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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/fs/dquot.c

2006 строки
56 KiB
C
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/*
* Implementation of the diskquota system for the LINUX operating system. QUOTA
* is implemented using the BSD system call interface as the means of
* communication with the user level. This file contains the generic routines
* called by the different filesystems on allocation of an inode or block.
* These routines take care of the administration needed to have a consistent
* diskquota tracking system. The ideas of both user and group quotas are based
* on the Melbourne quota system as used on BSD derived systems. The internal
* implementation is based on one of the several variants of the LINUX
* inode-subsystem with added complexity of the diskquota system.
*
* Version: $Id: dquot.c,v 6.3 1996/11/17 18:35:34 mvw Exp mvw $
*
* Author: Marco van Wieringen <mvw@planets.elm.net>
*
* Fixes: Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
*
* Revised list management to avoid races
* -- Bill Hawes, <whawes@star.net>, 9/98
*
* Fixed races in dquot_transfer(), dqget() and dquot_alloc_...().
* As the consequence the locking was moved from dquot_decr_...(),
* dquot_incr_...() to calling functions.
* invalidate_dquots() now writes modified dquots.
* Serialized quota_off() and quota_on() for mount point.
* Fixed a few bugs in grow_dquots().
* Fixed deadlock in write_dquot() - we no longer account quotas on
* quota files
* remove_dquot_ref() moved to inode.c - it now traverses through inodes
* add_dquot_ref() restarts after blocking
* Added check for bogus uid and fixed check for group in quotactl.
* Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99
*
* Used struct list_head instead of own list struct
* Invalidation of referenced dquots is no longer possible
* Improved free_dquots list management
* Quota and i_blocks are now updated in one place to avoid races
* Warnings are now delayed so we won't block in critical section
* Write updated not to require dquot lock
* Jan Kara, <jack@suse.cz>, 9/2000
*
* Added dynamic quota structure allocation
* Jan Kara <jack@suse.cz> 12/2000
*
* Rewritten quota interface. Implemented new quota format and
* formats registering.
* Jan Kara, <jack@suse.cz>, 2001,2002
*
* New SMP locking.
* Jan Kara, <jack@suse.cz>, 10/2002
*
* Added journalled quota support, fix lock inversion problems
* Jan Kara, <jack@suse.cz>, 2003,2004
*
* (C) Copyright 1994 - 1997 Marco van Wieringen
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/mm.h>
#include <linux/time.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/stat.h>
#include <linux/tty.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/security.h>
#include <linux/kmod.h>
#include <linux/namei.h>
#include <linux/buffer_head.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/writeback.h> /* for inode_lock, oddly enough.. */
#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
#include <net/netlink.h>
#include <net/genetlink.h>
#endif
#include <asm/uaccess.h>
#define __DQUOT_PARANOIA
/*
* There are two quota SMP locks. dq_list_lock protects all lists with quotas
* and quota formats and also dqstats structure containing statistics about the
* lists. dq_data_lock protects data from dq_dqb and also mem_dqinfo structures
* and also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
* i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
* in inode_add_bytes() and inode_sub_bytes().
*
* The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock
*
* Note that some things (eg. sb pointer, type, id) doesn't change during
* the life of the dquot structure and so needn't to be protected by a lock
*
* Any operation working on dquots via inode pointers must hold dqptr_sem. If
* operation is just reading pointers from inode (or not using them at all) the
* read lock is enough. If pointers are altered function must hold write lock
* (these locking rules also apply for S_NOQUOTA flag in the inode - note that
* for altering the flag i_mutex is also needed). If operation is holding
* reference to dquot in other way (e.g. quotactl ops) it must be guarded by
* dqonoff_mutex.
* This locking assures that:
* a) update/access to dquot pointers in inode is serialized
* b) everyone is guarded against invalidate_dquots()
*
* Each dquot has its dq_lock mutex. Locked dquots might not be referenced
* from inodes (dquot_alloc_space() and such don't check the dq_lock).
* Currently dquot is locked only when it is being read to memory (or space for
* it is being allocated) on the first dqget() and when it is being released on
* the last dqput(). The allocation and release oparations are serialized by
* the dq_lock and by checking the use count in dquot_release(). Write
* operations on dquots don't hold dq_lock as they copy data under dq_data_lock
* spinlock to internal buffers before writing.
*
* Lock ordering (including related VFS locks) is the following:
* i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock >
* dqio_mutex
* i_mutex on quota files is special (it's below dqio_mutex)
*/
static DEFINE_SPINLOCK(dq_list_lock);
DEFINE_SPINLOCK(dq_data_lock);
static char *quotatypes[] = INITQFNAMES;
static struct quota_format_type *quota_formats; /* List of registered formats */
static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
/* SLAB cache for dquot structures */
static struct kmem_cache *dquot_cachep;
int register_quota_format(struct quota_format_type *fmt)
{
spin_lock(&dq_list_lock);
fmt->qf_next = quota_formats;
quota_formats = fmt;
spin_unlock(&dq_list_lock);
return 0;
}
void unregister_quota_format(struct quota_format_type *fmt)
{
struct quota_format_type **actqf;
spin_lock(&dq_list_lock);
for (actqf = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
if (*actqf)
*actqf = (*actqf)->qf_next;
spin_unlock(&dq_list_lock);
}
static struct quota_format_type *find_quota_format(int id)
{
struct quota_format_type *actqf;
spin_lock(&dq_list_lock);
for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
if (!actqf || !try_module_get(actqf->qf_owner)) {
int qm;
spin_unlock(&dq_list_lock);
for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
return NULL;
spin_lock(&dq_list_lock);
for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
if (actqf && !try_module_get(actqf->qf_owner))
actqf = NULL;
}
spin_unlock(&dq_list_lock);
return actqf;
}
static void put_quota_format(struct quota_format_type *fmt)
{
module_put(fmt->qf_owner);
}
/*
* Dquot List Management:
* The quota code uses three lists for dquot management: the inuse_list,
* free_dquots, and dquot_hash[] array. A single dquot structure may be
* on all three lists, depending on its current state.
*
* All dquots are placed to the end of inuse_list when first created, and this
* list is used for invalidate operation, which must look at every dquot.
*
* Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
* and this list is searched whenever we need an available dquot. Dquots are
* removed from the list as soon as they are used again, and
* dqstats.free_dquots gives the number of dquots on the list. When
* dquot is invalidated it's completely released from memory.
*
* Dquots with a specific identity (device, type and id) are placed on
* one of the dquot_hash[] hash chains. The provides an efficient search
* mechanism to locate a specific dquot.
*/
static LIST_HEAD(inuse_list);
static LIST_HEAD(free_dquots);
static unsigned int dq_hash_bits, dq_hash_mask;
static struct hlist_head *dquot_hash;
struct dqstats dqstats;
static void dqput(struct dquot *dquot);
static inline unsigned int
hashfn(const struct super_block *sb, unsigned int id, int type)
{
unsigned long tmp;
tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
}
/*
* Following list functions expect dq_list_lock to be held
*/
static inline void insert_dquot_hash(struct dquot *dquot)
{
struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
hlist_add_head(&dquot->dq_hash, head);
}
static inline void remove_dquot_hash(struct dquot *dquot)
{
hlist_del_init(&dquot->dq_hash);
}
static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
{
struct hlist_node *node;
struct dquot *dquot;
hlist_for_each (node, dquot_hash+hashent) {
dquot = hlist_entry(node, struct dquot, dq_hash);
if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
return dquot;
}
return NODQUOT;
}
/* Add a dquot to the tail of the free list */
static inline void put_dquot_last(struct dquot *dquot)
{
list_add_tail(&dquot->dq_free, &free_dquots);
dqstats.free_dquots++;
}
static inline void remove_free_dquot(struct dquot *dquot)
{
if (list_empty(&dquot->dq_free))
return;
list_del_init(&dquot->dq_free);
dqstats.free_dquots--;
}
static inline void put_inuse(struct dquot *dquot)
{
/* We add to the back of inuse list so we don't have to restart
* when traversing this list and we block */
list_add_tail(&dquot->dq_inuse, &inuse_list);
dqstats.allocated_dquots++;
}
static inline void remove_inuse(struct dquot *dquot)
{
dqstats.allocated_dquots--;
list_del(&dquot->dq_inuse);
}
/*
* End of list functions needing dq_list_lock
*/
static void wait_on_dquot(struct dquot *dquot)
{
mutex_lock(&dquot->dq_lock);
mutex_unlock(&dquot->dq_lock);
}
#define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot))
int dquot_mark_dquot_dirty(struct dquot *dquot)
{
spin_lock(&dq_list_lock);
if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
info[dquot->dq_type].dqi_dirty_list);
spin_unlock(&dq_list_lock);
return 0;
}
/* This function needs dq_list_lock */
static inline int clear_dquot_dirty(struct dquot *dquot)
{
if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
return 0;
list_del_init(&dquot->dq_dirty);
return 1;
}
void mark_info_dirty(struct super_block *sb, int type)
{
set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
}
EXPORT_SYMBOL(mark_info_dirty);
/*
* Read dquot from disk and alloc space for it
*/
int dquot_acquire(struct dquot *dquot)
{
int ret = 0, ret2 = 0;
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
mutex_lock(&dquot->dq_lock);
mutex_lock(&dqopt->dqio_mutex);
if (!test_bit(DQ_READ_B, &dquot->dq_flags))
ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
if (ret < 0)
goto out_iolock;
set_bit(DQ_READ_B, &dquot->dq_flags);
/* Instantiate dquot if needed */
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
/* Write the info if needed */
if (info_dirty(&dqopt->info[dquot->dq_type]))
ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
if (ret < 0)
goto out_iolock;
if (ret2 < 0) {
ret = ret2;
goto out_iolock;
}
}
set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
out_iolock:
mutex_unlock(&dqopt->dqio_mutex);
mutex_unlock(&dquot->dq_lock);
return ret;
}
/*
* Write dquot to disk
*/
int dquot_commit(struct dquot *dquot)
{
int ret = 0, ret2 = 0;
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
mutex_lock(&dqopt->dqio_mutex);
spin_lock(&dq_list_lock);
if (!clear_dquot_dirty(dquot)) {
spin_unlock(&dq_list_lock);
goto out_sem;
}
spin_unlock(&dq_list_lock);
/* Inactive dquot can be only if there was error during read/init
* => we have better not writing it */
if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
if (info_dirty(&dqopt->info[dquot->dq_type]))
ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
if (ret >= 0)
ret = ret2;
}
out_sem:
mutex_unlock(&dqopt->dqio_mutex);
return ret;
}
/*
* Release dquot
*/
int dquot_release(struct dquot *dquot)
{
int ret = 0, ret2 = 0;
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
mutex_lock(&dquot->dq_lock);
/* Check whether we are not racing with some other dqget() */
if (atomic_read(&dquot->dq_count) > 1)
goto out_dqlock;
mutex_lock(&dqopt->dqio_mutex);
if (dqopt->ops[dquot->dq_type]->release_dqblk) {
ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
/* Write the info */
if (info_dirty(&dqopt->info[dquot->dq_type]))
ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
if (ret >= 0)
ret = ret2;
}
clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
mutex_unlock(&dqopt->dqio_mutex);
out_dqlock:
mutex_unlock(&dquot->dq_lock);
return ret;
}
/* Invalidate all dquots on the list. Note that this function is called after
* quota is disabled and pointers from inodes removed so there cannot be new
* quota users. There can still be some users of quotas due to inodes being
* just deleted or pruned by prune_icache() (those are not attached to any
* list). We have to wait for such users.
*/
static void invalidate_dquots(struct super_block *sb, int type)
{
struct dquot *dquot, *tmp;
restart:
spin_lock(&dq_list_lock);
list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
if (dquot->dq_sb != sb)
continue;
if (dquot->dq_type != type)
continue;
/* Wait for dquot users */
if (atomic_read(&dquot->dq_count)) {
DEFINE_WAIT(wait);
atomic_inc(&dquot->dq_count);
prepare_to_wait(&dquot->dq_wait_unused, &wait,
TASK_UNINTERRUPTIBLE);
spin_unlock(&dq_list_lock);
/* Once dqput() wakes us up, we know it's time to free
* the dquot.
* IMPORTANT: we rely on the fact that there is always
* at most one process waiting for dquot to free.
* Otherwise dq_count would be > 1 and we would never
* wake up.
*/
if (atomic_read(&dquot->dq_count) > 1)
schedule();
finish_wait(&dquot->dq_wait_unused, &wait);
dqput(dquot);
/* At this moment dquot() need not exist (it could be
* reclaimed by prune_dqcache(). Hence we must
* restart. */
goto restart;
}
/*
* Quota now has no users and it has been written on last
* dqput()
*/
remove_dquot_hash(dquot);
remove_free_dquot(dquot);
remove_inuse(dquot);
kmem_cache_free(dquot_cachep, dquot);
}
spin_unlock(&dq_list_lock);
}
int vfs_quota_sync(struct super_block *sb, int type)
{
struct list_head *dirty;
struct dquot *dquot;
struct quota_info *dqopt = sb_dqopt(sb);
int cnt;
mutex_lock(&dqopt->dqonoff_mutex);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
if (!sb_has_quota_enabled(sb, cnt))
continue;
spin_lock(&dq_list_lock);
dirty = &dqopt->info[cnt].dqi_dirty_list;
while (!list_empty(dirty)) {
dquot = list_first_entry(dirty, struct dquot, dq_dirty);
/* Dirty and inactive can be only bad dquot... */
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
clear_dquot_dirty(dquot);
continue;
}
/* Now we have active dquot from which someone is
* holding reference so we can safely just increase
* use count */
atomic_inc(&dquot->dq_count);
dqstats.lookups++;
spin_unlock(&dq_list_lock);
sb->dq_op->write_dquot(dquot);
dqput(dquot);
spin_lock(&dq_list_lock);
}
spin_unlock(&dq_list_lock);
}
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if ((cnt == type || type == -1) && sb_has_quota_enabled(sb, cnt)
&& info_dirty(&dqopt->info[cnt]))
sb->dq_op->write_info(sb, cnt);
spin_lock(&dq_list_lock);
dqstats.syncs++;
spin_unlock(&dq_list_lock);
mutex_unlock(&dqopt->dqonoff_mutex);
return 0;
}
/* Free unused dquots from cache */
static void prune_dqcache(int count)
{
struct list_head *head;
struct dquot *dquot;
head = free_dquots.prev;
while (head != &free_dquots && count) {
dquot = list_entry(head, struct dquot, dq_free);
remove_dquot_hash(dquot);
remove_free_dquot(dquot);
remove_inuse(dquot);
kmem_cache_free(dquot_cachep, dquot);
count--;
head = free_dquots.prev;
}
}
/*
* This is called from kswapd when we think we need some
* more memory
*/
static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
{
if (nr) {
spin_lock(&dq_list_lock);
prune_dqcache(nr);
spin_unlock(&dq_list_lock);
}
return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
}
static struct shrinker dqcache_shrinker = {
.shrink = shrink_dqcache_memory,
.seeks = DEFAULT_SEEKS,
};
/*
* Put reference to dquot
* NOTE: If you change this function please check whether dqput_blocks() works right...
* MUST be called with either dqptr_sem or dqonoff_mutex held
*/
static void dqput(struct dquot *dquot)
{
if (!dquot)
return;
#ifdef __DQUOT_PARANOIA
if (!atomic_read(&dquot->dq_count)) {
printk("VFS: dqput: trying to free free dquot\n");
printk("VFS: device %s, dquot of %s %d\n",
dquot->dq_sb->s_id,
quotatypes[dquot->dq_type],
dquot->dq_id);
BUG();
}
#endif
spin_lock(&dq_list_lock);
dqstats.drops++;
spin_unlock(&dq_list_lock);
we_slept:
spin_lock(&dq_list_lock);
if (atomic_read(&dquot->dq_count) > 1) {
/* We have more than one user... nothing to do */
atomic_dec(&dquot->dq_count);
/* Releasing dquot during quotaoff phase? */
if (!sb_has_quota_enabled(dquot->dq_sb, dquot->dq_type) &&
atomic_read(&dquot->dq_count) == 1)
wake_up(&dquot->dq_wait_unused);
spin_unlock(&dq_list_lock);
return;
}
/* Need to release dquot? */
if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
spin_unlock(&dq_list_lock);
/* Commit dquot before releasing */
dquot->dq_sb->dq_op->write_dquot(dquot);
goto we_slept;
}
/* Clear flag in case dquot was inactive (something bad happened) */
clear_dquot_dirty(dquot);
if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
spin_unlock(&dq_list_lock);
dquot->dq_sb->dq_op->release_dquot(dquot);
goto we_slept;
}
atomic_dec(&dquot->dq_count);
#ifdef __DQUOT_PARANOIA
/* sanity check */
BUG_ON(!list_empty(&dquot->dq_free));
#endif
put_dquot_last(dquot);
spin_unlock(&dq_list_lock);
}
static struct dquot *get_empty_dquot(struct super_block *sb, int type)
{
struct dquot *dquot;
dquot = kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
if(!dquot)
return NODQUOT;
mutex_init(&dquot->dq_lock);
INIT_LIST_HEAD(&dquot->dq_free);
INIT_LIST_HEAD(&dquot->dq_inuse);
INIT_HLIST_NODE(&dquot->dq_hash);
INIT_LIST_HEAD(&dquot->dq_dirty);
init_waitqueue_head(&dquot->dq_wait_unused);
dquot->dq_sb = sb;
dquot->dq_type = type;
atomic_set(&dquot->dq_count, 1);
return dquot;
}
/*
* Get reference to dquot
* MUST be called with either dqptr_sem or dqonoff_mutex held
*/
static struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
{
unsigned int hashent = hashfn(sb, id, type);
struct dquot *dquot, *empty = NODQUOT;
if (!sb_has_quota_enabled(sb, type))
return NODQUOT;
we_slept:
spin_lock(&dq_list_lock);
if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
if (empty == NODQUOT) {
spin_unlock(&dq_list_lock);
if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
schedule(); /* Try to wait for a moment... */
goto we_slept;
}
dquot = empty;
dquot->dq_id = id;
/* all dquots go on the inuse_list */
put_inuse(dquot);
/* hash it first so it can be found */
insert_dquot_hash(dquot);
dqstats.lookups++;
spin_unlock(&dq_list_lock);
} else {
if (!atomic_read(&dquot->dq_count))
remove_free_dquot(dquot);
atomic_inc(&dquot->dq_count);
dqstats.cache_hits++;
dqstats.lookups++;
spin_unlock(&dq_list_lock);
if (empty)
kmem_cache_free(dquot_cachep, empty);
}
/* Wait for dq_lock - after this we know that either dquot_release() is already
* finished or it will be canceled due to dq_count > 1 test */
wait_on_dquot(dquot);
/* Read the dquot and instantiate it (everything done only if needed) */
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
dqput(dquot);
return NODQUOT;
}
#ifdef __DQUOT_PARANOIA
BUG_ON(!dquot->dq_sb); /* Has somebody invalidated entry under us? */
#endif
return dquot;
}
static int dqinit_needed(struct inode *inode, int type)
{
int cnt;
if (IS_NOQUOTA(inode))
return 0;
if (type != -1)
return inode->i_dquot[type] == NODQUOT;
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (inode->i_dquot[cnt] == NODQUOT)
return 1;
return 0;
}
/* This routine is guarded by dqonoff_mutex mutex */
static void add_dquot_ref(struct super_block *sb, int type)
{
struct inode *inode, *old_inode = NULL;
spin_lock(&inode_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
if (!atomic_read(&inode->i_writecount))
continue;
if (!dqinit_needed(inode, type))
continue;
if (inode->i_state & (I_FREEING|I_WILL_FREE))
continue;
__iget(inode);
spin_unlock(&inode_lock);
iput(old_inode);
sb->dq_op->initialize(inode, type);
/* We hold a reference to 'inode' so it couldn't have been
* removed from s_inodes list while we dropped the inode_lock.
* We cannot iput the inode now as we can be holding the last
* reference and we cannot iput it under inode_lock. So we
* keep the reference and iput it later. */
old_inode = inode;
spin_lock(&inode_lock);
}
spin_unlock(&inode_lock);
iput(old_inode);
}
/* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
static inline int dqput_blocks(struct dquot *dquot)
{
if (atomic_read(&dquot->dq_count) <= 1)
return 1;
return 0;
}
/* Remove references to dquots from inode - add dquot to list for freeing if needed */
/* We can't race with anybody because we hold dqptr_sem for writing... */
static int remove_inode_dquot_ref(struct inode *inode, int type,
struct list_head *tofree_head)
{
struct dquot *dquot = inode->i_dquot[type];
inode->i_dquot[type] = NODQUOT;
if (dquot != NODQUOT) {
if (dqput_blocks(dquot)) {
#ifdef __DQUOT_PARANOIA
if (atomic_read(&dquot->dq_count) != 1)
printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
#endif
spin_lock(&dq_list_lock);
list_add(&dquot->dq_free, tofree_head); /* As dquot must have currently users it can't be on the free list... */
spin_unlock(&dq_list_lock);
return 1;
}
else
dqput(dquot); /* We have guaranteed we won't block */
}
return 0;
}
/* Free list of dquots - called from inode.c */
/* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
static void put_dquot_list(struct list_head *tofree_head)
{
struct list_head *act_head;
struct dquot *dquot;
act_head = tofree_head->next;
/* So now we have dquots on the list... Just free them */
while (act_head != tofree_head) {
dquot = list_entry(act_head, struct dquot, dq_free);
act_head = act_head->next;
list_del_init(&dquot->dq_free); /* Remove dquot from the list so we won't have problems... */
dqput(dquot);
}
}
static void remove_dquot_ref(struct super_block *sb, int type,
struct list_head *tofree_head)
{
struct inode *inode;
spin_lock(&inode_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
if (!IS_NOQUOTA(inode))
remove_inode_dquot_ref(inode, type, tofree_head);
}
spin_unlock(&inode_lock);
}
/* Gather all references from inodes and drop them */
static void drop_dquot_ref(struct super_block *sb, int type)
{
LIST_HEAD(tofree_head);
if (sb->dq_op) {
down_write(&sb_dqopt(sb)->dqptr_sem);
remove_dquot_ref(sb, type, &tofree_head);
up_write(&sb_dqopt(sb)->dqptr_sem);
put_dquot_list(&tofree_head);
}
}
static inline void dquot_incr_inodes(struct dquot *dquot, unsigned long number)
{
dquot->dq_dqb.dqb_curinodes += number;
}
static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
{
dquot->dq_dqb.dqb_curspace += number;
}
static inline void dquot_decr_inodes(struct dquot *dquot, unsigned long number)
{
if (dquot->dq_dqb.dqb_curinodes > number)
dquot->dq_dqb.dqb_curinodes -= number;
else
dquot->dq_dqb.dqb_curinodes = 0;
if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
dquot->dq_dqb.dqb_itime = (time_t) 0;
clear_bit(DQ_INODES_B, &dquot->dq_flags);
}
static inline void dquot_decr_space(struct dquot *dquot, qsize_t number)
{
if (dquot->dq_dqb.dqb_curspace > number)
dquot->dq_dqb.dqb_curspace -= number;
else
dquot->dq_dqb.dqb_curspace = 0;
if (toqb(dquot->dq_dqb.dqb_curspace) <= dquot->dq_dqb.dqb_bsoftlimit)
dquot->dq_dqb.dqb_btime = (time_t) 0;
clear_bit(DQ_BLKS_B, &dquot->dq_flags);
}
static int warning_issued(struct dquot *dquot, const int warntype)
{
int flag = (warntype == QUOTA_NL_BHARDWARN ||
warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
((warntype == QUOTA_NL_IHARDWARN ||
warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
if (!flag)
return 0;
return test_and_set_bit(flag, &dquot->dq_flags);
}
#ifdef CONFIG_PRINT_QUOTA_WARNING
static int flag_print_warnings = 1;
static inline int need_print_warning(struct dquot *dquot)
{
if (!flag_print_warnings)
return 0;
switch (dquot->dq_type) {
case USRQUOTA:
return current->fsuid == dquot->dq_id;
case GRPQUOTA:
return in_group_p(dquot->dq_id);
}
return 0;
}
/* Print warning to user which exceeded quota */
static void print_warning(struct dquot *dquot, const int warntype)
{
char *msg = NULL;
struct tty_struct *tty;
if (!need_print_warning(dquot))
return;
mutex_lock(&tty_mutex);
tty = get_current_tty();
if (!tty)
goto out_lock;
tty_write_message(tty, dquot->dq_sb->s_id);
if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
tty_write_message(tty, ": warning, ");
else
tty_write_message(tty, ": write failed, ");
tty_write_message(tty, quotatypes[dquot->dq_type]);
switch (warntype) {
case QUOTA_NL_IHARDWARN:
msg = " file limit reached.\r\n";
break;
case QUOTA_NL_ISOFTLONGWARN:
msg = " file quota exceeded too long.\r\n";
break;
case QUOTA_NL_ISOFTWARN:
msg = " file quota exceeded.\r\n";
break;
case QUOTA_NL_BHARDWARN:
msg = " block limit reached.\r\n";
break;
case QUOTA_NL_BSOFTLONGWARN:
msg = " block quota exceeded too long.\r\n";
break;
case QUOTA_NL_BSOFTWARN:
msg = " block quota exceeded.\r\n";
break;
}
tty_write_message(tty, msg);
out_lock:
mutex_unlock(&tty_mutex);
}
#endif
#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
/* Netlink family structure for quota */
static struct genl_family quota_genl_family = {
.id = GENL_ID_GENERATE,
.hdrsize = 0,
.name = "VFS_DQUOT",
.version = 1,
.maxattr = QUOTA_NL_A_MAX,
};
/* Send warning to userspace about user which exceeded quota */
static void send_warning(const struct dquot *dquot, const char warntype)
{
static atomic_t seq;
struct sk_buff *skb;
void *msg_head;
int ret;
int msg_size = 4 * nla_total_size(sizeof(u32)) +
2 * nla_total_size(sizeof(u64));
/* We have to allocate using GFP_NOFS as we are called from a
* filesystem performing write and thus further recursion into
* the fs to free some data could cause deadlocks. */
skb = genlmsg_new(msg_size, GFP_NOFS);
if (!skb) {
printk(KERN_ERR
"VFS: Not enough memory to send quota warning.\n");
return;
}
msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
&quota_genl_family, 0, QUOTA_NL_C_WARNING);
if (!msg_head) {
printk(KERN_ERR
"VFS: Cannot store netlink header in quota warning.\n");
goto err_out;
}
ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, dquot->dq_type);
if (ret)
goto attr_err_out;
ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, dquot->dq_id);
if (ret)
goto attr_err_out;
ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
if (ret)
goto attr_err_out;
ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR,
MAJOR(dquot->dq_sb->s_dev));
if (ret)
goto attr_err_out;
ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR,
MINOR(dquot->dq_sb->s_dev));
if (ret)
goto attr_err_out;
ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current->user->uid);
if (ret)
goto attr_err_out;
genlmsg_end(skb, msg_head);
ret = genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
if (ret < 0 && ret != -ESRCH)
printk(KERN_ERR
"VFS: Failed to send notification message: %d\n", ret);
return;
attr_err_out:
printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
err_out:
kfree_skb(skb);
}
#endif
static inline void flush_warnings(struct dquot * const *dquots, char *warntype)
{
int i;
for (i = 0; i < MAXQUOTAS; i++)
if (dquots[i] != NODQUOT && warntype[i] != QUOTA_NL_NOWARN &&
!warning_issued(dquots[i], warntype[i])) {
#ifdef CONFIG_PRINT_QUOTA_WARNING
print_warning(dquots[i], warntype[i]);
#endif
#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
send_warning(dquots[i], warntype[i]);
#endif
}
}
static inline char ignore_hardlimit(struct dquot *dquot)
{
struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
return capable(CAP_SYS_RESOURCE) &&
(info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
}
/* needs dq_data_lock */
static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
{
*warntype = QUOTA_NL_NOWARN;
if (inodes <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
return QUOTA_OK;
if (dquot->dq_dqb.dqb_ihardlimit &&
(dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
!ignore_hardlimit(dquot)) {
*warntype = QUOTA_NL_IHARDWARN;
return NO_QUOTA;
}
if (dquot->dq_dqb.dqb_isoftlimit &&
(dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
!ignore_hardlimit(dquot)) {
*warntype = QUOTA_NL_ISOFTLONGWARN;
return NO_QUOTA;
}
if (dquot->dq_dqb.dqb_isoftlimit &&
(dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
dquot->dq_dqb.dqb_itime == 0) {
*warntype = QUOTA_NL_ISOFTWARN;
dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
}
return QUOTA_OK;
}
/* needs dq_data_lock */
static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
{
*warntype = QUOTA_NL_NOWARN;
if (space <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
return QUOTA_OK;
if (dquot->dq_dqb.dqb_bhardlimit &&
toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bhardlimit &&
!ignore_hardlimit(dquot)) {
if (!prealloc)
*warntype = QUOTA_NL_BHARDWARN;
return NO_QUOTA;
}
if (dquot->dq_dqb.dqb_bsoftlimit &&
toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
!ignore_hardlimit(dquot)) {
if (!prealloc)
*warntype = QUOTA_NL_BSOFTLONGWARN;
return NO_QUOTA;
}
if (dquot->dq_dqb.dqb_bsoftlimit &&
toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
dquot->dq_dqb.dqb_btime == 0) {
if (!prealloc) {
*warntype = QUOTA_NL_BSOFTWARN;
dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
}
else
/*
* We don't allow preallocation to exceed softlimit so exceeding will
* be always printed
*/
return NO_QUOTA;
}
return QUOTA_OK;
}
/*
* Initialize quota pointers in inode
* Transaction must be started at entry
*/
int dquot_initialize(struct inode *inode, int type)
{
unsigned int id = 0;
int cnt, ret = 0;
/* First test before acquiring mutex - solves deadlocks when we
* re-enter the quota code and are already holding the mutex */
if (IS_NOQUOTA(inode))
return 0;
down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
/* Having dqptr_sem we know NOQUOTA flags can't be altered... */
if (IS_NOQUOTA(inode))
goto out_err;
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
if (inode->i_dquot[cnt] == NODQUOT) {
switch (cnt) {
case USRQUOTA:
id = inode->i_uid;
break;
case GRPQUOTA:
id = inode->i_gid;
break;
}
inode->i_dquot[cnt] = dqget(inode->i_sb, id, cnt);
}
}
out_err:
up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
return ret;
}
/*
* Release all quotas referenced by inode
* Transaction must be started at an entry
*/
int dquot_drop(struct inode *inode)
{
int cnt;
down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (inode->i_dquot[cnt] != NODQUOT) {
dqput(inode->i_dquot[cnt]);
inode->i_dquot[cnt] = NODQUOT;
}
}
up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
return 0;
}
/*
* Following four functions update i_blocks+i_bytes fields and
* quota information (together with appropriate checks)
* NOTE: We absolutely rely on the fact that caller dirties
* the inode (usually macros in quotaops.h care about this) and
* holds a handle for the current transaction so that dquot write and
* inode write go into the same transaction.
*/
/*
* This operation can block, but only after everything is updated
*/
int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
{
int cnt, ret = NO_QUOTA;
char warntype[MAXQUOTAS];
/* First test before acquiring mutex - solves deadlocks when we
* re-enter the quota code and are already holding the mutex */
if (IS_NOQUOTA(inode)) {
out_add:
inode_add_bytes(inode, number);
return QUOTA_OK;
}
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
warntype[cnt] = QUOTA_NL_NOWARN;
down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
if (IS_NOQUOTA(inode)) { /* Now we can do reliable test... */
up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
goto out_add;
}
spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (inode->i_dquot[cnt] == NODQUOT)
continue;
if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA)
goto warn_put_all;
}
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (inode->i_dquot[cnt] == NODQUOT)
continue;
dquot_incr_space(inode->i_dquot[cnt], number);
}
inode_add_bytes(inode, number);
ret = QUOTA_OK;
warn_put_all:
spin_unlock(&dq_data_lock);
if (ret == QUOTA_OK)
/* Dirtify all the dquots - this can block when journalling */
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (inode->i_dquot[cnt])
mark_dquot_dirty(inode->i_dquot[cnt]);
flush_warnings(inode->i_dquot, warntype);
up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
return ret;
}
/*
* This operation can block, but only after everything is updated
*/
int dquot_alloc_inode(const struct inode *inode, unsigned long number)
{
int cnt, ret = NO_QUOTA;
char warntype[MAXQUOTAS];
/* First test before acquiring mutex - solves deadlocks when we
* re-enter the quota code and are already holding the mutex */
if (IS_NOQUOTA(inode))
return QUOTA_OK;
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
warntype[cnt] = QUOTA_NL_NOWARN;
down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
if (IS_NOQUOTA(inode)) {
up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
return QUOTA_OK;
}
spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (inode->i_dquot[cnt] == NODQUOT)
continue;
if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA)
goto warn_put_all;
}
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (inode->i_dquot[cnt] == NODQUOT)
continue;
dquot_incr_inodes(inode->i_dquot[cnt], number);
}
ret = QUOTA_OK;
warn_put_all:
spin_unlock(&dq_data_lock);
if (ret == QUOTA_OK)
/* Dirtify all the dquots - this can block when journalling */
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (inode->i_dquot[cnt])
mark_dquot_dirty(inode->i_dquot[cnt]);
flush_warnings(inode->i_dquot, warntype);
up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
return ret;
}
/*
* This operation can block, but only after everything is updated
*/
int dquot_free_space(struct inode *inode, qsize_t number)
{
unsigned int cnt;
/* First test before acquiring mutex - solves deadlocks when we
* re-enter the quota code and are already holding the mutex */
if (IS_NOQUOTA(inode)) {
out_sub:
inode_sub_bytes(inode, number);
return QUOTA_OK;
}
down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
/* Now recheck reliably when holding dqptr_sem */
if (IS_NOQUOTA(inode)) {
up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
goto out_sub;
}
spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (inode->i_dquot[cnt] == NODQUOT)
continue;
dquot_decr_space(inode->i_dquot[cnt], number);
}
inode_sub_bytes(inode, number);
spin_unlock(&dq_data_lock);
/* Dirtify all the dquots - this can block when journalling */
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (inode->i_dquot[cnt])
mark_dquot_dirty(inode->i_dquot[cnt]);
up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
return QUOTA_OK;
}
/*
* This operation can block, but only after everything is updated
*/
int dquot_free_inode(const struct inode *inode, unsigned long number)
{
unsigned int cnt;
/* First test before acquiring mutex - solves deadlocks when we
* re-enter the quota code and are already holding the mutex */
if (IS_NOQUOTA(inode))
return QUOTA_OK;
down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
/* Now recheck reliably when holding dqptr_sem */
if (IS_NOQUOTA(inode)) {
up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
return QUOTA_OK;
}
spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (inode->i_dquot[cnt] == NODQUOT)
continue;
dquot_decr_inodes(inode->i_dquot[cnt], number);
}
spin_unlock(&dq_data_lock);
/* Dirtify all the dquots - this can block when journalling */
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (inode->i_dquot[cnt])
mark_dquot_dirty(inode->i_dquot[cnt]);
up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
return QUOTA_OK;
}
/*
* Transfer the number of inode and blocks from one diskquota to an other.
*
* This operation can block, but only after everything is updated
* A transaction must be started when entering this function.
*/
int dquot_transfer(struct inode *inode, struct iattr *iattr)
{
qsize_t space;
struct dquot *transfer_from[MAXQUOTAS];
struct dquot *transfer_to[MAXQUOTAS];
int cnt, ret = NO_QUOTA, chuid = (iattr->ia_valid & ATTR_UID) && inode->i_uid != iattr->ia_uid,
chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid;
char warntype[MAXQUOTAS];
/* First test before acquiring mutex - solves deadlocks when we
* re-enter the quota code and are already holding the mutex */
if (IS_NOQUOTA(inode))
return QUOTA_OK;
/* Clear the arrays */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
transfer_to[cnt] = transfer_from[cnt] = NODQUOT;
warntype[cnt] = QUOTA_NL_NOWARN;
}
down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
/* Now recheck reliably when holding dqptr_sem */
if (IS_NOQUOTA(inode)) { /* File without quota accounting? */
up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
return QUOTA_OK;
}
/* First build the transfer_to list - here we can block on
* reading/instantiating of dquots. We know that the transaction for
* us was already started so we don't violate lock ranking here */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
switch (cnt) {
case USRQUOTA:
if (!chuid)
continue;
transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt);
break;
case GRPQUOTA:
if (!chgid)
continue;
transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt);
break;
}
}
spin_lock(&dq_data_lock);
space = inode_get_bytes(inode);
/* Build the transfer_from list and check the limits */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (transfer_to[cnt] == NODQUOT)
continue;
transfer_from[cnt] = inode->i_dquot[cnt];
if (check_idq(transfer_to[cnt], 1, warntype+cnt) == NO_QUOTA ||
check_bdq(transfer_to[cnt], space, 0, warntype+cnt) == NO_QUOTA)
goto warn_put_all;
}
/*
* Finally perform the needed transfer from transfer_from to transfer_to
*/
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
/*
* Skip changes for same uid or gid or for turned off quota-type.
*/
if (transfer_to[cnt] == NODQUOT)
continue;
/* Due to IO error we might not have transfer_from[] structure */
if (transfer_from[cnt]) {
dquot_decr_inodes(transfer_from[cnt], 1);
dquot_decr_space(transfer_from[cnt], space);
}
dquot_incr_inodes(transfer_to[cnt], 1);
dquot_incr_space(transfer_to[cnt], space);
inode->i_dquot[cnt] = transfer_to[cnt];
}
ret = QUOTA_OK;
warn_put_all:
spin_unlock(&dq_data_lock);
/* Dirtify all the dquots - this can block when journalling */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (transfer_from[cnt])
mark_dquot_dirty(transfer_from[cnt]);
if (transfer_to[cnt])
mark_dquot_dirty(transfer_to[cnt]);
}
flush_warnings(transfer_to, warntype);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (ret == QUOTA_OK && transfer_from[cnt] != NODQUOT)
dqput(transfer_from[cnt]);
if (ret == NO_QUOTA && transfer_to[cnt] != NODQUOT)
dqput(transfer_to[cnt]);
}
up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
return ret;
}
/*
* Write info of quota file to disk
*/
int dquot_commit_info(struct super_block *sb, int type)
{
int ret;
struct quota_info *dqopt = sb_dqopt(sb);
mutex_lock(&dqopt->dqio_mutex);
ret = dqopt->ops[type]->write_file_info(sb, type);
mutex_unlock(&dqopt->dqio_mutex);
return ret;
}
/*
* Definitions of diskquota operations.
*/
struct dquot_operations dquot_operations = {
.initialize = dquot_initialize,
.drop = dquot_drop,
.alloc_space = dquot_alloc_space,
.alloc_inode = dquot_alloc_inode,
.free_space = dquot_free_space,
.free_inode = dquot_free_inode,
.transfer = dquot_transfer,
.write_dquot = dquot_commit,
.acquire_dquot = dquot_acquire,
.release_dquot = dquot_release,
.mark_dirty = dquot_mark_dquot_dirty,
.write_info = dquot_commit_info
};
static inline void set_enable_flags(struct quota_info *dqopt, int type)
{
switch (type) {
case USRQUOTA:
dqopt->flags |= DQUOT_USR_ENABLED;
break;
case GRPQUOTA:
dqopt->flags |= DQUOT_GRP_ENABLED;
break;
}
}
static inline void reset_enable_flags(struct quota_info *dqopt, int type)
{
switch (type) {
case USRQUOTA:
dqopt->flags &= ~DQUOT_USR_ENABLED;
break;
case GRPQUOTA:
dqopt->flags &= ~DQUOT_GRP_ENABLED;
break;
}
}
/*
* Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
*/
int vfs_quota_off(struct super_block *sb, int type)
{
int cnt;
struct quota_info *dqopt = sb_dqopt(sb);
struct inode *toputinode[MAXQUOTAS];
/* We need to serialize quota_off() for device */
mutex_lock(&dqopt->dqonoff_mutex);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
toputinode[cnt] = NULL;
if (type != -1 && cnt != type)
continue;
if (!sb_has_quota_enabled(sb, cnt))
continue;
reset_enable_flags(dqopt, cnt);
/* Note: these are blocking operations */
drop_dquot_ref(sb, cnt);
invalidate_dquots(sb, cnt);
/*
* Now all dquots should be invalidated, all writes done so we should be only
* users of the info. No locks needed.
*/
if (info_dirty(&dqopt->info[cnt]))
sb->dq_op->write_info(sb, cnt);
if (dqopt->ops[cnt]->free_file_info)
dqopt->ops[cnt]->free_file_info(sb, cnt);
put_quota_format(dqopt->info[cnt].dqi_format);
toputinode[cnt] = dqopt->files[cnt];
dqopt->files[cnt] = NULL;
dqopt->info[cnt].dqi_flags = 0;
dqopt->info[cnt].dqi_igrace = 0;
dqopt->info[cnt].dqi_bgrace = 0;
dqopt->ops[cnt] = NULL;
}
mutex_unlock(&dqopt->dqonoff_mutex);
/* Sync the superblock so that buffers with quota data are written to
* disk (and so userspace sees correct data afterwards). */
if (sb->s_op->sync_fs)
sb->s_op->sync_fs(sb, 1);
sync_blockdev(sb->s_bdev);
/* Now the quota files are just ordinary files and we can set the
* inode flags back. Moreover we discard the pagecache so that
* userspace sees the writes we did bypassing the pagecache. We
* must also discard the blockdev buffers so that we see the
* changes done by userspace on the next quotaon() */
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (toputinode[cnt]) {
mutex_lock(&dqopt->dqonoff_mutex);
/* If quota was reenabled in the meantime, we have
* nothing to do */
if (!sb_has_quota_enabled(sb, cnt)) {
mutex_lock_nested(&toputinode[cnt]->i_mutex, I_MUTEX_QUOTA);
toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
S_NOATIME | S_NOQUOTA);
truncate_inode_pages(&toputinode[cnt]->i_data, 0);
mutex_unlock(&toputinode[cnt]->i_mutex);
mark_inode_dirty(toputinode[cnt]);
iput(toputinode[cnt]);
}
mutex_unlock(&dqopt->dqonoff_mutex);
}
if (sb->s_bdev)
invalidate_bdev(sb->s_bdev);
return 0;
}
/*
* Turn quotas on on a device
*/
/* Helper function when we already have the inode */
static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
{
struct quota_format_type *fmt = find_quota_format(format_id);
struct super_block *sb = inode->i_sb;
struct quota_info *dqopt = sb_dqopt(sb);
int error;
int oldflags = -1;
if (!fmt)
return -ESRCH;
if (!S_ISREG(inode->i_mode)) {
error = -EACCES;
goto out_fmt;
}
if (IS_RDONLY(inode)) {
error = -EROFS;
goto out_fmt;
}
if (!sb->s_op->quota_write || !sb->s_op->quota_read) {
error = -EINVAL;
goto out_fmt;
}
/* As we bypass the pagecache we must now flush the inode so that
* we see all the changes from userspace... */
write_inode_now(inode, 1);
/* And now flush the block cache so that kernel sees the changes */
invalidate_bdev(sb->s_bdev);
mutex_lock(&inode->i_mutex);
mutex_lock(&dqopt->dqonoff_mutex);
if (sb_has_quota_enabled(sb, type)) {
error = -EBUSY;
goto out_lock;
}
/* We don't want quota and atime on quota files (deadlocks possible)
* Also nobody should write to the file - we use special IO operations
* which ignore the immutable bit. */
down_write(&dqopt->dqptr_sem);
oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
up_write(&dqopt->dqptr_sem);
sb->dq_op->drop(inode);
error = -EIO;
dqopt->files[type] = igrab(inode);
if (!dqopt->files[type])
goto out_lock;
error = -EINVAL;
if (!fmt->qf_ops->check_quota_file(sb, type))
goto out_file_init;
dqopt->ops[type] = fmt->qf_ops;
dqopt->info[type].dqi_format = fmt;
INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
mutex_lock(&dqopt->dqio_mutex);
if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
mutex_unlock(&dqopt->dqio_mutex);
goto out_file_init;
}
mutex_unlock(&dqopt->dqio_mutex);
mutex_unlock(&inode->i_mutex);
set_enable_flags(dqopt, type);
add_dquot_ref(sb, type);
mutex_unlock(&dqopt->dqonoff_mutex);
return 0;
out_file_init:
dqopt->files[type] = NULL;
iput(inode);
out_lock:
mutex_unlock(&dqopt->dqonoff_mutex);
if (oldflags != -1) {
down_write(&dqopt->dqptr_sem);
/* Set the flags back (in the case of accidental quotaon()
* on a wrong file we don't want to mess up the flags) */
inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE);
inode->i_flags |= oldflags;
up_write(&dqopt->dqptr_sem);
}
mutex_unlock(&inode->i_mutex);
out_fmt:
put_quota_format(fmt);
return error;
}
/* Actual function called from quotactl() */
int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
{
struct nameidata nd;
int error;
error = path_lookup(path, LOOKUP_FOLLOW, &nd);
if (error < 0)
return error;
error = security_quota_on(nd.path.dentry);
if (error)
goto out_path;
/* Quota file not on the same filesystem? */
if (nd.path.mnt->mnt_sb != sb)
error = -EXDEV;
else
error = vfs_quota_on_inode(nd.path.dentry->d_inode, type,
format_id);
out_path:
path_put(&nd.path);
return error;
}
/*
* This function is used when filesystem needs to initialize quotas
* during mount time.
*/
int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
int format_id, int type)
{
struct dentry *dentry;
int error;
dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name));
if (IS_ERR(dentry))
return PTR_ERR(dentry);
if (!dentry->d_inode) {
error = -ENOENT;
goto out;
}
error = security_quota_on(dentry);
if (!error)
error = vfs_quota_on_inode(dentry->d_inode, type, format_id);
out:
dput(dentry);
return error;
}
/* Generic routine for getting common part of quota structure */
static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
{
struct mem_dqblk *dm = &dquot->dq_dqb;
spin_lock(&dq_data_lock);
di->dqb_bhardlimit = dm->dqb_bhardlimit;
di->dqb_bsoftlimit = dm->dqb_bsoftlimit;
di->dqb_curspace = dm->dqb_curspace;
di->dqb_ihardlimit = dm->dqb_ihardlimit;
di->dqb_isoftlimit = dm->dqb_isoftlimit;
di->dqb_curinodes = dm->dqb_curinodes;
di->dqb_btime = dm->dqb_btime;
di->dqb_itime = dm->dqb_itime;
di->dqb_valid = QIF_ALL;
spin_unlock(&dq_data_lock);
}
int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
{
struct dquot *dquot;
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
if (!(dquot = dqget(sb, id, type))) {
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return -ESRCH;
}
do_get_dqblk(dquot, di);
dqput(dquot);
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return 0;
}
/* Generic routine for setting common part of quota structure */
static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
{
struct mem_dqblk *dm = &dquot->dq_dqb;
int check_blim = 0, check_ilim = 0;
spin_lock(&dq_data_lock);
if (di->dqb_valid & QIF_SPACE) {
dm->dqb_curspace = di->dqb_curspace;
check_blim = 1;
}
if (di->dqb_valid & QIF_BLIMITS) {
dm->dqb_bsoftlimit = di->dqb_bsoftlimit;
dm->dqb_bhardlimit = di->dqb_bhardlimit;
check_blim = 1;
}
if (di->dqb_valid & QIF_INODES) {
dm->dqb_curinodes = di->dqb_curinodes;
check_ilim = 1;
}
if (di->dqb_valid & QIF_ILIMITS) {
dm->dqb_isoftlimit = di->dqb_isoftlimit;
dm->dqb_ihardlimit = di->dqb_ihardlimit;
check_ilim = 1;
}
if (di->dqb_valid & QIF_BTIME)
dm->dqb_btime = di->dqb_btime;
if (di->dqb_valid & QIF_ITIME)
dm->dqb_itime = di->dqb_itime;
if (check_blim) {
if (!dm->dqb_bsoftlimit || toqb(dm->dqb_curspace) < dm->dqb_bsoftlimit) {
dm->dqb_btime = 0;
clear_bit(DQ_BLKS_B, &dquot->dq_flags);
}
else if (!(di->dqb_valid & QIF_BTIME)) /* Set grace only if user hasn't provided his own... */
dm->dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
}
if (check_ilim) {
if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
dm->dqb_itime = 0;
clear_bit(DQ_INODES_B, &dquot->dq_flags);
}
else if (!(di->dqb_valid & QIF_ITIME)) /* Set grace only if user hasn't provided his own... */
dm->dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
}
if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
clear_bit(DQ_FAKE_B, &dquot->dq_flags);
else
set_bit(DQ_FAKE_B, &dquot->dq_flags);
spin_unlock(&dq_data_lock);
mark_dquot_dirty(dquot);
}
int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
{
struct dquot *dquot;
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
if (!(dquot = dqget(sb, id, type))) {
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return -ESRCH;
}
do_set_dqblk(dquot, di);
dqput(dquot);
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return 0;
}
/* Generic routine for getting common part of quota file information */
int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
{
struct mem_dqinfo *mi;
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
if (!sb_has_quota_enabled(sb, type)) {
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return -ESRCH;
}
mi = sb_dqopt(sb)->info + type;
spin_lock(&dq_data_lock);
ii->dqi_bgrace = mi->dqi_bgrace;
ii->dqi_igrace = mi->dqi_igrace;
ii->dqi_flags = mi->dqi_flags & DQF_MASK;
ii->dqi_valid = IIF_ALL;
spin_unlock(&dq_data_lock);
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return 0;
}
/* Generic routine for setting common part of quota file information */
int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii)
{
struct mem_dqinfo *mi;
mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
if (!sb_has_quota_enabled(sb, type)) {
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return -ESRCH;
}
mi = sb_dqopt(sb)->info + type;
spin_lock(&dq_data_lock);
if (ii->dqi_valid & IIF_BGRACE)
mi->dqi_bgrace = ii->dqi_bgrace;
if (ii->dqi_valid & IIF_IGRACE)
mi->dqi_igrace = ii->dqi_igrace;
if (ii->dqi_valid & IIF_FLAGS)
mi->dqi_flags = (mi->dqi_flags & ~DQF_MASK) | (ii->dqi_flags & DQF_MASK);
spin_unlock(&dq_data_lock);
mark_info_dirty(sb, type);
/* Force write to disk */
sb->dq_op->write_info(sb, type);
mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
return 0;
}
struct quotactl_ops vfs_quotactl_ops = {
.quota_on = vfs_quota_on,
.quota_off = vfs_quota_off,
.quota_sync = vfs_quota_sync,
.get_info = vfs_get_dqinfo,
.set_info = vfs_set_dqinfo,
.get_dqblk = vfs_get_dqblk,
.set_dqblk = vfs_set_dqblk
};
static ctl_table fs_dqstats_table[] = {
{
.ctl_name = FS_DQ_LOOKUPS,
.procname = "lookups",
.data = &dqstats.lookups,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = FS_DQ_DROPS,
.procname = "drops",
.data = &dqstats.drops,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = FS_DQ_READS,
.procname = "reads",
.data = &dqstats.reads,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = FS_DQ_WRITES,
.procname = "writes",
.data = &dqstats.writes,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = FS_DQ_CACHE_HITS,
.procname = "cache_hits",
.data = &dqstats.cache_hits,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = FS_DQ_ALLOCATED,
.procname = "allocated_dquots",
.data = &dqstats.allocated_dquots,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = FS_DQ_FREE,
.procname = "free_dquots",
.data = &dqstats.free_dquots,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = FS_DQ_SYNCS,
.procname = "syncs",
.data = &dqstats.syncs,
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = &proc_dointvec,
},
#ifdef CONFIG_PRINT_QUOTA_WARNING
{
.ctl_name = FS_DQ_WARNINGS,
.procname = "warnings",
.data = &flag_print_warnings,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec,
},
#endif
{ .ctl_name = 0 },
};
static ctl_table fs_table[] = {
{
.ctl_name = FS_DQSTATS,
.procname = "quota",
.mode = 0555,
.child = fs_dqstats_table,
},
{ .ctl_name = 0 },
};
static ctl_table sys_table[] = {
{
.ctl_name = CTL_FS,
.procname = "fs",
.mode = 0555,
.child = fs_table,
},
{ .ctl_name = 0 },
};
static int __init dquot_init(void)
{
int i;
unsigned long nr_hash, order;
printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
register_sysctl_table(sys_table);
dquot_cachep = kmem_cache_create("dquot",
sizeof(struct dquot), sizeof(unsigned long) * 4,
(SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD|SLAB_PANIC),
NULL);
order = 0;
dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order);
if (!dquot_hash)
panic("Cannot create dquot hash table");
/* Find power-of-two hlist_heads which can fit into allocation */
nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head);
dq_hash_bits = 0;
do {
dq_hash_bits++;
} while (nr_hash >> dq_hash_bits);
dq_hash_bits--;
nr_hash = 1UL << dq_hash_bits;
dq_hash_mask = nr_hash - 1;
for (i = 0; i < nr_hash; i++)
INIT_HLIST_HEAD(dquot_hash + i);
printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
nr_hash, order, (PAGE_SIZE << order));
register_shrinker(&dqcache_shrinker);
#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
if (genl_register_family(&quota_genl_family) != 0)
printk(KERN_ERR "VFS: Failed to create quota netlink interface.\n");
#endif
return 0;
}
module_init(dquot_init);
EXPORT_SYMBOL(register_quota_format);
EXPORT_SYMBOL(unregister_quota_format);
EXPORT_SYMBOL(dqstats);
EXPORT_SYMBOL(dq_data_lock);
EXPORT_SYMBOL(vfs_quota_on);
EXPORT_SYMBOL(vfs_quota_on_mount);
EXPORT_SYMBOL(vfs_quota_off);
EXPORT_SYMBOL(vfs_quota_sync);
EXPORT_SYMBOL(vfs_get_dqinfo);
EXPORT_SYMBOL(vfs_set_dqinfo);
EXPORT_SYMBOL(vfs_get_dqblk);
EXPORT_SYMBOL(vfs_set_dqblk);
EXPORT_SYMBOL(dquot_commit);
EXPORT_SYMBOL(dquot_commit_info);
EXPORT_SYMBOL(dquot_acquire);
EXPORT_SYMBOL(dquot_release);
EXPORT_SYMBOL(dquot_mark_dquot_dirty);
EXPORT_SYMBOL(dquot_initialize);
EXPORT_SYMBOL(dquot_drop);
EXPORT_SYMBOL(dquot_alloc_space);
EXPORT_SYMBOL(dquot_alloc_inode);
EXPORT_SYMBOL(dquot_free_space);
EXPORT_SYMBOL(dquot_free_inode);
EXPORT_SYMBOL(dquot_transfer);
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