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dquot.c
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dquot.c
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/*
* Implementation of the diskquota system for the LINUX operating system. QUOTA
* is implemented using the BSD system call interface as the means of
* communication with the user level. This file contains the generic routines
* called by the different filesystems on allocation of an inode or block.
* These routines take care of the administration needed to have a consistent
* diskquota tracking system. The ideas of both user and group quotas are based
* on the Melbourne quota system as used on BSD derived systems. The internal
* implementation is based on one of the several variants of the LINUX
* inode-subsystem with added complexity of the diskquota system.
*
* Version: $Id: dquot.c,v 6.3 1996/11/17 18:35:34 mvw Exp mvw $
*
* Author: Marco van Wieringen <[email protected]>
*
* Fixes: Dmitry Gorodchanin <[email protected]>, 11 Feb 96
*
* Revised list management to avoid races
* -- Bill Hawes, <[email protected]>, 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, <[email protected]>, 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, <[email protected]>, 9/2000
*
* Added dynamic quota structure allocation
* Jan Kara <[email protected]> 12/2000
*
* Rewritten quota interface. Implemented new quota format and
* formats registering.
* Jan Kara, <[email protected]>, 2001,2002
*
* New SMP locking.
* Jan Kara, <[email protected]>, 10/2002
*
* Added journalled quota support, fix lock inversion problems
* Jan Kara, <[email protected]>, 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/smp_lock.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/security.h>
#include <linux/kmod.h>
#include <linux/namei.h>
#include <linux/buffer_head.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <asm/uaccess.h>
#define __DQUOT_PARANOIA
/*
* There are two quota SMP locks. dq_list_lock protects all lists with quotas
* and quota formats and also dqstats structure containing statistics about the
* lists. dq_data_lock protects data from dq_dqb and also mem_dqinfo structures
* and also guards consistency of dquot->dq_dqb with inode->i_blocks, i_bytes.
* i_blocks and i_bytes updates itself are guarded by i_lock acquired directly
* in inode_add_bytes() and inode_sub_bytes().
*
* The spinlock ordering is hence: dq_data_lock > dq_list_lock > i_lock
*
* Note that some things (eg. sb pointer, type, id) doesn't change during
* the life of the dquot structure and so needn't to be protected by a lock
*
* Any operation working on dquots via inode pointers must hold dqptr_sem. If
* operation is just reading pointers from inode (or not using them at all) the
* read lock is enough. If pointers are altered function must hold write lock
* (these locking rules also apply for S_NOQUOTA flag in the inode - note that
* for altering the flag i_mutex is also needed). If operation is holding
* reference to dquot in other way (e.g. quotactl ops) it must be guarded by
* dqonoff_sem.
* This locking assures that:
* a) update/access to dquot pointers in inode is serialized
* b) everyone is guarded against invalidate_dquots()
*
* Each dquot has its dq_lock semaphore. Locked dquots might not be referenced
* from inodes (dquot_alloc_space() and such don't check the dq_lock).
* Currently dquot is locked only when it is being read to memory (or space for
* it is being allocated) on the first dqget() and when it is being released on
* the last dqput(). The allocation and release oparations are serialized by
* the dq_lock and by checking the use count in dquot_release(). Write
* operations on dquots don't hold dq_lock as they copy data under dq_data_lock
* spinlock to internal buffers before writing.
*
* Lock ordering (including related VFS locks) is the following:
* i_mutex > dqonoff_sem > iprune_sem > journal_lock > dqptr_sem >
* > dquot->dq_lock > dqio_sem
* i_mutex on quota files is special (it's below dqio_sem)
*/
static DEFINE_SPINLOCK(dq_list_lock);
DEFINE_SPINLOCK(dq_data_lock);
static char *quotatypes[] = INITQFNAMES;
static struct quota_format_type *quota_formats; /* List of registered formats */
static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES;
/* SLAB cache for dquot structures */
static kmem_cache_t *dquot_cachep;
int register_quota_format(struct quota_format_type *fmt)
{
spin_lock(&dq_list_lock);
fmt->qf_next = quota_formats;
quota_formats = fmt;
spin_unlock(&dq_list_lock);
return 0;
}
void unregister_quota_format(struct quota_format_type *fmt)
{
struct quota_format_type **actqf;
spin_lock(&dq_list_lock);
for (actqf = "a_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next);
if (*actqf)
*actqf = (*actqf)->qf_next;
spin_unlock(&dq_list_lock);
}
static struct quota_format_type *find_quota_format(int id)
{
struct quota_format_type *actqf;
spin_lock(&dq_list_lock);
for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
if (!actqf || !try_module_get(actqf->qf_owner)) {
int qm;
spin_unlock(&dq_list_lock);
for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++);
if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name))
return NULL;
spin_lock(&dq_list_lock);
for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next);
if (actqf && !try_module_get(actqf->qf_owner))
actqf = NULL;
}
spin_unlock(&dq_list_lock);
return actqf;
}
static void put_quota_format(struct quota_format_type *fmt)
{
module_put(fmt->qf_owner);
}
/*
* Dquot List Management:
* The quota code uses three lists for dquot management: the inuse_list,
* free_dquots, and dquot_hash[] array. A single dquot structure may be
* on all three lists, depending on its current state.
*
* All dquots are placed to the end of inuse_list when first created, and this
* list is used for invalidate operation, which must look at every dquot.
*
* Unused dquots (dq_count == 0) are added to the free_dquots list when freed,
* and this list is searched whenever we need an available dquot. Dquots are
* removed from the list as soon as they are used again, and
* dqstats.free_dquots gives the number of dquots on the list. When
* dquot is invalidated it's completely released from memory.
*
* Dquots with a specific identity (device, type and id) are placed on
* one of the dquot_hash[] hash chains. The provides an efficient search
* mechanism to locate a specific dquot.
*/
static LIST_HEAD(inuse_list);
static LIST_HEAD(free_dquots);
static unsigned int dq_hash_bits, dq_hash_mask;
static struct hlist_head *dquot_hash;
struct dqstats dqstats;
static void dqput(struct dquot *dquot);
static inline unsigned int
hashfn(const struct super_block *sb, unsigned int id, int type)
{
unsigned long tmp;
tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type);
return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask;
}
/*
* Following list functions expect dq_list_lock to be held
*/
static inline void insert_dquot_hash(struct dquot *dquot)
{
struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type);
hlist_add_head(&dquot->dq_hash, head);
}
static inline void remove_dquot_hash(struct dquot *dquot)
{
hlist_del_init(&dquot->dq_hash);
}
static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type)
{
struct hlist_node *node;
struct dquot *dquot;
hlist_for_each (node, dquot_hash+hashent) {
dquot = hlist_entry(node, struct dquot, dq_hash);
if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type)
return dquot;
}
return NODQUOT;
}
/* Add a dquot to the tail of the free list */
static inline void put_dquot_last(struct dquot *dquot)
{
list_add(&dquot->dq_free, free_dquots.prev);
dqstats.free_dquots++;
}
static inline void remove_free_dquot(struct dquot *dquot)
{
if (list_empty(&dquot->dq_free))
return;
list_del_init(&dquot->dq_free);
dqstats.free_dquots--;
}
static inline void put_inuse(struct dquot *dquot)
{
/* We add to the back of inuse list so we don't have to restart
* when traversing this list and we block */
list_add(&dquot->dq_inuse, inuse_list.prev);
dqstats.allocated_dquots++;
}
static inline void remove_inuse(struct dquot *dquot)
{
dqstats.allocated_dquots--;
list_del(&dquot->dq_inuse);
}
/*
* End of list functions needing dq_list_lock
*/
static void wait_on_dquot(struct dquot *dquot)
{
down(&dquot->dq_lock);
up(&dquot->dq_lock);
}
#define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot))
int dquot_mark_dquot_dirty(struct dquot *dquot)
{
spin_lock(&dq_list_lock);
if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)->
info[dquot->dq_type].dqi_dirty_list);
spin_unlock(&dq_list_lock);
return 0;
}
/* This function needs dq_list_lock */
static inline int clear_dquot_dirty(struct dquot *dquot)
{
if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags))
return 0;
list_del_init(&dquot->dq_dirty);
return 1;
}
void mark_info_dirty(struct super_block *sb, int type)
{
set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
}
EXPORT_SYMBOL(mark_info_dirty);
/*
* Read dquot from disk and alloc space for it
*/
int dquot_acquire(struct dquot *dquot)
{
int ret = 0, ret2 = 0;
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
down(&dquot->dq_lock);
down(&dqopt->dqio_sem);
if (!test_bit(DQ_READ_B, &dquot->dq_flags))
ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot);
if (ret < 0)
goto out_iolock;
set_bit(DQ_READ_B, &dquot->dq_flags);
/* Instantiate dquot if needed */
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) {
ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
/* Write the info if needed */
if (info_dirty(&dqopt->info[dquot->dq_type]))
ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
if (ret < 0)
goto out_iolock;
if (ret2 < 0) {
ret = ret2;
goto out_iolock;
}
}
set_bit(DQ_ACTIVE_B, &dquot->dq_flags);
out_iolock:
up(&dqopt->dqio_sem);
up(&dquot->dq_lock);
return ret;
}
/*
* Write dquot to disk
*/
int dquot_commit(struct dquot *dquot)
{
int ret = 0, ret2 = 0;
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
down(&dqopt->dqio_sem);
spin_lock(&dq_list_lock);
if (!clear_dquot_dirty(dquot)) {
spin_unlock(&dq_list_lock);
goto out_sem;
}
spin_unlock(&dq_list_lock);
/* Inactive dquot can be only if there was error during read/init
* => we have better not writing it */
if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot);
if (info_dirty(&dqopt->info[dquot->dq_type]))
ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
if (ret >= 0)
ret = ret2;
}
out_sem:
up(&dqopt->dqio_sem);
return ret;
}
/*
* Release dquot
*/
int dquot_release(struct dquot *dquot)
{
int ret = 0, ret2 = 0;
struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
down(&dquot->dq_lock);
/* Check whether we are not racing with some other dqget() */
if (atomic_read(&dquot->dq_count) > 1)
goto out_dqlock;
down(&dqopt->dqio_sem);
if (dqopt->ops[dquot->dq_type]->release_dqblk) {
ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot);
/* Write the info */
if (info_dirty(&dqopt->info[dquot->dq_type]))
ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type);
if (ret >= 0)
ret = ret2;
}
clear_bit(DQ_ACTIVE_B, &dquot->dq_flags);
up(&dqopt->dqio_sem);
out_dqlock:
up(&dquot->dq_lock);
return ret;
}
/* Invalidate all dquots on the list. Note that this function is called after
* quota is disabled and pointers from inodes removed so there cannot be new
* quota users. Also because we hold dqonoff_sem there can be no quota users
* for this sb+type at all. */
static void invalidate_dquots(struct super_block *sb, int type)
{
struct dquot *dquot, *tmp;
spin_lock(&dq_list_lock);
list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) {
if (dquot->dq_sb != sb)
continue;
if (dquot->dq_type != type)
continue;
#ifdef __DQUOT_PARANOIA
if (atomic_read(&dquot->dq_count))
BUG();
#endif
/* Quota now has no users and it has been written on last dqput() */
remove_dquot_hash(dquot);
remove_free_dquot(dquot);
remove_inuse(dquot);
kmem_cache_free(dquot_cachep, dquot);
}
spin_unlock(&dq_list_lock);
}
int vfs_quota_sync(struct super_block *sb, int type)
{
struct list_head *dirty;
struct dquot *dquot;
struct quota_info *dqopt = sb_dqopt(sb);
int cnt;
down(&dqopt->dqonoff_sem);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
if (!sb_has_quota_enabled(sb, cnt))
continue;
spin_lock(&dq_list_lock);
dirty = &dqopt->info[cnt].dqi_dirty_list;
while (!list_empty(dirty)) {
dquot = list_entry(dirty->next, struct dquot, dq_dirty);
/* Dirty and inactive can be only bad dquot... */
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
clear_dquot_dirty(dquot);
continue;
}
/* Now we have active dquot from which someone is
* holding reference so we can safely just increase
* use count */
atomic_inc(&dquot->dq_count);
dqstats.lookups++;
spin_unlock(&dq_list_lock);
sb->dq_op->write_dquot(dquot);
dqput(dquot);
spin_lock(&dq_list_lock);
}
spin_unlock(&dq_list_lock);
}
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if ((cnt == type || type == -1) && sb_has_quota_enabled(sb, cnt)
&& info_dirty(&dqopt->info[cnt]))
sb->dq_op->write_info(sb, cnt);
spin_lock(&dq_list_lock);
dqstats.syncs++;
spin_unlock(&dq_list_lock);
up(&dqopt->dqonoff_sem);
return 0;
}
/* Free unused dquots from cache */
static void prune_dqcache(int count)
{
struct list_head *head;
struct dquot *dquot;
head = free_dquots.prev;
while (head != &free_dquots && count) {
dquot = list_entry(head, struct dquot, dq_free);
remove_dquot_hash(dquot);
remove_free_dquot(dquot);
remove_inuse(dquot);
kmem_cache_free(dquot_cachep, dquot);
count--;
head = free_dquots.prev;
}
}
/*
* This is called from kswapd when we think we need some
* more memory
*/
static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
{
if (nr) {
spin_lock(&dq_list_lock);
prune_dqcache(nr);
spin_unlock(&dq_list_lock);
}
return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
}
/*
* Put reference to dquot
* NOTE: If you change this function please check whether dqput_blocks() works right...
* MUST be called with either dqptr_sem or dqonoff_sem held
*/
static void dqput(struct dquot *dquot)
{
if (!dquot)
return;
#ifdef __DQUOT_PARANOIA
if (!atomic_read(&dquot->dq_count)) {
printk("VFS: dqput: trying to free free dquot\n");
printk("VFS: device %s, dquot of %s %d\n",
dquot->dq_sb->s_id,
quotatypes[dquot->dq_type],
dquot->dq_id);
BUG();
}
#endif
spin_lock(&dq_list_lock);
dqstats.drops++;
spin_unlock(&dq_list_lock);
we_slept:
spin_lock(&dq_list_lock);
if (atomic_read(&dquot->dq_count) > 1) {
/* We have more than one user... nothing to do */
atomic_dec(&dquot->dq_count);
spin_unlock(&dq_list_lock);
return;
}
/* Need to release dquot? */
if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
spin_unlock(&dq_list_lock);
/* Commit dquot before releasing */
dquot->dq_sb->dq_op->write_dquot(dquot);
goto we_slept;
}
/* Clear flag in case dquot was inactive (something bad happened) */
clear_dquot_dirty(dquot);
if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) {
spin_unlock(&dq_list_lock);
dquot->dq_sb->dq_op->release_dquot(dquot);
goto we_slept;
}
atomic_dec(&dquot->dq_count);
#ifdef __DQUOT_PARANOIA
/* sanity check */
if (!list_empty(&dquot->dq_free))
BUG();
#endif
put_dquot_last(dquot);
spin_unlock(&dq_list_lock);
}
static struct dquot *get_empty_dquot(struct super_block *sb, int type)
{
struct dquot *dquot;
dquot = kmem_cache_alloc(dquot_cachep, SLAB_NOFS);
if(!dquot)
return NODQUOT;
memset((caddr_t)dquot, 0, sizeof(struct dquot));
sema_init(&dquot->dq_lock, 1);
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_type = type;
atomic_set(&dquot->dq_count, 1);
return dquot;
}
/*
* Get reference to dquot
* MUST be called with either dqptr_sem or dqonoff_sem held
*/
static struct dquot *dqget(struct super_block *sb, unsigned int id, int type)
{
unsigned int hashent = hashfn(sb, id, type);
struct dquot *dquot, *empty = NODQUOT;
if (!sb_has_quota_enabled(sb, type))
return NODQUOT;
we_slept:
spin_lock(&dq_list_lock);
if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) {
if (empty == NODQUOT) {
spin_unlock(&dq_list_lock);
if ((empty = get_empty_dquot(sb, type)) == NODQUOT)
schedule(); /* Try to wait for a moment... */
goto we_slept;
}
dquot = empty;
dquot->dq_id = id;
/* all dquots go on the inuse_list */
put_inuse(dquot);
/* hash it first so it can be found */
insert_dquot_hash(dquot);
dqstats.lookups++;
spin_unlock(&dq_list_lock);
} else {
if (!atomic_read(&dquot->dq_count))
remove_free_dquot(dquot);
atomic_inc(&dquot->dq_count);
dqstats.cache_hits++;
dqstats.lookups++;
spin_unlock(&dq_list_lock);
if (empty)
kmem_cache_free(dquot_cachep, empty);
}
/* Wait for dq_lock - after this we know that either dquot_release() is already
* finished or it will be canceled due to dq_count > 1 test */
wait_on_dquot(dquot);
/* Read the dquot and instantiate it (everything done only if needed) */
if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) {
dqput(dquot);
return NODQUOT;
}
#ifdef __DQUOT_PARANOIA
if (!dquot->dq_sb) /* Has somebody invalidated entry under us? */
BUG();
#endif
return dquot;
}
static int dqinit_needed(struct inode *inode, int type)
{
int cnt;
if (IS_NOQUOTA(inode))
return 0;
if (type != -1)
return inode->i_dquot[type] == NODQUOT;
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
if (inode->i_dquot[cnt] == NODQUOT)
return 1;
return 0;
}
/* This routine is guarded by dqonoff_sem semaphore */
static void add_dquot_ref(struct super_block *sb, int type)
{
struct list_head *p;
restart:
file_list_lock();
list_for_each(p, &sb->s_files) {
struct file *filp = list_entry(p, struct file, f_u.fu_list);
struct inode *inode = filp->f_dentry->d_inode;
if (filp->f_mode & FMODE_WRITE && dqinit_needed(inode, type)) {
struct dentry *dentry = dget(filp->f_dentry);
file_list_unlock();
sb->dq_op->initialize(inode, type);
dput(dentry);
/* As we may have blocked we had better restart... */
goto restart;
}
}
file_list_unlock();
}
/* Return 0 if dqput() won't block (note that 1 doesn't necessarily mean blocking) */
static inline int dqput_blocks(struct dquot *dquot)
{
if (atomic_read(&dquot->dq_count) <= 1)
return 1;
return 0;
}
/* Remove references to dquots from inode - add dquot to list for freeing if needed */
/* We can't race with anybody because we hold dqptr_sem for writing... */
int remove_inode_dquot_ref(struct inode *inode, int type, struct list_head *tofree_head)
{
struct dquot *dquot = inode->i_dquot[type];
inode->i_dquot[type] = NODQUOT;
if (dquot != NODQUOT) {
if (dqput_blocks(dquot)) {
#ifdef __DQUOT_PARANOIA
if (atomic_read(&dquot->dq_count) != 1)
printk(KERN_WARNING "VFS: Adding dquot with dq_count %d to dispose list.\n", atomic_read(&dquot->dq_count));
#endif
spin_lock(&dq_list_lock);
list_add(&dquot->dq_free, tofree_head); /* As dquot must have currently users it can't be on the free list... */
spin_unlock(&dq_list_lock);
return 1;
}
else
dqput(dquot); /* We have guaranteed we won't block */
}
return 0;
}
/* Free list of dquots - called from inode.c */
/* dquots are removed from inodes, no new references can be got so we are the only ones holding reference */
static void put_dquot_list(struct list_head *tofree_head)
{
struct list_head *act_head;
struct dquot *dquot;
act_head = tofree_head->next;
/* So now we have dquots on the list... Just free them */
while (act_head != tofree_head) {
dquot = list_entry(act_head, struct dquot, dq_free);
act_head = act_head->next;
list_del_init(&dquot->dq_free); /* Remove dquot from the list so we won't have problems... */
dqput(dquot);
}
}
/* Gather all references from inodes and drop them */
static void drop_dquot_ref(struct super_block *sb, int type)
{
LIST_HEAD(tofree_head);
/* We need to be guarded against prune_icache to reach all the
* inodes - otherwise some can be on the local list of prune_icache */
down(&iprune_sem);
down_write(&sb_dqopt(sb)->dqptr_sem);
remove_dquot_ref(sb, type, &tofree_head);
up_write(&sb_dqopt(sb)->dqptr_sem);
up(&iprune_sem);
put_dquot_list(&tofree_head);
}
static inline void dquot_incr_inodes(struct dquot *dquot, unsigned long number)
{
dquot->dq_dqb.dqb_curinodes += number;
}
static inline void dquot_incr_space(struct dquot *dquot, qsize_t number)
{
dquot->dq_dqb.dqb_curspace += number;
}
static inline void dquot_decr_inodes(struct dquot *dquot, unsigned long number)
{
if (dquot->dq_dqb.dqb_curinodes > number)
dquot->dq_dqb.dqb_curinodes -= number;
else
dquot->dq_dqb.dqb_curinodes = 0;
if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
dquot->dq_dqb.dqb_itime = (time_t) 0;
clear_bit(DQ_INODES_B, &dquot->dq_flags);
}
static inline void dquot_decr_space(struct dquot *dquot, qsize_t number)
{
if (dquot->dq_dqb.dqb_curspace > number)
dquot->dq_dqb.dqb_curspace -= number;
else
dquot->dq_dqb.dqb_curspace = 0;
if (toqb(dquot->dq_dqb.dqb_curspace) <= dquot->dq_dqb.dqb_bsoftlimit)
dquot->dq_dqb.dqb_btime = (time_t) 0;
clear_bit(DQ_BLKS_B, &dquot->dq_flags);
}
static int flag_print_warnings = 1;
static inline int need_print_warning(struct dquot *dquot)
{
if (!flag_print_warnings)
return 0;
switch (dquot->dq_type) {
case USRQUOTA:
return current->fsuid == dquot->dq_id;
case GRPQUOTA:
return in_group_p(dquot->dq_id);
}
return 0;
}
/* Values of warnings */
#define NOWARN 0
#define IHARDWARN 1
#define ISOFTLONGWARN 2
#define ISOFTWARN 3
#define BHARDWARN 4
#define BSOFTLONGWARN 5
#define BSOFTWARN 6
/* Print warning to user which exceeded quota */
static void print_warning(struct dquot *dquot, const char warntype)
{
char *msg = NULL;
int flag = (warntype == BHARDWARN || warntype == BSOFTLONGWARN) ? DQ_BLKS_B :
((warntype == IHARDWARN || warntype == ISOFTLONGWARN) ? DQ_INODES_B : 0);
if (!need_print_warning(dquot) || (flag && test_and_set_bit(flag, &dquot->dq_flags)))
return;
tty_write_message(current->signal->tty, dquot->dq_sb->s_id);
if (warntype == ISOFTWARN || warntype == BSOFTWARN)
tty_write_message(current->signal->tty, ": warning, ");
else
tty_write_message(current->signal->tty, ": write failed, ");
tty_write_message(current->signal->tty, quotatypes[dquot->dq_type]);
switch (warntype) {
case IHARDWARN:
msg = " file limit reached.\r\n";
break;
case ISOFTLONGWARN:
msg = " file quota exceeded too long.\r\n";
break;
case ISOFTWARN:
msg = " file quota exceeded.\r\n";
break;
case BHARDWARN:
msg = " block limit reached.\r\n";
break;
case BSOFTLONGWARN:
msg = " block quota exceeded too long.\r\n";
break;
case BSOFTWARN:
msg = " block quota exceeded.\r\n";
break;
}
tty_write_message(current->signal->tty, msg);
}
static inline void flush_warnings(struct dquot **dquots, char *warntype)
{
int i;
for (i = 0; i < MAXQUOTAS; i++)
if (dquots[i] != NODQUOT && warntype[i] != NOWARN)
print_warning(dquots[i], warntype[i]);
}
static inline char ignore_hardlimit(struct dquot *dquot)
{
struct mem_dqinfo *info = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
return capable(CAP_SYS_RESOURCE) &&
(info->dqi_format->qf_fmt_id != QFMT_VFS_OLD || !(info->dqi_flags & V1_DQF_RSQUASH));
}
/* needs dq_data_lock */
static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
{
*warntype = NOWARN;
if (inodes <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
return QUOTA_OK;
if (dquot->dq_dqb.dqb_ihardlimit &&
(dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
!ignore_hardlimit(dquot)) {
*warntype = IHARDWARN;
return NO_QUOTA;
}
if (dquot->dq_dqb.dqb_isoftlimit &&
(dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
!ignore_hardlimit(dquot)) {
*warntype = ISOFTLONGWARN;
return NO_QUOTA;
}
if (dquot->dq_dqb.dqb_isoftlimit &&
(dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
dquot->dq_dqb.dqb_itime == 0) {
*warntype = ISOFTWARN;
dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
}
return QUOTA_OK;
}
/* needs dq_data_lock */
static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
{
*warntype = 0;
if (space <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
return QUOTA_OK;
if (dquot->dq_dqb.dqb_bhardlimit &&
toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bhardlimit &&
!ignore_hardlimit(dquot)) {
if (!prealloc)
*warntype = BHARDWARN;
return NO_QUOTA;
}
if (dquot->dq_dqb.dqb_bsoftlimit &&
toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
!ignore_hardlimit(dquot)) {
if (!prealloc)
*warntype = BSOFTLONGWARN;
return NO_QUOTA;
}
if (dquot->dq_dqb.dqb_bsoftlimit &&
toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
dquot->dq_dqb.dqb_btime == 0) {
if (!prealloc) {
*warntype = BSOFTWARN;
dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
}
else
/*
* We don't allow preallocation to exceed softlimit so exceeding will
* be always printed
*/
return NO_QUOTA;
}
return QUOTA_OK;
}
/*
* Initialize quota pointers in inode
* Transaction must be started at entry
*/
int dquot_initialize(struct inode *inode, int type)
{
unsigned int id = 0;
int cnt, ret = 0;
/* First test before acquiring semaphore - solves deadlocks when we
* re-enter the quota code and are already holding the semaphore */
if (IS_NOQUOTA(inode))
return 0;
down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
/* Having dqptr_sem we know NOQUOTA flags can't be altered... */
if (IS_NOQUOTA(inode))
goto out_err;
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (type != -1 && cnt != type)
continue;
if (inode->i_dquot[cnt] == NODQUOT) {
switch (cnt) {
case USRQUOTA:
id = inode->i_uid;
break;
case GRPQUOTA:
id = inode->i_gid;
break;
}
inode->i_dquot[cnt] = dqget(inode->i_sb, id, cnt);
}
}
out_err:
up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
return ret;
}
/*
* Release all quotas referenced by inode
* Transaction must be started at an entry
*/
int dquot_drop(struct inode *inode)
{
int cnt;
down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
if (inode->i_dquot[cnt] != NODQUOT) {
dqput(inode->i_dquot[cnt]);
inode->i_dquot[cnt] = NODQUOT;
}
}
up_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
return 0;
}
/*
* Following four functions update i_blocks+i_bytes fields and
* quota information (together with appropriate checks)
* NOTE: We absolutely rely on the fact that caller dirties
* the inode (usually macros in quotaops.h care about this) and
* holds a handle for the current transaction so that dquot write and
* inode write go into the same transaction.
*/
/*
* This operation can block, but only after everything is updated
*/
int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)