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454e2398be
linux/fs/hfsplus/super.c
David Howells 454e2398be [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 07:42:45 -07:00

501 lines
15 KiB
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/*
* linux/fs/hfsplus/super.c
*
* Copyright (C) 2001
* Brad Boyer (flar@allandria.com)
* (C) 2003 Ardis Technologies <roman@ardistech.com>
*
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vfs.h>
#include <linux/nls.h>
static struct inode *hfsplus_alloc_inode(struct super_block *sb);
static void hfsplus_destroy_inode(struct inode *inode);
#include "hfsplus_fs.h"
static void hfsplus_read_inode(struct inode *inode)
{
struct hfs_find_data fd;
struct hfsplus_vh *vhdr;
int err;
INIT_LIST_HEAD(&HFSPLUS_I(inode).open_dir_list);
init_MUTEX(&HFSPLUS_I(inode).extents_lock);
HFSPLUS_I(inode).flags = 0;
HFSPLUS_I(inode).rsrc_inode = NULL;
atomic_set(&HFSPLUS_I(inode).opencnt, 0);
if (inode->i_ino >= HFSPLUS_FIRSTUSER_CNID) {
read_inode:
hfs_find_init(HFSPLUS_SB(inode->i_sb).cat_tree, &fd);
err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
if (!err)
err = hfsplus_cat_read_inode(inode, &fd);
hfs_find_exit(&fd);
if (err)
goto bad_inode;
return;
}
vhdr = HFSPLUS_SB(inode->i_sb).s_vhdr;
switch(inode->i_ino) {
case HFSPLUS_ROOT_CNID:
goto read_inode;
case HFSPLUS_EXT_CNID:
hfsplus_inode_read_fork(inode, &vhdr->ext_file);
inode->i_mapping->a_ops = &hfsplus_btree_aops;
break;
case HFSPLUS_CAT_CNID:
hfsplus_inode_read_fork(inode, &vhdr->cat_file);
inode->i_mapping->a_ops = &hfsplus_btree_aops;
break;
case HFSPLUS_ALLOC_CNID:
hfsplus_inode_read_fork(inode, &vhdr->alloc_file);
inode->i_mapping->a_ops = &hfsplus_aops;
break;
case HFSPLUS_START_CNID:
hfsplus_inode_read_fork(inode, &vhdr->start_file);
break;
case HFSPLUS_ATTR_CNID:
hfsplus_inode_read_fork(inode, &vhdr->attr_file);
inode->i_mapping->a_ops = &hfsplus_btree_aops;
break;
default:
goto bad_inode;
}
return;
bad_inode:
make_bad_inode(inode);
}
static int hfsplus_write_inode(struct inode *inode, int unused)
{
struct hfsplus_vh *vhdr;
int ret = 0;
dprint(DBG_INODE, "hfsplus_write_inode: %lu\n", inode->i_ino);
hfsplus_ext_write_extent(inode);
if (inode->i_ino >= HFSPLUS_FIRSTUSER_CNID) {
return hfsplus_cat_write_inode(inode);
}
vhdr = HFSPLUS_SB(inode->i_sb).s_vhdr;
switch (inode->i_ino) {
case HFSPLUS_ROOT_CNID:
ret = hfsplus_cat_write_inode(inode);
break;
case HFSPLUS_EXT_CNID:
if (vhdr->ext_file.total_size != cpu_to_be64(inode->i_size)) {
HFSPLUS_SB(inode->i_sb).flags |= HFSPLUS_SB_WRITEBACKUP;
inode->i_sb->s_dirt = 1;
}
hfsplus_inode_write_fork(inode, &vhdr->ext_file);
hfs_btree_write(HFSPLUS_SB(inode->i_sb).ext_tree);
break;
case HFSPLUS_CAT_CNID:
if (vhdr->cat_file.total_size != cpu_to_be64(inode->i_size)) {
HFSPLUS_SB(inode->i_sb).flags |= HFSPLUS_SB_WRITEBACKUP;
inode->i_sb->s_dirt = 1;
}
hfsplus_inode_write_fork(inode, &vhdr->cat_file);
hfs_btree_write(HFSPLUS_SB(inode->i_sb).cat_tree);
break;
case HFSPLUS_ALLOC_CNID:
if (vhdr->alloc_file.total_size != cpu_to_be64(inode->i_size)) {
HFSPLUS_SB(inode->i_sb).flags |= HFSPLUS_SB_WRITEBACKUP;
inode->i_sb->s_dirt = 1;
}
hfsplus_inode_write_fork(inode, &vhdr->alloc_file);
break;
case HFSPLUS_START_CNID:
if (vhdr->start_file.total_size != cpu_to_be64(inode->i_size)) {
HFSPLUS_SB(inode->i_sb).flags |= HFSPLUS_SB_WRITEBACKUP;
inode->i_sb->s_dirt = 1;
}
hfsplus_inode_write_fork(inode, &vhdr->start_file);
break;
case HFSPLUS_ATTR_CNID:
if (vhdr->attr_file.total_size != cpu_to_be64(inode->i_size)) {
HFSPLUS_SB(inode->i_sb).flags |= HFSPLUS_SB_WRITEBACKUP;
inode->i_sb->s_dirt = 1;
}
hfsplus_inode_write_fork(inode, &vhdr->attr_file);
hfs_btree_write(HFSPLUS_SB(inode->i_sb).attr_tree);
break;
}
return ret;
}
static void hfsplus_clear_inode(struct inode *inode)
{
dprint(DBG_INODE, "hfsplus_clear_inode: %lu\n", inode->i_ino);
if (HFSPLUS_IS_RSRC(inode)) {
HFSPLUS_I(HFSPLUS_I(inode).rsrc_inode).rsrc_inode = NULL;
iput(HFSPLUS_I(inode).rsrc_inode);
}
}
static void hfsplus_write_super(struct super_block *sb)
{
struct hfsplus_vh *vhdr = HFSPLUS_SB(sb).s_vhdr;
dprint(DBG_SUPER, "hfsplus_write_super\n");
sb->s_dirt = 0;
if (sb->s_flags & MS_RDONLY)
/* warn? */
return;
vhdr->free_blocks = cpu_to_be32(HFSPLUS_SB(sb).free_blocks);
vhdr->next_alloc = cpu_to_be32(HFSPLUS_SB(sb).next_alloc);
vhdr->next_cnid = cpu_to_be32(HFSPLUS_SB(sb).next_cnid);
vhdr->folder_count = cpu_to_be32(HFSPLUS_SB(sb).folder_count);
vhdr->file_count = cpu_to_be32(HFSPLUS_SB(sb).file_count);
mark_buffer_dirty(HFSPLUS_SB(sb).s_vhbh);
if (HFSPLUS_SB(sb).flags & HFSPLUS_SB_WRITEBACKUP) {
if (HFSPLUS_SB(sb).sect_count) {
struct buffer_head *bh;
u32 block, offset;
block = HFSPLUS_SB(sb).blockoffset;
block += (HFSPLUS_SB(sb).sect_count - 2) >> (sb->s_blocksize_bits - 9);
offset = ((HFSPLUS_SB(sb).sect_count - 2) << 9) & (sb->s_blocksize - 1);
printk(KERN_DEBUG "hfs: backup: %u,%u,%u,%u\n", HFSPLUS_SB(sb).blockoffset,
HFSPLUS_SB(sb).sect_count, block, offset);
bh = sb_bread(sb, block);
if (bh) {
vhdr = (struct hfsplus_vh *)(bh->b_data + offset);
if (be16_to_cpu(vhdr->signature) == HFSPLUS_VOLHEAD_SIG) {
memcpy(vhdr, HFSPLUS_SB(sb).s_vhdr, sizeof(*vhdr));
mark_buffer_dirty(bh);
brelse(bh);
} else
printk(KERN_WARNING "hfs: backup not found!\n");
}
}
HFSPLUS_SB(sb).flags &= ~HFSPLUS_SB_WRITEBACKUP;
}
}
static void hfsplus_put_super(struct super_block *sb)
{
dprint(DBG_SUPER, "hfsplus_put_super\n");
if (!sb->s_fs_info)
return;
if (!(sb->s_flags & MS_RDONLY) && HFSPLUS_SB(sb).s_vhdr) {
struct hfsplus_vh *vhdr = HFSPLUS_SB(sb).s_vhdr;
vhdr->modify_date = hfsp_now2mt();
vhdr->attributes |= cpu_to_be32(HFSPLUS_VOL_UNMNT);
vhdr->attributes &= cpu_to_be32(~HFSPLUS_VOL_INCNSTNT);
mark_buffer_dirty(HFSPLUS_SB(sb).s_vhbh);
sync_dirty_buffer(HFSPLUS_SB(sb).s_vhbh);
}
hfs_btree_close(HFSPLUS_SB(sb).cat_tree);
hfs_btree_close(HFSPLUS_SB(sb).ext_tree);
iput(HFSPLUS_SB(sb).alloc_file);
iput(HFSPLUS_SB(sb).hidden_dir);
brelse(HFSPLUS_SB(sb).s_vhbh);
if (HFSPLUS_SB(sb).nls)
unload_nls(HFSPLUS_SB(sb).nls);
kfree(sb->s_fs_info);
sb->s_fs_info = NULL;
}
static int hfsplus_statfs(struct super_block *sb, struct kstatfs *buf)
{
buf->f_type = HFSPLUS_SUPER_MAGIC;
buf->f_bsize = sb->s_blocksize;
buf->f_blocks = HFSPLUS_SB(sb).total_blocks << HFSPLUS_SB(sb).fs_shift;
buf->f_bfree = HFSPLUS_SB(sb).free_blocks << HFSPLUS_SB(sb).fs_shift;
buf->f_bavail = buf->f_bfree;
buf->f_files = 0xFFFFFFFF;
buf->f_ffree = 0xFFFFFFFF - HFSPLUS_SB(sb).next_cnid;
buf->f_namelen = HFSPLUS_MAX_STRLEN;
return 0;
}
static int hfsplus_remount(struct super_block *sb, int *flags, char *data)
{
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
return 0;
if (!(*flags & MS_RDONLY)) {
struct hfsplus_vh *vhdr = HFSPLUS_SB(sb).s_vhdr;
struct hfsplus_sb_info sbi;
memset(&sbi, 0, sizeof(struct hfsplus_sb_info));
sbi.nls = HFSPLUS_SB(sb).nls;
if (!hfsplus_parse_options(data, &sbi))
return -EINVAL;
if (!(vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_UNMNT))) {
printk(KERN_WARNING "hfs: filesystem was not cleanly unmounted, "
"running fsck.hfsplus is recommended. leaving read-only.\n");
sb->s_flags |= MS_RDONLY;
*flags |= MS_RDONLY;
} else if (sbi.flags & HFSPLUS_SB_FORCE) {
/* nothing */
} else if (vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_SOFTLOCK)) {
printk(KERN_WARNING "hfs: filesystem is marked locked, leaving read-only.\n");
sb->s_flags |= MS_RDONLY;
*flags |= MS_RDONLY;
} else if (vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_JOURNALED)) {
printk(KERN_WARNING "hfs: filesystem is marked journaled, leaving read-only.\n");
sb->s_flags |= MS_RDONLY;
*flags |= MS_RDONLY;
}
}
return 0;
}
static struct super_operations hfsplus_sops = {
.alloc_inode = hfsplus_alloc_inode,
.destroy_inode = hfsplus_destroy_inode,
.read_inode = hfsplus_read_inode,
.write_inode = hfsplus_write_inode,
.clear_inode = hfsplus_clear_inode,
.put_super = hfsplus_put_super,
.write_super = hfsplus_write_super,
.statfs = hfsplus_statfs,
.remount_fs = hfsplus_remount,
.show_options = hfsplus_show_options,
};
static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
{
struct hfsplus_vh *vhdr;
struct hfsplus_sb_info *sbi;
hfsplus_cat_entry entry;
struct hfs_find_data fd;
struct inode *root;
struct qstr str;
struct nls_table *nls = NULL;
int err = -EINVAL;
sbi = kmalloc(sizeof(struct hfsplus_sb_info), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
memset(sbi, 0, sizeof(HFSPLUS_SB(sb)));
sb->s_fs_info = sbi;
INIT_HLIST_HEAD(&sbi->rsrc_inodes);
hfsplus_fill_defaults(sbi);
if (!hfsplus_parse_options(data, sbi)) {
printk(KERN_ERR "hfs: unable to parse mount options\n");
err = -EINVAL;
goto cleanup;
}
/* temporarily use utf8 to correctly find the hidden dir below */
nls = sbi->nls;
sbi->nls = load_nls("utf8");
if (!sbi->nls) {
printk(KERN_ERR "hfs: unable to load nls for utf8\n");
err = -EINVAL;
goto cleanup;
}
/* Grab the volume header */
if (hfsplus_read_wrapper(sb)) {
if (!silent)
printk(KERN_WARNING "hfs: unable to find HFS+ superblock\n");
err = -EINVAL;
goto cleanup;
}
vhdr = HFSPLUS_SB(sb).s_vhdr;
/* Copy parts of the volume header into the superblock */
sb->s_magic = HFSPLUS_VOLHEAD_SIG;
if (be16_to_cpu(vhdr->version) < HFSPLUS_MIN_VERSION ||
be16_to_cpu(vhdr->version) > HFSPLUS_CURRENT_VERSION) {
printk(KERN_ERR "hfs: wrong filesystem version\n");
goto cleanup;
}
HFSPLUS_SB(sb).total_blocks = be32_to_cpu(vhdr->total_blocks);
HFSPLUS_SB(sb).free_blocks = be32_to_cpu(vhdr->free_blocks);
HFSPLUS_SB(sb).next_alloc = be32_to_cpu(vhdr->next_alloc);
HFSPLUS_SB(sb).next_cnid = be32_to_cpu(vhdr->next_cnid);
HFSPLUS_SB(sb).file_count = be32_to_cpu(vhdr->file_count);
HFSPLUS_SB(sb).folder_count = be32_to_cpu(vhdr->folder_count);
HFSPLUS_SB(sb).data_clump_blocks = be32_to_cpu(vhdr->data_clump_sz) >> HFSPLUS_SB(sb).alloc_blksz_shift;
if (!HFSPLUS_SB(sb).data_clump_blocks)
HFSPLUS_SB(sb).data_clump_blocks = 1;
HFSPLUS_SB(sb).rsrc_clump_blocks = be32_to_cpu(vhdr->rsrc_clump_sz) >> HFSPLUS_SB(sb).alloc_blksz_shift;
if (!HFSPLUS_SB(sb).rsrc_clump_blocks)
HFSPLUS_SB(sb).rsrc_clump_blocks = 1;
/* Set up operations so we can load metadata */
sb->s_op = &hfsplus_sops;
sb->s_maxbytes = MAX_LFS_FILESIZE;
if (!(vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_UNMNT))) {
printk(KERN_WARNING "hfs: Filesystem was not cleanly unmounted, "
"running fsck.hfsplus is recommended. mounting read-only.\n");
sb->s_flags |= MS_RDONLY;
} else if (sbi->flags & HFSPLUS_SB_FORCE) {
/* nothing */
} else if (vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_SOFTLOCK)) {
printk(KERN_WARNING "hfs: Filesystem is marked locked, mounting read-only.\n");
sb->s_flags |= MS_RDONLY;
} else if (vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_JOURNALED)) {
printk(KERN_WARNING "hfs: write access to a jounaled filesystem is not supported, "
"use the force option at your own risk, mounting read-only.\n");
sb->s_flags |= MS_RDONLY;
}
sbi->flags &= ~HFSPLUS_SB_FORCE;
/* Load metadata objects (B*Trees) */
HFSPLUS_SB(sb).ext_tree = hfs_btree_open(sb, HFSPLUS_EXT_CNID);
if (!HFSPLUS_SB(sb).ext_tree) {
printk(KERN_ERR "hfs: failed to load extents file\n");
goto cleanup;
}
HFSPLUS_SB(sb).cat_tree = hfs_btree_open(sb, HFSPLUS_CAT_CNID);
if (!HFSPLUS_SB(sb).cat_tree) {
printk(KERN_ERR "hfs: failed to load catalog file\n");
goto cleanup;
}
HFSPLUS_SB(sb).alloc_file = iget(sb, HFSPLUS_ALLOC_CNID);
if (!HFSPLUS_SB(sb).alloc_file) {
printk(KERN_ERR "hfs: failed to load allocation file\n");
goto cleanup;
}
/* Load the root directory */
root = iget(sb, HFSPLUS_ROOT_CNID);
sb->s_root = d_alloc_root(root);
if (!sb->s_root) {
printk(KERN_ERR "hfs: failed to load root directory\n");
iput(root);
goto cleanup;
}
str.len = sizeof(HFSP_HIDDENDIR_NAME) - 1;
str.name = HFSP_HIDDENDIR_NAME;
hfs_find_init(HFSPLUS_SB(sb).cat_tree, &fd);
hfsplus_cat_build_key(sb, fd.search_key, HFSPLUS_ROOT_CNID, &str);
if (!hfs_brec_read(&fd, &entry, sizeof(entry))) {
hfs_find_exit(&fd);
if (entry.type != cpu_to_be16(HFSPLUS_FOLDER))
goto cleanup;
HFSPLUS_SB(sb).hidden_dir = iget(sb, be32_to_cpu(entry.folder.id));
if (!HFSPLUS_SB(sb).hidden_dir)
goto cleanup;
} else
hfs_find_exit(&fd);
if (sb->s_flags & MS_RDONLY)
goto out;
/* H+LX == hfsplusutils, H+Lx == this driver, H+lx is unused
* all three are registered with Apple for our use
*/
vhdr->last_mount_vers = cpu_to_be32(HFSP_MOUNT_VERSION);
vhdr->modify_date = hfsp_now2mt();
vhdr->write_count = cpu_to_be32(be32_to_cpu(vhdr->write_count) + 1);
vhdr->attributes &= cpu_to_be32(~HFSPLUS_VOL_UNMNT);
vhdr->attributes |= cpu_to_be32(HFSPLUS_VOL_INCNSTNT);
mark_buffer_dirty(HFSPLUS_SB(sb).s_vhbh);
sync_dirty_buffer(HFSPLUS_SB(sb).s_vhbh);
if (!HFSPLUS_SB(sb).hidden_dir) {
printk(KERN_DEBUG "hfs: create hidden dir...\n");
HFSPLUS_SB(sb).hidden_dir = hfsplus_new_inode(sb, S_IFDIR);
hfsplus_create_cat(HFSPLUS_SB(sb).hidden_dir->i_ino, sb->s_root->d_inode,
&str, HFSPLUS_SB(sb).hidden_dir);
mark_inode_dirty(HFSPLUS_SB(sb).hidden_dir);
}
out:
unload_nls(sbi->nls);
sbi->nls = nls;
return 0;
cleanup:
hfsplus_put_super(sb);
if (nls)
unload_nls(nls);
return err;
}
MODULE_AUTHOR("Brad Boyer");
MODULE_DESCRIPTION("Extended Macintosh Filesystem");
MODULE_LICENSE("GPL");
static kmem_cache_t *hfsplus_inode_cachep;
static struct inode *hfsplus_alloc_inode(struct super_block *sb)
{
struct hfsplus_inode_info *i;
i = kmem_cache_alloc(hfsplus_inode_cachep, SLAB_KERNEL);
return i ? &i->vfs_inode : NULL;
}
static void hfsplus_destroy_inode(struct inode *inode)
{
kmem_cache_free(hfsplus_inode_cachep, &HFSPLUS_I(inode));
}
#define HFSPLUS_INODE_SIZE sizeof(struct hfsplus_inode_info)
static int hfsplus_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, hfsplus_fill_super,
mnt);
}
static struct file_system_type hfsplus_fs_type = {
.owner = THIS_MODULE,
.name = "hfsplus",
.get_sb = hfsplus_get_sb,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
static void hfsplus_init_once(void *p, kmem_cache_t *cachep, unsigned long flags)
{
struct hfsplus_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_hfsplus_fs(void)
{
int err;
hfsplus_inode_cachep = kmem_cache_create("hfsplus_icache",
HFSPLUS_INODE_SIZE, 0, SLAB_HWCACHE_ALIGN,
hfsplus_init_once, NULL);
if (!hfsplus_inode_cachep)
return -ENOMEM;
err = register_filesystem(&hfsplus_fs_type);
if (err)
kmem_cache_destroy(hfsplus_inode_cachep);
return err;
}
static void __exit exit_hfsplus_fs(void)
{
unregister_filesystem(&hfsplus_fs_type);
if (kmem_cache_destroy(hfsplus_inode_cachep))
printk(KERN_ERR "hfsplus_inode_cache: not all structures were freed\n");
}
module_init(init_hfsplus_fs)
module_exit(exit_hfsplus_fs)
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