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![Kay Sievers](/assets/img/avatar_default.png)
Filesystem code usually destroys the option buffer while parsing it. This leads to errors when the same buffer is passed twice. In case we fill a new superblock do not call remount. This is needed to quite a warning that the debugfs code causes every boot. Cc: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
1019 lines
24 KiB
C
1019 lines
24 KiB
C
/*
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* linux/fs/super.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* super.c contains code to handle: - mount structures
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* - super-block tables
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* - filesystem drivers list
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* - mount system call
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* - umount system call
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* - ustat system call
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*
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* GK 2/5/95 - Changed to support mounting the root fs via NFS
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*
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* Added kerneld support: Jacques Gelinas and Bjorn Ekwall
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* Added change_root: Werner Almesberger & Hans Lermen, Feb '96
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* Added options to /proc/mounts:
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* Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996.
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* Added devfs support: Richard Gooch <rgooch@atnf.csiro.au>, 13-JAN-1998
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* Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/smp_lock.h>
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#include <linux/acct.h>
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#include <linux/blkdev.h>
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#include <linux/quotaops.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/vfs.h>
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#include <linux/writeback.h> /* for the emergency remount stuff */
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#include <linux/idr.h>
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#include <linux/kobject.h>
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#include <linux/mutex.h>
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#include <linux/file.h>
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#include <asm/uaccess.h>
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#include "internal.h"
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LIST_HEAD(super_blocks);
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DEFINE_SPINLOCK(sb_lock);
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/**
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* alloc_super - create new superblock
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* @type: filesystem type superblock should belong to
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*
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* Allocates and initializes a new &struct super_block. alloc_super()
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* returns a pointer new superblock or %NULL if allocation had failed.
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*/
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static struct super_block *alloc_super(struct file_system_type *type)
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{
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struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER);
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static const struct super_operations default_op;
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if (s) {
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if (security_sb_alloc(s)) {
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kfree(s);
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s = NULL;
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goto out;
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}
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INIT_LIST_HEAD(&s->s_files);
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INIT_LIST_HEAD(&s->s_instances);
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INIT_HLIST_HEAD(&s->s_anon);
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INIT_LIST_HEAD(&s->s_inodes);
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INIT_LIST_HEAD(&s->s_dentry_lru);
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init_rwsem(&s->s_umount);
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mutex_init(&s->s_lock);
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lockdep_set_class(&s->s_umount, &type->s_umount_key);
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/*
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* The locking rules for s_lock are up to the
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* filesystem. For example ext3fs has different
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* lock ordering than usbfs:
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*/
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lockdep_set_class(&s->s_lock, &type->s_lock_key);
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/*
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* sget() can have s_umount recursion.
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*
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* When it cannot find a suitable sb, it allocates a new
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* one (this one), and tries again to find a suitable old
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* one.
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*
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* In case that succeeds, it will acquire the s_umount
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* lock of the old one. Since these are clearly distrinct
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* locks, and this object isn't exposed yet, there's no
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* risk of deadlocks.
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*
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* Annotate this by putting this lock in a different
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* subclass.
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*/
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down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING);
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s->s_count = S_BIAS;
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atomic_set(&s->s_active, 1);
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mutex_init(&s->s_vfs_rename_mutex);
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mutex_init(&s->s_dquot.dqio_mutex);
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mutex_init(&s->s_dquot.dqonoff_mutex);
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init_rwsem(&s->s_dquot.dqptr_sem);
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init_waitqueue_head(&s->s_wait_unfrozen);
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s->s_maxbytes = MAX_NON_LFS;
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s->dq_op = sb_dquot_ops;
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s->s_qcop = sb_quotactl_ops;
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s->s_op = &default_op;
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s->s_time_gran = 1000000000;
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}
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out:
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return s;
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}
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/**
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* destroy_super - frees a superblock
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* @s: superblock to free
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*
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* Frees a superblock.
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*/
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static inline void destroy_super(struct super_block *s)
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{
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security_sb_free(s);
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kfree(s->s_subtype);
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kfree(s->s_options);
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kfree(s);
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}
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/* Superblock refcounting */
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/*
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* Drop a superblock's refcount. Returns non-zero if the superblock was
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* destroyed. The caller must hold sb_lock.
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*/
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static int __put_super(struct super_block *sb)
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{
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int ret = 0;
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if (!--sb->s_count) {
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destroy_super(sb);
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ret = 1;
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}
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return ret;
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}
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/*
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* Drop a superblock's refcount.
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* Returns non-zero if the superblock is about to be destroyed and
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* at least is already removed from super_blocks list, so if we are
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* making a loop through super blocks then we need to restart.
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* The caller must hold sb_lock.
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*/
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int __put_super_and_need_restart(struct super_block *sb)
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{
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/* check for race with generic_shutdown_super() */
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if (list_empty(&sb->s_list)) {
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/* super block is removed, need to restart... */
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__put_super(sb);
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return 1;
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}
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/* can't be the last, since s_list is still in use */
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sb->s_count--;
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BUG_ON(sb->s_count == 0);
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return 0;
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}
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/**
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* put_super - drop a temporary reference to superblock
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* @sb: superblock in question
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*
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* Drops a temporary reference, frees superblock if there's no
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* references left.
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*/
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void put_super(struct super_block *sb)
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{
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spin_lock(&sb_lock);
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__put_super(sb);
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spin_unlock(&sb_lock);
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}
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/**
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* deactivate_super - drop an active reference to superblock
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* @s: superblock to deactivate
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*
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* Drops an active reference to superblock, acquiring a temprory one if
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* there is no active references left. In that case we lock superblock,
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* tell fs driver to shut it down and drop the temporary reference we
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* had just acquired.
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*/
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void deactivate_super(struct super_block *s)
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{
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struct file_system_type *fs = s->s_type;
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if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
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s->s_count -= S_BIAS-1;
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spin_unlock(&sb_lock);
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vfs_dq_off(s, 0);
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down_write(&s->s_umount);
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fs->kill_sb(s);
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put_filesystem(fs);
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put_super(s);
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}
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}
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EXPORT_SYMBOL(deactivate_super);
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/**
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* deactivate_locked_super - drop an active reference to superblock
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* @s: superblock to deactivate
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*
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* Equivalent of up_write(&s->s_umount); deactivate_super(s);, except that
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* it does not unlock it until it's all over. As the result, it's safe to
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* use to dispose of new superblock on ->get_sb() failure exits - nobody
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* will see the sucker until it's all over. Equivalent using up_write +
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* deactivate_super is safe for that purpose only if superblock is either
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* safe to use or has NULL ->s_root when we unlock.
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*/
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void deactivate_locked_super(struct super_block *s)
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{
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struct file_system_type *fs = s->s_type;
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if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
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s->s_count -= S_BIAS-1;
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spin_unlock(&sb_lock);
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vfs_dq_off(s, 0);
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fs->kill_sb(s);
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put_filesystem(fs);
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put_super(s);
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} else {
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up_write(&s->s_umount);
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}
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}
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EXPORT_SYMBOL(deactivate_locked_super);
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/**
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* grab_super - acquire an active reference
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* @s: reference we are trying to make active
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*
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* Tries to acquire an active reference. grab_super() is used when we
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* had just found a superblock in super_blocks or fs_type->fs_supers
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* and want to turn it into a full-blown active reference. grab_super()
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* is called with sb_lock held and drops it. Returns 1 in case of
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* success, 0 if we had failed (superblock contents was already dead or
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* dying when grab_super() had been called).
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*/
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static int grab_super(struct super_block *s) __releases(sb_lock)
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{
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s->s_count++;
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spin_unlock(&sb_lock);
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down_write(&s->s_umount);
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if (s->s_root) {
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spin_lock(&sb_lock);
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if (s->s_count > S_BIAS) {
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atomic_inc(&s->s_active);
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s->s_count--;
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spin_unlock(&sb_lock);
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return 1;
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}
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spin_unlock(&sb_lock);
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}
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up_write(&s->s_umount);
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put_super(s);
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yield();
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return 0;
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}
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/*
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* Superblock locking. We really ought to get rid of these two.
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*/
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void lock_super(struct super_block * sb)
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{
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get_fs_excl();
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mutex_lock(&sb->s_lock);
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}
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void unlock_super(struct super_block * sb)
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{
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put_fs_excl();
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mutex_unlock(&sb->s_lock);
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}
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EXPORT_SYMBOL(lock_super);
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EXPORT_SYMBOL(unlock_super);
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/**
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* generic_shutdown_super - common helper for ->kill_sb()
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* @sb: superblock to kill
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*
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* generic_shutdown_super() does all fs-independent work on superblock
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* shutdown. Typical ->kill_sb() should pick all fs-specific objects
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* that need destruction out of superblock, call generic_shutdown_super()
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* and release aforementioned objects. Note: dentries and inodes _are_
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* taken care of and do not need specific handling.
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*
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* Upon calling this function, the filesystem may no longer alter or
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* rearrange the set of dentries belonging to this super_block, nor may it
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* change the attachments of dentries to inodes.
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*/
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void generic_shutdown_super(struct super_block *sb)
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{
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const struct super_operations *sop = sb->s_op;
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if (sb->s_root) {
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shrink_dcache_for_umount(sb);
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sync_filesystem(sb);
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get_fs_excl();
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sb->s_flags &= ~MS_ACTIVE;
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/* bad name - it should be evict_inodes() */
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invalidate_inodes(sb);
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if (sop->put_super)
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sop->put_super(sb);
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/* Forget any remaining inodes */
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if (invalidate_inodes(sb)) {
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printk("VFS: Busy inodes after unmount of %s. "
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"Self-destruct in 5 seconds. Have a nice day...\n",
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sb->s_id);
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}
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put_fs_excl();
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}
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spin_lock(&sb_lock);
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/* should be initialized for __put_super_and_need_restart() */
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list_del_init(&sb->s_list);
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list_del(&sb->s_instances);
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spin_unlock(&sb_lock);
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up_write(&sb->s_umount);
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}
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EXPORT_SYMBOL(generic_shutdown_super);
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/**
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* sget - find or create a superblock
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* @type: filesystem type superblock should belong to
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* @test: comparison callback
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* @set: setup callback
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* @data: argument to each of them
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*/
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struct super_block *sget(struct file_system_type *type,
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int (*test)(struct super_block *,void *),
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int (*set)(struct super_block *,void *),
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void *data)
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{
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struct super_block *s = NULL;
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struct super_block *old;
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int err;
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retry:
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spin_lock(&sb_lock);
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if (test) {
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list_for_each_entry(old, &type->fs_supers, s_instances) {
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if (!test(old, data))
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continue;
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if (!grab_super(old))
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goto retry;
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if (s) {
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up_write(&s->s_umount);
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destroy_super(s);
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}
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return old;
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}
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}
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if (!s) {
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spin_unlock(&sb_lock);
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s = alloc_super(type);
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if (!s)
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return ERR_PTR(-ENOMEM);
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goto retry;
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}
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err = set(s, data);
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if (err) {
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spin_unlock(&sb_lock);
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up_write(&s->s_umount);
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destroy_super(s);
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return ERR_PTR(err);
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}
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s->s_type = type;
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strlcpy(s->s_id, type->name, sizeof(s->s_id));
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list_add_tail(&s->s_list, &super_blocks);
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list_add(&s->s_instances, &type->fs_supers);
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spin_unlock(&sb_lock);
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get_filesystem(type);
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return s;
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}
|
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EXPORT_SYMBOL(sget);
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void drop_super(struct super_block *sb)
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{
|
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up_read(&sb->s_umount);
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put_super(sb);
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}
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EXPORT_SYMBOL(drop_super);
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/**
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* sync_supers - helper for periodic superblock writeback
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*
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* Call the write_super method if present on all dirty superblocks in
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* the system. This is for the periodic writeback used by most older
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* filesystems. For data integrity superblock writeback use
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* sync_filesystems() instead.
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*
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* Note: check the dirty flag before waiting, so we don't
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* hold up the sync while mounting a device. (The newly
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* mounted device won't need syncing.)
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*/
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void sync_supers(void)
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{
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struct super_block *sb;
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spin_lock(&sb_lock);
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restart:
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list_for_each_entry(sb, &super_blocks, s_list) {
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if (sb->s_op->write_super && sb->s_dirt) {
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sb->s_count++;
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spin_unlock(&sb_lock);
|
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|
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down_read(&sb->s_umount);
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if (sb->s_root && sb->s_dirt)
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sb->s_op->write_super(sb);
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up_read(&sb->s_umount);
|
|
|
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spin_lock(&sb_lock);
|
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if (__put_super_and_need_restart(sb))
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goto restart;
|
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}
|
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}
|
|
spin_unlock(&sb_lock);
|
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}
|
|
|
|
/**
|
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* get_super - get the superblock of a device
|
|
* @bdev: device to get the superblock for
|
|
*
|
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* Scans the superblock list and finds the superblock of the file system
|
|
* mounted on the device given. %NULL is returned if no match is found.
|
|
*/
|
|
|
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struct super_block * get_super(struct block_device *bdev)
|
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{
|
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struct super_block *sb;
|
|
|
|
if (!bdev)
|
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return NULL;
|
|
|
|
spin_lock(&sb_lock);
|
|
rescan:
|
|
list_for_each_entry(sb, &super_blocks, s_list) {
|
|
if (sb->s_bdev == bdev) {
|
|
sb->s_count++;
|
|
spin_unlock(&sb_lock);
|
|
down_read(&sb->s_umount);
|
|
if (sb->s_root)
|
|
return sb;
|
|
up_read(&sb->s_umount);
|
|
/* restart only when sb is no longer on the list */
|
|
spin_lock(&sb_lock);
|
|
if (__put_super_and_need_restart(sb))
|
|
goto rescan;
|
|
}
|
|
}
|
|
spin_unlock(&sb_lock);
|
|
return NULL;
|
|
}
|
|
|
|
EXPORT_SYMBOL(get_super);
|
|
|
|
/**
|
|
* get_active_super - get an active reference to the superblock of a device
|
|
* @bdev: device to get the superblock for
|
|
*
|
|
* Scans the superblock list and finds the superblock of the file system
|
|
* mounted on the device given. Returns the superblock with an active
|
|
* reference and s_umount held exclusively or %NULL if none was found.
|
|
*/
|
|
struct super_block *get_active_super(struct block_device *bdev)
|
|
{
|
|
struct super_block *sb;
|
|
|
|
if (!bdev)
|
|
return NULL;
|
|
|
|
spin_lock(&sb_lock);
|
|
list_for_each_entry(sb, &super_blocks, s_list) {
|
|
if (sb->s_bdev != bdev)
|
|
continue;
|
|
|
|
sb->s_count++;
|
|
spin_unlock(&sb_lock);
|
|
down_write(&sb->s_umount);
|
|
if (sb->s_root) {
|
|
spin_lock(&sb_lock);
|
|
if (sb->s_count > S_BIAS) {
|
|
atomic_inc(&sb->s_active);
|
|
sb->s_count--;
|
|
spin_unlock(&sb_lock);
|
|
return sb;
|
|
}
|
|
spin_unlock(&sb_lock);
|
|
}
|
|
up_write(&sb->s_umount);
|
|
put_super(sb);
|
|
yield();
|
|
spin_lock(&sb_lock);
|
|
}
|
|
spin_unlock(&sb_lock);
|
|
return NULL;
|
|
}
|
|
|
|
struct super_block * user_get_super(dev_t dev)
|
|
{
|
|
struct super_block *sb;
|
|
|
|
spin_lock(&sb_lock);
|
|
rescan:
|
|
list_for_each_entry(sb, &super_blocks, s_list) {
|
|
if (sb->s_dev == dev) {
|
|
sb->s_count++;
|
|
spin_unlock(&sb_lock);
|
|
down_read(&sb->s_umount);
|
|
if (sb->s_root)
|
|
return sb;
|
|
up_read(&sb->s_umount);
|
|
/* restart only when sb is no longer on the list */
|
|
spin_lock(&sb_lock);
|
|
if (__put_super_and_need_restart(sb))
|
|
goto rescan;
|
|
}
|
|
}
|
|
spin_unlock(&sb_lock);
|
|
return NULL;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
|
|
{
|
|
struct super_block *s;
|
|
struct ustat tmp;
|
|
struct kstatfs sbuf;
|
|
int err = -EINVAL;
|
|
|
|
s = user_get_super(new_decode_dev(dev));
|
|
if (s == NULL)
|
|
goto out;
|
|
err = vfs_statfs(s->s_root, &sbuf);
|
|
drop_super(s);
|
|
if (err)
|
|
goto out;
|
|
|
|
memset(&tmp,0,sizeof(struct ustat));
|
|
tmp.f_tfree = sbuf.f_bfree;
|
|
tmp.f_tinode = sbuf.f_ffree;
|
|
|
|
err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0;
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* do_remount_sb - asks filesystem to change mount options.
|
|
* @sb: superblock in question
|
|
* @flags: numeric part of options
|
|
* @data: the rest of options
|
|
* @force: whether or not to force the change
|
|
*
|
|
* Alters the mount options of a mounted file system.
|
|
*/
|
|
int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
|
|
{
|
|
int retval;
|
|
int remount_rw;
|
|
|
|
if (sb->s_frozen != SB_UNFROZEN)
|
|
return -EBUSY;
|
|
|
|
#ifdef CONFIG_BLOCK
|
|
if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
|
|
return -EACCES;
|
|
#endif
|
|
|
|
if (flags & MS_RDONLY)
|
|
acct_auto_close(sb);
|
|
shrink_dcache_sb(sb);
|
|
sync_filesystem(sb);
|
|
|
|
/* If we are remounting RDONLY and current sb is read/write,
|
|
make sure there are no rw files opened */
|
|
if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
|
|
if (force)
|
|
mark_files_ro(sb);
|
|
else if (!fs_may_remount_ro(sb))
|
|
return -EBUSY;
|
|
retval = vfs_dq_off(sb, 1);
|
|
if (retval < 0 && retval != -ENOSYS)
|
|
return -EBUSY;
|
|
}
|
|
remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY);
|
|
|
|
if (sb->s_op->remount_fs) {
|
|
retval = sb->s_op->remount_fs(sb, &flags, data);
|
|
if (retval)
|
|
return retval;
|
|
}
|
|
sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
|
|
if (remount_rw)
|
|
vfs_dq_quota_on_remount(sb);
|
|
return 0;
|
|
}
|
|
|
|
static void do_emergency_remount(struct work_struct *work)
|
|
{
|
|
struct super_block *sb;
|
|
|
|
spin_lock(&sb_lock);
|
|
list_for_each_entry(sb, &super_blocks, s_list) {
|
|
sb->s_count++;
|
|
spin_unlock(&sb_lock);
|
|
down_write(&sb->s_umount);
|
|
if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
|
|
/*
|
|
* ->remount_fs needs lock_kernel().
|
|
*
|
|
* What lock protects sb->s_flags??
|
|
*/
|
|
do_remount_sb(sb, MS_RDONLY, NULL, 1);
|
|
}
|
|
up_write(&sb->s_umount);
|
|
put_super(sb);
|
|
spin_lock(&sb_lock);
|
|
}
|
|
spin_unlock(&sb_lock);
|
|
kfree(work);
|
|
printk("Emergency Remount complete\n");
|
|
}
|
|
|
|
void emergency_remount(void)
|
|
{
|
|
struct work_struct *work;
|
|
|
|
work = kmalloc(sizeof(*work), GFP_ATOMIC);
|
|
if (work) {
|
|
INIT_WORK(work, do_emergency_remount);
|
|
schedule_work(work);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Unnamed block devices are dummy devices used by virtual
|
|
* filesystems which don't use real block-devices. -- jrs
|
|
*/
|
|
|
|
static DEFINE_IDA(unnamed_dev_ida);
|
|
static DEFINE_SPINLOCK(unnamed_dev_lock);/* protects the above */
|
|
static int unnamed_dev_start = 0; /* don't bother trying below it */
|
|
|
|
int set_anon_super(struct super_block *s, void *data)
|
|
{
|
|
int dev;
|
|
int error;
|
|
|
|
retry:
|
|
if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0)
|
|
return -ENOMEM;
|
|
spin_lock(&unnamed_dev_lock);
|
|
error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev);
|
|
if (!error)
|
|
unnamed_dev_start = dev + 1;
|
|
spin_unlock(&unnamed_dev_lock);
|
|
if (error == -EAGAIN)
|
|
/* We raced and lost with another CPU. */
|
|
goto retry;
|
|
else if (error)
|
|
return -EAGAIN;
|
|
|
|
if ((dev & MAX_ID_MASK) == (1 << MINORBITS)) {
|
|
spin_lock(&unnamed_dev_lock);
|
|
ida_remove(&unnamed_dev_ida, dev);
|
|
if (unnamed_dev_start > dev)
|
|
unnamed_dev_start = dev;
|
|
spin_unlock(&unnamed_dev_lock);
|
|
return -EMFILE;
|
|
}
|
|
s->s_dev = MKDEV(0, dev & MINORMASK);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(set_anon_super);
|
|
|
|
void kill_anon_super(struct super_block *sb)
|
|
{
|
|
int slot = MINOR(sb->s_dev);
|
|
|
|
generic_shutdown_super(sb);
|
|
spin_lock(&unnamed_dev_lock);
|
|
ida_remove(&unnamed_dev_ida, slot);
|
|
if (slot < unnamed_dev_start)
|
|
unnamed_dev_start = slot;
|
|
spin_unlock(&unnamed_dev_lock);
|
|
}
|
|
|
|
EXPORT_SYMBOL(kill_anon_super);
|
|
|
|
void kill_litter_super(struct super_block *sb)
|
|
{
|
|
if (sb->s_root)
|
|
d_genocide(sb->s_root);
|
|
kill_anon_super(sb);
|
|
}
|
|
|
|
EXPORT_SYMBOL(kill_litter_super);
|
|
|
|
static int ns_test_super(struct super_block *sb, void *data)
|
|
{
|
|
return sb->s_fs_info == data;
|
|
}
|
|
|
|
static int ns_set_super(struct super_block *sb, void *data)
|
|
{
|
|
sb->s_fs_info = data;
|
|
return set_anon_super(sb, NULL);
|
|
}
|
|
|
|
int get_sb_ns(struct file_system_type *fs_type, int flags, void *data,
|
|
int (*fill_super)(struct super_block *, void *, int),
|
|
struct vfsmount *mnt)
|
|
{
|
|
struct super_block *sb;
|
|
|
|
sb = sget(fs_type, ns_test_super, ns_set_super, data);
|
|
if (IS_ERR(sb))
|
|
return PTR_ERR(sb);
|
|
|
|
if (!sb->s_root) {
|
|
int err;
|
|
sb->s_flags = flags;
|
|
err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
|
|
if (err) {
|
|
deactivate_locked_super(sb);
|
|
return err;
|
|
}
|
|
|
|
sb->s_flags |= MS_ACTIVE;
|
|
}
|
|
|
|
simple_set_mnt(mnt, sb);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(get_sb_ns);
|
|
|
|
#ifdef CONFIG_BLOCK
|
|
static int set_bdev_super(struct super_block *s, void *data)
|
|
{
|
|
s->s_bdev = data;
|
|
s->s_dev = s->s_bdev->bd_dev;
|
|
|
|
/*
|
|
* We set the bdi here to the queue backing, file systems can
|
|
* overwrite this in ->fill_super()
|
|
*/
|
|
s->s_bdi = &bdev_get_queue(s->s_bdev)->backing_dev_info;
|
|
return 0;
|
|
}
|
|
|
|
static int test_bdev_super(struct super_block *s, void *data)
|
|
{
|
|
return (void *)s->s_bdev == data;
|
|
}
|
|
|
|
int get_sb_bdev(struct file_system_type *fs_type,
|
|
int flags, const char *dev_name, void *data,
|
|
int (*fill_super)(struct super_block *, void *, int),
|
|
struct vfsmount *mnt)
|
|
{
|
|
struct block_device *bdev;
|
|
struct super_block *s;
|
|
fmode_t mode = FMODE_READ;
|
|
int error = 0;
|
|
|
|
if (!(flags & MS_RDONLY))
|
|
mode |= FMODE_WRITE;
|
|
|
|
bdev = open_bdev_exclusive(dev_name, mode, fs_type);
|
|
if (IS_ERR(bdev))
|
|
return PTR_ERR(bdev);
|
|
|
|
/*
|
|
* once the super is inserted into the list by sget, s_umount
|
|
* will protect the lockfs code from trying to start a snapshot
|
|
* while we are mounting
|
|
*/
|
|
mutex_lock(&bdev->bd_fsfreeze_mutex);
|
|
if (bdev->bd_fsfreeze_count > 0) {
|
|
mutex_unlock(&bdev->bd_fsfreeze_mutex);
|
|
error = -EBUSY;
|
|
goto error_bdev;
|
|
}
|
|
s = sget(fs_type, test_bdev_super, set_bdev_super, bdev);
|
|
mutex_unlock(&bdev->bd_fsfreeze_mutex);
|
|
if (IS_ERR(s))
|
|
goto error_s;
|
|
|
|
if (s->s_root) {
|
|
if ((flags ^ s->s_flags) & MS_RDONLY) {
|
|
deactivate_locked_super(s);
|
|
error = -EBUSY;
|
|
goto error_bdev;
|
|
}
|
|
|
|
close_bdev_exclusive(bdev, mode);
|
|
} else {
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
s->s_flags = flags;
|
|
s->s_mode = mode;
|
|
strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
|
|
sb_set_blocksize(s, block_size(bdev));
|
|
error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
|
|
if (error) {
|
|
deactivate_locked_super(s);
|
|
goto error;
|
|
}
|
|
|
|
s->s_flags |= MS_ACTIVE;
|
|
bdev->bd_super = s;
|
|
}
|
|
|
|
simple_set_mnt(mnt, s);
|
|
return 0;
|
|
|
|
error_s:
|
|
error = PTR_ERR(s);
|
|
error_bdev:
|
|
close_bdev_exclusive(bdev, mode);
|
|
error:
|
|
return error;
|
|
}
|
|
|
|
EXPORT_SYMBOL(get_sb_bdev);
|
|
|
|
void kill_block_super(struct super_block *sb)
|
|
{
|
|
struct block_device *bdev = sb->s_bdev;
|
|
fmode_t mode = sb->s_mode;
|
|
|
|
bdev->bd_super = NULL;
|
|
generic_shutdown_super(sb);
|
|
sync_blockdev(bdev);
|
|
close_bdev_exclusive(bdev, mode);
|
|
}
|
|
|
|
EXPORT_SYMBOL(kill_block_super);
|
|
#endif
|
|
|
|
int get_sb_nodev(struct file_system_type *fs_type,
|
|
int flags, void *data,
|
|
int (*fill_super)(struct super_block *, void *, int),
|
|
struct vfsmount *mnt)
|
|
{
|
|
int error;
|
|
struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
|
|
|
|
if (IS_ERR(s))
|
|
return PTR_ERR(s);
|
|
|
|
s->s_flags = flags;
|
|
|
|
error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
|
|
if (error) {
|
|
deactivate_locked_super(s);
|
|
return error;
|
|
}
|
|
s->s_flags |= MS_ACTIVE;
|
|
simple_set_mnt(mnt, s);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(get_sb_nodev);
|
|
|
|
static int compare_single(struct super_block *s, void *p)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
int get_sb_single(struct file_system_type *fs_type,
|
|
int flags, void *data,
|
|
int (*fill_super)(struct super_block *, void *, int),
|
|
struct vfsmount *mnt)
|
|
{
|
|
struct super_block *s;
|
|
int error;
|
|
|
|
s = sget(fs_type, compare_single, set_anon_super, NULL);
|
|
if (IS_ERR(s))
|
|
return PTR_ERR(s);
|
|
if (!s->s_root) {
|
|
s->s_flags = flags;
|
|
error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
|
|
if (error) {
|
|
deactivate_locked_super(s);
|
|
return error;
|
|
}
|
|
s->s_flags |= MS_ACTIVE;
|
|
} else {
|
|
do_remount_sb(s, flags, data, 0);
|
|
}
|
|
simple_set_mnt(mnt, s);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(get_sb_single);
|
|
|
|
struct vfsmount *
|
|
vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data)
|
|
{
|
|
struct vfsmount *mnt;
|
|
char *secdata = NULL;
|
|
int error;
|
|
|
|
if (!type)
|
|
return ERR_PTR(-ENODEV);
|
|
|
|
error = -ENOMEM;
|
|
mnt = alloc_vfsmnt(name);
|
|
if (!mnt)
|
|
goto out;
|
|
|
|
if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
|
|
secdata = alloc_secdata();
|
|
if (!secdata)
|
|
goto out_mnt;
|
|
|
|
error = security_sb_copy_data(data, secdata);
|
|
if (error)
|
|
goto out_free_secdata;
|
|
}
|
|
|
|
error = type->get_sb(type, flags, name, data, mnt);
|
|
if (error < 0)
|
|
goto out_free_secdata;
|
|
BUG_ON(!mnt->mnt_sb);
|
|
|
|
error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata);
|
|
if (error)
|
|
goto out_sb;
|
|
|
|
/*
|
|
* filesystems should never set s_maxbytes larger than MAX_LFS_FILESIZE
|
|
* but s_maxbytes was an unsigned long long for many releases. Throw
|
|
* this warning for a little while to try and catch filesystems that
|
|
* violate this rule. This warning should be either removed or
|
|
* converted to a BUG() in 2.6.34.
|
|
*/
|
|
WARN((mnt->mnt_sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
|
|
"negative value (%lld)\n", type->name, mnt->mnt_sb->s_maxbytes);
|
|
|
|
mnt->mnt_mountpoint = mnt->mnt_root;
|
|
mnt->mnt_parent = mnt;
|
|
up_write(&mnt->mnt_sb->s_umount);
|
|
free_secdata(secdata);
|
|
return mnt;
|
|
out_sb:
|
|
dput(mnt->mnt_root);
|
|
deactivate_locked_super(mnt->mnt_sb);
|
|
out_free_secdata:
|
|
free_secdata(secdata);
|
|
out_mnt:
|
|
free_vfsmnt(mnt);
|
|
out:
|
|
return ERR_PTR(error);
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(vfs_kern_mount);
|
|
|
|
static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
|
|
{
|
|
int err;
|
|
const char *subtype = strchr(fstype, '.');
|
|
if (subtype) {
|
|
subtype++;
|
|
err = -EINVAL;
|
|
if (!subtype[0])
|
|
goto err;
|
|
} else
|
|
subtype = "";
|
|
|
|
mnt->mnt_sb->s_subtype = kstrdup(subtype, GFP_KERNEL);
|
|
err = -ENOMEM;
|
|
if (!mnt->mnt_sb->s_subtype)
|
|
goto err;
|
|
return mnt;
|
|
|
|
err:
|
|
mntput(mnt);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
struct vfsmount *
|
|
do_kern_mount(const char *fstype, int flags, const char *name, void *data)
|
|
{
|
|
struct file_system_type *type = get_fs_type(fstype);
|
|
struct vfsmount *mnt;
|
|
if (!type)
|
|
return ERR_PTR(-ENODEV);
|
|
mnt = vfs_kern_mount(type, flags, name, data);
|
|
if (!IS_ERR(mnt) && (type->fs_flags & FS_HAS_SUBTYPE) &&
|
|
!mnt->mnt_sb->s_subtype)
|
|
mnt = fs_set_subtype(mnt, fstype);
|
|
put_filesystem(type);
|
|
return mnt;
|
|
}
|
|
EXPORT_SYMBOL_GPL(do_kern_mount);
|
|
|
|
struct vfsmount *kern_mount_data(struct file_system_type *type, void *data)
|
|
{
|
|
return vfs_kern_mount(type, MS_KERNMOUNT, type->name, data);
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(kern_mount_data);
|