linux-sg2042/fs/hfs/super.c

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/*
* linux/fs/hfs/super.c
*
* Copyright (C) 1995-1997 Paul H. Hargrove
* (C) 2003 Ardis Technologies <roman@ardistech.com>
* This file may be distributed under the terms of the GNU General Public License.
*
* This file contains hfs_read_super(), some of the super_ops and
* init_module() and cleanup_module(). The remaining super_ops are in
* inode.c since they deal with inodes.
*
* Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
*/
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/mount.h>
#include <linux/init.h>
#include <linux/nls.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
#include <linux/vfs.h>
#include "hfs_fs.h"
#include "btree.h"
static kmem_cache_t *hfs_inode_cachep;
MODULE_LICENSE("GPL");
/*
* hfs_write_super()
*
* Description:
* This function is called by the VFS only. When the filesystem
* is mounted r/w it updates the MDB on disk.
* Input Variable(s):
* struct super_block *sb: Pointer to the hfs superblock
* Output Variable(s):
* NONE
* Returns:
* void
* Preconditions:
* 'sb' points to a "valid" (struct super_block).
* Postconditions:
* The MDB is marked 'unsuccessfully unmounted' by clearing bit 8 of drAtrb
* (hfs_put_super() must set this flag!). Some MDB fields are updated
* and the MDB buffer is written to disk by calling hfs_mdb_commit().
*/
static void hfs_write_super(struct super_block *sb)
{
sb->s_dirt = 0;
if (sb->s_flags & MS_RDONLY)
return;
/* sync everything to the buffers */
hfs_mdb_commit(sb);
}
/*
* hfs_put_super()
*
* This is the put_super() entry in the super_operations structure for
* HFS filesystems. The purpose is to release the resources
* associated with the superblock sb.
*/
static void hfs_put_super(struct super_block *sb)
{
hfs_mdb_close(sb);
/* release the MDB's resources */
hfs_mdb_put(sb);
}
/*
* hfs_statfs()
*
* This is the statfs() entry in the super_operations structure for
* HFS filesystems. The purpose is to return various data about the
* filesystem.
*
* changed f_files/f_ffree to reflect the fs_ablock/free_ablocks.
*/
static int hfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *sb = dentry->d_sb;
buf->f_type = HFS_SUPER_MAGIC;
buf->f_bsize = sb->s_blocksize;
buf->f_blocks = (u32)HFS_SB(sb)->fs_ablocks * HFS_SB(sb)->fs_div;
buf->f_bfree = (u32)HFS_SB(sb)->free_ablocks * HFS_SB(sb)->fs_div;
buf->f_bavail = buf->f_bfree;
buf->f_files = HFS_SB(sb)->fs_ablocks;
buf->f_ffree = HFS_SB(sb)->free_ablocks;
buf->f_namelen = HFS_NAMELEN;
return 0;
}
static int hfs_remount(struct super_block *sb, int *flags, char *data)
{
*flags |= MS_NODIRATIME;
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
return 0;
if (!(*flags & MS_RDONLY)) {
if (!(HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_UNMNT))) {
printk(KERN_WARNING "hfs: filesystem was not cleanly unmounted, "
"running fsck.hfs is recommended. leaving read-only.\n");
sb->s_flags |= MS_RDONLY;
*flags |= MS_RDONLY;
} else if (HFS_SB(sb)->mdb->drAtrb & cpu_to_be16(HFS_SB_ATTRIB_SLOCK)) {
printk(KERN_WARNING "hfs: filesystem is marked locked, leaving read-only.\n");
sb->s_flags |= MS_RDONLY;
*flags |= MS_RDONLY;
}
}
return 0;
}
static int hfs_show_options(struct seq_file *seq, struct vfsmount *mnt)
{
struct hfs_sb_info *sbi = HFS_SB(mnt->mnt_sb);
if (sbi->s_creator != cpu_to_be32(0x3f3f3f3f))
seq_printf(seq, ",creator=%.4s", (char *)&sbi->s_creator);
if (sbi->s_type != cpu_to_be32(0x3f3f3f3f))
seq_printf(seq, ",type=%.4s", (char *)&sbi->s_type);
seq_printf(seq, ",uid=%u,gid=%u", sbi->s_uid, sbi->s_gid);
if (sbi->s_file_umask != 0133)
seq_printf(seq, ",file_umask=%o", sbi->s_file_umask);
if (sbi->s_dir_umask != 0022)
seq_printf(seq, ",dir_umask=%o", sbi->s_dir_umask);
if (sbi->part >= 0)
seq_printf(seq, ",part=%u", sbi->part);
if (sbi->session >= 0)
seq_printf(seq, ",session=%u", sbi->session);
if (sbi->nls_disk)
seq_printf(seq, ",codepage=%s", sbi->nls_disk->charset);
if (sbi->nls_io)
seq_printf(seq, ",iocharset=%s", sbi->nls_io->charset);
if (sbi->s_quiet)
seq_printf(seq, ",quiet");
return 0;
}
static struct inode *hfs_alloc_inode(struct super_block *sb)
{
struct hfs_inode_info *i;
i = kmem_cache_alloc(hfs_inode_cachep, SLAB_KERNEL);
return i ? &i->vfs_inode : NULL;
}
static void hfs_destroy_inode(struct inode *inode)
{
kmem_cache_free(hfs_inode_cachep, HFS_I(inode));
}
static struct super_operations hfs_super_operations = {
.alloc_inode = hfs_alloc_inode,
.destroy_inode = hfs_destroy_inode,
.write_inode = hfs_write_inode,
.clear_inode = hfs_clear_inode,
.put_super = hfs_put_super,
.write_super = hfs_write_super,
.statfs = hfs_statfs,
.remount_fs = hfs_remount,
.show_options = hfs_show_options,
};
enum {
opt_uid, opt_gid, opt_umask, opt_file_umask, opt_dir_umask,
opt_part, opt_session, opt_type, opt_creator, opt_quiet,
opt_codepage, opt_iocharset,
opt_err
};
static match_table_t tokens = {
{ opt_uid, "uid=%u" },
{ opt_gid, "gid=%u" },
{ opt_umask, "umask=%o" },
{ opt_file_umask, "file_umask=%o" },
{ opt_dir_umask, "dir_umask=%o" },
{ opt_part, "part=%u" },
{ opt_session, "session=%u" },
{ opt_type, "type=%s" },
{ opt_creator, "creator=%s" },
{ opt_quiet, "quiet" },
{ opt_codepage, "codepage=%s" },
{ opt_iocharset, "iocharset=%s" },
{ opt_err, NULL }
};
static inline int match_fourchar(substring_t *arg, u32 *result)
{
if (arg->to - arg->from != 4)
return -EINVAL;
memcpy(result, arg->from, 4);
return 0;
}
/*
* parse_options()
*
* adapted from linux/fs/msdos/inode.c written 1992,93 by Werner Almesberger
* This function is called by hfs_read_super() to parse the mount options.
*/
static int parse_options(char *options, struct hfs_sb_info *hsb)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int tmp, token;
/* initialize the sb with defaults */
hsb->s_uid = current->uid;
hsb->s_gid = current->gid;
hsb->s_file_umask = 0133;
hsb->s_dir_umask = 0022;
hsb->s_type = hsb->s_creator = cpu_to_be32(0x3f3f3f3f); /* == '????' */
hsb->s_quiet = 0;
hsb->part = -1;
hsb->session = -1;
if (!options)
return 1;
while ((p = strsep(&options, ",")) != NULL) {
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case opt_uid:
if (match_int(&args[0], &tmp)) {
printk(KERN_ERR "hfs: uid requires an argument\n");
return 0;
}
hsb->s_uid = (uid_t)tmp;
break;
case opt_gid:
if (match_int(&args[0], &tmp)) {
printk(KERN_ERR "hfs: gid requires an argument\n");
return 0;
}
hsb->s_gid = (gid_t)tmp;
break;
case opt_umask:
if (match_octal(&args[0], &tmp)) {
printk(KERN_ERR "hfs: umask requires a value\n");
return 0;
}
hsb->s_file_umask = (umode_t)tmp;
hsb->s_dir_umask = (umode_t)tmp;
break;
case opt_file_umask:
if (match_octal(&args[0], &tmp)) {
printk(KERN_ERR "hfs: file_umask requires a value\n");
return 0;
}
hsb->s_file_umask = (umode_t)tmp;
break;
case opt_dir_umask:
if (match_octal(&args[0], &tmp)) {
printk(KERN_ERR "hfs: dir_umask requires a value\n");
return 0;
}
hsb->s_dir_umask = (umode_t)tmp;
break;
case opt_part:
if (match_int(&args[0], &hsb->part)) {
printk(KERN_ERR "hfs: part requires an argument\n");
return 0;
}
break;
case opt_session:
if (match_int(&args[0], &hsb->session)) {
printk(KERN_ERR "hfs: session requires an argument\n");
return 0;
}
break;
case opt_type:
if (match_fourchar(&args[0], &hsb->s_type)) {
printk(KERN_ERR "hfs: type requires a 4 character value\n");
return 0;
}
break;
case opt_creator:
if (match_fourchar(&args[0], &hsb->s_creator)) {
printk(KERN_ERR "hfs: creator requires a 4 character value\n");
return 0;
}
break;
case opt_quiet:
hsb->s_quiet = 1;
break;
case opt_codepage:
if (hsb->nls_disk) {
printk(KERN_ERR "hfs: unable to change codepage\n");
return 0;
}
p = match_strdup(&args[0]);
hsb->nls_disk = load_nls(p);
if (!hsb->nls_disk) {
printk(KERN_ERR "hfs: unable to load codepage \"%s\"\n", p);
kfree(p);
return 0;
}
kfree(p);
break;
case opt_iocharset:
if (hsb->nls_io) {
printk(KERN_ERR "hfs: unable to change iocharset\n");
return 0;
}
p = match_strdup(&args[0]);
hsb->nls_io = load_nls(p);
if (!hsb->nls_io) {
printk(KERN_ERR "hfs: unable to load iocharset \"%s\"\n", p);
kfree(p);
return 0;
}
kfree(p);
break;
default:
return 0;
}
}
if (hsb->nls_disk && !hsb->nls_io) {
hsb->nls_io = load_nls_default();
if (!hsb->nls_io) {
printk(KERN_ERR "hfs: unable to load default iocharset\n");
return 0;
}
}
hsb->s_dir_umask &= 0777;
hsb->s_file_umask &= 0577;
return 1;
}
/*
* hfs_read_super()
*
* This is the function that is responsible for mounting an HFS
* filesystem. It performs all the tasks necessary to get enough data
* from the disk to read the root inode. This includes parsing the
* mount options, dealing with Macintosh partitions, reading the
* superblock and the allocation bitmap blocks, calling
* hfs_btree_init() to get the necessary data about the extents and
* catalog B-trees and, finally, reading the root inode into memory.
*/
static int hfs_fill_super(struct super_block *sb, void *data, int silent)
{
struct hfs_sb_info *sbi;
struct hfs_find_data fd;
hfs_cat_rec rec;
struct inode *root_inode;
int res;
sbi = kzalloc(sizeof(struct hfs_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
sb->s_fs_info = sbi;
INIT_HLIST_HEAD(&sbi->rsrc_inodes);
res = -EINVAL;
if (!parse_options((char *)data, sbi)) {
printk(KERN_ERR "hfs: unable to parse mount options.\n");
goto bail;
}
sb->s_op = &hfs_super_operations;
sb->s_flags |= MS_NODIRATIME;
init_MUTEX(&sbi->bitmap_lock);
res = hfs_mdb_get(sb);
if (res) {
if (!silent)
printk(KERN_WARNING "hfs: can't find a HFS filesystem on dev %s.\n",
hfs_mdb_name(sb));
res = -EINVAL;
goto bail;
}
/* try to get the root inode */
hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd);
if (!res)
hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength);
if (res) {
hfs_find_exit(&fd);
goto bail_no_root;
}
root_inode = hfs_iget(sb, &fd.search_key->cat, &rec);
hfs_find_exit(&fd);
if (!root_inode)
goto bail_no_root;
sb->s_root = d_alloc_root(root_inode);
if (!sb->s_root)
goto bail_iput;
sb->s_root->d_op = &hfs_dentry_operations;
/* everything's okay */
return 0;
bail_iput:
iput(root_inode);
bail_no_root:
printk(KERN_ERR "hfs: get root inode failed.\n");
bail:
hfs_mdb_put(sb);
return res;
}
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 17:02:57 +08:00
static int hfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data,
struct vfsmount *mnt)
{
[PATCH] VFS: Permit filesystem to override root dentry on mount Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 17:02:57 +08:00
return get_sb_bdev(fs_type, flags, dev_name, data, hfs_fill_super, mnt);
}
static struct file_system_type hfs_fs_type = {
.owner = THIS_MODULE,
.name = "hfs",
.get_sb = hfs_get_sb,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
static void hfs_init_once(void *p, kmem_cache_t *cachep, unsigned long flags)
{
struct hfs_inode_info *i = p;
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == SLAB_CTOR_CONSTRUCTOR)
inode_init_once(&i->vfs_inode);
}
static int __init init_hfs_fs(void)
{
int err;
hfs_inode_cachep = kmem_cache_create("hfs_inode_cache",
sizeof(struct hfs_inode_info), 0, SLAB_HWCACHE_ALIGN,
hfs_init_once, NULL);
if (!hfs_inode_cachep)
return -ENOMEM;
err = register_filesystem(&hfs_fs_type);
if (err)
kmem_cache_destroy(hfs_inode_cachep);
return err;
}
static void __exit exit_hfs_fs(void)
{
unregister_filesystem(&hfs_fs_type);
kmem_cache_destroy(hfs_inode_cachep);
}
module_init(init_hfs_fs)
module_exit(exit_hfs_fs)