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linux_dsm_epyc7002/fs/quota/dquot.c
Jan Kara 1822193b5d quota: Cleanup list iteration in dqcache_shrink_scan() 
Use list_first_entry() and list_empty() instead of opencoded variants.

Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-06-20 11:04:26 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* 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.
*
* 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/sched.h>
#include <linux/cred.h>
#include <linux/kmod.h>
#include <linux/namei.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include "../internal.h" /* ugh */
#include <linux/uaccess.h>
/*
* There are five quota SMP locks:
* * dq_list_lock protects all lists with quotas and quota formats.
* * dquot->dq_dqb_lock protects data from dq_dqb
* * inode->i_lock protects inode->i_blocks, i_bytes and also guards
* consistency of dquot->dq_dqb with inode->i_blocks, i_bytes so that
* dquot_transfer() can stabilize amount it transfers
* * dq_data_lock protects mem_dqinfo structures and modifications of dquot
* pointers in the inode
* * dq_state_lock protects modifications of quota state (on quotaon and
* quotaoff) and readers who care about latest values take it as well.
*
* The spinlock ordering is hence:
* dq_data_lock > dq_list_lock > i_lock > dquot->dq_dqb_lock,
* dq_list_lock > dq_state_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
*
* Operation accessing dquots via inode pointers are protected by dquot_srcu.
* Operation of reading pointer needs srcu_read_lock(&dquot_srcu), and
* synchronize_srcu(&dquot_srcu) is called after clearing pointers from
* inode and before dropping dquot references to avoid use of dquots after
* they are freed. dq_data_lock is used to serialize the pointer setting and
* clearing operations.
* Special care needs to be taken about S_NOQUOTA inode flag (marking that
* inode is a quota file). Functions adding pointers from inode to dquots have
* to check this flag under dq_data_lock and then (if S_NOQUOTA is not set) they
* have to do all pointer modifications before dropping dq_data_lock. This makes
* sure they cannot race with quotaon which first sets S_NOQUOTA flag and
* then drops all pointers to dquots from an inode.
*
* Each dquot has its dq_lock mutex. Dquot is locked when it is being read to
* memory (or space for it is being allocated) on the first dqget(), when it is
* being written out, and when it is being released on the last dqput(). The
* allocation and release operations are serialized by the dq_lock and by
* checking the use count in dquot_release().
*
* Lock ordering (including related VFS locks) is the following:
* s_umount > i_mutex > journal_lock > dquot->dq_lock > dqio_sem
*/
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock);
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_state_lock);
__cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_data_lock);
EXPORT_SYMBOL(dq_data_lock);
DEFINE_STATIC_SRCU(dquot_srcu);
static DECLARE_WAIT_QUEUE_HEAD(dquot_ref_wq);
void __quota_error(struct super_block *sb, const char *func,
const char *fmt, ...)
{
if (printk_ratelimit()) {
va_list args;
struct va_format vaf;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
printk(KERN_ERR "Quota error (device %s): %s: %pV\n",
sb->s_id, func, &vaf);
va_end(args);
}
}
EXPORT_SYMBOL(__quota_error);
#if defined(CONFIG_QUOTA_DEBUG) || defined(CONFIG_PRINT_QUOTA_WARNING)
static char *quotatypes[] = INITQFNAMES;
#endif
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;
}
EXPORT_SYMBOL(register_quota_format);
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);
}
EXPORT_SYMBOL(unregister_quota_format);
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;
EXPORT_SYMBOL(dqstats);
static qsize_t inode_get_rsv_space(struct inode *inode);
static qsize_t __inode_get_rsv_space(struct inode *inode);
static int __dquot_initialize(struct inode *inode, int type);
static inline unsigned int
hashfn(const struct super_block *sb, struct kqid qid)
{
unsigned int id = from_kqid(&init_user_ns, qid);
int type = qid.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;
head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id);
hlist_add_head(&dquot->dq_hash, head);
}
static inline void remove_dquot_hash(struct dquot *dquot)
{
hlist_del_init(&dquot->dq_hash);
}
static struct dquot *find_dquot(unsigned int hashent, struct super_block *sb,
struct kqid qid)
{
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 && qid_eq(dquot->dq_id, qid))
return dquot;
}
return NULL;
}
/* 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_inc(DQST_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_dec(DQST_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_inc(DQST_ALLOC_DQUOTS);
}
static inline void remove_inuse(struct dquot *dquot)
{
dqstats_dec(DQST_ALLOC_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);
}
static inline int dquot_dirty(struct dquot *dquot)
{
return test_bit(DQ_MOD_B, &dquot->dq_flags);
}
static inline int mark_dquot_dirty(struct dquot *dquot)
{
return dquot->dq_sb->dq_op->mark_dirty(dquot);
}
/* Mark dquot dirty in atomic manner, and return it's old dirty flag state */
int dquot_mark_dquot_dirty(struct dquot *dquot)
{
int ret = 1;
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
return 0;
if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
return test_and_set_bit(DQ_MOD_B, &dquot->dq_flags);
/* If quota is dirty already, we don't have to acquire dq_list_lock */
if (test_bit(DQ_MOD_B, &dquot->dq_flags))
return 1;
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_id.type].dqi_dirty_list);
ret = 0;
}
spin_unlock(&dq_list_lock);
return ret;
}
EXPORT_SYMBOL(dquot_mark_dquot_dirty);
/* Dirtify all the dquots - this can block when journalling */
static inline int mark_all_dquot_dirty(struct dquot * const *dquot)
{
int ret, err, cnt;
ret = err = 0;
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (dquot[cnt])
/* Even in case of error we have to continue */
ret = mark_dquot_dirty(dquot[cnt]);
if (!err)
err = ret;
}
return err;
}
static inline void dqput_all(struct dquot **dquot)
{
unsigned int cnt;
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
dqput(dquot[cnt]);
}
static inline int clear_dquot_dirty(struct dquot *dquot)
{
if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NOLIST_DIRTY)
return test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags);
spin_lock(&dq_list_lock);
if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags)) {
spin_unlock(&dq_list_lock);
return 0;
}
list_del_init(&dquot->dq_dirty);
spin_unlock(&dq_list_lock);
return 1;
}
void mark_info_dirty(struct super_block *sb, int type)
{
spin_lock(&dq_data_lock);
sb_dqopt(sb)->info[type].dqi_flags |= DQF_INFO_DIRTY;
spin_unlock(&dq_data_lock);
}
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);
if (!test_bit(DQ_READ_B, &dquot->dq_flags))
ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot);
if (ret < 0)
goto out_iolock;
/* Make sure flags update is visible after dquot has been filled */
smp_mb__before_atomic();
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_id.type]->commit_dqblk(dquot);
/* Write the info if needed */
if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
dquot->dq_sb, dquot->dq_id.type);
}
if (ret < 0)
goto out_iolock;
if (ret2 < 0) {
ret = ret2;
goto out_iolock;
}
}
/*
* Make sure flags update is visible after on-disk struct has been
* allocated. Paired with smp_rmb() in dqget().
*/
smp_mb__before_atomic();
set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
out_iolock:
mutex_unlock(&dquot->dq_lock);
return ret;
}
EXPORT_SYMBOL(dquot_acquire);
/*
* Write dquot to disk
*/
int dquot_commit(struct dquot *dquot)
{
int ret = 0;
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
mutex_lock(&dquot->dq_lock);
if (!clear_dquot_dirty(dquot))
goto out_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_id.type]->commit_dqblk(dquot);
else
ret = -EIO;
out_lock:
mutex_unlock(&dquot->dq_lock);
return ret;
}
EXPORT_SYMBOL(dquot_commit);
/*
* 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;
if (dqopt->ops[dquot->dq_id.type]->release_dqblk) {
ret = dqopt->ops[dquot->dq_id.type]->release_dqblk(dquot);
/* Write the info */
if (info_dirty(&dqopt->info[dquot->dq_id.type])) {
ret2 = dqopt->ops[dquot->dq_id.type]->write_file_info(
dquot->dq_sb, dquot->dq_id.type);
}
if (ret >= 0)
ret = ret2;
}
clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
out_dqlock:
mutex_unlock(&dquot->dq_lock);
return ret;
}
EXPORT_SYMBOL(dquot_release);
void dquot_destroy(struct dquot *dquot)
{
kmem_cache_free(dquot_cachep, dquot);
}
EXPORT_SYMBOL(dquot_destroy);
static inline void do_destroy_dquot(struct dquot *dquot)
{
dquot->dq_sb->dq_op->destroy_dquot(dquot);
}
/* 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) or parallel quotactl call. 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_id.type != type)
continue;
/* Wait for dquot users */
if (atomic_read(&dquot->dq_count)) {
dqgrab(dquot);
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.
*/
wait_event(dquot_ref_wq,
atomic_read(&dquot->dq_count) == 1);
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);
do_destroy_dquot(dquot);
}
spin_unlock(&dq_list_lock);
}
/* Call callback for every active dquot on given filesystem */
int dquot_scan_active(struct super_block *sb,
int (*fn)(struct dquot *dquot, unsigned long priv),
unsigned long priv)
{
struct dquot *dquot, *old_dquot = NULL;
int ret = 0;
WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
spin_lock(&dq_list_lock);
list_for_each_entry(dquot, &inuse_list, dq_inuse) {
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags))
continue;
if (dquot->dq_sb != sb)
continue;
/* Now we have active dquot so we can just increase use count */
atomic_inc(&dquot->dq_count);
spin_unlock(&dq_list_lock);
dqstats_inc(DQST_LOOKUPS);
dqput(old_dquot);
old_dquot = dquot;
/*
* ->release_dquot() can be racing with us. Our reference
* protects us from new calls to it so just wait for any
* outstanding call and recheck the DQ_ACTIVE_B after that.
*/
wait_on_dquot(dquot);
if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
ret = fn(dquot, priv);
if (ret < 0)
goto out;
}
spin_lock(&dq_list_lock);
/* We are safe to continue now because our dquot could not
* be moved out of the inuse list while we hold the reference */
}
spin_unlock(&dq_list_lock);
out:
dqput(old_dquot);
return ret;
}
EXPORT_SYMBOL(dquot_scan_active);
/* Write all dquot structures to quota files */
int dquot_writeback_dquots(struct super_block *sb, int type)
{
struct list_head *dirty;
struct dquot *dquot;
struct quota_info *dqopt = sb_dqopt(sb);
int cnt;
int err, ret = 0;
WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount));
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
if (!sb_has_quota_active(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);
WARN_ON(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags));
/* Now we have active dquot from which someone is
* holding reference so we can safely just increase
* use count */
dqgrab(dquot);
spin_unlock(&dq_list_lock);
dqstats_inc(DQST_LOOKUPS);
err = sb->dq_op->write_dquot(dquot);
if (err) {
/*
* Clear dirty bit anyway to avoid infinite
* loop here.
*/
clear_dquot_dirty(dquot);
if (!ret)
ret = err;
}
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_active(sb, cnt)
&& info_dirty(&dqopt->info[cnt]))
sb->dq_op->write_info(sb, cnt);
dqstats_inc(DQST_SYNCS);
return ret;
}
EXPORT_SYMBOL(dquot_writeback_dquots);
/* Write all dquot structures to disk and make them visible from userspace */
int dquot_quota_sync(struct super_block *sb, int type)
{
struct quota_info *dqopt = sb_dqopt(sb);
int cnt;
int ret;
ret = dquot_writeback_dquots(sb, type);
if (ret)
return ret;
if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
return 0;
/* This is not very clever (and fast) but currently I don't know about
* any other simple way of getting quota data to disk and we must get
* them there for userspace to be visible... */
if (sb->s_op->sync_fs)
sb->s_op->sync_fs(sb, 1);
sync_blockdev(sb->s_bdev);
/*
* Now when everything is written we can discard the pagecache so
* that userspace sees the changes.
*/
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
if (!sb_has_quota_active(sb, cnt))
continue;
inode_lock(dqopt->files[cnt]);
truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
inode_unlock(dqopt->files[cnt]);
}
return 0;
}
EXPORT_SYMBOL(dquot_quota_sync);
static unsigned long
dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
{
struct dquot *dquot;
unsigned long freed = 0;
spin_lock(&dq_list_lock);
while (!list_empty(&free_dquots) && sc->nr_to_scan) {
dquot = list_first_entry(&free_dquots, struct dquot, dq_free);
remove_dquot_hash(dquot);
remove_free_dquot(dquot);
remove_inuse(dquot);
do_destroy_dquot(dquot);
sc->nr_to_scan--;
freed++;
}
spin_unlock(&dq_list_lock);
return freed;
}
static unsigned long
dqcache_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
{
return vfs_pressure_ratio(
percpu_counter_read_positive(&dqstats.counter[DQST_FREE_DQUOTS]));
}
static struct shrinker dqcache_shrinker = {
.count_objects = dqcache_shrink_count,
.scan_objects = dqcache_shrink_scan,
.seeks = DEFAULT_SEEKS,
};
/*
* Put reference to dquot
*/
void dqput(struct dquot *dquot)
{
int ret;
if (!dquot)
return;
#ifdef CONFIG_QUOTA_DEBUG
if (!atomic_read(&dquot->dq_count)) {
quota_error(dquot->dq_sb, "trying to free free dquot of %s %d",
quotatypes[dquot->dq_id.type],
from_kqid(&init_user_ns, dquot->dq_id));
BUG();
}
#endif
dqstats_inc(DQST_DROPS);
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_active(dquot->dq_sb, dquot->dq_id.type) &&
atomic_read(&dquot->dq_count) == 1)
wake_up(&dquot_ref_wq);
spin_unlock(&dq_list_lock);
return;
}
/* Need to release dquot? */
if (dquot_dirty(dquot)) {
spin_unlock(&dq_list_lock);
/* Commit dquot before releasing */
ret = dquot->dq_sb->dq_op->write_dquot(dquot);
if (ret < 0) {
quota_error(dquot->dq_sb, "Can't write quota structure"
" (error %d). Quota may get out of sync!",
ret);
/*
* We clear dirty bit anyway, so that we avoid
* infinite loop here
*/
clear_dquot_dirty(dquot);
}
goto we_slept;
}
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 CONFIG_QUOTA_DEBUG
/* sanity check */
BUG_ON(!list_empty(&dquot->dq_free));
#endif
put_dquot_last(dquot);
spin_unlock(&dq_list_lock);
}
EXPORT_SYMBOL(dqput);
struct dquot *dquot_alloc(struct super_block *sb, int type)
{
return kmem_cache_zalloc(dquot_cachep, GFP_NOFS);
}
EXPORT_SYMBOL(dquot_alloc);
static struct dquot *get_empty_dquot(struct super_block *sb, int type)
{
struct dquot *dquot;
dquot = sb->dq_op->alloc_dquot(sb, type);
if(!dquot)
return NULL;
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);
dquot->dq_sb = sb;
dquot->dq_id = make_kqid_invalid(type);
atomic_set(&dquot->dq_count, 1);
spin_lock_init(&dquot->dq_dqb_lock);
return dquot;
}
/*
* Get reference to dquot
*
* Locking is slightly tricky here. We are guarded from parallel quotaoff()
* destroying our dquot by:
* a) checking for quota flags under dq_list_lock and
* b) getting a reference to dquot before we release dq_list_lock
*/
struct dquot *dqget(struct super_block *sb, struct kqid qid)
{
unsigned int hashent = hashfn(sb, qid);
struct dquot *dquot, *empty = NULL;
if (!qid_has_mapping(sb->s_user_ns, qid))
return ERR_PTR(-EINVAL);
if (!sb_has_quota_active(sb, qid.type))
return ERR_PTR(-ESRCH);
we_slept:
spin_lock(&dq_list_lock);
spin_lock(&dq_state_lock);
if (!sb_has_quota_active(sb, qid.type)) {
spin_unlock(&dq_state_lock);
spin_unlock(&dq_list_lock);
dquot = ERR_PTR(-ESRCH);
goto out;
}
spin_unlock(&dq_state_lock);
dquot = find_dquot(hashent, sb, qid);
if (!dquot) {
if (!empty) {
spin_unlock(&dq_list_lock);
empty = get_empty_dquot(sb, qid.type);
if (!empty)
schedule(); /* Try to wait for a moment... */
goto we_slept;
}
dquot = empty;
empty = NULL;
dquot->dq_id = qid;
/* all dquots go on the inuse_list */
put_inuse(dquot);
/* hash it first so it can be found */
insert_dquot_hash(dquot);
spin_unlock(&dq_list_lock);
dqstats_inc(DQST_LOOKUPS);
} else {
if (!atomic_read(&dquot->dq_count))
remove_free_dquot(dquot);
atomic_inc(&dquot->dq_count);
spin_unlock(&dq_list_lock);
dqstats_inc(DQST_CACHE_HITS);
dqstats_inc(DQST_LOOKUPS);
}
/* 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 / allocate space in quota file */
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
int err;
err = sb->dq_op->acquire_dquot(dquot);
if (err < 0) {
dqput(dquot);
dquot = ERR_PTR(err);
goto out;
}
}
/*
* Make sure following reads see filled structure - paired with
* smp_mb__before_atomic() in dquot_acquire().
*/
smp_rmb();
#ifdef CONFIG_QUOTA_DEBUG
BUG_ON(!dquot->dq_sb); /* Has somebody invalidated entry under us? */
#endif
out:
if (empty)
do_destroy_dquot(empty);
return dquot;
}
EXPORT_SYMBOL(dqget);
static inline struct dquot **i_dquot(struct inode *inode)
{
return inode->i_sb->s_op->get_dquots(inode);
}
static int dqinit_needed(struct inode *inode, int type)
{
struct dquot * const *dquots;
int cnt;
if (IS_NOQUOTA(inode))
return 0;
dquots = i_dquot(inode);
if (type != -1)
return !dquots[type];
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (!dquots[cnt])
return 1;
return 0;
}
/* This routine is guarded by s_umount semaphore */
static int add_dquot_ref(struct super_block *sb, int type)
{
struct inode *inode, *old_inode = NULL;
#ifdef CONFIG_QUOTA_DEBUG
int reserved = 0;
#endif
int err = 0;
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
spin_lock(&inode->i_lock);
if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
!atomic_read(&inode->i_writecount) ||
!dqinit_needed(inode, type)) {
spin_unlock(&inode->i_lock);
continue;
}
__iget(inode);
spin_unlock(&inode->i_lock);
spin_unlock(&sb->s_inode_list_lock);
#ifdef CONFIG_QUOTA_DEBUG
if (unlikely(inode_get_rsv_space(inode) > 0))
reserved = 1;
#endif
iput(old_inode);
err = __dquot_initialize(inode, type);
if (err) {
iput(inode);
goto out;
}
/*
* We hold a reference to 'inode' so it couldn't have been
* removed from s_inodes list while we dropped the
* s_inode_list_lock. We cannot iput the inode now as we can be
* holding the last reference and we cannot iput it under
* s_inode_list_lock. So we keep the reference and iput it
* later.
*/
old_inode = inode;
spin_lock(&sb->s_inode_list_lock);
}
spin_unlock(&sb->s_inode_list_lock);
iput(old_inode);
out:
#ifdef CONFIG_QUOTA_DEBUG
if (reserved) {
quota_error(sb, "Writes happened before quota was turned on "
"thus quota information is probably inconsistent. "
"Please run quotacheck(8)");
}
#endif
return err;
}
/*
* Remove references to dquots from inode and add dquot to list for freeing
* if we have the last reference to dquot
*/
static void remove_inode_dquot_ref(struct inode *inode, int type,
struct list_head *tofree_head)
{
struct dquot **dquots = i_dquot(inode);
struct dquot *dquot = dquots[type];
if (!dquot)
return;
dquots[type] = NULL;
if (list_empty(&dquot->dq_free)) {
/*
* The inode still has reference to dquot so it can't be in the
* free list
*/
spin_lock(&dq_list_lock);
list_add(&dquot->dq_free, tofree_head);
spin_unlock(&dq_list_lock);
} else {
/*
* Dquot is already in a list to put so we won't drop the last
* reference here.
*/
dqput(dquot);
}
}
/*
* Free list of dquots
* Dquots are removed from inodes and 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;
while (act_head != tofree_head) {
dquot = list_entry(act_head, struct dquot, dq_free);
act_head = act_head->next;
/* Remove dquot from the list so we won't have problems... */
list_del_init(&dquot->dq_free);
dqput(dquot);
}
}
static void remove_dquot_ref(struct super_block *sb, int type,
struct list_head *tofree_head)
{
struct inode *inode;
int reserved = 0;
spin_lock(&sb->s_inode_list_lock);
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
/*
* We have to scan also I_NEW inodes because they can already
* have quota pointer initialized. Luckily, we need to touch
* only quota pointers and these have separate locking
* (dq_data_lock).
*/
spin_lock(&dq_data_lock);
if (!IS_NOQUOTA(inode)) {
if (unlikely(inode_get_rsv_space(inode) > 0))
reserved = 1;
remove_inode_dquot_ref(inode, type, tofree_head);
}
spin_unlock(&dq_data_lock);
}
spin_unlock(&sb->s_inode_list_lock);
#ifdef CONFIG_QUOTA_DEBUG
if (reserved) {
printk(KERN_WARNING "VFS (%s): Writes happened after quota"
" was disabled thus quota information is probably "
"inconsistent. Please run quotacheck(8).\n", sb->s_id);
}
#endif
}
/* 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) {
remove_dquot_ref(sb, type, &tofree_head);
synchronize_srcu(&dquot_srcu);
put_dquot_list(&tofree_head);
}
}
static inline
void dquot_free_reserved_space(struct dquot *dquot, qsize_t number)
{
if (dquot->dq_dqb.dqb_rsvspace >= number)
dquot->dq_dqb.dqb_rsvspace -= number;
else {
WARN_ON_ONCE(1);
dquot->dq_dqb.dqb_rsvspace = 0;
}
if (dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace <=
dquot->dq_dqb.dqb_bsoftlimit)
dquot->dq_dqb.dqb_btime = (time64_t) 0;
clear_bit(DQ_BLKS_B, &dquot->dq_flags);
}
static void dquot_decr_inodes(struct dquot *dquot, qsize_t number)
{
if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
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 = (time64_t) 0;
clear_bit(DQ_INODES_B, &dquot->dq_flags);
}
static void dquot_decr_space(struct dquot *dquot, qsize_t number)
{
if (sb_dqopt(dquot->dq_sb)->flags & DQUOT_NEGATIVE_USAGE ||
dquot->dq_dqb.dqb_curspace >= number)
dquot->dq_dqb.dqb_curspace -= number;
else
dquot->dq_dqb.dqb_curspace = 0;
if (dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace <=
dquot->dq_dqb.dqb_bsoftlimit)
dquot->dq_dqb.dqb_btime = (time64_t) 0;
clear_bit(DQ_BLKS_B, &dquot->dq_flags);
}
struct dquot_warn {
struct super_block *w_sb;
struct kqid w_dq_id;
short w_type;
};
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 int need_print_warning(struct dquot_warn *warn)
{
if (!flag_print_warnings)
return 0;
switch (warn->w_dq_id.type) {
case USRQUOTA:
return uid_eq(current_fsuid(), warn->w_dq_id.uid);
case GRPQUOTA:
return in_group_p(warn->w_dq_id.gid);
case PRJQUOTA:
return 1;
}
return 0;
}
/* Print warning to user which exceeded quota */
static void print_warning(struct dquot_warn *warn)
{
char *msg = NULL;
struct tty_struct *tty;
int warntype = warn->w_type;
if (warntype == QUOTA_NL_IHARDBELOW ||
warntype == QUOTA_NL_ISOFTBELOW ||
warntype == QUOTA_NL_BHARDBELOW ||
warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(warn))
return;
tty = get_current_tty();
if (!tty)
return;
tty_write_message(tty, warn->w_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[warn->w_dq_id.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);
tty_kref_put(tty);
}
#endif
static void prepare_warning(struct dquot_warn *warn, struct dquot *dquot,
int warntype)
{
if (warning_issued(dquot, warntype))
return;
warn->w_type = warntype;
warn->w_sb = dquot->dq_sb;
warn->w_dq_id = dquot->dq_id;
}
/*
* Write warnings to the console and send warning messages over netlink.
*
* Note that this function can call into tty and networking code.
*/
static void flush_warnings(struct dquot_warn *warn)
{
int i;
for (i = 0; i < MAXQUOTAS; i++) {
if (warn[i].w_type == QUOTA_NL_NOWARN)
continue;
#ifdef CONFIG_PRINT_QUOTA_WARNING
print_warning(&warn[i]);
#endif
quota_send_warning(warn[i].w_dq_id,
warn[i].w_sb->s_dev, warn[i].w_type);
}
}
static int ignore_hardlimit(struct dquot *dquot)
{
struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
return capable(CAP_SYS_RESOURCE) &&
(info->dqi_format->qf_fmt_id != QFMT_VFS_OLD ||
!(info->dqi_flags & DQF_ROOT_SQUASH));
}
static int dquot_add_inodes(struct dquot *dquot, qsize_t inodes,
struct dquot_warn *warn)
{
qsize_t newinodes;
int ret = 0;
spin_lock(&dquot->dq_dqb_lock);
newinodes = dquot->dq_dqb.dqb_curinodes + inodes;
if (!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type) ||
test_bit(DQ_FAKE_B, &dquot->dq_flags))
goto add;
if (dquot->dq_dqb.dqb_ihardlimit &&
newinodes > dquot->dq_dqb.dqb_ihardlimit &&
!ignore_hardlimit(dquot)) {
prepare_warning(warn, dquot, QUOTA_NL_IHARDWARN);
ret = -EDQUOT;
goto out;
}
if (dquot->dq_dqb.dqb_isoftlimit &&
newinodes > dquot->dq_dqb.dqb_isoftlimit &&
dquot->dq_dqb.dqb_itime &&
ktime_get_real_seconds() >= dquot->dq_dqb.dqb_itime &&
!ignore_hardlimit(dquot)) {
prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN);
ret = -EDQUOT;
goto out;
}
if (dquot->dq_dqb.dqb_isoftlimit &&
newinodes > dquot->dq_dqb.dqb_isoftlimit &&
dquot->dq_dqb.dqb_itime == 0) {
prepare_warning(warn, dquot, QUOTA_NL_ISOFTWARN);
dquot->dq_dqb.dqb_itime = ktime_get_real_seconds() +
sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type].dqi_igrace;
}
add:
dquot->dq_dqb.dqb_curinodes = newinodes;
out:
spin_unlock(&dquot->dq_dqb_lock);
return ret;
}
static int dquot_add_space(struct dquot *dquot, qsize_t space,
qsize_t rsv_space, unsigned int flags,
struct dquot_warn *warn)
{
qsize_t tspace;
struct super_block *sb = dquot->dq_sb;
int ret = 0;
spin_lock(&dquot->dq_dqb_lock);
if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.type) ||
test_bit(DQ_FAKE_B, &dquot->dq_flags))
goto finish;
tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace
+ space + rsv_space;
if (dquot->dq_dqb.dqb_bhardlimit &&
tspace > dquot->dq_dqb.dqb_bhardlimit &&
!ignore_hardlimit(dquot)) {
if (flags & DQUOT_SPACE_WARN)
prepare_warning(warn, dquot, QUOTA_NL_BHARDWARN);
ret = -EDQUOT;
goto finish;
}
if (dquot->dq_dqb.dqb_bsoftlimit &&
tspace > dquot->dq_dqb.dqb_bsoftlimit &&
dquot->dq_dqb.dqb_btime &&
ktime_get_real_seconds() >= dquot->dq_dqb.dqb_btime &&
!ignore_hardlimit(dquot)) {
if (flags & DQUOT_SPACE_WARN)
prepare_warning(warn, dquot, QUOTA_NL_BSOFTLONGWARN);
ret = -EDQUOT;
goto finish;
}
if (dquot->dq_dqb.dqb_bsoftlimit &&
tspace > dquot->dq_dqb.dqb_bsoftlimit &&
dquot->dq_dqb.dqb_btime == 0) {
if (flags & DQUOT_SPACE_WARN) {
prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN);
dquot->dq_dqb.dqb_btime = ktime_get_real_seconds() +
sb_dqopt(sb)->info[dquot->dq_id.type].dqi_bgrace;
} else {
/*
* We don't allow preallocation to exceed softlimit so exceeding will
* be always printed
*/
ret = -EDQUOT;
goto finish;
}
}
finish:
/*
* We have to be careful and go through warning generation & grace time
* setting even if DQUOT_SPACE_NOFAIL is set. That's why we check it
* only here...
*/
if (flags & DQUOT_SPACE_NOFAIL)
ret = 0;
if (!ret) {
dquot->dq_dqb.dqb_rsvspace += rsv_space;
dquot->dq_dqb.dqb_curspace += space;
}
spin_unlock(&dquot->dq_dqb_lock);
return ret;
}
static int info_idq_free(struct dquot *dquot, qsize_t inodes)
{
qsize_t newinodes;
if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit ||
!sb_has_quota_limits_enabled(dquot->dq_sb, dquot->dq_id.type))
return QUOTA_NL_NOWARN;
newinodes = dquot->dq_dqb.dqb_curinodes - inodes;
if (newinodes <= dquot->dq_dqb.dqb_isoftlimit)
return QUOTA_NL_ISOFTBELOW;
if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
newinodes < dquot->dq_dqb.dqb_ihardlimit)
return QUOTA_NL_IHARDBELOW;
return QUOTA_NL_NOWARN;
}
static int info_bdq_free(struct dquot *dquot, qsize_t space)
{
qsize_t tspace;
tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace;
if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
tspace <= dquot->dq_dqb.dqb_bsoftlimit)
return QUOTA_NL_NOWARN;
if (tspace - space <= dquot->dq_dqb.dqb_bsoftlimit)
return QUOTA_NL_BSOFTBELOW;
if (tspace >= dquot->dq_dqb.dqb_bhardlimit &&
tspace - space < dquot->dq_dqb.dqb_bhardlimit)
return QUOTA_NL_BHARDBELOW;
return QUOTA_NL_NOWARN;
}
static int dquot_active(const struct inode *inode)
{
struct super_block *sb = inode->i_sb;
if (IS_NOQUOTA(inode))
return 0;
return sb_any_quota_loaded(sb) & ~sb_any_quota_suspended(sb);
}
/*
* Initialize quota pointers in inode
*
* It is better to call this function outside of any transaction as it
* might need a lot of space in journal for dquot structure allocation.
*/
static int __dquot_initialize(struct inode *inode, int type)
{
int cnt, init_needed = 0;
struct dquot **dquots, *got[MAXQUOTAS] = {};
struct super_block *sb = inode->i_sb;
qsize_t rsv;
int ret = 0;
if (!dquot_active(inode))
return 0;
dquots = i_dquot(inode);
/* First get references to structures we might need. */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
struct kqid qid;
kprojid_t projid;
int rc;
struct dquot *dquot;
if (type != -1 && cnt != type)
continue;
/*
* The i_dquot should have been initialized in most cases,
* we check it without locking here to avoid unnecessary
* dqget()/dqput() calls.
*/
if (dquots[cnt])
continue;
if (!sb_has_quota_active(sb, cnt))
continue;
init_needed = 1;
switch (cnt) {
case USRQUOTA:
qid = make_kqid_uid(inode->i_uid);
break;
case GRPQUOTA:
qid = make_kqid_gid(inode->i_gid);
break;
case PRJQUOTA:
rc = inode->i_sb->dq_op->get_projid(inode, &projid);
if (rc)
continue;
qid = make_kqid_projid(projid);
break;
}
dquot = dqget(sb, qid);
if (IS_ERR(dquot)) {
/* We raced with somebody turning quotas off... */
if (PTR_ERR(dquot) != -ESRCH) {
ret = PTR_ERR(dquot);
goto out_put;
}
dquot = NULL;
}
got[cnt] = dquot;
}
/* All required i_dquot has been initialized */
if (!init_needed)
return 0;
spin_lock(&dq_data_lock);
if (IS_NOQUOTA(inode))
goto out_lock;
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
/* Avoid races with quotaoff() */
if (!sb_has_quota_active(sb, cnt))
continue;
/* We could race with quotaon or dqget() could have failed */
if (!got[cnt])
continue;
if (!dquots[cnt]) {
dquots[cnt] = got[cnt];
got[cnt] = NULL;
/*
* Make quota reservation system happy if someone
* did a write before quota was turned on
*/
rsv = inode_get_rsv_space(inode);
if (unlikely(rsv)) {
spin_lock(&inode->i_lock);
/* Get reservation again under proper lock */
rsv = __inode_get_rsv_space(inode);
spin_lock(&dquots[cnt]->dq_dqb_lock);
dquots[cnt]->dq_dqb.dqb_rsvspace += rsv;
spin_unlock(&dquots[cnt]->dq_dqb_lock);
spin_unlock(&inode->i_lock);
}
}
}
out_lock:
spin_unlock(&dq_data_lock);
out_put:
/* Drop unused references */
dqput_all(got);
return ret;
}
int dquot_initialize(struct inode *inode)
{
return __dquot_initialize(inode, -1);
}
EXPORT_SYMBOL(dquot_initialize);
bool dquot_initialize_needed(struct inode *inode)
{
struct dquot **dquots;
int i;
if (!dquot_active(inode))
return false;
dquots = i_dquot(inode);
for (i = 0; i < MAXQUOTAS; i++)
if (!dquots[i] && sb_has_quota_active(inode->i_sb, i))
return true;
return false;
}
EXPORT_SYMBOL(dquot_initialize_needed);
/*
* Release all quotas referenced by inode.
*
* This function only be called on inode free or converting
* a file to quota file, no other users for the i_dquot in
* both cases, so we needn't call synchronize_srcu() after
* clearing i_dquot.
*/
static void __dquot_drop(struct inode *inode)
{
int cnt;
struct dquot **dquots = i_dquot(inode);
struct dquot *put[MAXQUOTAS];
spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
put[cnt] = dquots[cnt];
dquots[cnt] = NULL;
}
spin_unlock(&dq_data_lock);
dqput_all(put);
}
void dquot_drop(struct inode *inode)
{
struct dquot * const *dquots;
int cnt;
if (IS_NOQUOTA(inode))
return;
/*
* Test before calling to rule out calls from proc and such
* where we are not allowed to block. Note that this is
* actually reliable test even without the lock - the caller
* must assure that nobody can come after the DQUOT_DROP and
* add quota pointers back anyway.
*/
dquots = i_dquot(inode);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (dquots[cnt])
break;
}
if (cnt < MAXQUOTAS)
__dquot_drop(inode);
}
EXPORT_SYMBOL(dquot_drop);
/*
* inode_reserved_space is managed internally by quota, and protected by
* i_lock similar to i_blocks+i_bytes.
*/
static qsize_t *inode_reserved_space(struct inode * inode)
{
/* Filesystem must explicitly define it's own method in order to use
* quota reservation interface */
BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
return inode->i_sb->dq_op->get_reserved_space(inode);
}
static qsize_t __inode_get_rsv_space(struct inode *inode)
{
if (!inode->i_sb->dq_op->get_reserved_space)
return 0;
return *inode_reserved_space(inode);
}
static qsize_t inode_get_rsv_space(struct inode *inode)
{
qsize_t ret;
if (!inode->i_sb->dq_op->get_reserved_space)
return 0;
spin_lock(&inode->i_lock);
ret = __inode_get_rsv_space(inode);
spin_unlock(&inode->i_lock);
return ret;
}
/*
* This functions updates 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 helpers 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 flags)
{
int cnt, ret = 0, index;
struct dquot_warn warn[MAXQUOTAS];
int reserve = flags & DQUOT_SPACE_RESERVE;
struct dquot **dquots;
if (!dquot_active(inode)) {
if (reserve) {
spin_lock(&inode->i_lock);
*inode_reserved_space(inode) += number;
spin_unlock(&inode->i_lock);
} else {
inode_add_bytes(inode, number);
}
goto out;
}
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
warn[cnt].w_type = QUOTA_NL_NOWARN;
dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&inode->i_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (!dquots[cnt])
continue;
if (flags & DQUOT_SPACE_RESERVE) {
ret = dquot_add_space(dquots[cnt], 0, number, flags,
&warn[cnt]);
} else {
ret = dquot_add_space(dquots[cnt], number, 0, flags,
&warn[cnt]);
}
if (ret) {
/* Back out changes we already did */
for (cnt--; cnt >= 0; cnt--) {
if (!dquots[cnt])
continue;
spin_lock(&dquots[cnt]->dq_dqb_lock);
if (flags & DQUOT_SPACE_RESERVE) {
dquots[cnt]->dq_dqb.dqb_rsvspace -=
number;
} else {
dquots[cnt]->dq_dqb.dqb_curspace -=
number;
}
spin_unlock(&dquots[cnt]->dq_dqb_lock);
}
spin_unlock(&inode->i_lock);
goto out_flush_warn;
}
}
if (reserve)
*inode_reserved_space(inode) += number;
else
__inode_add_bytes(inode, number);
spin_unlock(&inode->i_lock);
if (reserve)
goto out_flush_warn;
mark_all_dquot_dirty(dquots);
out_flush_warn:
srcu_read_unlock(&dquot_srcu, index);
flush_warnings(warn);
out:
return ret;
}
EXPORT_SYMBOL(__dquot_alloc_space);
/*
* This operation can block, but only after everything is updated
*/
int dquot_alloc_inode(struct inode *inode)
{
int cnt, ret = 0, index;
struct dquot_warn warn[MAXQUOTAS];
struct dquot * const *dquots;
if (!dquot_active(inode))
return 0;
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
warn[cnt].w_type = QUOTA_NL_NOWARN;
dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&inode->i_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (!dquots[cnt])
continue;
ret = dquot_add_inodes(dquots[cnt], 1, &warn[cnt]);
if (ret) {
for (cnt--; cnt >= 0; cnt--) {
if (!dquots[cnt])
continue;
/* Back out changes we already did */
spin_lock(&dquots[cnt]->dq_dqb_lock);
dquots[cnt]->dq_dqb.dqb_curinodes--;
spin_unlock(&dquots[cnt]->dq_dqb_lock);
}
goto warn_put_all;
}
}
warn_put_all:
spin_unlock(&inode->i_lock);
if (ret == 0)
mark_all_dquot_dirty(dquots);
srcu_read_unlock(&dquot_srcu, index);
flush_warnings(warn);
return ret;
}
EXPORT_SYMBOL(dquot_alloc_inode);
/*
* Convert in-memory reserved quotas to real consumed quotas
*/
int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
{
struct dquot **dquots;
int cnt, index;
if (!dquot_active(inode)) {
spin_lock(&inode->i_lock);
*inode_reserved_space(inode) -= number;
__inode_add_bytes(inode, number);
spin_unlock(&inode->i_lock);
return 0;
}
dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&inode->i_lock);
/* Claim reserved quotas to allocated quotas */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (dquots[cnt]) {
struct dquot *dquot = dquots[cnt];
spin_lock(&dquot->dq_dqb_lock);
if (WARN_ON_ONCE(dquot->dq_dqb.dqb_rsvspace < number))
number = dquot->dq_dqb.dqb_rsvspace;
dquot->dq_dqb.dqb_curspace += number;
dquot->dq_dqb.dqb_rsvspace -= number;
spin_unlock(&dquot->dq_dqb_lock);
}
}
/* Update inode bytes */
*inode_reserved_space(inode) -= number;
__inode_add_bytes(inode, number);
spin_unlock(&inode->i_lock);
mark_all_dquot_dirty(dquots);
srcu_read_unlock(&dquot_srcu, index);
return 0;
}
EXPORT_SYMBOL(dquot_claim_space_nodirty);
/*
* Convert allocated space back to in-memory reserved quotas
*/
void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
{
struct dquot **dquots;
int cnt, index;
if (!dquot_active(inode)) {
spin_lock(&inode->i_lock);
*inode_reserved_space(inode) += number;
__inode_sub_bytes(inode, number);
spin_unlock(&inode->i_lock);
return;
}
dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&inode->i_lock);
/* Claim reserved quotas to allocated quotas */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (dquots[cnt]) {
struct dquot *dquot = dquots[cnt];
spin_lock(&dquot->dq_dqb_lock);
if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number))
number = dquot->dq_dqb.dqb_curspace;
dquot->dq_dqb.dqb_rsvspace += number;
dquot->dq_dqb.dqb_curspace -= number;
spin_unlock(&dquot->dq_dqb_lock);
}
}
/* Update inode bytes */
*inode_reserved_space(inode) += number;
__inode_sub_bytes(inode, number);
spin_unlock(&inode->i_lock);
mark_all_dquot_dirty(dquots);
srcu_read_unlock(&dquot_srcu, index);
return;
}
EXPORT_SYMBOL(dquot_reclaim_space_nodirty);
/*
* This operation can block, but only after everything is updated
*/
void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
{
unsigned int cnt;
struct dquot_warn warn[MAXQUOTAS];
struct dquot **dquots;
int reserve = flags & DQUOT_SPACE_RESERVE, index;
if (!dquot_active(inode)) {
if (reserve) {
spin_lock(&inode->i_lock);
*inode_reserved_space(inode) -= number;
spin_unlock(&inode->i_lock);
} else {
inode_sub_bytes(inode, number);
}
return;
}
dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&inode->i_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
int wtype;
warn[cnt].w_type = QUOTA_NL_NOWARN;
if (!dquots[cnt])
continue;
spin_lock(&dquots[cnt]->dq_dqb_lock);
wtype = info_bdq_free(dquots[cnt], number);
if (wtype != QUOTA_NL_NOWARN)
prepare_warning(&warn[cnt], dquots[cnt], wtype);
if (reserve)
dquot_free_reserved_space(dquots[cnt], number);
else
dquot_decr_space(dquots[cnt], number);
spin_unlock(&dquots[cnt]->dq_dqb_lock);
}
if (reserve)
*inode_reserved_space(inode) -= number;
else
__inode_sub_bytes(inode, number);
spin_unlock(&inode->i_lock);
if (reserve)
goto out_unlock;
mark_all_dquot_dirty(dquots);
out_unlock:
srcu_read_unlock(&dquot_srcu, index);
flush_warnings(warn);
}
EXPORT_SYMBOL(__dquot_free_space);
/*
* This operation can block, but only after everything is updated
*/
void dquot_free_inode(struct inode *inode)
{
unsigned int cnt;
struct dquot_warn warn[MAXQUOTAS];
struct dquot * const *dquots;
int index;
if (!dquot_active(inode))
return;
dquots = i_dquot(inode);
index = srcu_read_lock(&dquot_srcu);
spin_lock(&inode->i_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
int wtype;
warn[cnt].w_type = QUOTA_NL_NOWARN;
if (!dquots[cnt])
continue;
spin_lock(&dquots[cnt]->dq_dqb_lock);
wtype = info_idq_free(dquots[cnt], 1);
if (wtype != QUOTA_NL_NOWARN)
prepare_warning(&warn[cnt], dquots[cnt], wtype);
dquot_decr_inodes(dquots[cnt], 1);
spin_unlock(&dquots[cnt]->dq_dqb_lock);
}
spin_unlock(&inode->i_lock);
mark_all_dquot_dirty(dquots);
srcu_read_unlock(&dquot_srcu, index);
flush_warnings(warn);
}
EXPORT_SYMBOL(dquot_free_inode);
/*
* Transfer the number of inode and blocks from one diskquota to an other.
* On success, dquot references in transfer_to are consumed and references
* to original dquots that need to be released are placed there. On failure,
* references are kept untouched.
*
* This operation can block, but only after everything is updated
* A transaction must be started when entering this function.
*
* We are holding reference on transfer_from & transfer_to, no need to
* protect them by srcu_read_lock().
*/
int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
{
qsize_t cur_space;
qsize_t rsv_space = 0;
qsize_t inode_usage = 1;
struct dquot *transfer_from[MAXQUOTAS] = {};
int cnt, ret = 0;
char is_valid[MAXQUOTAS] = {};
struct dquot_warn warn_to[MAXQUOTAS];
struct dquot_warn warn_from_inodes[MAXQUOTAS];
struct dquot_warn warn_from_space[MAXQUOTAS];
if (IS_NOQUOTA(inode))
return 0;
if (inode->i_sb->dq_op->get_inode_usage) {
ret = inode->i_sb->dq_op->get_inode_usage(inode, &inode_usage);
if (ret)
return ret;
}
/* Initialize the arrays */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
warn_to[cnt].w_type = QUOTA_NL_NOWARN;
warn_from_inodes[cnt].w_type = QUOTA_NL_NOWARN;
warn_from_space[cnt].w_type = QUOTA_NL_NOWARN;
}
spin_lock(&dq_data_lock);
spin_lock(&inode->i_lock);
if (IS_NOQUOTA(inode)) { /* File without quota accounting? */
spin_unlock(&inode->i_lock);
spin_unlock(&dq_data_lock);
return 0;
}
cur_space = __inode_get_bytes(inode);
rsv_space = __inode_get_rsv_space(inode);
/*
* Build the transfer_from list, check limits, and update usage in
* the target structures.
*/
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
/*
* Skip changes for same uid or gid or for turned off quota-type.
*/
if (!transfer_to[cnt])
continue;
/* Avoid races with quotaoff() */
if (!sb_has_quota_active(inode->i_sb, cnt))
continue;
is_valid[cnt] = 1;
transfer_from[cnt] = i_dquot(inode)[cnt];
ret = dquot_add_inodes(transfer_to[cnt], inode_usage,
&warn_to[cnt]);
if (ret)
goto over_quota;
ret = dquot_add_space(transfer_to[cnt], cur_space, rsv_space, 0,
&warn_to[cnt]);
if (ret) {
spin_lock(&transfer_to[cnt]->dq_dqb_lock);
dquot_decr_inodes(transfer_to[cnt], inode_usage);
spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
goto over_quota;
}
}
/* Decrease usage for source structures and update quota pointers */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (!is_valid[cnt])
continue;
/* Due to IO error we might not have transfer_from[] structure */
if (transfer_from[cnt]) {
int wtype;
spin_lock(&transfer_from[cnt]->dq_dqb_lock);
wtype = info_idq_free(transfer_from[cnt], inode_usage);
if (wtype != QUOTA_NL_NOWARN)
prepare_warning(&warn_from_inodes[cnt],
transfer_from[cnt], wtype);
wtype = info_bdq_free(transfer_from[cnt],
cur_space + rsv_space);
if (wtype != QUOTA_NL_NOWARN)
prepare_warning(&warn_from_space[cnt],
transfer_from[cnt], wtype);
dquot_decr_inodes(transfer_from[cnt], inode_usage);
dquot_decr_space(transfer_from[cnt], cur_space);
dquot_free_reserved_space(transfer_from[cnt],
rsv_space);
spin_unlock(&transfer_from[cnt]->dq_dqb_lock);
}
i_dquot(inode)[cnt] = transfer_to[cnt];
}
spin_unlock(&inode->i_lock);
spin_unlock(&dq_data_lock);
mark_all_dquot_dirty(transfer_from);
mark_all_dquot_dirty(transfer_to);
flush_warnings(warn_to);
flush_warnings(warn_from_inodes);
flush_warnings(warn_from_space);
/* Pass back references to put */
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (is_valid[cnt])
transfer_to[cnt] = transfer_from[cnt];
return 0;
over_quota:
/* Back out changes we already did */
for (cnt--; cnt >= 0; cnt--) {
if (!is_valid[cnt])
continue;
spin_lock(&transfer_to[cnt]->dq_dqb_lock);
dquot_decr_inodes(transfer_to[cnt], inode_usage);
dquot_decr_space(transfer_to[cnt], cur_space);
dquot_free_reserved_space(transfer_to[cnt], rsv_space);
spin_unlock(&transfer_to[cnt]->dq_dqb_lock);
}
spin_unlock(&inode->i_lock);
spin_unlock(&dq_data_lock);
flush_warnings(warn_to);
return ret;
}
EXPORT_SYMBOL(__dquot_transfer);
/* Wrapper for transferring ownership of an inode for uid/gid only
* Called from FSXXX_setattr()
*/
int dquot_transfer(struct inode *inode, struct iattr *iattr)
{
struct dquot *transfer_to[MAXQUOTAS] = {};
struct dquot *dquot;
struct super_block *sb = inode->i_sb;
int ret;
if (!dquot_active(inode))
return 0;
if (iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)){
dquot = dqget(sb, make_kqid_uid(iattr->ia_uid));
if (IS_ERR(dquot)) {
if (PTR_ERR(dquot) != -ESRCH) {
ret = PTR_ERR(dquot);
goto out_put;
}
dquot = NULL;
}
transfer_to[USRQUOTA] = dquot;
}
if (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid)){
dquot = dqget(sb, make_kqid_gid(iattr->ia_gid));
if (IS_ERR(dquot)) {
if (PTR_ERR(dquot) != -ESRCH) {
ret = PTR_ERR(dquot);
goto out_put;
}
dquot = NULL;
}
transfer_to[GRPQUOTA] = dquot;
}
ret = __dquot_transfer(inode, transfer_to);
out_put:
dqput_all(transfer_to);
return ret;
}
EXPORT_SYMBOL(dquot_transfer);
/*
* Write info of quota file to disk
*/
int dquot_commit_info(struct super_block *sb, int type)
{
struct quota_info *dqopt = sb_dqopt(sb);
return dqopt->ops[type]->write_file_info(sb, type);
}
EXPORT_SYMBOL(dquot_commit_info);
int dquot_get_next_id(struct super_block *sb, struct kqid *qid)
{
struct quota_info *dqopt = sb_dqopt(sb);
if (!sb_has_quota_active(sb, qid->type))
return -ESRCH;
if (!dqopt->ops[qid->type]->get_next_id)
return -ENOSYS;
return dqopt->ops[qid->type]->get_next_id(sb, qid);
}
EXPORT_SYMBOL(dquot_get_next_id);
/*
* Definitions of diskquota operations.
*/
const struct dquot_operations dquot_operations = {
.write_dquot = dquot_commit,
.acquire_dquot = dquot_acquire,
.release_dquot = dquot_release,
.mark_dirty = dquot_mark_dquot_dirty,
.write_info = dquot_commit_info,
.alloc_dquot = dquot_alloc,
.destroy_dquot = dquot_destroy,
.get_next_id = dquot_get_next_id,
};
EXPORT_SYMBOL(dquot_operations);
/*
* Generic helper for ->open on filesystems supporting disk quotas.
*/
int dquot_file_open(struct inode *inode, struct file *file)
{
int error;
error = generic_file_open(inode, file);
if (!error && (file->f_mode & FMODE_WRITE))
error = dquot_initialize(inode);
return error;
}
EXPORT_SYMBOL(dquot_file_open);
/*
* Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
*/
int dquot_disable(struct super_block *sb, int type, unsigned int flags)
{
int cnt, ret = 0;
struct quota_info *dqopt = sb_dqopt(sb);
struct inode *toputinode[MAXQUOTAS];
/* s_umount should be held in exclusive mode */
if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
up_read(&sb->s_umount);
/* Cannot turn off usage accounting without turning off limits, or
* suspend quotas and simultaneously turn quotas off. */
if ((flags & DQUOT_USAGE_ENABLED && !(flags & DQUOT_LIMITS_ENABLED))
|| (flags & DQUOT_SUSPENDED && flags & (DQUOT_LIMITS_ENABLED |
DQUOT_USAGE_ENABLED)))
return -EINVAL;
/*
* Skip everything if there's nothing to do. We have to do this because
* sometimes we are called when fill_super() failed and calling
* sync_fs() in such cases does no good.
*/
if (!sb_any_quota_loaded(sb))
return 0;
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
toputinode[cnt] = NULL;
if (type != -1 && cnt != type)
continue;
if (!sb_has_quota_loaded(sb, cnt))
continue;
if (flags & DQUOT_SUSPENDED) {
spin_lock(&dq_state_lock);
dqopt->flags |=
dquot_state_flag(DQUOT_SUSPENDED, cnt);
spin_unlock(&dq_state_lock);
} else {
spin_lock(&dq_state_lock);
dqopt->flags &= ~dquot_state_flag(flags, cnt);
/* Turning off suspended quotas? */
if (!sb_has_quota_loaded(sb, cnt) &&
sb_has_quota_suspended(sb, cnt)) {
dqopt->flags &= ~dquot_state_flag(
DQUOT_SUSPENDED, cnt);
spin_unlock(&dq_state_lock);
iput(dqopt->files[cnt]);
dqopt->files[cnt] = NULL;
continue;
}
spin_unlock(&dq_state_lock);
}
/* We still have to keep quota loaded? */
if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED))
continue;
/* 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];
if (!sb_has_quota_loaded(sb, 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;
}
/* Skip syncing and setting flags if quota files are hidden */
if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
goto put_inodes;
/* 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++)
/* This can happen when suspending quotas on remount-ro... */
if (toputinode[cnt] && !sb_has_quota_loaded(sb, cnt)) {
inode_lock(toputinode[cnt]);
toputinode[cnt]->i_flags &= ~S_NOQUOTA;
truncate_inode_pages(&toputinode[cnt]->i_data, 0);
inode_unlock(toputinode[cnt]);
mark_inode_dirty_sync(toputinode[cnt]);
}
if (sb->s_bdev)
invalidate_bdev(sb->s_bdev);
put_inodes:
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (toputinode[cnt]) {
/* On remount RO, we keep the inode pointer so that we
* can reenable quota on the subsequent remount RW. We
* have to check 'flags' variable and not use sb_has_
* function because another quotaon / quotaoff could
* change global state before we got here. We refuse
* to suspend quotas when there is pending delete on
* the quota file... */
if (!(flags & DQUOT_SUSPENDED))
iput(toputinode[cnt]);
else if (!toputinode[cnt]->i_nlink)
ret = -EBUSY;
}
return ret;
}
EXPORT_SYMBOL(dquot_disable);
int dquot_quota_off(struct super_block *sb, int type)
{
return dquot_disable(sb, type,
DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
}
EXPORT_SYMBOL(dquot_quota_off);
/*
* Turn quotas on on a device
*/
/*
* Helper function to turn quotas on when we already have the inode of
* quota file and no quota information is loaded.
*/
static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
unsigned int flags)
{
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;
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 ||
(type == PRJQUOTA && sb->dq_op->get_projid == NULL)) {
error = -EINVAL;
goto out_fmt;
}
/* Filesystems outside of init_user_ns not yet supported */
if (sb->s_user_ns != &init_user_ns) {
error = -EINVAL;
goto out_fmt;
}
/* Usage always has to be set... */
if (!(flags & DQUOT_USAGE_ENABLED)) {
error = -EINVAL;
goto out_fmt;
}
if (sb_has_quota_loaded(sb, type)) {
error = -EBUSY;
goto out_fmt;
}
if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
/* As we bypass the pagecache we must now flush all the
* dirty data and invalidate caches so that kernel sees
* changes from userspace. It is not enough to just flush
* the quota file since if blocksize < pagesize, invalidation
* of the cache could fail because of other unrelated dirty
* data */
sync_filesystem(sb);
invalidate_bdev(sb->s_bdev);
}
if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
/* 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. */
inode_lock(inode);
inode->i_flags |= S_NOQUOTA;
inode_unlock(inode);
/*
* When S_NOQUOTA is set, remove dquot references as no more
* references can be added
*/
__dquot_drop(inode);
}
error = -EIO;
dqopt->files[type] = igrab(inode);
if (!dqopt->files[type])
goto out_file_flags;
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;
dqopt->info[type].dqi_fmt_id = format_id;
INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
error = dqopt->ops[type]->read_file_info(sb, type);
if (error < 0)
goto out_file_init;
if (dqopt->flags & DQUOT_QUOTA_SYS_FILE) {
spin_lock(&dq_data_lock);
dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
spin_unlock(&dq_data_lock);
}
spin_lock(&dq_state_lock);
dqopt->flags |= dquot_state_flag(flags, type);
spin_unlock(&dq_state_lock);
error = add_dquot_ref(sb, type);
if (error)
dquot_disable(sb, type, flags);
return error;
out_file_init:
dqopt->files[type] = NULL;
iput(inode);
out_file_flags:
inode_lock(inode);
inode->i_flags &= ~S_NOQUOTA;
inode_unlock(inode);
out_fmt:
put_quota_format(fmt);
return error;
}
/* Reenable quotas on remount RW */
int dquot_resume(struct super_block *sb, int type)
{
struct quota_info *dqopt = sb_dqopt(sb);
struct inode *inode;
int ret = 0, cnt;
unsigned int flags;
/* s_umount should be held in exclusive mode */
if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
up_read(&sb->s_umount);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
if (!sb_has_quota_suspended(sb, cnt))
continue;
inode = dqopt->files[cnt];
dqopt->files[cnt] = NULL;
spin_lock(&dq_state_lock);
flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED |
DQUOT_LIMITS_ENABLED,
cnt);
dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt);
spin_unlock(&dq_state_lock);
flags = dquot_generic_flag(flags, cnt);
ret = vfs_load_quota_inode(inode, cnt,
dqopt->info[cnt].dqi_fmt_id, flags);
iput(inode);
}
return ret;
}
EXPORT_SYMBOL(dquot_resume);
int dquot_quota_on(struct super_block *sb, int type, int format_id,
const struct path *path)
{
int error = security_quota_on(path->dentry);
if (error)
return error;
/* Quota file not on the same filesystem? */
if (path->dentry->d_sb != sb)
error = -EXDEV;
else
error = vfs_load_quota_inode(d_inode(path->dentry), type,
format_id, DQUOT_USAGE_ENABLED |
DQUOT_LIMITS_ENABLED);
return error;
}
EXPORT_SYMBOL(dquot_quota_on);
/*
* More powerful function for turning on quotas allowing setting
* of individual quota flags
*/
int dquot_enable(struct inode *inode, int type, int format_id,
unsigned int flags)
{
struct super_block *sb = inode->i_sb;
/* Just unsuspend quotas? */
BUG_ON(flags & DQUOT_SUSPENDED);
/* s_umount should be held in exclusive mode */
if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
up_read(&sb->s_umount);
if (!flags)
return 0;
/* Just updating flags needed? */
if (sb_has_quota_loaded(sb, type)) {
if (flags & DQUOT_USAGE_ENABLED &&
sb_has_quota_usage_enabled(sb, type))
return -EBUSY;
if (flags & DQUOT_LIMITS_ENABLED &&
sb_has_quota_limits_enabled(sb, type))
return -EBUSY;
spin_lock(&dq_state_lock);
sb_dqopt(sb)->flags |= dquot_state_flag(flags, type);
spin_unlock(&dq_state_lock);
return 0;
}
return vfs_load_quota_inode(inode, type, format_id, flags);
}
EXPORT_SYMBOL(dquot_enable);
/*
* This function is used when filesystem needs to initialize quotas
* during mount time.
*/
int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
int format_id, int type)
{
struct dentry *dentry;
int error;
dentry = lookup_one_len_unlocked(qf_name, sb->s_root, strlen(qf_name));
if (IS_ERR(dentry))
return PTR_ERR(dentry);
if (d_really_is_negative(dentry)) {
error = -ENOENT;
goto out;
}
error = security_quota_on(dentry);
if (!error)
error = vfs_load_quota_inode(d_inode(dentry), type, format_id,
DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
out:
dput(dentry);
return error;
}
EXPORT_SYMBOL(dquot_quota_on_mount);
static int dquot_quota_enable(struct super_block *sb, unsigned int flags)
{
int ret;
int type;
struct quota_info *dqopt = sb_dqopt(sb);
if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
return -ENOSYS;
/* Accounting cannot be turned on while fs is mounted */
flags &= ~(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT);
if (!flags)
return -EINVAL;
for (type = 0; type < MAXQUOTAS; type++) {
if (!(flags & qtype_enforce_flag(type)))
continue;
/* Can't enforce without accounting */
if (!sb_has_quota_usage_enabled(sb, type))
return -EINVAL;
ret = dquot_enable(dqopt->files[type], type,
dqopt->info[type].dqi_fmt_id,
DQUOT_LIMITS_ENABLED);
if (ret < 0)
goto out_err;
}
return 0;
out_err:
/* Backout enforcement enablement we already did */
for (type--; type >= 0; type--) {
if (flags & qtype_enforce_flag(type))
dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
}
/* Error code translation for better compatibility with XFS */
if (ret == -EBUSY)
ret = -EEXIST;
return ret;
}
static int dquot_quota_disable(struct super_block *sb, unsigned int flags)
{
int ret;
int type;
struct quota_info *dqopt = sb_dqopt(sb);
if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
return -ENOSYS;
/*
* We don't support turning off accounting via quotactl. In principle
* quota infrastructure can do this but filesystems don't expect
* userspace to be able to do it.
*/
if (flags &
(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT))
return -EOPNOTSUPP;
/* Filter out limits not enabled */
for (type = 0; type < MAXQUOTAS; type++)
if (!sb_has_quota_limits_enabled(sb, type))
flags &= ~qtype_enforce_flag(type);
/* Nothing left? */
if (!flags)
return -EEXIST;
for (type = 0; type < MAXQUOTAS; type++) {
if (flags & qtype_enforce_flag(type)) {
ret = dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
if (ret < 0)
goto out_err;
}
}
return 0;
out_err:
/* Backout enforcement disabling we already did */
for (type--; type >= 0; type--) {
if (flags & qtype_enforce_flag(type))
dquot_enable(dqopt->files[type], type,
dqopt->info[type].dqi_fmt_id,
DQUOT_LIMITS_ENABLED);
}
return ret;
}
/* Generic routine for getting common part of quota structure */
static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di)
{
struct mem_dqblk *dm = &dquot->dq_dqb;
memset(di, 0, sizeof(*di));
spin_lock(&dquot->dq_dqb_lock);
di->d_spc_hardlimit = dm->dqb_bhardlimit;
di->d_spc_softlimit = dm->dqb_bsoftlimit;
di->d_ino_hardlimit = dm->dqb_ihardlimit;
di->d_ino_softlimit = dm->dqb_isoftlimit;
di->d_space = dm->dqb_curspace + dm->dqb_rsvspace;
di->d_ino_count = dm->dqb_curinodes;
di->d_spc_timer = dm->dqb_btime;
di->d_ino_timer = dm->dqb_itime;
spin_unlock(&dquot->dq_dqb_lock);
}
int dquot_get_dqblk(struct super_block *sb, struct kqid qid,
struct qc_dqblk *di)
{
struct dquot *dquot;
dquot = dqget(sb, qid);
if (IS_ERR(dquot))
return PTR_ERR(dquot);
do_get_dqblk(dquot, di);
dqput(dquot);
return 0;
}
EXPORT_SYMBOL(dquot_get_dqblk);
int dquot_get_next_dqblk(struct super_block *sb, struct kqid *qid,
struct qc_dqblk *di)
{
struct dquot *dquot;
int err;
if (!sb->dq_op->get_next_id)
return -ENOSYS;
err = sb->dq_op->get_next_id(sb, qid);
if (err < 0)
return err;
dquot = dqget(sb, *qid);
if (IS_ERR(dquot))
return PTR_ERR(dquot);
do_get_dqblk(dquot, di);
dqput(dquot);
return 0;
}
EXPORT_SYMBOL(dquot_get_next_dqblk);
#define VFS_QC_MASK \
(QC_SPACE | QC_SPC_SOFT | QC_SPC_HARD | \
QC_INO_COUNT | QC_INO_SOFT | QC_INO_HARD | \
QC_SPC_TIMER | QC_INO_TIMER)
/* Generic routine for setting common part of quota structure */
static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
{
struct mem_dqblk *dm = &dquot->dq_dqb;
int check_blim = 0, check_ilim = 0;
struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
if (di->d_fieldmask & ~VFS_QC_MASK)
return -EINVAL;
if (((di->d_fieldmask & QC_SPC_SOFT) &&
di->d_spc_softlimit > dqi->dqi_max_spc_limit) ||
((di->d_fieldmask & QC_SPC_HARD) &&
di->d_spc_hardlimit > dqi->dqi_max_spc_limit) ||
((di->d_fieldmask & QC_INO_SOFT) &&
(di->d_ino_softlimit > dqi->dqi_max_ino_limit)) ||
((di->d_fieldmask & QC_INO_HARD) &&
(di->d_ino_hardlimit > dqi->dqi_max_ino_limit)))
return -ERANGE;
spin_lock(&dquot->dq_dqb_lock);
if (di->d_fieldmask & QC_SPACE) {
dm->dqb_curspace = di->d_space - dm->dqb_rsvspace;
check_blim = 1;
set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
}
if (di->d_fieldmask & QC_SPC_SOFT)
dm->dqb_bsoftlimit = di->d_spc_softlimit;
if (di->d_fieldmask & QC_SPC_HARD)
dm->dqb_bhardlimit = di->d_spc_hardlimit;
if (di->d_fieldmask & (QC_SPC_SOFT | QC_SPC_HARD)) {
check_blim = 1;
set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
}
if (di->d_fieldmask & QC_INO_COUNT) {
dm->dqb_curinodes = di->d_ino_count;
check_ilim = 1;
set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
}
if (di->d_fieldmask & QC_INO_SOFT)
dm->dqb_isoftlimit = di->d_ino_softlimit;
if (di->d_fieldmask & QC_INO_HARD)
dm->dqb_ihardlimit = di->d_ino_hardlimit;
if (di->d_fieldmask & (QC_INO_SOFT | QC_INO_HARD)) {
check_ilim = 1;
set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
}
if (di->d_fieldmask & QC_SPC_TIMER) {
dm->dqb_btime = di->d_spc_timer;
check_blim = 1;
set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
}
if (di->d_fieldmask & QC_INO_TIMER) {
dm->dqb_itime = di->d_ino_timer;
check_ilim = 1;
set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
}
if (check_blim) {
if (!dm->dqb_bsoftlimit ||
dm->dqb_curspace + dm->dqb_rsvspace < dm->dqb_bsoftlimit) {
dm->dqb_btime = 0;
clear_bit(DQ_BLKS_B, &dquot->dq_flags);
} else if (!(di->d_fieldmask & QC_SPC_TIMER))
/* Set grace only if user hasn't provided his own... */
dm->dqb_btime = ktime_get_real_seconds() + dqi->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->d_fieldmask & QC_INO_TIMER))
/* Set grace only if user hasn't provided his own... */
dm->dqb_itime = ktime_get_real_seconds() + dqi->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(&dquot->dq_dqb_lock);
mark_dquot_dirty(dquot);
return 0;
}
int dquot_set_dqblk(struct super_block *sb, struct kqid qid,
struct qc_dqblk *di)
{
struct dquot *dquot;
int rc;
dquot = dqget(sb, qid);
if (IS_ERR(dquot)) {
rc = PTR_ERR(dquot);
goto out;
}
rc = do_set_dqblk(dquot, di);
dqput(dquot);
out:
return rc;
}
EXPORT_SYMBOL(dquot_set_dqblk);
/* Generic routine for getting common part of quota file information */
int dquot_get_state(struct super_block *sb, struct qc_state *state)
{
struct mem_dqinfo *mi;
struct qc_type_state *tstate;
struct quota_info *dqopt = sb_dqopt(sb);
int type;
memset(state, 0, sizeof(*state));
for (type = 0; type < MAXQUOTAS; type++) {
if (!sb_has_quota_active(sb, type))
continue;
tstate = state->s_state + type;
mi = sb_dqopt(sb)->info + type;
tstate->flags = QCI_ACCT_ENABLED;
spin_lock(&dq_data_lock);
if (mi->dqi_flags & DQF_SYS_FILE)
tstate->flags |= QCI_SYSFILE;
if (mi->dqi_flags & DQF_ROOT_SQUASH)
tstate->flags |= QCI_ROOT_SQUASH;
if (sb_has_quota_limits_enabled(sb, type))
tstate->flags |= QCI_LIMITS_ENFORCED;
tstate->spc_timelimit = mi->dqi_bgrace;
tstate->ino_timelimit = mi->dqi_igrace;
tstate->ino = dqopt->files[type]->i_ino;
tstate->blocks = dqopt->files[type]->i_blocks;
tstate->nextents = 1; /* We don't know... */
spin_unlock(&dq_data_lock);
}
return 0;
}
EXPORT_SYMBOL(dquot_get_state);
/* Generic routine for setting common part of quota file information */
int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii)
{
struct mem_dqinfo *mi;
int err = 0;
if ((ii->i_fieldmask & QC_WARNS_MASK) ||
(ii->i_fieldmask & QC_RT_SPC_TIMER))
return -EINVAL;
if (!sb_has_quota_active(sb, type))
return -ESRCH;
mi = sb_dqopt(sb)->info + type;
if (ii->i_fieldmask & QC_FLAGS) {
if ((ii->i_flags & QCI_ROOT_SQUASH &&
mi->dqi_format->qf_fmt_id != QFMT_VFS_OLD))
return -EINVAL;
}
spin_lock(&dq_data_lock);
if (ii->i_fieldmask & QC_SPC_TIMER)
mi->dqi_bgrace = ii->i_spc_timelimit;
if (ii->i_fieldmask & QC_INO_TIMER)
mi->dqi_igrace = ii->i_ino_timelimit;
if (ii->i_fieldmask & QC_FLAGS) {
if (ii->i_flags & QCI_ROOT_SQUASH)
mi->dqi_flags |= DQF_ROOT_SQUASH;
else
mi->dqi_flags &= ~DQF_ROOT_SQUASH;
}
spin_unlock(&dq_data_lock);
mark_info_dirty(sb, type);
/* Force write to disk */
sb->dq_op->write_info(sb, type);
return err;
}
EXPORT_SYMBOL(dquot_set_dqinfo);
const struct quotactl_ops dquot_quotactl_sysfile_ops = {
.quota_enable = dquot_quota_enable,
.quota_disable = dquot_quota_disable,
.quota_sync = dquot_quota_sync,
.get_state = dquot_get_state,
.set_info = dquot_set_dqinfo,
.get_dqblk = dquot_get_dqblk,
.get_nextdqblk = dquot_get_next_dqblk,
.set_dqblk = dquot_set_dqblk
};
EXPORT_SYMBOL(dquot_quotactl_sysfile_ops);
static int do_proc_dqstats(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
unsigned int type = (int *)table->data - dqstats.stat;
/* Update global table */
dqstats.stat[type] =
percpu_counter_sum_positive(&dqstats.counter[type]);
return proc_dointvec(table, write, buffer, lenp, ppos);
}
static struct ctl_table fs_dqstats_table[] = {
{
.procname = "lookups",
.data = &dqstats.stat[DQST_LOOKUPS],
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "drops",
.data = &dqstats.stat[DQST_DROPS],
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "reads",
.data = &dqstats.stat[DQST_READS],
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "writes",
.data = &dqstats.stat[DQST_WRITES],
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "cache_hits",
.data = &dqstats.stat[DQST_CACHE_HITS],
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "allocated_dquots",
.data = &dqstats.stat[DQST_ALLOC_DQUOTS],
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "free_dquots",
.data = &dqstats.stat[DQST_FREE_DQUOTS],
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "syncs",
.data = &dqstats.stat[DQST_SYNCS],
.maxlen = sizeof(int),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
#ifdef CONFIG_PRINT_QUOTA_WARNING
{
.procname = "warnings",
.data = &flag_print_warnings,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif
{ },
};
static struct ctl_table fs_table[] = {
{
.procname = "quota",
.mode = 0555,
.child = fs_dqstats_table,
},
{ },
};
static struct ctl_table sys_table[] = {
{
.procname = "fs",
.mode = 0555,
.child = fs_table,
},
{ },
};
static int __init dquot_init(void)
{
int i, ret;
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_KERNEL, order);
if (!dquot_hash)
panic("Cannot create dquot hash table");
for (i = 0; i < _DQST_DQSTAT_LAST; i++) {
ret = percpu_counter_init(&dqstats.counter[i], 0, GFP_KERNEL);
if (ret)
panic("Cannot create dquot stat counters");
}
/* 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);
pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld,"
" %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order));
if (register_shrinker(&dqcache_shrinker))
panic("Cannot register dquot shrinker");
return 0;
}
fs_initcall(dquot_init);
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