[GitHub/LineageOS/android_kernel_motorola_exynos9610.git] / 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 <linux/uaccess.h>
#include <linux/idr.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;
        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_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 == 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.
                 */
                fid = v9fs_writeback_fid(file_dentry(file));
                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);
        if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
                v9fs_cache_inode_set_cookie(inode, file);
        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 = P9_LOCK_ERROR;
        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 = 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;

        /*
         * 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(P9_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);
                /* fallthough */
        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);

        /* 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: %pD\n",
                 filp, cmd, fl, filp);

        /* 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_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 - 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_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);

        ret = p9_client_read(fid, iocb->ki_pos, to, &err);
        if (!ret)
                return err;

        iocb->ki_pos += ret;
        return ret;
}

/**
 * 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_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);
                        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_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 int
v9fs_vm_page_mkwrite(struct vm_fault *vmf)
{
        struct v9fs_inode *v9inode;
        struct page *page = vmf->page;
        struct file *filp = vmf->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;
}

/**
 * v9fs_mmap_file_read - read from a file
 * @filp: file pointer to read
 * @data: user data buffer to read data into
 * @count: size of buffer
 * @offset: offset at which to read data
 *
 */
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 - 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_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 = vma->vm_pgoff * PAGE_SIZE,
                 /* absolute end, byte at end included */
                .range_end = vma->vm_pgoff * PAGE_SIZE +
                        (vma->vm_end - vma->vm_start - 1),
        };


        p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);

        inode = file_inode(vma->vm_file);

        if (!mapping_cap_writeback_dirty(inode->i_mapping))
                wbc.nr_to_write = 0;

        might_sleep();
        sync_inode(inode, &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,
        .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,
        .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,
        .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,
        .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,
        .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,
        .fsync = v9fs_file_fsync_dotl,
};