WSL2-Linux-Kernel/fs/hpfs/super.c

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/*
* linux/fs/hpfs/super.c
*
* Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
*
* mounting, unmounting, error handling
*/
#include "hpfs_fn.h"
#include <linux/module.h>
#include <linux/parser.h>
#include <linux/init.h>
#include <linux/statfs.h>
#include <linux/magic.h>
/* Mark the filesystem dirty, so that chkdsk checks it when os/2 booted */
static void mark_dirty(struct super_block *s)
{
if (hpfs_sb(s)->sb_chkdsk && !(s->s_flags & MS_RDONLY)) {
struct buffer_head *bh;
struct hpfs_spare_block *sb;
if ((sb = hpfs_map_sector(s, 17, &bh, 0))) {
sb->dirty = 1;
sb->old_wrote = 0;
mark_buffer_dirty(bh);
brelse(bh);
}
}
}
/* Mark the filesystem clean (mark it dirty for chkdsk if chkdsk==2 or if there
were errors) */
static void unmark_dirty(struct super_block *s)
{
struct buffer_head *bh;
struct hpfs_spare_block *sb;
if (s->s_flags & MS_RDONLY) return;
if ((sb = hpfs_map_sector(s, 17, &bh, 0))) {
sb->dirty = hpfs_sb(s)->sb_chkdsk > 1 - hpfs_sb(s)->sb_was_error;
sb->old_wrote = hpfs_sb(s)->sb_chkdsk >= 2 && !hpfs_sb(s)->sb_was_error;
mark_buffer_dirty(bh);
brelse(bh);
}
}
/* Filesystem error... */
static char err_buf[1024];
void hpfs_error(struct super_block *s, const char *fmt, ...)
{
va_list args;
va_start(args, fmt);
vsnprintf(err_buf, sizeof(err_buf), fmt, args);
va_end(args);
printk("HPFS: filesystem error: %s", err_buf);
if (!hpfs_sb(s)->sb_was_error) {
if (hpfs_sb(s)->sb_err == 2) {
printk("; crashing the system because you wanted it\n");
mark_dirty(s);
panic("HPFS panic");
} else if (hpfs_sb(s)->sb_err == 1) {
if (s->s_flags & MS_RDONLY) printk("; already mounted read-only\n");
else {
printk("; remounting read-only\n");
mark_dirty(s);
s->s_flags |= MS_RDONLY;
}
} else if (s->s_flags & MS_RDONLY) printk("; going on - but anything won't be destroyed because it's read-only\n");
else printk("; corrupted filesystem mounted read/write - your computer will explode within 20 seconds ... but you wanted it so!\n");
} else printk("\n");
hpfs_sb(s)->sb_was_error = 1;
}
/*
* A little trick to detect cycles in many hpfs structures and don't let the
* kernel crash on corrupted filesystem. When first called, set c2 to 0.
*
* BTW. chkdsk doesn't detect cycles correctly. When I had 2 lost directories
* nested each in other, chkdsk locked up happilly.
*/
int hpfs_stop_cycles(struct super_block *s, int key, int *c1, int *c2,
char *msg)
{
if (*c2 && *c1 == key) {
hpfs_error(s, "cycle detected on key %08x in %s", key, msg);
return 1;
}
(*c2)++;
if (!((*c2 - 1) & *c2)) *c1 = key;
return 0;
}
static void hpfs_put_super(struct super_block *s)
{
struct hpfs_sb_info *sbi = hpfs_sb(s);
kfree(sbi->sb_cp_table);
kfree(sbi->sb_bmp_dir);
unmark_dirty(s);
s->s_fs_info = NULL;
kfree(sbi);
}
unsigned hpfs_count_one_bitmap(struct super_block *s, secno secno)
{
struct quad_buffer_head qbh;
unsigned *bits;
unsigned i, count;
if (!(bits = hpfs_map_4sectors(s, secno, &qbh, 4))) return 0;
count = 0;
for (i = 0; i < 2048 / sizeof(unsigned); i++) {
unsigned b;
if (!bits[i]) continue;
for (b = bits[i]; b; b>>=1) count += b & 1;
}
hpfs_brelse4(&qbh);
return count;
}
static unsigned count_bitmaps(struct super_block *s)
{
unsigned n, count, n_bands;
n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
count = 0;
for (n = 0; n < n_bands; n++)
count += hpfs_count_one_bitmap(s, hpfs_sb(s)->sb_bmp_dir[n]);
return count;
}
static int hpfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct super_block *s = dentry->d_sb;
struct hpfs_sb_info *sbi = hpfs_sb(s);
lock_kernel();
/*if (sbi->sb_n_free == -1) {*/
sbi->sb_n_free = count_bitmaps(s);
sbi->sb_n_free_dnodes = hpfs_count_one_bitmap(s, sbi->sb_dmap);
/*}*/
buf->f_type = s->s_magic;
buf->f_bsize = 512;
buf->f_blocks = sbi->sb_fs_size;
buf->f_bfree = sbi->sb_n_free;
buf->f_bavail = sbi->sb_n_free;
buf->f_files = sbi->sb_dirband_size / 4;
buf->f_ffree = sbi->sb_n_free_dnodes;
buf->f_namelen = 254;
unlock_kernel();
return 0;
}
static struct kmem_cache * hpfs_inode_cachep;
static struct inode *hpfs_alloc_inode(struct super_block *sb)
{
struct hpfs_inode_info *ei;
ei = (struct hpfs_inode_info *)kmem_cache_alloc(hpfs_inode_cachep, GFP_NOFS);
if (!ei)
return NULL;
ei->vfs_inode.i_version = 1;
return &ei->vfs_inode;
}
static void hpfs_destroy_inode(struct inode *inode)
{
kmem_cache_free(hpfs_inode_cachep, hpfs_i(inode));
}
static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
{
struct hpfs_inode_info *ei = (struct hpfs_inode_info *) foo;
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR) {
mutex_init(&ei->i_mutex);
mutex_init(&ei->i_parent_mutex);
inode_init_once(&ei->vfs_inode);
}
}
static int init_inodecache(void)
{
hpfs_inode_cachep = kmem_cache_create("hpfs_inode_cache",
sizeof(struct hpfs_inode_info),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
init_once, NULL);
if (hpfs_inode_cachep == NULL)
return -ENOMEM;
return 0;
}
static void destroy_inodecache(void)
{
kmem_cache_destroy(hpfs_inode_cachep);
}
/*
* A tiny parser for option strings, stolen from dosfs.
* Stolen again from read-only hpfs.
* And updated for table-driven option parsing.
*/
enum {
Opt_help, Opt_uid, Opt_gid, Opt_umask, Opt_case_lower, Opt_case_asis,
Opt_conv_binary, Opt_conv_text, Opt_conv_auto,
Opt_check_none, Opt_check_normal, Opt_check_strict,
Opt_err_cont, Opt_err_ro, Opt_err_panic,
Opt_eas_no, Opt_eas_ro, Opt_eas_rw,
Opt_chkdsk_no, Opt_chkdsk_errors, Opt_chkdsk_always,
Opt_timeshift, Opt_err,
};
static match_table_t tokens = {
{Opt_help, "help"},
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_umask, "umask=%o"},
{Opt_case_lower, "case=lower"},
{Opt_case_asis, "case=asis"},
{Opt_conv_binary, "conv=binary"},
{Opt_conv_text, "conv=text"},
{Opt_conv_auto, "conv=auto"},
{Opt_check_none, "check=none"},
{Opt_check_normal, "check=normal"},
{Opt_check_strict, "check=strict"},
{Opt_err_cont, "errors=continue"},
{Opt_err_ro, "errors=remount-ro"},
{Opt_err_panic, "errors=panic"},
{Opt_eas_no, "eas=no"},
{Opt_eas_ro, "eas=ro"},
{Opt_eas_rw, "eas=rw"},
{Opt_chkdsk_no, "chkdsk=no"},
{Opt_chkdsk_errors, "chkdsk=errors"},
{Opt_chkdsk_always, "chkdsk=always"},
{Opt_timeshift, "timeshift=%d"},
{Opt_err, NULL},
};
static int parse_opts(char *opts, uid_t *uid, gid_t *gid, umode_t *umask,
int *lowercase, int *conv, int *eas, int *chk, int *errs,
int *chkdsk, int *timeshift)
{
char *p;
int option;
if (!opts)
return 1;
/*printk("Parsing opts: '%s'\n",opts);*/
while ((p = strsep(&opts, ",")) != NULL) {
substring_t args[MAX_OPT_ARGS];
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_help:
return 2;
case Opt_uid:
if (match_int(args, &option))
return 0;
*uid = option;
break;
case Opt_gid:
if (match_int(args, &option))
return 0;
*gid = option;
break;
case Opt_umask:
if (match_octal(args, &option))
return 0;
*umask = option;
break;
case Opt_case_lower:
*lowercase = 1;
break;
case Opt_case_asis:
*lowercase = 0;
break;
case Opt_conv_binary:
*conv = CONV_BINARY;
break;
case Opt_conv_text:
*conv = CONV_TEXT;
break;
case Opt_conv_auto:
*conv = CONV_AUTO;
break;
case Opt_check_none:
*chk = 0;
break;
case Opt_check_normal:
*chk = 1;
break;
case Opt_check_strict:
*chk = 2;
break;
case Opt_err_cont:
*errs = 0;
break;
case Opt_err_ro:
*errs = 1;
break;
case Opt_err_panic:
*errs = 2;
break;
case Opt_eas_no:
*eas = 0;
break;
case Opt_eas_ro:
*eas = 1;
break;
case Opt_eas_rw:
*eas = 2;
break;
case Opt_chkdsk_no:
*chkdsk = 0;
break;
case Opt_chkdsk_errors:
*chkdsk = 1;
break;
case Opt_chkdsk_always:
*chkdsk = 2;
break;
case Opt_timeshift:
{
int m = 1;
char *rhs = args[0].from;
if (!rhs || !*rhs)
return 0;
if (*rhs == '-') m = -1;
if (*rhs == '+' || *rhs == '-') rhs++;
*timeshift = simple_strtoul(rhs, &rhs, 0) * m;
if (*rhs)
return 0;
break;
}
default:
return 0;
}
}
return 1;
}
static inline void hpfs_help(void)
{
printk("\n\
HPFS filesystem options:\n\
help do not mount and display this text\n\
uid=xxx set uid of files that don't have uid specified in eas\n\
gid=xxx set gid of files that don't have gid specified in eas\n\
umask=xxx set mode of files that don't have mode specified in eas\n\
case=lower lowercase all files\n\
case=asis do not lowercase files (default)\n\
conv=binary do not convert CR/LF -> LF (default)\n\
conv=auto convert only files with known text extensions\n\
conv=text convert all files\n\
check=none no fs checks - kernel may crash on corrupted filesystem\n\
check=normal do some checks - it should not crash (default)\n\
check=strict do extra time-consuming checks, used for debugging\n\
errors=continue continue on errors\n\
errors=remount-ro remount read-only if errors found (default)\n\
errors=panic panic on errors\n\
chkdsk=no do not mark fs for chkdsking even if there were errors\n\
chkdsk=errors mark fs dirty if errors found (default)\n\
chkdsk=always always mark fs dirty - used for debugging\n\
eas=no ignore extended attributes\n\
eas=ro read but do not write extended attributes\n\
eas=rw r/w eas => enables chmod, chown, mknod, ln -s (default)\n\
timeshift=nnn add nnn seconds to file times\n\
\n");
}
static int hpfs_remount_fs(struct super_block *s, int *flags, char *data)
{
uid_t uid;
gid_t gid;
umode_t umask;
int lowercase, conv, eas, chk, errs, chkdsk, timeshift;
int o;
struct hpfs_sb_info *sbi = hpfs_sb(s);
*flags |= MS_NOATIME;
uid = sbi->sb_uid; gid = sbi->sb_gid;
umask = 0777 & ~sbi->sb_mode;
lowercase = sbi->sb_lowercase; conv = sbi->sb_conv;
eas = sbi->sb_eas; chk = sbi->sb_chk; chkdsk = sbi->sb_chkdsk;
errs = sbi->sb_err; timeshift = sbi->sb_timeshift;
if (!(o = parse_opts(data, &uid, &gid, &umask, &lowercase, &conv,
&eas, &chk, &errs, &chkdsk, &timeshift))) {
printk("HPFS: bad mount options.\n");
return 1;
}
if (o == 2) {
hpfs_help();
return 1;
}
if (timeshift != sbi->sb_timeshift) {
printk("HPFS: timeshift can't be changed using remount.\n");
return 1;
}
unmark_dirty(s);
sbi->sb_uid = uid; sbi->sb_gid = gid;
sbi->sb_mode = 0777 & ~umask;
sbi->sb_lowercase = lowercase; sbi->sb_conv = conv;
sbi->sb_eas = eas; sbi->sb_chk = chk; sbi->sb_chkdsk = chkdsk;
sbi->sb_err = errs; sbi->sb_timeshift = timeshift;
if (!(*flags & MS_RDONLY)) mark_dirty(s);
return 0;
}
/* Super operations */
static struct super_operations hpfs_sops =
{
.alloc_inode = hpfs_alloc_inode,
.destroy_inode = hpfs_destroy_inode,
.delete_inode = hpfs_delete_inode,
.put_super = hpfs_put_super,
.statfs = hpfs_statfs,
.remount_fs = hpfs_remount_fs,
};
static int hpfs_fill_super(struct super_block *s, void *options, int silent)
{
struct buffer_head *bh0, *bh1, *bh2;
struct hpfs_boot_block *bootblock;
struct hpfs_super_block *superblock;
struct hpfs_spare_block *spareblock;
struct hpfs_sb_info *sbi;
struct inode *root;
uid_t uid;
gid_t gid;
umode_t umask;
int lowercase, conv, eas, chk, errs, chkdsk, timeshift;
dnode_secno root_dno;
struct hpfs_dirent *de = NULL;
struct quad_buffer_head qbh;
int o;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
s->s_fs_info = sbi;
sbi->sb_bmp_dir = NULL;
sbi->sb_cp_table = NULL;
init_MUTEX(&sbi->hpfs_creation_de);
uid = current->uid;
gid = current->gid;
umask = current->fs->umask;
lowercase = 0;
conv = CONV_BINARY;
eas = 2;
chk = 1;
errs = 1;
chkdsk = 1;
timeshift = 0;
if (!(o = parse_opts(options, &uid, &gid, &umask, &lowercase, &conv,
&eas, &chk, &errs, &chkdsk, &timeshift))) {
printk("HPFS: bad mount options.\n");
goto bail0;
}
if (o==2) {
hpfs_help();
goto bail0;
}
/*sbi->sb_mounting = 1;*/
sb_set_blocksize(s, 512);
sbi->sb_fs_size = -1;
if (!(bootblock = hpfs_map_sector(s, 0, &bh0, 0))) goto bail1;
if (!(superblock = hpfs_map_sector(s, 16, &bh1, 1))) goto bail2;
if (!(spareblock = hpfs_map_sector(s, 17, &bh2, 0))) goto bail3;
/* Check magics */
if (/*bootblock->magic != BB_MAGIC
||*/ superblock->magic != SB_MAGIC
|| spareblock->magic != SP_MAGIC) {
if (!silent) printk("HPFS: Bad magic ... probably not HPFS\n");
goto bail4;
}
/* Check version */
if (!(s->s_flags & MS_RDONLY) &&
superblock->funcversion != 2 && superblock->funcversion != 3) {
printk("HPFS: Bad version %d,%d. Mount readonly to go around\n",
(int)superblock->version, (int)superblock->funcversion);
printk("HPFS: please try recent version of HPFS driver at http://artax.karlin.mff.cuni.cz/~mikulas/vyplody/hpfs/index-e.cgi and if it still can't understand this format, contact author - mikulas@artax.karlin.mff.cuni.cz\n");
goto bail4;
}
s->s_flags |= MS_NOATIME;
/* Fill superblock stuff */
s->s_magic = HPFS_SUPER_MAGIC;
s->s_op = &hpfs_sops;
sbi->sb_root = superblock->root;
sbi->sb_fs_size = superblock->n_sectors;
sbi->sb_bitmaps = superblock->bitmaps;
sbi->sb_dirband_start = superblock->dir_band_start;
sbi->sb_dirband_size = superblock->n_dir_band;
sbi->sb_dmap = superblock->dir_band_bitmap;
sbi->sb_uid = uid;
sbi->sb_gid = gid;
sbi->sb_mode = 0777 & ~umask;
sbi->sb_n_free = -1;
sbi->sb_n_free_dnodes = -1;
sbi->sb_lowercase = lowercase;
sbi->sb_conv = conv;
sbi->sb_eas = eas;
sbi->sb_chk = chk;
sbi->sb_chkdsk = chkdsk;
sbi->sb_err = errs;
sbi->sb_timeshift = timeshift;
sbi->sb_was_error = 0;
sbi->sb_cp_table = NULL;
sbi->sb_c_bitmap = -1;
sbi->sb_max_fwd_alloc = 0xffffff;
/* Load bitmap directory */
if (!(sbi->sb_bmp_dir = hpfs_load_bitmap_directory(s, superblock->bitmaps)))
goto bail4;
/* Check for general fs errors*/
if (spareblock->dirty && !spareblock->old_wrote) {
if (errs == 2) {
printk("HPFS: Improperly stopped, not mounted\n");
goto bail4;
}
hpfs_error(s, "improperly stopped");
}
if (!(s->s_flags & MS_RDONLY)) {
spareblock->dirty = 1;
spareblock->old_wrote = 0;
mark_buffer_dirty(bh2);
}
if (spareblock->hotfixes_used || spareblock->n_spares_used) {
if (errs >= 2) {
printk("HPFS: Hotfixes not supported here, try chkdsk\n");
mark_dirty(s);
goto bail4;
}
hpfs_error(s, "hotfixes not supported here, try chkdsk");
if (errs == 0) printk("HPFS: Proceeding, but your filesystem will be probably corrupted by this driver...\n");
else printk("HPFS: This driver may read bad files or crash when operating on disk with hotfixes.\n");
}
if (spareblock->n_dnode_spares != spareblock->n_dnode_spares_free) {
if (errs >= 2) {
printk("HPFS: Spare dnodes used, try chkdsk\n");
mark_dirty(s);
goto bail4;
}
hpfs_error(s, "warning: spare dnodes used, try chkdsk");
if (errs == 0) printk("HPFS: Proceeding, but your filesystem could be corrupted if you delete files or directories\n");
}
if (chk) {
unsigned a;
if (superblock->dir_band_end - superblock->dir_band_start + 1 != superblock->n_dir_band ||
superblock->dir_band_end < superblock->dir_band_start || superblock->n_dir_band > 0x4000) {
hpfs_error(s, "dir band size mismatch: dir_band_start==%08x, dir_band_end==%08x, n_dir_band==%08x",
superblock->dir_band_start, superblock->dir_band_end, superblock->n_dir_band);
goto bail4;
}
a = sbi->sb_dirband_size;
sbi->sb_dirband_size = 0;
if (hpfs_chk_sectors(s, superblock->dir_band_start, superblock->n_dir_band, "dir_band") ||
hpfs_chk_sectors(s, superblock->dir_band_bitmap, 4, "dir_band_bitmap") ||
hpfs_chk_sectors(s, superblock->bitmaps, 4, "bitmaps")) {
mark_dirty(s);
goto bail4;
}
sbi->sb_dirband_size = a;
} else printk("HPFS: You really don't want any checks? You are crazy...\n");
/* Load code page table */
if (spareblock->n_code_pages)
if (!(sbi->sb_cp_table = hpfs_load_code_page(s, spareblock->code_page_dir)))
printk("HPFS: Warning: code page support is disabled\n");
brelse(bh2);
brelse(bh1);
brelse(bh0);
root = iget_locked(s, sbi->sb_root);
if (!root)
goto bail0;
hpfs_init_inode(root);
hpfs_read_inode(root);
unlock_new_inode(root);
s->s_root = d_alloc_root(root);
if (!s->s_root) {
iput(root);
goto bail0;
}
hpfs_set_dentry_operations(s->s_root);
/*
* find the root directory's . pointer & finish filling in the inode
*/
root_dno = hpfs_fnode_dno(s, sbi->sb_root);
if (root_dno)
de = map_dirent(root, root_dno, "\001\001", 2, NULL, &qbh);
if (!de)
hpfs_error(s, "unable to find root dir");
else {
root->i_atime.tv_sec = local_to_gmt(s, de->read_date);
root->i_atime.tv_nsec = 0;
root->i_mtime.tv_sec = local_to_gmt(s, de->write_date);
root->i_mtime.tv_nsec = 0;
root->i_ctime.tv_sec = local_to_gmt(s, de->creation_date);
root->i_ctime.tv_nsec = 0;
hpfs_i(root)->i_ea_size = de->ea_size;
hpfs_i(root)->i_parent_dir = root->i_ino;
if (root->i_size == -1)
root->i_size = 2048;
if (root->i_blocks == -1)
root->i_blocks = 5;
hpfs_brelse4(&qbh);
}
return 0;
bail4: brelse(bh2);
bail3: brelse(bh1);
bail2: brelse(bh0);
bail1:
bail0:
kfree(sbi->sb_bmp_dir);
kfree(sbi->sb_cp_table);
s->s_fs_info = NULL;
kfree(sbi);
return -EINVAL;
}
[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 13:02:57 +04:00
static int hpfs_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 13:02:57 +04:00
return get_sb_bdev(fs_type, flags, dev_name, data, hpfs_fill_super,
mnt);
}
static struct file_system_type hpfs_fs_type = {
.owner = THIS_MODULE,
.name = "hpfs",
.get_sb = hpfs_get_sb,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
static int __init init_hpfs_fs(void)
{
int err = init_inodecache();
if (err)
goto out1;
err = register_filesystem(&hpfs_fs_type);
if (err)
goto out;
return 0;
out:
destroy_inodecache();
out1:
return err;
}
static void __exit exit_hpfs_fs(void)
{
unregister_filesystem(&hpfs_fs_type);
destroy_inodecache();
}
module_init(init_hpfs_fs)
module_exit(exit_hpfs_fs)
MODULE_LICENSE("GPL");