linux-stable/fs/9p/vfs_file.c
Jeff Layton 5970e15dbc filelock: move file locking definitions to separate header file
The file locking definitions have lived in fs.h since the dawn of time,
but they are only used by a small subset of the source files that
include it.

Move the file locking definitions to a new header file, and add the
appropriate #include directives to the source files that need them. By
doing this we trim down fs.h a bit and limit the amount of rebuilding
that has to be done when we make changes to the file locking APIs.

Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Acked-by: Steve French <stfrench@microsoft.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
2023-01-11 06:52:32 -05:00

711 lines
17 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* 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>
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/filelock.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 <linux/uaccess.h>
#include <linux/uio.h>
#include <linux/slab.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;
static const struct vm_operations_struct v9fs_mmap_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, *writeback_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_dentry(file));
if (IS_ERR(fid))
return PTR_ERR(fid);
err = p9_client_open(fid, omode);
if (err < 0) {
p9_fid_put(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 == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
!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.
*/
writeback_fid = v9fs_writeback_fid(file_dentry(file));
if (IS_ERR(writeback_fid)) {
err = PTR_ERR(writeback_fid);
mutex_unlock(&v9inode->v_mutex);
goto out_error;
}
v9inode->writeback_fid = (void *) writeback_fid;
}
mutex_unlock(&v9inode->v_mutex);
if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
fscache_use_cookie(v9fs_inode_cookie(v9inode),
file->f_mode & FMODE_WRITE);
v9fs_open_fid_add(inode, &fid);
return 0;
out_error:
p9_fid_put(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)
{
struct inode *inode = file_inode(filp);
p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
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 0;
}
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 = P9_LOCK_ERROR;
int res = 0;
unsigned char fl_type;
struct v9fs_session_info *v9ses;
fid = filp->private_data;
BUG_ON(fid == NULL);
BUG_ON((fl->fl_flags & FL_POSIX) != FL_POSIX);
res = locks_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 = fid->clnt->name;
if (IS_SETLKW(cmd))
flock.flags = P9_LOCK_FLAGS_BLOCK;
v9ses = v9fs_inode2v9ses(file_inode(filp));
/*
* 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)
goto out_unlock;
if (status != P9_LOCK_BLOCKED)
break;
if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
break;
if (schedule_timeout_interruptible(v9ses->session_lock_timeout)
!= 0)
break;
/*
* p9_client_lock_dotl overwrites flock.client_id with the
* server message, free and reuse the client name
*/
if (flock.client_id != fid->clnt->name) {
kfree(flock.client_id);
flock.client_id = fid->clnt->name;
}
}
/* map 9p status to VFS status */
switch (status) {
case P9_LOCK_SUCCESS:
res = 0;
break;
case P9_LOCK_BLOCKED:
res = -EAGAIN;
break;
default:
WARN_ONCE(1, "unknown lock status code: %d\n", status);
fallthrough;
case P9_LOCK_ERROR:
case P9_LOCK_GRACE:
res = -ENOLCK;
break;
}
out_unlock:
/*
* 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;
/* Even if this fails we want to return the remote error */
locks_lock_file_wait(filp, fl);
fl->fl_type = fl_type;
}
if (flock.client_id != fid->clnt->name)
kfree(flock.client_id);
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 = fid->clnt->name;
res = p9_client_getlock_dotl(fid, &glock);
if (res < 0)
goto out;
/* 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;
}
out:
if (glock.client_id != fid->clnt->name)
kfree(glock.client_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: %pD\n",
filp, cmd, fl, filp);
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;
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: %pD\n",
filp, cmd, fl, filp);
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_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_file_read_iter - read from a file
* @iocb: The operation parameters
* @to: The buffer to read into
*
*/
static ssize_t
v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct p9_fid *fid = iocb->ki_filp->private_data;
int ret, err = 0;
p9_debug(P9_DEBUG_VFS, "count %zu offset %lld\n",
iov_iter_count(to), iocb->ki_pos);
if (iocb->ki_filp->f_flags & O_NONBLOCK)
ret = p9_client_read_once(fid, iocb->ki_pos, to, &err);
else
ret = p9_client_read(fid, iocb->ki_pos, to, &err);
if (!ret)
return err;
iocb->ki_pos += ret;
return ret;
}
/**
* v9fs_file_write_iter - write to a file
* @iocb: The operation parameters
* @from: The data to write
*
*/
static ssize_t
v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
ssize_t retval;
loff_t origin;
int err = 0;
retval = generic_write_checks(iocb, from);
if (retval <= 0)
return retval;
origin = iocb->ki_pos;
retval = p9_client_write(file->private_data, iocb->ki_pos, from, &err);
if (retval > 0) {
struct inode *inode = file_inode(file);
loff_t i_size;
unsigned long pg_start, pg_end;
pg_start = origin >> PAGE_SHIFT;
pg_end = (origin + retval - 1) >> PAGE_SHIFT;
if (inode->i_mapping && inode->i_mapping->nrpages)
invalidate_inode_pages2_range(inode->i_mapping,
pg_start, pg_end);
iocb->ki_pos += retval;
i_size = i_size_read(inode);
if (iocb->ki_pos > i_size) {
inode_add_bytes(inode, iocb->ki_pos - i_size);
/*
* Need to serialize against i_size_write() in
* v9fs_stat2inode()
*/
v9fs_i_size_write(inode, iocb->ki_pos);
}
return retval;
}
return err;
}
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 = file_write_and_wait_range(filp, start, end);
if (retval)
return retval;
inode_lock(inode);
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);
inode_unlock(inode);
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 = file_write_and_wait_range(filp, start, end);
if (retval)
return retval;
inode_lock(inode);
p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
fid = filp->private_data;
retval = p9_client_fsync(fid, datasync);
inode_unlock(inode);
return retval;
}
static int
v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
int retval;
retval = generic_file_mmap(filp, vma);
if (!retval)
vma->vm_ops = &v9fs_file_vm_ops;
return retval;
}
static int
v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
int retval;
struct inode *inode;
struct v9fs_inode *v9inode;
struct p9_fid *fid;
inode = file_inode(filp);
v9inode = V9FS_I(inode);
mutex_lock(&v9inode->v_mutex);
if (!v9inode->writeback_fid &&
(vma->vm_flags & VM_SHARED) &&
(vma->vm_flags & VM_WRITE)) {
/*
* clone a fid and add it to writeback_fid
* we do it during mmap instead of
* page dirty time via write_begin/page_mkwrite
* because we want write after unlink usecase
* to work.
*/
fid = v9fs_writeback_fid(file_dentry(filp));
if (IS_ERR(fid)) {
retval = PTR_ERR(fid);
mutex_unlock(&v9inode->v_mutex);
return retval;
}
v9inode->writeback_fid = (void *) fid;
}
mutex_unlock(&v9inode->v_mutex);
retval = generic_file_mmap(filp, vma);
if (!retval)
vma->vm_ops = &v9fs_mmap_file_vm_ops;
return retval;
}
static vm_fault_t
v9fs_vm_page_mkwrite(struct vm_fault *vmf)
{
struct v9fs_inode *v9inode;
struct folio *folio = page_folio(vmf->page);
struct file *filp = vmf->vma->vm_file;
struct inode *inode = file_inode(filp);
p9_debug(P9_DEBUG_VFS, "folio %p fid %lx\n",
folio, (unsigned long)filp->private_data);
v9inode = V9FS_I(inode);
/* Wait for the page to be written to the cache before we allow it to
* be modified. We then assume the entire page will need writing back.
*/
#ifdef CONFIG_9P_FSCACHE
if (folio_test_fscache(folio) &&
folio_wait_fscache_killable(folio) < 0)
return VM_FAULT_NOPAGE;
#endif
/* Update file times before taking page lock */
file_update_time(filp);
BUG_ON(!v9inode->writeback_fid);
if (folio_lock_killable(folio) < 0)
return VM_FAULT_RETRY;
if (folio_mapping(folio) != inode->i_mapping)
goto out_unlock;
folio_wait_stable(folio);
return VM_FAULT_LOCKED;
out_unlock:
folio_unlock(folio);
return VM_FAULT_NOPAGE;
}
/**
* v9fs_mmap_file_read_iter - read from a file
* @iocb: The operation parameters
* @to: The buffer to read into
*
*/
static ssize_t
v9fs_mmap_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
/* TODO: Check if there are dirty pages */
return v9fs_file_read_iter(iocb, to);
}
/**
* v9fs_mmap_file_write_iter - write to a file
* @iocb: The operation parameters
* @from: The data to write
*
*/
static ssize_t
v9fs_mmap_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
/*
* TODO: invalidate mmaps on filp's inode between
* offset and offset+count
*/
return v9fs_file_write_iter(iocb, from);
}
static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
{
struct inode *inode;
struct writeback_control wbc = {
.nr_to_write = LONG_MAX,
.sync_mode = WB_SYNC_ALL,
.range_start = (loff_t)vma->vm_pgoff * PAGE_SIZE,
/* absolute end, byte at end included */
.range_end = (loff_t)vma->vm_pgoff * PAGE_SIZE +
(vma->vm_end - vma->vm_start - 1),
};
if (!(vma->vm_flags & VM_SHARED))
return;
p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);
inode = file_inode(vma->vm_file);
filemap_fdatawrite_wbc(inode->i_mapping, &wbc);
}
static const struct vm_operations_struct v9fs_file_vm_ops = {
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = v9fs_vm_page_mkwrite,
};
static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
.close = v9fs_mmap_vm_close,
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = v9fs_vm_page_mkwrite,
};
const struct file_operations v9fs_cached_file_operations = {
.llseek = generic_file_llseek,
.read_iter = generic_file_read_iter,
.write_iter = generic_file_write_iter,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock,
.mmap = v9fs_file_mmap,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.fsync = v9fs_file_fsync,
};
const struct file_operations v9fs_cached_file_operations_dotl = {
.llseek = generic_file_llseek,
.read_iter = generic_file_read_iter,
.write_iter = generic_file_write_iter,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock_dotl,
.flock = v9fs_file_flock_dotl,
.mmap = v9fs_file_mmap,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.fsync = v9fs_file_fsync_dotl,
};
const struct file_operations v9fs_file_operations = {
.llseek = generic_file_llseek,
.read_iter = v9fs_file_read_iter,
.write_iter = v9fs_file_write_iter,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock,
.mmap = generic_file_readonly_mmap,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.fsync = v9fs_file_fsync,
};
const struct file_operations v9fs_file_operations_dotl = {
.llseek = generic_file_llseek,
.read_iter = v9fs_file_read_iter,
.write_iter = v9fs_file_write_iter,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock_dotl,
.flock = v9fs_file_flock_dotl,
.mmap = generic_file_readonly_mmap,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.fsync = v9fs_file_fsync_dotl,
};
const struct file_operations v9fs_mmap_file_operations = {
.llseek = generic_file_llseek,
.read_iter = v9fs_mmap_file_read_iter,
.write_iter = v9fs_mmap_file_write_iter,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock,
.mmap = v9fs_mmap_file_mmap,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.fsync = v9fs_file_fsync,
};
const struct file_operations v9fs_mmap_file_operations_dotl = {
.llseek = generic_file_llseek,
.read_iter = v9fs_mmap_file_read_iter,
.write_iter = v9fs_mmap_file_write_iter,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock_dotl,
.flock = v9fs_file_flock_dotl,
.mmap = v9fs_mmap_file_mmap,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.fsync = v9fs_file_fsync_dotl,
};