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linux-next/fs/ext2/super.c
Eric W. Biederman 7f78e03513 fs: Limit sys_mount to only request filesystem modules. 
Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.

A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.

Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.

Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives.  Allowing simple, safe,
well understood work-arounds to known problematic software.

This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work.  While writing this patch I saw a handful of such
cases.  The most significant being autofs that lives in the module
autofs4.

This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.

After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module.  The common pattern in the kernel is to call request_module()
without regards to the users permissions.  In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted.  In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-03 19:36:31 -08:00

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/*
* linux/fs/ext2/super.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/inode.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/parser.h>
#include <linux/random.h>
#include <linux/buffer_head.h>
#include <linux/exportfs.h>
#include <linux/vfs.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/log2.h>
#include <linux/quotaops.h>
#include <asm/uaccess.h>
#include "ext2.h"
#include "xattr.h"
#include "acl.h"
#include "xip.h"
static void ext2_sync_super(struct super_block *sb,
struct ext2_super_block *es, int wait);
static int ext2_remount (struct super_block * sb, int * flags, char * data);
static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
static int ext2_sync_fs(struct super_block *sb, int wait);
static int ext2_freeze(struct super_block *sb);
static int ext2_unfreeze(struct super_block *sb);
void ext2_error(struct super_block *sb, const char *function,
const char *fmt, ...)
{
struct va_format vaf;
va_list args;
struct ext2_sb_info *sbi = EXT2_SB(sb);
struct ext2_super_block *es = sbi->s_es;
if (!(sb->s_flags & MS_RDONLY)) {
spin_lock(&sbi->s_lock);
sbi->s_mount_state |= EXT2_ERROR_FS;
es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
spin_unlock(&sbi->s_lock);
ext2_sync_super(sb, es, 1);
}
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
sb->s_id, function, &vaf);
va_end(args);
if (test_opt(sb, ERRORS_PANIC))
panic("EXT2-fs: panic from previous error\n");
if (test_opt(sb, ERRORS_RO)) {
ext2_msg(sb, KERN_CRIT,
"error: remounting filesystem read-only");
sb->s_flags |= MS_RDONLY;
}
}
void ext2_msg(struct super_block *sb, const char *prefix,
const char *fmt, ...)
{
struct va_format vaf;
va_list args;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
va_end(args);
}
/*
* This must be called with sbi->s_lock held.
*/
void ext2_update_dynamic_rev(struct super_block *sb)
{
struct ext2_super_block *es = EXT2_SB(sb)->s_es;
if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
return;
ext2_msg(sb, KERN_WARNING,
"warning: updating to rev %d because of "
"new feature flag, running e2fsck is recommended",
EXT2_DYNAMIC_REV);
es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
/* leave es->s_feature_*compat flags alone */
/* es->s_uuid will be set by e2fsck if empty */
/*
* The rest of the superblock fields should be zero, and if not it
* means they are likely already in use, so leave them alone. We
* can leave it up to e2fsck to clean up any inconsistencies there.
*/
}
static void ext2_put_super (struct super_block * sb)
{
int db_count;
int i;
struct ext2_sb_info *sbi = EXT2_SB(sb);
dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
ext2_xattr_put_super(sb);
if (!(sb->s_flags & MS_RDONLY)) {
struct ext2_super_block *es = sbi->s_es;
spin_lock(&sbi->s_lock);
es->s_state = cpu_to_le16(sbi->s_mount_state);
spin_unlock(&sbi->s_lock);
ext2_sync_super(sb, es, 1);
}
db_count = sbi->s_gdb_count;
for (i = 0; i < db_count; i++)
if (sbi->s_group_desc[i])
brelse (sbi->s_group_desc[i]);
kfree(sbi->s_group_desc);
kfree(sbi->s_debts);
percpu_counter_destroy(&sbi->s_freeblocks_counter);
percpu_counter_destroy(&sbi->s_freeinodes_counter);
percpu_counter_destroy(&sbi->s_dirs_counter);
brelse (sbi->s_sbh);
sb->s_fs_info = NULL;
kfree(sbi->s_blockgroup_lock);
kfree(sbi);
}
static struct kmem_cache * ext2_inode_cachep;
static struct inode *ext2_alloc_inode(struct super_block *sb)
{
struct ext2_inode_info *ei;
ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
if (!ei)
return NULL;
ei->i_block_alloc_info = NULL;
ei->vfs_inode.i_version = 1;
return &ei->vfs_inode;
}
static void ext2_i_callback(struct rcu_head *head)
{
struct inode *inode = container_of(head, struct inode, i_rcu);
kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
}
static void ext2_destroy_inode(struct inode *inode)
{
call_rcu(&inode->i_rcu, ext2_i_callback);
}
static void init_once(void *foo)
{
struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
rwlock_init(&ei->i_meta_lock);
#ifdef CONFIG_EXT2_FS_XATTR
init_rwsem(&ei->xattr_sem);
#endif
mutex_init(&ei->truncate_mutex);
inode_init_once(&ei->vfs_inode);
}
static int init_inodecache(void)
{
ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
sizeof(struct ext2_inode_info),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
init_once);
if (ext2_inode_cachep == NULL)
return -ENOMEM;
return 0;
}
static void destroy_inodecache(void)
{
/*
* Make sure all delayed rcu free inodes are flushed before we
* destroy cache.
*/
rcu_barrier();
kmem_cache_destroy(ext2_inode_cachep);
}
static int ext2_show_options(struct seq_file *seq, struct dentry *root)
{
struct super_block *sb = root->d_sb;
struct ext2_sb_info *sbi = EXT2_SB(sb);
struct ext2_super_block *es = sbi->s_es;
unsigned long def_mount_opts;
spin_lock(&sbi->s_lock);
def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
if (sbi->s_sb_block != 1)
seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
if (test_opt(sb, MINIX_DF))
seq_puts(seq, ",minixdf");
if (test_opt(sb, GRPID))
seq_puts(seq, ",grpid");
if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
seq_puts(seq, ",nogrpid");
if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
seq_printf(seq, ",resuid=%u",
from_kuid_munged(&init_user_ns, sbi->s_resuid));
}
if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
seq_printf(seq, ",resgid=%u",
from_kgid_munged(&init_user_ns, sbi->s_resgid));
}
if (test_opt(sb, ERRORS_RO)) {
int def_errors = le16_to_cpu(es->s_errors);
if (def_errors == EXT2_ERRORS_PANIC ||
def_errors == EXT2_ERRORS_CONTINUE) {
seq_puts(seq, ",errors=remount-ro");
}
}
if (test_opt(sb, ERRORS_CONT))
seq_puts(seq, ",errors=continue");
if (test_opt(sb, ERRORS_PANIC))
seq_puts(seq, ",errors=panic");
if (test_opt(sb, NO_UID32))
seq_puts(seq, ",nouid32");
if (test_opt(sb, DEBUG))
seq_puts(seq, ",debug");
if (test_opt(sb, OLDALLOC))
seq_puts(seq, ",oldalloc");
#ifdef CONFIG_EXT2_FS_XATTR
if (test_opt(sb, XATTR_USER))
seq_puts(seq, ",user_xattr");
if (!test_opt(sb, XATTR_USER) &&
(def_mount_opts & EXT2_DEFM_XATTR_USER)) {
seq_puts(seq, ",nouser_xattr");
}
#endif
#ifdef CONFIG_EXT2_FS_POSIX_ACL
if (test_opt(sb, POSIX_ACL))
seq_puts(seq, ",acl");
if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
seq_puts(seq, ",noacl");
#endif
if (test_opt(sb, NOBH))
seq_puts(seq, ",nobh");
#if defined(CONFIG_QUOTA)
if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
seq_puts(seq, ",usrquota");
if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
seq_puts(seq, ",grpquota");
#endif
#if defined(CONFIG_EXT2_FS_XIP)
if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
seq_puts(seq, ",xip");
#endif
if (!test_opt(sb, RESERVATION))
seq_puts(seq, ",noreservation");
spin_unlock(&sbi->s_lock);
return 0;
}
#ifdef CONFIG_QUOTA
static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
#endif
static const struct super_operations ext2_sops = {
.alloc_inode = ext2_alloc_inode,
.destroy_inode = ext2_destroy_inode,
.write_inode = ext2_write_inode,
.evict_inode = ext2_evict_inode,
.put_super = ext2_put_super,
.sync_fs = ext2_sync_fs,
.freeze_fs = ext2_freeze,
.unfreeze_fs = ext2_unfreeze,
.statfs = ext2_statfs,
.remount_fs = ext2_remount,
.show_options = ext2_show_options,
#ifdef CONFIG_QUOTA
.quota_read = ext2_quota_read,
.quota_write = ext2_quota_write,
#endif
};
static struct inode *ext2_nfs_get_inode(struct super_block *sb,
u64 ino, u32 generation)
{
struct inode *inode;
if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
return ERR_PTR(-ESTALE);
if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
return ERR_PTR(-ESTALE);
/*
* ext2_iget isn't quite right if the inode is currently unallocated!
* However ext2_iget currently does appropriate checks to handle stale
* inodes so everything is OK.
*/
inode = ext2_iget(sb, ino);
if (IS_ERR(inode))
return ERR_CAST(inode);
if (generation && inode->i_generation != generation) {
/* we didn't find the right inode.. */
iput(inode);
return ERR_PTR(-ESTALE);
}
return inode;
}
static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
ext2_nfs_get_inode);
}
static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
return generic_fh_to_parent(sb, fid, fh_len, fh_type,
ext2_nfs_get_inode);
}
static const struct export_operations ext2_export_ops = {
.fh_to_dentry = ext2_fh_to_dentry,
.fh_to_parent = ext2_fh_to_parent,
.get_parent = ext2_get_parent,
};
static unsigned long get_sb_block(void **data)
{
unsigned long sb_block;
char *options = (char *) *data;
if (!options || strncmp(options, "sb=", 3) != 0)
return 1; /* Default location */
options += 3;
sb_block = simple_strtoul(options, &options, 0);
if (*options && *options != ',') {
printk("EXT2-fs: Invalid sb specification: %s\n",
(char *) *data);
return 1;
}
if (*options == ',')
options++;
*data = (void *) options;
return sb_block;
}
enum {
Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
};
static const match_table_t tokens = {
{Opt_bsd_df, "bsddf"},
{Opt_minix_df, "minixdf"},
{Opt_grpid, "grpid"},
{Opt_grpid, "bsdgroups"},
{Opt_nogrpid, "nogrpid"},
{Opt_nogrpid, "sysvgroups"},
{Opt_resgid, "resgid=%u"},
{Opt_resuid, "resuid=%u"},
{Opt_sb, "sb=%u"},
{Opt_err_cont, "errors=continue"},
{Opt_err_panic, "errors=panic"},
{Opt_err_ro, "errors=remount-ro"},
{Opt_nouid32, "nouid32"},
{Opt_nocheck, "check=none"},
{Opt_nocheck, "nocheck"},
{Opt_debug, "debug"},
{Opt_oldalloc, "oldalloc"},
{Opt_orlov, "orlov"},
{Opt_nobh, "nobh"},
{Opt_user_xattr, "user_xattr"},
{Opt_nouser_xattr, "nouser_xattr"},
{Opt_acl, "acl"},
{Opt_noacl, "noacl"},
{Opt_xip, "xip"},
{Opt_grpquota, "grpquota"},
{Opt_ignore, "noquota"},
{Opt_quota, "quota"},
{Opt_usrquota, "usrquota"},
{Opt_reservation, "reservation"},
{Opt_noreservation, "noreservation"},
{Opt_err, NULL}
};
static int parse_options(char *options, struct super_block *sb)
{
char *p;
struct ext2_sb_info *sbi = EXT2_SB(sb);
substring_t args[MAX_OPT_ARGS];
int option;
kuid_t uid;
kgid_t gid;
if (!options)
return 1;
while ((p = strsep (&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_bsd_df:
clear_opt (sbi->s_mount_opt, MINIX_DF);
break;
case Opt_minix_df:
set_opt (sbi->s_mount_opt, MINIX_DF);
break;
case Opt_grpid:
set_opt (sbi->s_mount_opt, GRPID);
break;
case Opt_nogrpid:
clear_opt (sbi->s_mount_opt, GRPID);
break;
case Opt_resuid:
if (match_int(&args[0], &option))
return 0;
uid = make_kuid(current_user_ns(), option);
if (!uid_valid(uid)) {
ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
return 0;
}
sbi->s_resuid = uid;
break;
case Opt_resgid:
if (match_int(&args[0], &option))
return 0;
gid = make_kgid(current_user_ns(), option);
if (!gid_valid(gid)) {
ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
return 0;
}
sbi->s_resgid = gid;
break;
case Opt_sb:
/* handled by get_sb_block() instead of here */
/* *sb_block = match_int(&args[0]); */
break;
case Opt_err_panic:
clear_opt (sbi->s_mount_opt, ERRORS_CONT);
clear_opt (sbi->s_mount_opt, ERRORS_RO);
set_opt (sbi->s_mount_opt, ERRORS_PANIC);
break;
case Opt_err_ro:
clear_opt (sbi->s_mount_opt, ERRORS_CONT);
clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
set_opt (sbi->s_mount_opt, ERRORS_RO);
break;
case Opt_err_cont:
clear_opt (sbi->s_mount_opt, ERRORS_RO);
clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
set_opt (sbi->s_mount_opt, ERRORS_CONT);
break;
case Opt_nouid32:
set_opt (sbi->s_mount_opt, NO_UID32);
break;
case Opt_nocheck:
clear_opt (sbi->s_mount_opt, CHECK);
break;
case Opt_debug:
set_opt (sbi->s_mount_opt, DEBUG);
break;
case Opt_oldalloc:
set_opt (sbi->s_mount_opt, OLDALLOC);
break;
case Opt_orlov:
clear_opt (sbi->s_mount_opt, OLDALLOC);
break;
case Opt_nobh:
set_opt (sbi->s_mount_opt, NOBH);
break;
#ifdef CONFIG_EXT2_FS_XATTR
case Opt_user_xattr:
set_opt (sbi->s_mount_opt, XATTR_USER);
break;
case Opt_nouser_xattr:
clear_opt (sbi->s_mount_opt, XATTR_USER);
break;
#else
case Opt_user_xattr:
case Opt_nouser_xattr:
ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
"not supported");
break;
#endif
#ifdef CONFIG_EXT2_FS_POSIX_ACL
case Opt_acl:
set_opt(sbi->s_mount_opt, POSIX_ACL);
break;
case Opt_noacl:
clear_opt(sbi->s_mount_opt, POSIX_ACL);
break;
#else
case Opt_acl:
case Opt_noacl:
ext2_msg(sb, KERN_INFO,
"(no)acl options not supported");
break;
#endif
case Opt_xip:
#ifdef CONFIG_EXT2_FS_XIP
set_opt (sbi->s_mount_opt, XIP);
#else
ext2_msg(sb, KERN_INFO, "xip option not supported");
#endif
break;
#if defined(CONFIG_QUOTA)
case Opt_quota:
case Opt_usrquota:
set_opt(sbi->s_mount_opt, USRQUOTA);
break;
case Opt_grpquota:
set_opt(sbi->s_mount_opt, GRPQUOTA);
break;
#else
case Opt_quota:
case Opt_usrquota:
case Opt_grpquota:
ext2_msg(sb, KERN_INFO,
"quota operations not supported");
break;
#endif
case Opt_reservation:
set_opt(sbi->s_mount_opt, RESERVATION);
ext2_msg(sb, KERN_INFO, "reservations ON");
break;
case Opt_noreservation:
clear_opt(sbi->s_mount_opt, RESERVATION);
ext2_msg(sb, KERN_INFO, "reservations OFF");
break;
case Opt_ignore:
break;
default:
return 0;
}
}
return 1;
}
static int ext2_setup_super (struct super_block * sb,
struct ext2_super_block * es,
int read_only)
{
int res = 0;
struct ext2_sb_info *sbi = EXT2_SB(sb);
if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
ext2_msg(sb, KERN_ERR,
"error: revision level too high, "
"forcing read-only mode");
res = MS_RDONLY;
}
if (read_only)
return res;
if (!(sbi->s_mount_state & EXT2_VALID_FS))
ext2_msg(sb, KERN_WARNING,
"warning: mounting unchecked fs, "
"running e2fsck is recommended");
else if ((sbi->s_mount_state & EXT2_ERROR_FS))
ext2_msg(sb, KERN_WARNING,
"warning: mounting fs with errors, "
"running e2fsck is recommended");
else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
le16_to_cpu(es->s_mnt_count) >=
(unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
ext2_msg(sb, KERN_WARNING,
"warning: maximal mount count reached, "
"running e2fsck is recommended");
else if (le32_to_cpu(es->s_checkinterval) &&
(le32_to_cpu(es->s_lastcheck) +
le32_to_cpu(es->s_checkinterval) <= get_seconds()))
ext2_msg(sb, KERN_WARNING,
"warning: checktime reached, "
"running e2fsck is recommended");
if (!le16_to_cpu(es->s_max_mnt_count))
es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
le16_add_cpu(&es->s_mnt_count, 1);
if (test_opt (sb, DEBUG))
ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
"bpg=%lu, ipg=%lu, mo=%04lx]",
EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
sbi->s_frag_size,
sbi->s_groups_count,
EXT2_BLOCKS_PER_GROUP(sb),
EXT2_INODES_PER_GROUP(sb),
sbi->s_mount_opt);
return res;
}
static int ext2_check_descriptors(struct super_block *sb)
{
int i;
struct ext2_sb_info *sbi = EXT2_SB(sb);
ext2_debug ("Checking group descriptors");
for (i = 0; i < sbi->s_groups_count; i++) {
struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
ext2_fsblk_t last_block;
if (i == sbi->s_groups_count - 1)
last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
else
last_block = first_block +
(EXT2_BLOCKS_PER_GROUP(sb) - 1);
if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
le32_to_cpu(gdp->bg_block_bitmap) > last_block)
{
ext2_error (sb, "ext2_check_descriptors",
"Block bitmap for group %d"
" not in group (block %lu)!",
i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
return 0;
}
if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
{
ext2_error (sb, "ext2_check_descriptors",
"Inode bitmap for group %d"
" not in group (block %lu)!",
i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
return 0;
}
if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
last_block)
{
ext2_error (sb, "ext2_check_descriptors",
"Inode table for group %d"
" not in group (block %lu)!",
i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
return 0;
}
}
return 1;
}
/*
* Maximal file size. There is a direct, and {,double-,triple-}indirect
* block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
* We need to be 1 filesystem block less than the 2^32 sector limit.
*/
static loff_t ext2_max_size(int bits)
{
loff_t res = EXT2_NDIR_BLOCKS;
int meta_blocks;
loff_t upper_limit;
/* This is calculated to be the largest file size for a
* dense, file such that the total number of
* sectors in the file, including data and all indirect blocks,
* does not exceed 2^32 -1
* __u32 i_blocks representing the total number of
* 512 bytes blocks of the file
*/
upper_limit = (1LL << 32) - 1;
/* total blocks in file system block size */
upper_limit >>= (bits - 9);
/* indirect blocks */
meta_blocks = 1;
/* double indirect blocks */
meta_blocks += 1 + (1LL << (bits-2));
/* tripple indirect blocks */
meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
upper_limit -= meta_blocks;
upper_limit <<= bits;
res += 1LL << (bits-2);
res += 1LL << (2*(bits-2));
res += 1LL << (3*(bits-2));
res <<= bits;
if (res > upper_limit)
res = upper_limit;
if (res > MAX_LFS_FILESIZE)
res = MAX_LFS_FILESIZE;
return res;
}
static unsigned long descriptor_loc(struct super_block *sb,
unsigned long logic_sb_block,
int nr)
{
struct ext2_sb_info *sbi = EXT2_SB(sb);
unsigned long bg, first_meta_bg;
int has_super = 0;
first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
nr < first_meta_bg)
return (logic_sb_block + nr + 1);
bg = sbi->s_desc_per_block * nr;
if (ext2_bg_has_super(sb, bg))
has_super = 1;
return ext2_group_first_block_no(sb, bg) + has_super;
}
static int ext2_fill_super(struct super_block *sb, void *data, int silent)
{
struct buffer_head * bh;
struct ext2_sb_info * sbi;
struct ext2_super_block * es;
struct inode *root;
unsigned long block;
unsigned long sb_block = get_sb_block(&data);
unsigned long logic_sb_block;
unsigned long offset = 0;
unsigned long def_mount_opts;
long ret = -EINVAL;
int blocksize = BLOCK_SIZE;
int db_count;
int i, j;
__le32 features;
int err;
err = -ENOMEM;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
goto failed;
sbi->s_blockgroup_lock =
kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
if (!sbi->s_blockgroup_lock) {
kfree(sbi);
goto failed;
}
sb->s_fs_info = sbi;
sbi->s_sb_block = sb_block;
spin_lock_init(&sbi->s_lock);
/*
* See what the current blocksize for the device is, and
* use that as the blocksize. Otherwise (or if the blocksize
* is smaller than the default) use the default.
* This is important for devices that have a hardware
* sectorsize that is larger than the default.
*/
blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
if (!blocksize) {
ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
goto failed_sbi;
}
/*
* If the superblock doesn't start on a hardware sector boundary,
* calculate the offset.
*/
if (blocksize != BLOCK_SIZE) {
logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
offset = (sb_block*BLOCK_SIZE) % blocksize;
} else {
logic_sb_block = sb_block;
}
if (!(bh = sb_bread(sb, logic_sb_block))) {
ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
goto failed_sbi;
}
/*
* Note: s_es must be initialized as soon as possible because
* some ext2 macro-instructions depend on its value
*/
es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
sbi->s_es = es;
sb->s_magic = le16_to_cpu(es->s_magic);
if (sb->s_magic != EXT2_SUPER_MAGIC)
goto cantfind_ext2;
/* Set defaults before we parse the mount options */
def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
if (def_mount_opts & EXT2_DEFM_DEBUG)
set_opt(sbi->s_mount_opt, DEBUG);
if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
set_opt(sbi->s_mount_opt, GRPID);
if (def_mount_opts & EXT2_DEFM_UID16)
set_opt(sbi->s_mount_opt, NO_UID32);
#ifdef CONFIG_EXT2_FS_XATTR
if (def_mount_opts & EXT2_DEFM_XATTR_USER)
set_opt(sbi->s_mount_opt, XATTR_USER);
#endif
#ifdef CONFIG_EXT2_FS_POSIX_ACL
if (def_mount_opts & EXT2_DEFM_ACL)
set_opt(sbi->s_mount_opt, POSIX_ACL);
#endif
if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
set_opt(sbi->s_mount_opt, ERRORS_PANIC);
else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
set_opt(sbi->s_mount_opt, ERRORS_CONT);
else
set_opt(sbi->s_mount_opt, ERRORS_RO);
sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
set_opt(sbi->s_mount_opt, RESERVATION);
if (!parse_options((char *) data, sb))
goto failed_mount;
sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
MS_POSIXACL : 0);
ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
EXT2_MOUNT_XIP if not */
if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
(EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
ext2_msg(sb, KERN_WARNING,
"warning: feature flags set on rev 0 fs, "
"running e2fsck is recommended");
/*
* Check feature flags regardless of the revision level, since we
* previously didn't change the revision level when setting the flags,
* so there is a chance incompat flags are set on a rev 0 filesystem.
*/
features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
if (features) {
ext2_msg(sb, KERN_ERR, "error: couldn't mount because of "
"unsupported optional features (%x)",
le32_to_cpu(features));
goto failed_mount;
}
if (!(sb->s_flags & MS_RDONLY) &&
(features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
"unsupported optional features (%x)",
le32_to_cpu(features));
goto failed_mount;
}
blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
if (!silent)
ext2_msg(sb, KERN_ERR,
"error: unsupported blocksize for xip");
goto failed_mount;
}
/* If the blocksize doesn't match, re-read the thing.. */
if (sb->s_blocksize != blocksize) {
brelse(bh);
if (!sb_set_blocksize(sb, blocksize)) {
ext2_msg(sb, KERN_ERR,
"error: bad blocksize %d", blocksize);
goto failed_sbi;
}
logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
offset = (sb_block*BLOCK_SIZE) % blocksize;
bh = sb_bread(sb, logic_sb_block);
if(!bh) {
ext2_msg(sb, KERN_ERR, "error: couldn't read"
"superblock on 2nd try");
goto failed_sbi;
}
es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
sbi->s_es = es;
if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
ext2_msg(sb, KERN_ERR, "error: magic mismatch");
goto failed_mount;
}
}
sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
sb->s_max_links = EXT2_LINK_MAX;
if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
} else {
sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
!is_power_of_2(sbi->s_inode_size) ||
(sbi->s_inode_size > blocksize)) {
ext2_msg(sb, KERN_ERR,
"error: unsupported inode size: %d",
sbi->s_inode_size);
goto failed_mount;
}
}
sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
le32_to_cpu(es->s_log_frag_size);
if (sbi->s_frag_size == 0)
goto cantfind_ext2;
sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
if (EXT2_INODE_SIZE(sb) == 0)
goto cantfind_ext2;
sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
goto cantfind_ext2;
sbi->s_itb_per_group = sbi->s_inodes_per_group /
sbi->s_inodes_per_block;
sbi->s_desc_per_block = sb->s_blocksize /
sizeof (struct ext2_group_desc);
sbi->s_sbh = bh;
sbi->s_mount_state = le16_to_cpu(es->s_state);
sbi->s_addr_per_block_bits =
ilog2 (EXT2_ADDR_PER_BLOCK(sb));
sbi->s_desc_per_block_bits =
ilog2 (EXT2_DESC_PER_BLOCK(sb));
if (sb->s_magic != EXT2_SUPER_MAGIC)
goto cantfind_ext2;
if (sb->s_blocksize != bh->b_size) {
if (!silent)
ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
goto failed_mount;
}
if (sb->s_blocksize != sbi->s_frag_size) {
ext2_msg(sb, KERN_ERR,
"error: fragsize %lu != blocksize %lu"
"(not supported yet)",
sbi->s_frag_size, sb->s_blocksize);
goto failed_mount;
}
if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
ext2_msg(sb, KERN_ERR,
"error: #blocks per group too big: %lu",
sbi->s_blocks_per_group);
goto failed_mount;
}
if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
ext2_msg(sb, KERN_ERR,
"error: #fragments per group too big: %lu",
sbi->s_frags_per_group);
goto failed_mount;
}
if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
ext2_msg(sb, KERN_ERR,
"error: #inodes per group too big: %lu",
sbi->s_inodes_per_group);
goto failed_mount;
}
if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
goto cantfind_ext2;
sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
le32_to_cpu(es->s_first_data_block) - 1)
/ EXT2_BLOCKS_PER_GROUP(sb)) + 1;
db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
EXT2_DESC_PER_BLOCK(sb);
sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
if (sbi->s_group_desc == NULL) {
ext2_msg(sb, KERN_ERR, "error: not enough memory");
goto failed_mount;
}
bgl_lock_init(sbi->s_blockgroup_lock);
sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
if (!sbi->s_debts) {
ext2_msg(sb, KERN_ERR, "error: not enough memory");
goto failed_mount_group_desc;
}
for (i = 0; i < db_count; i++) {
block = descriptor_loc(sb, logic_sb_block, i);
sbi->s_group_desc[i] = sb_bread(sb, block);
if (!sbi->s_group_desc[i]) {
for (j = 0; j < i; j++)
brelse (sbi->s_group_desc[j]);
ext2_msg(sb, KERN_ERR,
"error: unable to read group descriptors");
goto failed_mount_group_desc;
}
}
if (!ext2_check_descriptors (sb)) {
ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
goto failed_mount2;
}
sbi->s_gdb_count = db_count;
get_random_bytes(&sbi->s_next_generation, sizeof(u32));
spin_lock_init(&sbi->s_next_gen_lock);
/* per fileystem reservation list head & lock */
spin_lock_init(&sbi->s_rsv_window_lock);
sbi->s_rsv_window_root = RB_ROOT;
/*
* Add a single, static dummy reservation to the start of the
* reservation window list --- it gives us a placeholder for
* append-at-start-of-list which makes the allocation logic
* _much_ simpler.
*/
sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
sbi->s_rsv_window_head.rsv_alloc_hit = 0;
sbi->s_rsv_window_head.rsv_goal_size = 0;
ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
err = percpu_counter_init(&sbi->s_freeblocks_counter,
ext2_count_free_blocks(sb));
if (!err) {
err = percpu_counter_init(&sbi->s_freeinodes_counter,
ext2_count_free_inodes(sb));
}
if (!err) {
err = percpu_counter_init(&sbi->s_dirs_counter,
ext2_count_dirs(sb));
}
if (err) {
ext2_msg(sb, KERN_ERR, "error: insufficient memory");
goto failed_mount3;
}
/*
* set up enough so that it can read an inode
*/
sb->s_op = &ext2_sops;
sb->s_export_op = &ext2_export_ops;
sb->s_xattr = ext2_xattr_handlers;
#ifdef CONFIG_QUOTA
sb->dq_op = &dquot_operations;
sb->s_qcop = &dquot_quotactl_ops;
#endif
root = ext2_iget(sb, EXT2_ROOT_INO);
if (IS_ERR(root)) {
ret = PTR_ERR(root);
goto failed_mount3;
}
if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
iput(root);
ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
goto failed_mount3;
}
sb->s_root = d_make_root(root);
if (!sb->s_root) {
ext2_msg(sb, KERN_ERR, "error: get root inode failed");
ret = -ENOMEM;
goto failed_mount3;
}
if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
ext2_msg(sb, KERN_WARNING,
"warning: mounting ext3 filesystem as ext2");
if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
sb->s_flags |= MS_RDONLY;
ext2_write_super(sb);
return 0;
cantfind_ext2:
if (!silent)
ext2_msg(sb, KERN_ERR,
"error: can't find an ext2 filesystem on dev %s.",
sb->s_id);
goto failed_mount;
failed_mount3:
percpu_counter_destroy(&sbi->s_freeblocks_counter);
percpu_counter_destroy(&sbi->s_freeinodes_counter);
percpu_counter_destroy(&sbi->s_dirs_counter);
failed_mount2:
for (i = 0; i < db_count; i++)
brelse(sbi->s_group_desc[i]);
failed_mount_group_desc:
kfree(sbi->s_group_desc);
kfree(sbi->s_debts);
failed_mount:
brelse(bh);
failed_sbi:
sb->s_fs_info = NULL;
kfree(sbi->s_blockgroup_lock);
kfree(sbi);
failed:
return ret;
}
static void ext2_clear_super_error(struct super_block *sb)
{
struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
if (buffer_write_io_error(sbh)) {
/*
* Oh, dear. A previous attempt to write the
* superblock failed. This could happen because the
* USB device was yanked out. Or it could happen to
* be a transient write error and maybe the block will
* be remapped. Nothing we can do but to retry the
* write and hope for the best.
*/
ext2_msg(sb, KERN_ERR,
"previous I/O error to superblock detected\n");
clear_buffer_write_io_error(sbh);
set_buffer_uptodate(sbh);
}
}
static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
int wait)
{
ext2_clear_super_error(sb);
spin_lock(&EXT2_SB(sb)->s_lock);
es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
es->s_wtime = cpu_to_le32(get_seconds());
/* unlock before we do IO */
spin_unlock(&EXT2_SB(sb)->s_lock);
mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
if (wait)
sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
}
/*
* In the second extended file system, it is not necessary to
* write the super block since we use a mapping of the
* disk super block in a buffer.
*
* However, this function is still used to set the fs valid
* flags to 0. We need to set this flag to 0 since the fs
* may have been checked while mounted and e2fsck may have
* set s_state to EXT2_VALID_FS after some corrections.
*/
static int ext2_sync_fs(struct super_block *sb, int wait)
{
struct ext2_sb_info *sbi = EXT2_SB(sb);
struct ext2_super_block *es = EXT2_SB(sb)->s_es;
/*
* Write quota structures to quota file, sync_blockdev() will write
* them to disk later
*/
dquot_writeback_dquots(sb, -1);
spin_lock(&sbi->s_lock);
if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
ext2_debug("setting valid to 0\n");
es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
}
spin_unlock(&sbi->s_lock);
ext2_sync_super(sb, es, wait);
return 0;
}
static int ext2_freeze(struct super_block *sb)
{
struct ext2_sb_info *sbi = EXT2_SB(sb);
/*
* Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
* because we have unattached inodes and thus filesystem is not fully
* consistent.
*/
if (atomic_long_read(&sb->s_remove_count)) {
ext2_sync_fs(sb, 1);
return 0;
}
/* Set EXT2_FS_VALID flag */
spin_lock(&sbi->s_lock);
sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
spin_unlock(&sbi->s_lock);
ext2_sync_super(sb, sbi->s_es, 1);
return 0;
}
static int ext2_unfreeze(struct super_block *sb)
{
/* Just write sb to clear EXT2_VALID_FS flag */
ext2_write_super(sb);
return 0;
}
void ext2_write_super(struct super_block *sb)
{
if (!(sb->s_flags & MS_RDONLY))
ext2_sync_fs(sb, 1);
}
static int ext2_remount (struct super_block * sb, int * flags, char * data)
{
struct ext2_sb_info * sbi = EXT2_SB(sb);
struct ext2_super_block * es;
unsigned long old_mount_opt = sbi->s_mount_opt;
struct ext2_mount_options old_opts;
unsigned long old_sb_flags;
int err;
spin_lock(&sbi->s_lock);
/* Store the old options */
old_sb_flags = sb->s_flags;
old_opts.s_mount_opt = sbi->s_mount_opt;
old_opts.s_resuid = sbi->s_resuid;
old_opts.s_resgid = sbi->s_resgid;
/*
* Allow the "check" option to be passed as a remount option.
*/
if (!parse_options(data, sb)) {
err = -EINVAL;
goto restore_opts;
}
sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
EXT2_MOUNT_XIP if not */
if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
ext2_msg(sb, KERN_WARNING,
"warning: unsupported blocksize for xip");
err = -EINVAL;
goto restore_opts;
}
es = sbi->s_es;
if ((sbi->s_mount_opt ^ old_mount_opt) & EXT2_MOUNT_XIP) {
ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
"xip flag with busy inodes while remounting");
sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
}
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
spin_unlock(&sbi->s_lock);
return 0;
}
if (*flags & MS_RDONLY) {
if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
!(sbi->s_mount_state & EXT2_VALID_FS)) {
spin_unlock(&sbi->s_lock);
return 0;
}
/*
* OK, we are remounting a valid rw partition rdonly, so set
* the rdonly flag and then mark the partition as valid again.
*/
es->s_state = cpu_to_le16(sbi->s_mount_state);
es->s_mtime = cpu_to_le32(get_seconds());
spin_unlock(&sbi->s_lock);
err = dquot_suspend(sb, -1);
if (err < 0) {
spin_lock(&sbi->s_lock);
goto restore_opts;
}
ext2_sync_super(sb, es, 1);
} else {
__le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
~EXT2_FEATURE_RO_COMPAT_SUPP);
if (ret) {
ext2_msg(sb, KERN_WARNING,
"warning: couldn't remount RDWR because of "
"unsupported optional features (%x).",
le32_to_cpu(ret));
err = -EROFS;
goto restore_opts;
}
/*
* Mounting a RDONLY partition read-write, so reread and
* store the current valid flag. (It may have been changed
* by e2fsck since we originally mounted the partition.)
*/
sbi->s_mount_state = le16_to_cpu(es->s_state);
if (!ext2_setup_super (sb, es, 0))
sb->s_flags &= ~MS_RDONLY;
spin_unlock(&sbi->s_lock);
ext2_write_super(sb);
dquot_resume(sb, -1);
}
return 0;
restore_opts:
sbi->s_mount_opt = old_opts.s_mount_opt;
sbi->s_resuid = old_opts.s_resuid;
sbi->s_resgid = old_opts.s_resgid;
sb->s_flags = old_sb_flags;
spin_unlock(&sbi->s_lock);
return err;
}
static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
{
struct super_block *sb = dentry->d_sb;
struct ext2_sb_info *sbi = EXT2_SB(sb);
struct ext2_super_block *es = sbi->s_es;
u64 fsid;
spin_lock(&sbi->s_lock);
if (test_opt (sb, MINIX_DF))
sbi->s_overhead_last = 0;
else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
unsigned long i, overhead = 0;
smp_rmb();
/*
* Compute the overhead (FS structures). This is constant
* for a given filesystem unless the number of block groups
* changes so we cache the previous value until it does.
*/
/*
* All of the blocks before first_data_block are
* overhead
*/
overhead = le32_to_cpu(es->s_first_data_block);
/*
* Add the overhead attributed to the superblock and
* block group descriptors. If the sparse superblocks
* feature is turned on, then not all groups have this.
*/
for (i = 0; i < sbi->s_groups_count; i++)
overhead += ext2_bg_has_super(sb, i) +
ext2_bg_num_gdb(sb, i);
/*
* Every block group has an inode bitmap, a block
* bitmap, and an inode table.
*/
overhead += (sbi->s_groups_count *
(2 + sbi->s_itb_per_group));
sbi->s_overhead_last = overhead;
smp_wmb();
sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
}
buf->f_type = EXT2_SUPER_MAGIC;
buf->f_bsize = sb->s_blocksize;
buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
buf->f_bfree = ext2_count_free_blocks(sb);
es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
buf->f_bavail = 0;
buf->f_files = le32_to_cpu(es->s_inodes_count);
buf->f_ffree = ext2_count_free_inodes(sb);
es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
buf->f_namelen = EXT2_NAME_LEN;
fsid = le64_to_cpup((void *)es->s_uuid) ^
le64_to_cpup((void *)es->s_uuid + sizeof(u64));
buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
spin_unlock(&sbi->s_lock);
return 0;
}
static struct dentry *ext2_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data)
{
return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
}
#ifdef CONFIG_QUOTA
/* Read data from quotafile - avoid pagecache and such because we cannot afford
* acquiring the locks... As quota files are never truncated and quota code
* itself serializes the operations (and no one else should touch the files)
* we don't have to be afraid of races */
static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
size_t len, loff_t off)
{
struct inode *inode = sb_dqopt(sb)->files[type];
sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
int err = 0;
int offset = off & (sb->s_blocksize - 1);
int tocopy;
size_t toread;
struct buffer_head tmp_bh;
struct buffer_head *bh;
loff_t i_size = i_size_read(inode);
if (off > i_size)
return 0;
if (off+len > i_size)
len = i_size-off;
toread = len;
while (toread > 0) {
tocopy = sb->s_blocksize - offset < toread ?
sb->s_blocksize - offset : toread;
tmp_bh.b_state = 0;
tmp_bh.b_size = sb->s_blocksize;
err = ext2_get_block(inode, blk, &tmp_bh, 0);
if (err < 0)
return err;
if (!buffer_mapped(&tmp_bh)) /* A hole? */
memset(data, 0, tocopy);
else {
bh = sb_bread(sb, tmp_bh.b_blocknr);
if (!bh)
return -EIO;
memcpy(data, bh->b_data+offset, tocopy);
brelse(bh);
}
offset = 0;
toread -= tocopy;
data += tocopy;
blk++;
}
return len;
}
/* Write to quotafile */
static ssize_t ext2_quota_write(struct super_block *sb, int type,
const char *data, size_t len, loff_t off)
{
struct inode *inode = sb_dqopt(sb)->files[type];
sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
int err = 0;
int offset = off & (sb->s_blocksize - 1);
int tocopy;
size_t towrite = len;
struct buffer_head tmp_bh;
struct buffer_head *bh;
while (towrite > 0) {
tocopy = sb->s_blocksize - offset < towrite ?
sb->s_blocksize - offset : towrite;
tmp_bh.b_state = 0;
err = ext2_get_block(inode, blk, &tmp_bh, 1);
if (err < 0)
goto out;
if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
bh = sb_bread(sb, tmp_bh.b_blocknr);
else
bh = sb_getblk(sb, tmp_bh.b_blocknr);
if (unlikely(!bh)) {
err = -EIO;
goto out;
}
lock_buffer(bh);
memcpy(bh->b_data+offset, data, tocopy);
flush_dcache_page(bh->b_page);
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
unlock_buffer(bh);
brelse(bh);
offset = 0;
towrite -= tocopy;
data += tocopy;
blk++;
}
out:
if (len == towrite)
return err;
if (inode->i_size < off+len-towrite)
i_size_write(inode, off+len-towrite);
inode->i_version++;
inode->i_mtime = inode->i_ctime = CURRENT_TIME;
mark_inode_dirty(inode);
return len - towrite;
}
#endif
static struct file_system_type ext2_fs_type = {
.owner = THIS_MODULE,
.name = "ext2",
.mount = ext2_mount,
.kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("ext2");
static int __init init_ext2_fs(void)
{
int err = init_ext2_xattr();
if (err)
return err;
err = init_inodecache();
if (err)
goto out1;
err = register_filesystem(&ext2_fs_type);
if (err)
goto out;
return 0;
out:
destroy_inodecache();
out1:
exit_ext2_xattr();
return err;
}
static void __exit exit_ext2_fs(void)
{
unregister_filesystem(&ext2_fs_type);
destroy_inodecache();
exit_ext2_xattr();
}
MODULE_AUTHOR("Remy Card and others");
MODULE_DESCRIPTION("Second Extended Filesystem");
MODULE_LICENSE("GPL");
module_init(init_ext2_fs)
module_exit(exit_ext2_fs)
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