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kernel_optimize_test/fs/quota/dquot.c
Christoph Hellwig 32927393dc sysctl: pass kernel pointers to ->proc_handler 
Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from  userspace in common code.  This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-04-27 02:07:40 -04:00

2990 lines
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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 four lists for dquot management: the inuse_list,
* free_dquots, dqi_dirty_list, and dquot_hash[] array. A single dquot
* structure may be on some of those 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.
*
* Dirty dquots are added to the dqi_dirty_list of quota_info when mark
* dirtied, and this list is searched when writing dirty dquots back to
* quota file. Note that some filesystems do dirty dquot tracking on their
* own (e.g. in a journal) and thus don't use dqi_dirty_list.
*
* 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 (dquot_is_busy(dquot))
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);
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);
/* Move list away to avoid livelock. */
list_replace_init(&dqopt->info[cnt].dqi_dirty_list, &dirty);
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);
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;
cond_resched();
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;
#ifdef CONFIG_QUOTA_DEBUG
int reserved = 0;
#endif
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)) {
#ifdef CONFIG_QUOTA_DEBUG
if (unlikely(inode_get_rsv_space(inode) > 0))
reserved = 1;
#endif
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 (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 (reserve)
dquot_free_reserved_space(dquots[cnt],
number);
else
dquot_decr_space(dquots[cnt], 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);
dquot_decr_inodes(dquots[cnt], 1);
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,
DQUOT_SPACE_WARN, &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);
static void vfs_cleanup_quota_inode(struct super_block *sb, int type)
{
struct quota_info *dqopt = sb_dqopt(sb);
struct inode *inode = dqopt->files[type];
if (!inode)
return;
if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
inode_lock(inode);
inode->i_flags &= ~S_NOQUOTA;
inode_unlock(inode);
}
dqopt->files[type] = NULL;
iput(inode);
}
/*
* 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;
struct quota_info *dqopt = sb_dqopt(sb);
/* 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++) {
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);
vfs_cleanup_quota_inode(sb, cnt);
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);
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++)
if (!sb_has_quota_loaded(sb, cnt) && dqopt->files[cnt]) {
inode_lock(dqopt->files[cnt]);
truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);
inode_unlock(dqopt->files[cnt]);
}
if (sb->s_bdev)
invalidate_bdev(sb->s_bdev);
put_inodes:
/* We are done when suspending quotas */
if (flags & DQUOT_SUSPENDED)
return 0;
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (!sb_has_quota_loaded(sb, cnt))
vfs_cleanup_quota_inode(sb, cnt);
return 0;
}
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
*/
static int vfs_setup_quota_inode(struct inode *inode, int type)
{
struct super_block *sb = inode->i_sb;
struct quota_info *dqopt = sb_dqopt(sb);
if (!S_ISREG(inode->i_mode))
return -EACCES;
if (IS_RDONLY(inode))
return -EROFS;
if (sb_has_quota_loaded(sb, type))
return -EBUSY;
dqopt->files[type] = igrab(inode);
if (!dqopt->files[type])
return -EIO;
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);
}
return 0;
}
int dquot_load_quota_sb(struct super_block *sb, int type, int format_id,
unsigned int flags)
{
struct quota_format_type *fmt = find_quota_format(format_id);
struct quota_info *dqopt = sb_dqopt(sb);
int error;
/* 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 (!fmt)
return -ESRCH;
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);
}
error = -EINVAL;
if (!fmt->qf_ops->check_quota_file(sb, type))
goto out_fmt;
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_fmt;
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_fmt:
put_quota_format(fmt);
return error;
}
EXPORT_SYMBOL(dquot_load_quota_sb);
/*
* More powerful function for turning on quotas on given quota inode allowing
* setting of individual quota flags
*/
int dquot_load_quota_inode(struct inode *inode, int type, int format_id,
unsigned int flags)
{
int err;
err = vfs_setup_quota_inode(inode, type);
if (err < 0)
return err;
err = dquot_load_quota_sb(inode->i_sb, type, format_id, flags);
if (err < 0)
vfs_cleanup_quota_inode(inode->i_sb, type);
return err;
}
EXPORT_SYMBOL(dquot_load_quota_inode);
/* Reenable quotas on remount RW */
int dquot_resume(struct super_block *sb, int type)
{
struct quota_info *dqopt = sb_dqopt(sb);
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;
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 = dquot_load_quota_sb(sb, cnt, dqopt->info[cnt].dqi_fmt_id,
flags);
if (ret < 0)
vfs_cleanup_quota_inode(sb, type);
}
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 = dquot_load_quota_inode(d_inode(path->dentry), type,
format_id, DQUOT_USAGE_ENABLED |
DQUOT_LIMITS_ENABLED);
return error;
}
EXPORT_SYMBOL(dquot_quota_on);
/*
* 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_positive_unlocked(qf_name, sb->s_root, strlen(qf_name));
if (IS_ERR(dentry))
return PTR_ERR(dentry);
error = security_quota_on(dentry);
if (!error)
error = dquot_load_quota_inode(d_inode(dentry), type, format_id,
DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
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)) {
ret = -EINVAL;
goto out_err;
}
if (sb_has_quota_limits_enabled(sb, type)) {
ret = -EBUSY;
goto out_err;
}
spin_lock(&dq_state_lock);
dqopt->flags |= dquot_state_flag(DQUOT_LIMITS_ENABLED, type);
spin_unlock(&dq_state_lock);
}
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)) {
spin_lock(&dq_state_lock);
dqopt->flags |=
dquot_state_flag(DQUOT_LIMITS_ENABLED, type);
spin_unlock(&dq_state_lock);
}
}
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;
if (dqopt->files[type]) {
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 *buffer, size_t *lenp, loff_t *ppos)
{
unsigned int type = (unsigned long *)table->data - dqstats.stat;
s64 value = percpu_counter_sum(&dqstats.counter[type]);
/* Filter negative values for non-monotonic counters */
if (value < 0 && (type == DQST_ALLOC_DQUOTS ||
type == DQST_FREE_DQUOTS))
value = 0;
/* Update global table */
dqstats.stat[type] = value;
return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
}
static struct ctl_table fs_dqstats_table[] = {
{
.procname = "lookups",
.data = &dqstats.stat[DQST_LOOKUPS],
.maxlen = sizeof(unsigned long),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "drops",
.data = &dqstats.stat[DQST_DROPS],
.maxlen = sizeof(unsigned long),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "reads",
.data = &dqstats.stat[DQST_READS],
.maxlen = sizeof(unsigned long),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "writes",
.data = &dqstats.stat[DQST_WRITES],
.maxlen = sizeof(unsigned long),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "cache_hits",
.data = &dqstats.stat[DQST_CACHE_HITS],
.maxlen = sizeof(unsigned long),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "allocated_dquots",
.data = &dqstats.stat[DQST_ALLOC_DQUOTS],
.maxlen = sizeof(unsigned long),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "free_dquots",
.data = &dqstats.stat[DQST_FREE_DQUOTS],
.maxlen = sizeof(unsigned long),
.mode = 0444,
.proc_handler = do_proc_dqstats,
},
{
.procname = "syncs",
.data = &dqstats.stat[DQST_SYNCS],
.maxlen = sizeof(unsigned long),
.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 = ilog2(nr_hash);
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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