linux/fs/freevxfs/vxfs_super.c
David Howells 726c334223 [PATCH] VFS: Permit filesystem to perform statfs with a known root dentry
Give the statfs superblock operation a dentry pointer rather than a superblock
pointer.

This complements the get_sb() patch.  That reduced the significance of
sb->s_root, allowing NFS to place a fake root there.  However, NFS does
require a dentry to use as a target for the statfs operation.  This permits
the root in the vfsmount to be used instead.

linux/mount.h has been added where necessary to make allyesconfig build
successfully.

Interest has also been expressed for use with the FUSE and XFS filesystems.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:42:45 -07:00

280 lines
7.1 KiB
C

/*
* Copyright (c) 2000-2001 Christoph Hellwig.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL").
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Veritas filesystem driver - superblock related routines.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/vfs.h>
#include <linux/mount.h>
#include "vxfs.h"
#include "vxfs_extern.h"
#include "vxfs_dir.h"
#include "vxfs_inode.h"
MODULE_AUTHOR("Christoph Hellwig");
MODULE_DESCRIPTION("Veritas Filesystem (VxFS) driver");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_ALIAS("vxfs"); /* makes mount -t vxfs autoload the module */
static void vxfs_put_super(struct super_block *);
static int vxfs_statfs(struct dentry *, struct kstatfs *);
static int vxfs_remount(struct super_block *, int *, char *);
static struct super_operations vxfs_super_ops = {
.read_inode = vxfs_read_inode,
.clear_inode = vxfs_clear_inode,
.put_super = vxfs_put_super,
.statfs = vxfs_statfs,
.remount_fs = vxfs_remount,
};
/**
* vxfs_put_super - free superblock resources
* @sbp: VFS superblock.
*
* Description:
* vxfs_put_super frees all resources allocated for @sbp
* after the last instance of the filesystem is unmounted.
*/
static void
vxfs_put_super(struct super_block *sbp)
{
struct vxfs_sb_info *infp = VXFS_SBI(sbp);
vxfs_put_fake_inode(infp->vsi_fship);
vxfs_put_fake_inode(infp->vsi_ilist);
vxfs_put_fake_inode(infp->vsi_stilist);
brelse(infp->vsi_bp);
kfree(infp);
}
/**
* vxfs_statfs - get filesystem information
* @dentry: VFS dentry to locate superblock
* @bufp: output buffer
*
* Description:
* vxfs_statfs fills the statfs buffer @bufp with information
* about the filesystem described by @dentry.
*
* Returns:
* Zero.
*
* Locking:
* No locks held.
*
* Notes:
* This is everything but complete...
*/
static int
vxfs_statfs(struct dentry *dentry, struct kstatfs *bufp)
{
struct vxfs_sb_info *infp = VXFS_SBI(dentry->d_sb);
bufp->f_type = VXFS_SUPER_MAGIC;
bufp->f_bsize = dentry->d_sb->s_blocksize;
bufp->f_blocks = infp->vsi_raw->vs_dsize;
bufp->f_bfree = infp->vsi_raw->vs_free;
bufp->f_bavail = 0;
bufp->f_files = 0;
bufp->f_ffree = infp->vsi_raw->vs_ifree;
bufp->f_namelen = VXFS_NAMELEN;
return 0;
}
static int vxfs_remount(struct super_block *sb, int *flags, char *data)
{
*flags |= MS_RDONLY;
return 0;
}
/**
* vxfs_read_super - read superblock into memory and initalize filesystem
* @sbp: VFS superblock (to fill)
* @dp: fs private mount data
* @silent: do not complain loudly when sth is wrong
*
* Description:
* We are called on the first mount of a filesystem to read the
* superblock into memory and do some basic setup.
*
* Returns:
* The superblock on success, else %NULL.
*
* Locking:
* We are under the bkl and @sbp->s_lock.
*/
static int vxfs_fill_super(struct super_block *sbp, void *dp, int silent)
{
struct vxfs_sb_info *infp;
struct vxfs_sb *rsbp;
struct buffer_head *bp = NULL;
u_long bsize;
struct inode *root;
sbp->s_flags |= MS_RDONLY;
infp = kzalloc(sizeof(*infp), GFP_KERNEL);
if (!infp) {
printk(KERN_WARNING "vxfs: unable to allocate incore superblock\n");
return -ENOMEM;
}
bsize = sb_min_blocksize(sbp, BLOCK_SIZE);
if (!bsize) {
printk(KERN_WARNING "vxfs: unable to set blocksize\n");
goto out;
}
bp = sb_bread(sbp, 1);
if (!bp || !buffer_mapped(bp)) {
if (!silent) {
printk(KERN_WARNING
"vxfs: unable to read disk superblock\n");
}
goto out;
}
rsbp = (struct vxfs_sb *)bp->b_data;
if (rsbp->vs_magic != VXFS_SUPER_MAGIC) {
if (!silent)
printk(KERN_NOTICE "vxfs: WRONG superblock magic\n");
goto out;
}
if ((rsbp->vs_version < 2 || rsbp->vs_version > 4) && !silent) {
printk(KERN_NOTICE "vxfs: unsupported VxFS version (%d)\n",
rsbp->vs_version);
goto out;
}
#ifdef DIAGNOSTIC
printk(KERN_DEBUG "vxfs: supported VxFS version (%d)\n", rsbp->vs_version);
printk(KERN_DEBUG "vxfs: blocksize: %d\n", rsbp->vs_bsize);
#endif
sbp->s_magic = rsbp->vs_magic;
sbp->s_fs_info = infp;
infp->vsi_raw = rsbp;
infp->vsi_bp = bp;
infp->vsi_oltext = rsbp->vs_oltext[0];
infp->vsi_oltsize = rsbp->vs_oltsize;
if (!sb_set_blocksize(sbp, rsbp->vs_bsize)) {
printk(KERN_WARNING "vxfs: unable to set final block size\n");
goto out;
}
if (vxfs_read_olt(sbp, bsize)) {
printk(KERN_WARNING "vxfs: unable to read olt\n");
goto out;
}
if (vxfs_read_fshead(sbp)) {
printk(KERN_WARNING "vxfs: unable to read fshead\n");
goto out;
}
sbp->s_op = &vxfs_super_ops;
root = iget(sbp, VXFS_ROOT_INO);
sbp->s_root = d_alloc_root(root);
if (!sbp->s_root) {
iput(root);
printk(KERN_WARNING "vxfs: unable to get root dentry.\n");
goto out_free_ilist;
}
return 0;
out_free_ilist:
vxfs_put_fake_inode(infp->vsi_fship);
vxfs_put_fake_inode(infp->vsi_ilist);
vxfs_put_fake_inode(infp->vsi_stilist);
out:
brelse(bp);
kfree(infp);
return -EINVAL;
}
/*
* The usual module blurb.
*/
static int vxfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
return get_sb_bdev(fs_type, flags, dev_name, data, vxfs_fill_super,
mnt);
}
static struct file_system_type vxfs_fs_type = {
.owner = THIS_MODULE,
.name = "vxfs",
.get_sb = vxfs_get_sb,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
static int __init
vxfs_init(void)
{
vxfs_inode_cachep = kmem_cache_create("vxfs_inode",
sizeof(struct vxfs_inode_info), 0,
SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, NULL, NULL);
if (vxfs_inode_cachep)
return register_filesystem(&vxfs_fs_type);
return -ENOMEM;
}
static void __exit
vxfs_cleanup(void)
{
unregister_filesystem(&vxfs_fs_type);
kmem_cache_destroy(vxfs_inode_cachep);
}
module_init(vxfs_init);
module_exit(vxfs_cleanup);