diff options
Diffstat (limited to 'kernel/fs/quota/dquot.c')
| -rw-r--r-- | kernel/fs/quota/dquot.c | 2889 |
1 files changed, 2889 insertions, 0 deletions
diff --git a/kernel/fs/quota/dquot.c b/kernel/fs/quota/dquot.c new file mode 100644 index 000000000..20d1f7456 --- /dev/null +++ b/kernel/fs/quota/dquot.c @@ -0,0 +1,2889 @@ +/* + * 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/kmod.h> +#include <linux/namei.h> +#include <linux/capability.h> +#include <linux/quotaops.h> +#include "../internal.h" /* ugh */ + +#include <linux/uaccess.h> + +/* + * There are three quota SMP locks. dq_list_lock protects all lists with quotas + * and quota formats. + * 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(). 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, + * 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. 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: + * dqonoff_mutex > i_mutex > journal_lock > dquot->dq_lock > dqio_mutex + * dqonoff_mutex > i_mutex comes from dquot_quota_sync, dquot_enable, etc. + */ + +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); + +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 = "a_formats; *actqf && *actqf != fmt; + actqf = &(*actqf)->qf_next) + ; + if (*actqf) + *actqf = (*actqf)->qf_next; + spin_unlock(&dq_list_lock); +} +EXPORT_SYMBOL(unregister_quota_format); + +static struct quota_format_type *find_quota_format(int id) +{ + struct quota_format_type *actqf; + + spin_lock(&dq_list_lock); + for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; + actqf = actqf->qf_next) + ; + if (!actqf || !try_module_get(actqf->qf_owner)) { + int qm; + + spin_unlock(&dq_list_lock); + + for (qm = 0; module_names[qm].qm_fmt_id && + module_names[qm].qm_fmt_id != id; qm++) + ; + if (!module_names[qm].qm_fmt_id || + request_module(module_names[qm].qm_mod_name)) + return NULL; + + spin_lock(&dq_list_lock); + for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; + actqf = actqf->qf_next) + ; + if (actqf && !try_module_get(actqf->qf_owner)) + actqf = NULL; + } + spin_unlock(&dq_list_lock); + return actqf; +} + +static void put_quota_format(struct quota_format_type *fmt) +{ + module_put(fmt->qf_owner); +} + +/* + * Dquot List Management: + * The quota code uses three lists for dquot management: the inuse_list, + * free_dquots, and dquot_hash[] array. A single dquot structure may be + * on all three lists, depending on its current state. + * + * All dquots are placed to the end of inuse_list when first created, and this + * list is used for invalidate operation, which must look at every dquot. + * + * Unused dquots (dq_count == 0) are added to the free_dquots list when freed, + * and this list is searched whenever we need an available dquot. Dquots are + * removed from the list as soon as they are used again, and + * dqstats.free_dquots gives the number of dquots on the list. When + * dquot is invalidated it's completely released from memory. + * + * Dquots with a specific identity (device, type and id) are placed on + * one of the dquot_hash[] hash chains. The provides an efficient search + * mechanism to locate a specific dquot. + */ + +static LIST_HEAD(inuse_list); +static LIST_HEAD(free_dquots); +static unsigned int dq_hash_bits, dq_hash_mask; +static struct hlist_head *dquot_hash; + +struct dqstats dqstats; +EXPORT_SYMBOL(dqstats); + +static qsize_t inode_get_rsv_space(struct inode *inode); +static void __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 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]); +} + +/* This function needs dq_list_lock */ +static inline int clear_dquot_dirty(struct dquot *dquot) +{ + if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags)) + return 0; + list_del_init(&dquot->dq_dirty); + return 1; +} + +void mark_info_dirty(struct super_block *sb, int type) +{ + set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags); +} +EXPORT_SYMBOL(mark_info_dirty); + +/* + * Read dquot from disk and alloc space for it + */ + +int dquot_acquire(struct dquot *dquot) +{ + int ret = 0, ret2 = 0; + struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); + + mutex_lock(&dquot->dq_lock); + mutex_lock(&dqopt->dqio_mutex); + if (!test_bit(DQ_READ_B, &dquot->dq_flags)) + ret = dqopt->ops[dquot->dq_id.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_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; + } + } + set_bit(DQ_ACTIVE_B, &dquot->dq_flags); +out_iolock: + mutex_unlock(&dqopt->dqio_mutex); + 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(&dqopt->dqio_mutex); + spin_lock(&dq_list_lock); + if (!clear_dquot_dirty(dquot)) { + spin_unlock(&dq_list_lock); + goto out_sem; + } + spin_unlock(&dq_list_lock); + /* Inactive dquot can be only if there was error during read/init + * => we have better not writing it */ + if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) + ret = dqopt->ops[dquot->dq_id.type]->commit_dqblk(dquot); + else + ret = -EIO; +out_sem: + mutex_unlock(&dqopt->dqio_mutex); + return ret; +} +EXPORT_SYMBOL(dquot_commit); + +/* + * Release dquot + */ +int dquot_release(struct dquot *dquot) +{ + int ret = 0, ret2 = 0; + struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); + + mutex_lock(&dquot->dq_lock); + /* Check whether we are not racing with some other dqget() */ + if (atomic_read(&dquot->dq_count) > 1) + goto out_dqlock; + mutex_lock(&dqopt->dqio_mutex); + 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); + mutex_unlock(&dqopt->dqio_mutex); +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)) { + DEFINE_WAIT(wait); + + dqgrab(dquot); + prepare_to_wait(&dquot->dq_wait_unused, &wait, + TASK_UNINTERRUPTIBLE); + spin_unlock(&dq_list_lock); + /* Once dqput() wakes us up, we know it's time to free + * the dquot. + * IMPORTANT: we rely on the fact that there is always + * at most one process waiting for dquot to free. + * Otherwise dq_count would be > 1 and we would never + * wake up. + */ + if (atomic_read(&dquot->dq_count) > 1) + schedule(); + finish_wait(&dquot->dq_wait_unused, &wait); + dqput(dquot); + /* At this moment dquot() need not exist (it could be + * reclaimed by prune_dqcache(). Hence we must + * restart. */ + goto restart; + } + /* + * Quota now has no users and it has been written on last + * dqput() + */ + remove_dquot_hash(dquot); + remove_free_dquot(dquot); + remove_inuse(dquot); + 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; + + mutex_lock(&sb_dqopt(sb)->dqonoff_mutex); + spin_lock(&dq_list_lock); + list_for_each_entry(dquot, &inuse_list, dq_inuse) { + if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) + continue; + if (dquot->dq_sb != sb) + continue; + /* Now we have active dquot so we can just increase use count */ + atomic_inc(&dquot->dq_count); + spin_unlock(&dq_list_lock); + dqstats_inc(DQST_LOOKUPS); + dqput(old_dquot); + old_dquot = dquot; + /* + * ->release_dquot() can be racing with us. Our reference + * protects us from new calls to it so just wait for any + * outstanding call and recheck the DQ_ACTIVE_B after that. + */ + wait_on_dquot(dquot); + if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) { + ret = fn(dquot, priv); + if (ret < 0) + goto out; + } + spin_lock(&dq_list_lock); + /* We are safe to continue now because our dquot could not + * be moved out of the inuse list while we hold the reference */ + } + spin_unlock(&dq_list_lock); +out: + dqput(old_dquot); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); + 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; + + mutex_lock(&dqopt->dqonoff_mutex); + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + if (type != -1 && cnt != type) + continue; + if (!sb_has_quota_active(sb, cnt)) + continue; + spin_lock(&dq_list_lock); + dirty = &dqopt->info[cnt].dqi_dirty_list; + while (!list_empty(dirty)) { + dquot = list_first_entry(dirty, struct dquot, + dq_dirty); + /* 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 */ + dqgrab(dquot); + spin_unlock(&dq_list_lock); + dqstats_inc(DQST_LOOKUPS); + err = sb->dq_op->write_dquot(dquot); + if (!ret && err) + 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); + mutex_unlock(&dqopt->dqonoff_mutex); + + 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. + */ + mutex_lock(&dqopt->dqonoff_mutex); + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + if (type != -1 && cnt != type) + continue; + if (!sb_has_quota_active(sb, cnt)) + continue; + mutex_lock(&dqopt->files[cnt]->i_mutex); + truncate_inode_pages(&dqopt->files[cnt]->i_data, 0); + mutex_unlock(&dqopt->files[cnt]->i_mutex); + } + mutex_unlock(&dqopt->dqonoff_mutex); + + return 0; +} +EXPORT_SYMBOL(dquot_quota_sync); + +static unsigned long +dqcache_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) +{ + struct list_head *head; + struct dquot *dquot; + unsigned long freed = 0; + + spin_lock(&dq_list_lock); + head = free_dquots.prev; + while (head != &free_dquots && sc->nr_to_scan) { + dquot = list_entry(head, struct dquot, dq_free); + remove_dquot_hash(dquot); + remove_free_dquot(dquot); + remove_inuse(dquot); + do_destroy_dquot(dquot); + sc->nr_to_scan--; + freed++; + head = free_dquots.prev; + } + 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->dq_wait_unused); + spin_unlock(&dq_list_lock); + return; + } + /* Need to release dquot? */ + if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) { + spin_unlock(&dq_list_lock); + /* Commit dquot before releasing */ + 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 + */ + spin_lock(&dq_list_lock); + clear_dquot_dirty(dquot); + spin_unlock(&dq_list_lock); + } + 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 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); + init_waitqueue_head(&dquot->dq_wait_unused); + dquot->dq_sb = sb; + dquot->dq_id = make_kqid_invalid(type); + atomic_set(&dquot->dq_count, 1); + + 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 = NULL, *empty = NULL; + + if (!sb_has_quota_active(sb, qid.type)) + return NULL; +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); + 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) && + sb->dq_op->acquire_dquot(dquot) < 0) { + dqput(dquot); + dquot = NULL; + goto out; + } +#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 dqonoff_mutex mutex */ +static void add_dquot_ref(struct super_block *sb, int type) +{ + struct inode *inode, *old_inode = NULL; +#ifdef CONFIG_QUOTA_DEBUG + int reserved = 0; +#endif + + spin_lock(&inode_sb_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(&inode_sb_list_lock); + +#ifdef CONFIG_QUOTA_DEBUG + if (unlikely(inode_get_rsv_space(inode) > 0)) + reserved = 1; +#endif + iput(old_inode); + __dquot_initialize(inode, type); + + /* + * We hold a reference to 'inode' so it couldn't have been + * removed from s_inodes list while we dropped the + * inode_sb_list_lock We cannot iput the inode now as we can be + * holding the last reference and we cannot iput it under + * inode_sb_list_lock. So we keep the reference and iput it + * later. + */ + old_inode = inode; + spin_lock(&inode_sb_list_lock); + } + spin_unlock(&inode_sb_list_lock); + iput(old_inode); + +#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 +} + +/* + * Remove references to dquots from inode and add dquot to list for freeing + * if we have the last reference to dquot + */ +static void remove_inode_dquot_ref(struct inode *inode, int type, + struct list_head *tofree_head) +{ + struct dquot **dquots = i_dquot(inode); + struct dquot *dquot = dquots[type]; + + if (!dquot) + return; + + dquots[type] = NULL; + if (list_empty(&dquot->dq_free)) { + /* + * The inode still has reference to dquot so it can't be in the + * free list + */ + spin_lock(&dq_list_lock); + list_add(&dquot->dq_free, tofree_head); + spin_unlock(&dq_list_lock); + } else { + /* + * Dquot is already in a list to put so we won't drop the last + * reference here. + */ + dqput(dquot); + } +} + +/* + * Free list of dquots + * Dquots are removed from inodes and no new references can be got so we are + * the only ones holding reference + */ +static void put_dquot_list(struct list_head *tofree_head) +{ + struct list_head *act_head; + struct dquot *dquot; + + act_head = tofree_head->next; + while (act_head != tofree_head) { + dquot = list_entry(act_head, struct dquot, dq_free); + act_head = act_head->next; + /* Remove dquot from the list so we won't have problems... */ + list_del_init(&dquot->dq_free); + dqput(dquot); + } +} + +static void remove_dquot_ref(struct super_block *sb, int type, + struct list_head *tofree_head) +{ + struct inode *inode; + int reserved = 0; + + spin_lock(&inode_sb_list_lock); + list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { + /* + * We have to scan also I_NEW inodes because they can already + * have quota pointer initialized. Luckily, we need to touch + * only quota pointers and these have separate locking + * (dq_data_lock). + */ + spin_lock(&dq_data_lock); + if (!IS_NOQUOTA(inode)) { + if (unlikely(inode_get_rsv_space(inode) > 0)) + reserved = 1; + remove_inode_dquot_ref(inode, type, tofree_head); + } + spin_unlock(&dq_data_lock); + } + spin_unlock(&inode_sb_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_incr_inodes(struct dquot *dquot, qsize_t 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_resv_space(struct dquot *dquot, qsize_t number) +{ + dquot->dq_dqb.dqb_rsvspace += number; +} + +/* + * Claim reserved quota space + */ +static void dquot_claim_reserved_space(struct dquot *dquot, qsize_t number) +{ + if (dquot->dq_dqb.dqb_rsvspace < number) { + WARN_ON_ONCE(1); + number = dquot->dq_dqb.dqb_rsvspace; + } + dquot->dq_dqb.dqb_curspace += number; + dquot->dq_dqb.dqb_rsvspace -= number; +} + +static void dquot_reclaim_reserved_space(struct dquot *dquot, qsize_t number) +{ + 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; +} + +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; + } +} + +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 = (time_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_bsoftlimit) + dquot->dq_dqb.dqb_btime = (time_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)); +} + +/* needs dq_data_lock */ +static int check_idq(struct dquot *dquot, qsize_t inodes, + struct dquot_warn *warn) +{ + qsize_t 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)) + return 0; + + if (dquot->dq_dqb.dqb_ihardlimit && + newinodes > dquot->dq_dqb.dqb_ihardlimit && + !ignore_hardlimit(dquot)) { + prepare_warning(warn, dquot, QUOTA_NL_IHARDWARN); + return -EDQUOT; + } + + if (dquot->dq_dqb.dqb_isoftlimit && + newinodes > dquot->dq_dqb.dqb_isoftlimit && + dquot->dq_dqb.dqb_itime && + get_seconds() >= dquot->dq_dqb.dqb_itime && + !ignore_hardlimit(dquot)) { + prepare_warning(warn, dquot, QUOTA_NL_ISOFTLONGWARN); + return -EDQUOT; + } + + 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 = get_seconds() + + sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type].dqi_igrace; + } + + return 0; +} + +/* needs dq_data_lock */ +static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, + struct dquot_warn *warn) +{ + qsize_t tspace; + struct super_block *sb = dquot->dq_sb; + + if (!sb_has_quota_limits_enabled(sb, dquot->dq_id.type) || + test_bit(DQ_FAKE_B, &dquot->dq_flags)) + return 0; + + tspace = dquot->dq_dqb.dqb_curspace + dquot->dq_dqb.dqb_rsvspace + + space; + + if (dquot->dq_dqb.dqb_bhardlimit && + tspace > dquot->dq_dqb.dqb_bhardlimit && + !ignore_hardlimit(dquot)) { + if (!prealloc) + prepare_warning(warn, dquot, QUOTA_NL_BHARDWARN); + return -EDQUOT; + } + + if (dquot->dq_dqb.dqb_bsoftlimit && + tspace > dquot->dq_dqb.dqb_bsoftlimit && + dquot->dq_dqb.dqb_btime && + get_seconds() >= dquot->dq_dqb.dqb_btime && + !ignore_hardlimit(dquot)) { + if (!prealloc) + prepare_warning(warn, dquot, QUOTA_NL_BSOFTLONGWARN); + return -EDQUOT; + } + + if (dquot->dq_dqb.dqb_bsoftlimit && + tspace > dquot->dq_dqb.dqb_bsoftlimit && + dquot->dq_dqb.dqb_btime == 0) { + if (!prealloc) { + prepare_warning(warn, dquot, QUOTA_NL_BSOFTWARN); + dquot->dq_dqb.dqb_btime = get_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 + */ + return -EDQUOT; + } + + return 0; +} + +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) +{ + if (test_bit(DQ_FAKE_B, &dquot->dq_flags) || + dquot->dq_dqb.dqb_curspace <= dquot->dq_dqb.dqb_bsoftlimit) + return QUOTA_NL_NOWARN; + + if (dquot->dq_dqb.dqb_curspace - space <= dquot->dq_dqb.dqb_bsoftlimit) + return QUOTA_NL_BSOFTBELOW; + if (dquot->dq_dqb.dqb_curspace >= dquot->dq_dqb.dqb_bhardlimit && + dquot->dq_dqb.dqb_curspace - 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 void __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; + + if (!dquot_active(inode)) + return; + + 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; + + got[cnt] = NULL; + 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; + } + got[cnt] = dqget(sb, qid); + } + + /* All required i_dquot has been initialized */ + if (!init_needed) + return; + + spin_lock(&dq_data_lock); + if (IS_NOQUOTA(inode)) + goto out_err; + 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)) + dquot_resv_space(dquots[cnt], rsv); + } + } +out_err: + spin_unlock(&dq_data_lock); + /* Drop unused references */ + dqput_all(got); +} + +void dquot_initialize(struct inode *inode) +{ + __dquot_initialize(inode, -1); +} +EXPORT_SYMBOL(dquot_initialize); + +/* + * 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); +} + +void inode_add_rsv_space(struct inode *inode, qsize_t number) +{ + spin_lock(&inode->i_lock); + *inode_reserved_space(inode) += number; + spin_unlock(&inode->i_lock); +} +EXPORT_SYMBOL(inode_add_rsv_space); + +void inode_claim_rsv_space(struct inode *inode, qsize_t number) +{ + spin_lock(&inode->i_lock); + *inode_reserved_space(inode) -= number; + __inode_add_bytes(inode, number); + spin_unlock(&inode->i_lock); +} +EXPORT_SYMBOL(inode_claim_rsv_space); + +void inode_reclaim_rsv_space(struct inode *inode, qsize_t number) +{ + spin_lock(&inode->i_lock); + *inode_reserved_space(inode) += number; + __inode_sub_bytes(inode, number); + spin_unlock(&inode->i_lock); +} +EXPORT_SYMBOL(inode_reclaim_rsv_space); + +void inode_sub_rsv_space(struct inode *inode, qsize_t number) +{ + spin_lock(&inode->i_lock); + *inode_reserved_space(inode) -= number; + spin_unlock(&inode->i_lock); +} +EXPORT_SYMBOL(inode_sub_rsv_space); + +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_reserved_space(inode); + spin_unlock(&inode->i_lock); + return ret; +} + +static void inode_incr_space(struct inode *inode, qsize_t number, + int reserve) +{ + if (reserve) + inode_add_rsv_space(inode, number); + else + inode_add_bytes(inode, number); +} + +static void inode_decr_space(struct inode *inode, qsize_t number, int reserve) +{ + if (reserve) + inode_sub_rsv_space(inode, number); + else + inode_sub_bytes(inode, number); +} + +/* + * 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)) { + inode_incr_space(inode, number, reserve); + 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(&dq_data_lock); + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + if (!dquots[cnt]) + continue; + ret = check_bdq(dquots[cnt], number, + !(flags & DQUOT_SPACE_WARN), &warn[cnt]); + if (ret && !(flags & DQUOT_SPACE_NOFAIL)) { + spin_unlock(&dq_data_lock); + goto out_flush_warn; + } + } + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + if (!dquots[cnt]) + continue; + if (reserve) + dquot_resv_space(dquots[cnt], number); + else + dquot_incr_space(dquots[cnt], number); + } + inode_incr_space(inode, number, reserve); + spin_unlock(&dq_data_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(&dq_data_lock); + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + if (!dquots[cnt]) + continue; + ret = check_idq(dquots[cnt], 1, &warn[cnt]); + if (ret) + goto warn_put_all; + } + + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + if (!dquots[cnt]) + continue; + dquot_incr_inodes(dquots[cnt], 1); + } + +warn_put_all: + spin_unlock(&dq_data_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)) { + inode_claim_rsv_space(inode, number); + return 0; + } + + dquots = i_dquot(inode); + index = srcu_read_lock(&dquot_srcu); + spin_lock(&dq_data_lock); + /* Claim reserved quotas to allocated quotas */ + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + if (dquots[cnt]) + dquot_claim_reserved_space(dquots[cnt], number); + } + /* Update inode bytes */ + inode_claim_rsv_space(inode, number); + spin_unlock(&dq_data_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)) { + inode_reclaim_rsv_space(inode, number); + return; + } + + dquots = i_dquot(inode); + index = srcu_read_lock(&dquot_srcu); + spin_lock(&dq_data_lock); + /* Claim reserved quotas to allocated quotas */ + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + if (dquots[cnt]) + dquot_reclaim_reserved_space(dquots[cnt], number); + } + /* Update inode bytes */ + inode_reclaim_rsv_space(inode, number); + spin_unlock(&dq_data_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)) { + inode_decr_space(inode, number, reserve); + return; + } + + dquots = i_dquot(inode); + index = srcu_read_lock(&dquot_srcu); + spin_lock(&dq_data_lock); + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + int wtype; + + warn[cnt].w_type = QUOTA_NL_NOWARN; + if (!dquots[cnt]) + continue; + 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); + } + inode_decr_space(inode, number, reserve); + spin_unlock(&dq_data_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(&dq_data_lock); + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + int wtype; + + warn[cnt].w_type = QUOTA_NL_NOWARN; + if (!dquots[cnt]) + continue; + 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(&dq_data_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 space, cur_space; + qsize_t rsv_space = 0; + 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; + /* 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); + if (IS_NOQUOTA(inode)) { /* File without quota accounting? */ + spin_unlock(&dq_data_lock); + return 0; + } + cur_space = inode_get_bytes(inode); + rsv_space = inode_get_rsv_space(inode); + space = cur_space + rsv_space; + /* Build the transfer_from list and check the limits */ + 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 = check_idq(transfer_to[cnt], 1, &warn_to[cnt]); + if (ret) + goto over_quota; + ret = check_bdq(transfer_to[cnt], space, 0, &warn_to[cnt]); + if (ret) + goto over_quota; + } + + /* + * Finally perform the needed transfer from transfer_from to transfer_to + */ + 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; + wtype = info_idq_free(transfer_from[cnt], 1); + if (wtype != QUOTA_NL_NOWARN) + prepare_warning(&warn_from_inodes[cnt], + transfer_from[cnt], wtype); + wtype = info_bdq_free(transfer_from[cnt], space); + if (wtype != QUOTA_NL_NOWARN) + prepare_warning(&warn_from_space[cnt], + transfer_from[cnt], wtype); + dquot_decr_inodes(transfer_from[cnt], 1); + dquot_decr_space(transfer_from[cnt], cur_space); + dquot_free_reserved_space(transfer_from[cnt], + rsv_space); + } + + dquot_incr_inodes(transfer_to[cnt], 1); + dquot_incr_space(transfer_to[cnt], cur_space); + dquot_resv_space(transfer_to[cnt], rsv_space); + + i_dquot(inode)[cnt] = transfer_to[cnt]; + } + 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: + 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 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)) + transfer_to[USRQUOTA] = dqget(sb, make_kqid_uid(iattr->ia_uid)); + if (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid)) + transfer_to[GRPQUOTA] = dqget(sb, make_kqid_gid(iattr->ia_gid)); + + ret = __dquot_transfer(inode, transfer_to); + 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) +{ + int ret; + struct quota_info *dqopt = sb_dqopt(sb); + + mutex_lock(&dqopt->dqio_mutex); + ret = dqopt->ops[type]->write_file_info(sb, type); + mutex_unlock(&dqopt->dqio_mutex); + return ret; +} +EXPORT_SYMBOL(dquot_commit_info); + +/* + * 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, +}; +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)) + dquot_initialize(inode); + return error; +} +EXPORT_SYMBOL(dquot_file_open); + +/* + * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount) + */ +int dquot_disable(struct super_block *sb, int type, unsigned int flags) +{ + int cnt, ret = 0; + struct quota_info *dqopt = sb_dqopt(sb); + struct inode *toputinode[MAXQUOTAS]; + + /* 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; + + /* We need to serialize quota_off() for device */ + mutex_lock(&dqopt->dqonoff_mutex); + + /* + * 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)) { + mutex_unlock(&dqopt->dqonoff_mutex); + return 0; + } + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + toputinode[cnt] = NULL; + if (type != -1 && cnt != type) + continue; + if (!sb_has_quota_loaded(sb, cnt)) + continue; + + if (flags & DQUOT_SUSPENDED) { + spin_lock(&dq_state_lock); + dqopt->flags |= + dquot_state_flag(DQUOT_SUSPENDED, cnt); + spin_unlock(&dq_state_lock); + } else { + spin_lock(&dq_state_lock); + dqopt->flags &= ~dquot_state_flag(flags, cnt); + /* Turning off suspended quotas? */ + if (!sb_has_quota_loaded(sb, cnt) && + sb_has_quota_suspended(sb, cnt)) { + dqopt->flags &= ~dquot_state_flag( + DQUOT_SUSPENDED, cnt); + spin_unlock(&dq_state_lock); + iput(dqopt->files[cnt]); + dqopt->files[cnt] = NULL; + continue; + } + spin_unlock(&dq_state_lock); + } + + /* We still have to keep quota loaded? */ + if (sb_has_quota_loaded(sb, cnt) && !(flags & DQUOT_SUSPENDED)) + continue; + + /* Note: these are blocking operations */ + drop_dquot_ref(sb, cnt); + invalidate_dquots(sb, cnt); + /* + * Now all dquots should be invalidated, all writes done so we + * should be only users of the info. No locks needed. + */ + if (info_dirty(&dqopt->info[cnt])) + sb->dq_op->write_info(sb, cnt); + if (dqopt->ops[cnt]->free_file_info) + dqopt->ops[cnt]->free_file_info(sb, cnt); + put_quota_format(dqopt->info[cnt].dqi_format); + + toputinode[cnt] = dqopt->files[cnt]; + if (!sb_has_quota_loaded(sb, cnt)) + dqopt->files[cnt] = NULL; + dqopt->info[cnt].dqi_flags = 0; + dqopt->info[cnt].dqi_igrace = 0; + dqopt->info[cnt].dqi_bgrace = 0; + dqopt->ops[cnt] = NULL; + } + mutex_unlock(&dqopt->dqonoff_mutex); + + /* 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 (toputinode[cnt]) { + mutex_lock(&dqopt->dqonoff_mutex); + /* If quota was reenabled in the meantime, we have + * nothing to do */ + if (!sb_has_quota_loaded(sb, cnt)) { + mutex_lock(&toputinode[cnt]->i_mutex); + toputinode[cnt]->i_flags &= ~(S_IMMUTABLE | + S_NOATIME | S_NOQUOTA); + truncate_inode_pages(&toputinode[cnt]->i_data, + 0); + mutex_unlock(&toputinode[cnt]->i_mutex); + mark_inode_dirty_sync(toputinode[cnt]); + } + mutex_unlock(&dqopt->dqonoff_mutex); + } + if (sb->s_bdev) + invalidate_bdev(sb->s_bdev); +put_inodes: + for (cnt = 0; cnt < MAXQUOTAS; cnt++) + if (toputinode[cnt]) { + /* On remount RO, we keep the inode pointer so that we + * can reenable quota on the subsequent remount RW. We + * have to check 'flags' variable and not use sb_has_ + * function because another quotaon / quotaoff could + * change global state before we got here. We refuse + * to suspend quotas when there is pending delete on + * the quota file... */ + if (!(flags & DQUOT_SUSPENDED)) + iput(toputinode[cnt]); + else if (!toputinode[cnt]->i_nlink) + ret = -EBUSY; + } + return ret; +} +EXPORT_SYMBOL(dquot_disable); + +int dquot_quota_off(struct super_block *sb, int type) +{ + return dquot_disable(sb, type, + DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED); +} +EXPORT_SYMBOL(dquot_quota_off); + +/* + * Turn quotas on on a device + */ + +/* + * Helper function to turn quotas on when we already have the inode of + * quota file and no quota information is loaded. + */ +static int vfs_load_quota_inode(struct inode *inode, int type, int format_id, + unsigned int flags) +{ + struct quota_format_type *fmt = find_quota_format(format_id); + struct super_block *sb = inode->i_sb; + struct quota_info *dqopt = sb_dqopt(sb); + int error; + int oldflags = -1; + + if (!fmt) + return -ESRCH; + if (!S_ISREG(inode->i_mode)) { + error = -EACCES; + goto out_fmt; + } + if (IS_RDONLY(inode)) { + error = -EROFS; + goto out_fmt; + } + if (!sb->s_op->quota_write || !sb->s_op->quota_read || + (type == PRJQUOTA && sb->dq_op->get_projid == NULL)) { + error = -EINVAL; + goto out_fmt; + } + /* Usage always has to be set... */ + if (!(flags & DQUOT_USAGE_ENABLED)) { + error = -EINVAL; + 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); + } + mutex_lock(&dqopt->dqonoff_mutex); + if (sb_has_quota_loaded(sb, type)) { + error = -EBUSY; + goto out_lock; + } + + 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. */ + mutex_lock(&inode->i_mutex); + oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | + S_NOQUOTA); + inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE; + mutex_unlock(&inode->i_mutex); + /* + * When S_NOQUOTA is set, remove dquot references as no more + * references can be added + */ + __dquot_drop(inode); + } + + error = -EIO; + dqopt->files[type] = igrab(inode); + if (!dqopt->files[type]) + goto out_lock; + error = -EINVAL; + if (!fmt->qf_ops->check_quota_file(sb, type)) + goto out_file_init; + + dqopt->ops[type] = fmt->qf_ops; + dqopt->info[type].dqi_format = fmt; + dqopt->info[type].dqi_fmt_id = format_id; + INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list); + mutex_lock(&dqopt->dqio_mutex); + error = dqopt->ops[type]->read_file_info(sb, type); + if (error < 0) { + mutex_unlock(&dqopt->dqio_mutex); + goto out_file_init; + } + if (dqopt->flags & DQUOT_QUOTA_SYS_FILE) + dqopt->info[type].dqi_flags |= DQF_SYS_FILE; + mutex_unlock(&dqopt->dqio_mutex); + spin_lock(&dq_state_lock); + dqopt->flags |= dquot_state_flag(flags, type); + spin_unlock(&dq_state_lock); + + add_dquot_ref(sb, type); + mutex_unlock(&dqopt->dqonoff_mutex); + + return 0; + +out_file_init: + dqopt->files[type] = NULL; + iput(inode); +out_lock: + if (oldflags != -1) { + mutex_lock(&inode->i_mutex); + /* Set the flags back (in the case of accidental quotaon() + * on a wrong file we don't want to mess up the flags) */ + inode->i_flags &= ~(S_NOATIME | S_NOQUOTA | S_IMMUTABLE); + inode->i_flags |= oldflags; + mutex_unlock(&inode->i_mutex); + } + mutex_unlock(&dqopt->dqonoff_mutex); +out_fmt: + put_quota_format(fmt); + + return error; +} + +/* Reenable quotas on remount RW */ +int dquot_resume(struct super_block *sb, int type) +{ + struct quota_info *dqopt = sb_dqopt(sb); + struct inode *inode; + int ret = 0, cnt; + unsigned int flags; + + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { + if (type != -1 && cnt != type) + continue; + + mutex_lock(&dqopt->dqonoff_mutex); + if (!sb_has_quota_suspended(sb, cnt)) { + mutex_unlock(&dqopt->dqonoff_mutex); + continue; + } + inode = dqopt->files[cnt]; + dqopt->files[cnt] = NULL; + spin_lock(&dq_state_lock); + flags = dqopt->flags & dquot_state_flag(DQUOT_USAGE_ENABLED | + DQUOT_LIMITS_ENABLED, + cnt); + dqopt->flags &= ~dquot_state_flag(DQUOT_STATE_FLAGS, cnt); + spin_unlock(&dq_state_lock); + mutex_unlock(&dqopt->dqonoff_mutex); + + flags = dquot_generic_flag(flags, cnt); + ret = vfs_load_quota_inode(inode, cnt, + dqopt->info[cnt].dqi_fmt_id, flags); + iput(inode); + } + + return ret; +} +EXPORT_SYMBOL(dquot_resume); + +int dquot_quota_on(struct super_block *sb, int type, int format_id, + struct path *path) +{ + int error = security_quota_on(path->dentry); + if (error) + return error; + /* Quota file not on the same filesystem? */ + if (path->dentry->d_sb != sb) + error = -EXDEV; + else + error = vfs_load_quota_inode(d_inode(path->dentry), type, + format_id, DQUOT_USAGE_ENABLED | + DQUOT_LIMITS_ENABLED); + return error; +} +EXPORT_SYMBOL(dquot_quota_on); + +/* + * More powerful function for turning on quotas allowing setting + * of individual quota flags + */ +int dquot_enable(struct inode *inode, int type, int format_id, + unsigned int flags) +{ + int ret = 0; + struct super_block *sb = inode->i_sb; + struct quota_info *dqopt = sb_dqopt(sb); + + /* Just unsuspend quotas? */ + BUG_ON(flags & DQUOT_SUSPENDED); + + if (!flags) + return 0; + /* Just updating flags needed? */ + if (sb_has_quota_loaded(sb, type)) { + mutex_lock(&dqopt->dqonoff_mutex); + /* Now do a reliable test... */ + if (!sb_has_quota_loaded(sb, type)) { + mutex_unlock(&dqopt->dqonoff_mutex); + goto load_quota; + } + if (flags & DQUOT_USAGE_ENABLED && + sb_has_quota_usage_enabled(sb, type)) { + ret = -EBUSY; + goto out_lock; + } + if (flags & DQUOT_LIMITS_ENABLED && + sb_has_quota_limits_enabled(sb, type)) { + ret = -EBUSY; + goto out_lock; + } + spin_lock(&dq_state_lock); + sb_dqopt(sb)->flags |= dquot_state_flag(flags, type); + spin_unlock(&dq_state_lock); +out_lock: + mutex_unlock(&dqopt->dqonoff_mutex); + return ret; + } + +load_quota: + return vfs_load_quota_inode(inode, type, format_id, flags); +} +EXPORT_SYMBOL(dquot_enable); + +/* + * This function is used when filesystem needs to initialize quotas + * during mount time. + */ +int dquot_quota_on_mount(struct super_block *sb, char *qf_name, + int format_id, int type) +{ + struct dentry *dentry; + int error; + + mutex_lock(&d_inode(sb->s_root)->i_mutex); + dentry = lookup_one_len(qf_name, sb->s_root, strlen(qf_name)); + mutex_unlock(&d_inode(sb->s_root)->i_mutex); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + + if (d_really_is_negative(dentry)) { + error = -ENOENT; + goto out; + } + + error = security_quota_on(dentry); + if (!error) + error = vfs_load_quota_inode(d_inode(dentry), type, format_id, + DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED); + +out: + dput(dentry); + return error; +} +EXPORT_SYMBOL(dquot_quota_on_mount); + +static int dquot_quota_enable(struct super_block *sb, unsigned int flags) +{ + int ret; + int type; + struct quota_info *dqopt = sb_dqopt(sb); + + if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) + return -ENOSYS; + /* Accounting cannot be turned on while fs is mounted */ + flags &= ~(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT); + if (!flags) + return -EINVAL; + for (type = 0; type < MAXQUOTAS; type++) { + if (!(flags & qtype_enforce_flag(type))) + continue; + /* Can't enforce without accounting */ + if (!sb_has_quota_usage_enabled(sb, type)) + return -EINVAL; + ret = dquot_enable(dqopt->files[type], type, + dqopt->info[type].dqi_fmt_id, + DQUOT_LIMITS_ENABLED); + if (ret < 0) + goto out_err; + } + return 0; +out_err: + /* Backout enforcement enablement we already did */ + for (type--; type >= 0; type--) { + if (flags & qtype_enforce_flag(type)) + dquot_disable(sb, type, DQUOT_LIMITS_ENABLED); + } + /* Error code translation for better compatibility with XFS */ + if (ret == -EBUSY) + ret = -EEXIST; + return ret; +} + +static int dquot_quota_disable(struct super_block *sb, unsigned int flags) +{ + int ret; + int type; + struct quota_info *dqopt = sb_dqopt(sb); + + if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) + return -ENOSYS; + /* + * We don't support turning off accounting via quotactl. In principle + * quota infrastructure can do this but filesystems don't expect + * userspace to be able to do it. + */ + if (flags & + (FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT)) + return -EOPNOTSUPP; + + /* Filter out limits not enabled */ + for (type = 0; type < MAXQUOTAS; type++) + if (!sb_has_quota_limits_enabled(sb, type)) + flags &= ~qtype_enforce_flag(type); + /* Nothing left? */ + if (!flags) + return -EEXIST; + for (type = 0; type < MAXQUOTAS; type++) { + if (flags & qtype_enforce_flag(type)) { + ret = dquot_disable(sb, type, DQUOT_LIMITS_ENABLED); + if (ret < 0) + goto out_err; + } + } + return 0; +out_err: + /* Backout enforcement disabling we already did */ + for (type--; type >= 0; type--) { + if (flags & qtype_enforce_flag(type)) + dquot_enable(dqopt->files[type], type, + dqopt->info[type].dqi_fmt_id, + DQUOT_LIMITS_ENABLED); + } + return ret; +} + +/* Generic routine for getting common part of quota structure */ +static void do_get_dqblk(struct dquot *dquot, struct qc_dqblk *di) +{ + struct mem_dqblk *dm = &dquot->dq_dqb; + + memset(di, 0, sizeof(*di)); + spin_lock(&dq_data_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(&dq_data_lock); +} + +int dquot_get_dqblk(struct super_block *sb, struct kqid qid, + struct qc_dqblk *di) +{ + struct dquot *dquot; + + dquot = dqget(sb, qid); + if (!dquot) + return -ESRCH; + do_get_dqblk(dquot, di); + dqput(dquot); + + return 0; +} +EXPORT_SYMBOL(dquot_get_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(&dq_data_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_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 = get_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 = get_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(&dq_data_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 (!dquot) { + rc = -ESRCH; + 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; + + mutex_lock(&sb_dqopt(sb)->dqonoff_mutex); + memset(state, 0, sizeof(*state)); + for (type = 0; type < MAXQUOTAS; type++) { + if (!sb_has_quota_active(sb, type)) + continue; + tstate = state->s_state + type; + mi = sb_dqopt(sb)->info + type; + tstate->flags = QCI_ACCT_ENABLED; + spin_lock(&dq_data_lock); + if (mi->dqi_flags & DQF_SYS_FILE) + tstate->flags |= QCI_SYSFILE; + if (mi->dqi_flags & DQF_ROOT_SQUASH) + tstate->flags |= QCI_ROOT_SQUASH; + if (sb_has_quota_limits_enabled(sb, type)) + tstate->flags |= QCI_LIMITS_ENFORCED; + tstate->spc_timelimit = mi->dqi_bgrace; + tstate->ino_timelimit = mi->dqi_igrace; + tstate->ino = dqopt->files[type]->i_ino; + tstate->blocks = dqopt->files[type]->i_blocks; + tstate->nextents = 1; /* We don't know... */ + spin_unlock(&dq_data_lock); + } + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); + 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; + mutex_lock(&sb_dqopt(sb)->dqonoff_mutex); + if (!sb_has_quota_active(sb, type)) { + err = -ESRCH; + goto out; + } + 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)) { + err = -EINVAL; + goto out; + } + } + 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); +out: + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); + return err; +} +EXPORT_SYMBOL(dquot_set_dqinfo); + +const struct quotactl_ops dquot_quotactl_ops = { + .quota_on = dquot_quota_on, + .quota_off = dquot_quota_off, + .quota_sync = dquot_quota_sync, + .get_state = dquot_get_state, + .set_info = dquot_set_dqinfo, + .get_dqblk = dquot_get_dqblk, + .set_dqblk = dquot_set_dqblk +}; +EXPORT_SYMBOL(dquot_quotactl_ops); + +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, + .set_dqblk = dquot_set_dqblk +}; +EXPORT_SYMBOL(dquot_quotactl_sysfile_ops); + +static int do_proc_dqstats(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + unsigned int type = (int *)table->data - dqstats.stat; + + /* Update global table */ + dqstats.stat[type] = + percpu_counter_sum_positive(&dqstats.counter[type]); + return proc_dointvec(table, write, buffer, lenp, ppos); +} + +static struct ctl_table fs_dqstats_table[] = { + { + .procname = "lookups", + .data = &dqstats.stat[DQST_LOOKUPS], + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = do_proc_dqstats, + }, + { + .procname = "drops", + .data = &dqstats.stat[DQST_DROPS], + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = do_proc_dqstats, + }, + { + .procname = "reads", + .data = &dqstats.stat[DQST_READS], + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = do_proc_dqstats, + }, + { + .procname = "writes", + .data = &dqstats.stat[DQST_WRITES], + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = do_proc_dqstats, + }, + { + .procname = "cache_hits", + .data = &dqstats.stat[DQST_CACHE_HITS], + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = do_proc_dqstats, + }, + { + .procname = "allocated_dquots", + .data = &dqstats.stat[DQST_ALLOC_DQUOTS], + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = do_proc_dqstats, + }, + { + .procname = "free_dquots", + .data = &dqstats.stat[DQST_FREE_DQUOTS], + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = do_proc_dqstats, + }, + { + .procname = "syncs", + .data = &dqstats.stat[DQST_SYNCS], + .maxlen = sizeof(int), + .mode = 0444, + .proc_handler = do_proc_dqstats, + }, +#ifdef CONFIG_PRINT_QUOTA_WARNING + { + .procname = "warnings", + .data = &flag_print_warnings, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, +#endif + { }, +}; + +static struct ctl_table fs_table[] = { + { + .procname = "quota", + .mode = 0555, + .child = fs_dqstats_table, + }, + { }, +}; + +static struct ctl_table sys_table[] = { + { + .procname = "fs", + .mode = 0555, + .child = fs_table, + }, + { }, +}; + +static int __init dquot_init(void) +{ + int i, ret; + unsigned long nr_hash, order; + + printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__); + + register_sysctl_table(sys_table); + + dquot_cachep = kmem_cache_create("dquot", + sizeof(struct dquot), sizeof(unsigned long) * 4, + (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| + SLAB_MEM_SPREAD|SLAB_PANIC), + NULL); + + order = 0; + dquot_hash = (struct hlist_head *)__get_free_pages(GFP_ATOMIC, order); + if (!dquot_hash) + panic("Cannot create dquot hash table"); + + for (i = 0; i < _DQST_DQSTAT_LAST; i++) { + ret = percpu_counter_init(&dqstats.counter[i], 0, GFP_KERNEL); + if (ret) + panic("Cannot create dquot stat counters"); + } + + /* Find power-of-two hlist_heads which can fit into allocation */ + nr_hash = (1UL << order) * PAGE_SIZE / sizeof(struct hlist_head); + dq_hash_bits = 0; + do { + dq_hash_bits++; + } while (nr_hash >> dq_hash_bits); + dq_hash_bits--; + + nr_hash = 1UL << dq_hash_bits; + dq_hash_mask = nr_hash - 1; + for (i = 0; i < nr_hash; i++) + INIT_HLIST_HEAD(dquot_hash + i); + + pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld," + " %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order)); + + register_shrinker(&dqcache_shrinker); + + return 0; +} +module_init(dquot_init); |