
if (n <= 0)
break;
if (data)
data += n;
if (udata)
udata += n;
offset += n;
count -= n;
total += n;
} while (count > 0 && n == size);
if (n < 0)
total = n;
return total;
}
/**
* v9fs_file_readn - read from a file
* @filp: file pointer to read
* @data: data buffer to read data into
* @udata: user data buffer to read data into
* @count: size of buffer
* @offset: offset at which to read data
*
*/
ssize_t
v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
u64 offset)
{
return v9fs_fid_readn(filp->private_data, data, udata, count, offset);
}
/**
* v9fs_file_read - read from a file
* @filp: file pointer to read
* @udata: user data buffer to read data into
* @count: size of buffer
* @offset: offset at which to read data
*
*/
static ssize_t
v9fs_file_read(struct file *filp, char __user *udata, size_t count,
loff_t * offset)
{
int ret;
struct p9_fid *fid;
size_t size;
p9_debug(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset);
fid = filp->private_data;
size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
if (count > size)
ret = v9fs_file_readn(filp, NULL, udata, count, *offset);
else
ret = p9_client_read(fid, NULL, udata, *offset, count);
if (ret > 0)
*offset += ret;
return ret;
}
ssize_t
v9fs_file_write_internal(struct inode *inode, struct p9_fid *fid,
const char __user *data, size_t count,
loff_t *offset, int invalidate)
{
int n;
loff_t i_size;
size_t total = 0;
struct p9_client *clnt;
loff_t origin = *offset;
unsigned long pg_start, pg_end;
p9_debug(P9_DEBUG_VFS, "data %p count %d offset %x\n",
data, (int)count, (int)*offset);
clnt = fid->clnt;
do {
n = p9_client_write(fid, NULL, data+total, origin+total, count);
if (n <= 0)
break;
count -= n;
total += n;
} while (count > 0);
if (invalidate && (total > 0)) {
pg_start = origin >> PAGE_CACHE_SHIFT;
pg_end = (origin + total - 1) >> PAGE_CACHE_SHIFT;
if (inode->i_mapping && inode->i_mapping->nrpages)
invalidate_inode_pages2_range(inode->i_mapping,
pg_start, pg_end);
*offset += total;
i_size = i_size_read(inode);
if (*offset > i_size) {
inode_add_bytes(inode, *offset - i_size);
i_size_write(inode, *offset);
}
}
if (n < 0)
return n;
return total;
}
/**
* v9fs_file_write - write to a file
* @filp: file pointer to write
* @data: data buffer to write data from
* @count: size of buffer
* @offset: offset at which to write data
*
*/
static ssize_t
v9fs_file_write(struct file *filp, const char __user * data,
size_t count, loff_t *offset)
{
ssize_t retval = 0;
loff_t origin = *offset;
retval = generic_write_checks(filp, &origin, &count, 0);
if (retval)
goto out;
retval = -EINVAL;
if ((ssize_t) count < 0)
goto out;
retval = 0;
if (!count)
goto out;
retval = v9fs_file_write_internal(file_inode(filp),
filp->private_data,
data, count, &origin, 1);
/* update offset on successful write */
if (retval > 0)
*offset = origin;
out:
return retval;
}
static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
int datasync)
{
struct p9_fid *fid;
struct inode *inode = filp->f_mapping->host;
struct p9_wstat wstat;
int retval;
retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
if (retval)
return retval;
mutex_lock(&inode->i_mutex);
p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
fid = filp->private_data;
v9fs_blank_wstat(&wstat);
retval = p9_client_wstat(fid, &wstat);
mutex_unlock(&inode->i_mutex);
return retval;
}
int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
int datasync)
{
struct p9_fid *fid;
struct inode *inode = filp->f_mapping->host;
int retval;
retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
if (retval)
return retval;
mutex_lock(&inode->i_mutex);
p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
fid = filp->private_data;
retval = p9_client_fsync(fid, datasync);
mutex_unlock(&inode->i_mutex);
return retval;
}
static int
v9fs_file_mmap(struct file *file, struct vm_area_struct *vma)
{
int retval;
retval = generic_file_mmap(file, vma);
if (!retval)
vma->vm_ops = &v9fs_file_vm_ops;
return retval;
}
static int
v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct v9fs_inode *v9inode;
struct page *page = vmf->page;
struct file *filp = vma->vm_file;
struct inode *inode = file_inode(filp);
p9_debug(P9_DEBUG_VFS, "page %p fid %lx\n",
page, (unsigned long)filp->private_data);
/* Update file times before taking page lock */
file_update_time(filp);
v9inode = V9FS_I(inode);
/* make sure the cache has finished storing the page */
v9fs_fscache_wait_on_page_write(inode, page);
BUG_ON(!v9inode->writeback_fid);
lock_page(page);
if (page->mapping != inode->i_mapping)
goto out_unlock;
wait_for_stable_page(page);
return VM_FAULT_LOCKED;
out_unlock:
unlock_page(page);
return VM_FAULT_NOPAGE;
}
static ssize_t
v9fs_direct_read(struct file *filp, char __user *udata, size_t count,
loff_t *offsetp)
{
loff_t size, offset;
struct inode *inode;
struct address_space *mapping;
offset = *offsetp;
mapping = filp->f_mapping;
inode = mapping->host;
if (!count)
return 0;
size = i_size_read(inode);
if (offset < size)
filemap_write_and_wait_range(mapping, offset,
offset + count - 1);
return v9fs_file_read(filp, udata, count, offsetp);
}
/**
* v9fs_cached_file_read - read from a file
* @filp: file pointer to read
* @udata: user data buffer to read data into
* @count: size of buffer
* @offset: offset at which to read data
*
*/
static ssize_t
v9fs_cached_file_read(struct file *filp, char __user *data, size_t count,
loff_t *offset)
{
if (filp->f_flags & O_DIRECT)
return v9fs_direct_read(filp, data, count, offset);
return do_sync_read(filp, data, count, offset);
}
static ssize_t
v9fs_direct_write(struct file *filp, const char __user * data,
size_t count, loff_t *offsetp)
{
loff_t offset;
ssize_t retval;
struct inode *inode;
struct address_space *mapping;
offset = *offsetp;
mapping = filp->f_mapping;
inode = mapping->host;
if (!count)
return 0;
mutex_lock(&inode->i_mutex);
retval = filemap_write_and_wait_range(mapping, offset,
offset + count - 1);
if (retval)
goto err_out;
/*
* After a write we want buffered reads to be sure to go to disk to get
* the new data. We invalidate clean cached page from the region we're
* about to write. We do this *before* the write so that if we fail
* here we fall back to buffered write
*/
if (mapping->nrpages) {
pgoff_t pg_start = offset >> PAGE_CACHE_SHIFT;
pgoff_t pg_end = (offset + count - 1) >> PAGE_CACHE_SHIFT;
retval = invalidate_inode_pages2_range(mapping,
pg_start, pg_end);
/*
* If a page can not be invalidated, fall back
* to buffered write.
*/
if (retval) {
if (retval == -EBUSY)
goto buff_write;
goto err_out;
}
}
retval = v9fs_file_write(filp, data, count, offsetp);
err_out:
mutex_unlock(&inode->i_mutex);
return retval;
buff_write:
mutex_unlock(&inode->i_mutex);
return do_sync_write(filp, data, count, offsetp);
}
/**
* v9fs_cached_file_write - write to a file
* @filp: file pointer to write
* @data: data buffer to write data from
* @count: size of buffer
* @offset: offset at which to write data
*
*/
static ssize_t
v9fs_cached_file_write(struct file *filp, const char __user * data,
size_t count, loff_t *offset)
{
if (filp->f_flags & O_DIRECT)
return v9fs_direct_write(filp, data, count, offset);
return do_sync_write(filp, data, count, offset);
}
static const struct vm_operations_struct v9fs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = v9fs_vm_page_mkwrite,
.remap_pages = generic_file_remap_pages,
};
const struct file_operations v9fs_cached_file_operations = {
.llseek = generic_file_llseek,
.read = v9fs_cached_file_read,
.write = v9fs_cached_file_write,
.aio_read = generic_file_aio_read,
.aio_write = generic_file_aio_write,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock,
.mmap = v9fs_file_mmap,
.fsync = v9fs_file_fsync,
};
const struct file_operations v9fs_cached_file_operations_dotl = {
.llseek = generic_file_llseek,
.read = v9fs_cached_file_read,
.write = v9fs_cached_file_write,
.aio_read = generic_file_aio_read,
.aio_write = generic_file_aio_write,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock_dotl,
.flock = v9fs_file_flock_dotl,
.mmap = v9fs_file_mmap,
.fsync = v9fs_file_fsync_dotl,
};
const struct file_operations v9fs_file_operations = {
.llseek = generic_file_llseek,
.read = v9fs_file_read,
.write = v9fs_file_write,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock,
.mmap = generic_file_readonly_mmap,
.fsync = v9fs_file_fsync,
};
const struct file_operations v9fs_file_operations_dotl = {
.llseek = generic_file_llseek,
.read = v9fs_file_read,
.write = v9fs_file_write,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock_dotl,
.flock = v9fs_file_flock_dotl,
.mmap = generic_file_readonly_mmap,
.fsync = v9fs_file_fsync_dotl,
};