linux/fs/9p/vfs_file.c
Aneesh Kumar K.V 03f0e02273 fs/9p: Don't use O_TRUNC flag in TOPEN and TLOPEN request
We do the truncate via setattr request, hence don't pass the O_TRUNC flag in
open request. Without this patch we end up sending zero sized write request
to server when we try to truncate. Some servers (VirtFS) were not handling that
properly.

Reported-by: M. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2013-02-10 16:29:47 -06:00

790 lines
18 KiB
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 = filp->f_path.dentry->d_inode;
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 = filp->f_path.dentry->d_inode;
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 = filp->f_path.dentry->d_inode;
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(filp->f_path.dentry->d_inode,
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 = filp->f_path.dentry->d_inode;
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;
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,
};