[PATCH] LSM: remove BSD secure level security module

[usb.git] / fs / nfs / file.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 <asm/uaccess.h>
#include <asm/system.h>

#include "delegation.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_sendfile(struct file *, loff_t *, size_t, read_actor_t, void *);
static ssize_t nfs_file_read(struct kiocb *, char __user *, size_t, loff_t);
static ssize_t nfs_file_write(struct kiocb *, const char __user *, size_t, loff_t);
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);

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,
        .sendfile       = nfs_file_sendfile,
        .check_flags    = nfs_check_flags,
};

struct inode_operations nfs_file_inode_operations = {
        .permission     = nfs_permission,
        .getattr        = nfs_getattr,
        .setattr        = nfs_setattr,
};

#ifdef CONFIG_NFS_V3
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)
                filemap_fdatawrite(filp->f_mapping);
        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);
}

/*
 * 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 = (struct nfs_open_context *)file->private_data;
        struct inode    *inode = file->f_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);
        lock_kernel();
        /* Ensure that data+attribute caches are up to date after close() */
        status = nfs_wb_all(inode);
        if (!status) {
                status = ctx->error;
                ctx->error = 0;
                if (!status)
                        nfs_revalidate_inode(NFS_SERVER(inode), inode);
        }
        unlock_kernel();
        return status;
}

static ssize_t
nfs_file_read(struct kiocb *iocb, char __user * buf, size_t count, loff_t pos)
{
        struct dentry * dentry = iocb->ki_filp->f_dentry;
        struct inode * inode = dentry->d_inode;
        ssize_t result;

#ifdef CONFIG_NFS_DIRECTIO
        if (iocb->ki_filp->f_flags & O_DIRECT)
                return nfs_file_direct_read(iocb, buf, count, 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, buf, count, pos);
        return result;
}

static ssize_t
nfs_file_sendfile(struct file *filp, loff_t *ppos, size_t count,
                read_actor_t actor, void *target)
{
        struct dentry *dentry = filp->f_dentry;
        struct inode *inode = dentry->d_inode;
        ssize_t res;

        dfprintk(VFS, "nfs: sendfile(%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_sendfile(filp, ppos, count, actor, target);
        return res;
}

static int
nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
{
        struct dentry *dentry = file->f_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)
                status = generic_file_mmap(file, vma);
        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 = (struct nfs_open_context *)file->private_data;
        struct inode *inode = dentry->d_inode;
        int status;

        dfprintk(VFS, "nfs: fsync(%s/%ld)\n", inode->i_sb->s_id, inode->i_ino);

        nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
        lock_kernel();
        status = nfs_wb_all(inode);
        if (!status) {
                status = ctx->error;
                ctx->error = 0;
        }
        unlock_kernel();
        return status;
}

/*
 * This does the "real" work of the write. The generic routine has
 * allocated the page, locked it, done all the page alignment stuff
 * calculations etc. Now we should just copy the data from user
 * space and write it back to the real medium..
 *
 * 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_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to)
{
        return nfs_flush_incompatible(file, page);
}

static int nfs_commit_write(struct file *file, struct page *page, unsigned offset, unsigned to)
{
        long status;

        lock_kernel();
        status = nfs_updatepage(file, page, offset, to-offset);
        unlock_kernel();
        return status;
}

static void nfs_invalidate_page(struct page *page, unsigned long offset)
{
        struct inode *inode = page->mapping->host;

        /* Cancel any unstarted writes on this page */
        if (offset == 0)
                nfs_sync_inode_wait(inode, page->index, 1, FLUSH_INVALIDATE);
}

static int nfs_release_page(struct page *page, gfp_t gfp)
{
        if (gfp & __GFP_FS)
                return !nfs_wb_page(page->mapping->host, page);
        else
                /*
                 * Avoid deadlock on nfs_wait_on_request().
                 */
                return 0;
}

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,
        .prepare_write = nfs_prepare_write,
        .commit_write = nfs_commit_write,
        .invalidatepage = nfs_invalidate_page,
        .releasepage = nfs_release_page,
#ifdef CONFIG_NFS_DIRECTIO
        .direct_IO = nfs_direct_IO,
#endif
};

/* 
 * Write to a file (through the page cache).
 */
static ssize_t
nfs_file_write(struct kiocb *iocb, const char __user *buf, size_t count, loff_t pos)
{
        struct dentry * dentry = iocb->ki_filp->f_dentry;
        struct inode * inode = dentry->d_inode;
        ssize_t result;

#ifdef CONFIG_NFS_DIRECTIO
        if (iocb->ki_filp->f_flags & O_DIRECT)
                return nfs_file_direct_write(iocb, buf, count, pos);
#endif

        dfprintk(VFS, "nfs: write(%s/%s(%ld), %lu@%lu)\n",
                dentry->d_parent->d_name.name, dentry->d_name.name,
                inode->i_ino, (unsigned long) count, (unsigned 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, buf, count, pos);
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 file_lock cfl;
        struct inode *inode = filp->f_mapping->host;
        int status = 0;

        lock_kernel();
        /* Try local locking first */
        if (posix_test_lock(filp, fl, &cfl)) {
                fl->fl_start = cfl.fl_start;
                fl->fl_end = cfl.fl_end;
                fl->fl_type = cfl.fl_type;
                fl->fl_pid = cfl.fl_pid;
                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)
                printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n",
                                __FUNCTION__);
        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 ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
            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_dentry->d_inode->i_sb->s_id,
                        filp->f_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);
}