litmus-rt.git - The LITMUS^RT kernel.

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/* * Implementation of the diskquota system for the LINUX operating system. QUOTA * is implemented using the BSD system call interface as the means of * communication with the user level. This file contains the generic routines * called by the different filesystems on allocation of an inode or block. * These routines take care of the administration needed to have a consistent * diskquota tracking system. The ideas of both user and group quotas are based * on the Melbourne quota system as used on BSD derived systems. The internal * implementation is based on one of the several variants of the LINUX * inode-subsystem with added complexity of the diskquota system. * * Version: $Id: dquot.c,v 6.3 1996/11/17 18:35:34 mvw Exp mvw $ * * Author: Marco van Wieringen <mvw@planets.elm.net> * * Fixes: Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96 * * Revised list management to avoid races * -- Bill Hawes, <whawes@star.net>, 9/98 * * Fixed races in dquot_transfer(), dqget() and dquot_alloc_...(). * As the consequence the locking was moved from dquot_decr_...(), * dquot_incr_...() to calling functions. * invalidate_dquots() now writes modified dquots. * Serialized quota_off() and quota_on() for mount point. * Fixed a few bugs in grow_dquots(). * Fixed deadlock in write_dquot() - we no longer account quotas on * quota files * remove_dquot_ref() moved to inode.c - it now traverses through inodes * add_dquot_ref() restarts after blocking * Added check for bogus uid and fixed check for group in quotactl. * Jan Kara, <jack@suse.cz>, sponsored by SuSE CR, 10-11/99 * * Used struct list_head instead of own list struct * Invalidation of referenced dquots is no longer possible * Improved free_dquots list management * Quota and i_blocks are now updated in one place to avoid races * Warnings are now delayed so we won't block in critical section * Write updated not to require dquot lock * Jan Kara, <jack@suse.cz>, 9/2000 * * Added dynamic quota structure allocation * Jan Kara <jack@suse.cz> 12/2000 * * Rewritten quota interface. Implemented new quota format and * formats registering. * Jan Kara, <jack@suse.cz>, 2001,2002 * * New SMP locking. * Jan Kara, <jack@suse.cz>, 10/2002 * * Added journalled quota support, fix lock inversion problems * Jan Kara, <jack@suse.cz>, 2003,2004 * * (C) Copyright 1994 - 1997 Marco van Wieringen */ #include <linux/errno.h> #include <linux/kernel.h> #include <linux/fs.h> #include <linux/mount.h> #include <linux/mm.h> #include <linux/time.h> #include <linux/types.h> #include <linux/string.h> #include <linux/fcntl.h> #include <linux/stat.h> #include <linux/tty.h> #include <linux/file.h> #include <linux/slab.h> #include <linux/sysctl.h> #include <linux/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_mutex. * This locking assures that: * a) update/access to dquot pointers in inode is serialized * b) everyone is guarded against invalidate_dquots() * * Each dquot has its dq_lock mutex. Locked dquots might not be referenced * from inodes (dquot_alloc_space() and such don't check the dq_lock). * Currently dquot is locked only when it is being read to memory (or space for * it is being allocated) on the first dqget() and when it is being released on * the last dqput(). The allocation and release oparations are serialized by * the dq_lock and by checking the use count in dquot_release(). Write * operations on dquots don't hold dq_lock as they copy data under dq_data_lock * spinlock to internal buffers before writing. * * Lock ordering (including related VFS locks) is the following: * i_mutex > dqonoff_sem > journal_lock > dqptr_sem > dquot->dq_lock > * dqio_mutex * i_mutex on quota files is special (it's below dqio_mutex) */ static DEFINE_SPINLOCK(dq_list_lock); DEFINE_SPINLOCK(dq_data_lock); static char *quotatypes[] = INITQFNAMES; static struct quota_format_type *quota_formats; /* List of registered formats */ static struct quota_module_name module_names[] = INIT_QUOTA_MODULE_NAMES; /* SLAB cache for dquot structures */ static 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 = &quota_formats; *actqf && *actqf != fmt; actqf = &(*actqf)->qf_next); if (*actqf) *actqf = (*actqf)->qf_next; spin_unlock(&dq_list_lock); } static struct quota_format_type *find_quota_format(int id) { struct quota_format_type *actqf; spin_lock(&dq_list_lock); for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next); if (!actqf || !try_module_get(actqf->qf_owner)) { int qm; spin_unlock(&dq_list_lock); for (qm = 0; module_names[qm].qm_fmt_id && module_names[qm].qm_fmt_id != id; qm++); if (!module_names[qm].qm_fmt_id || request_module(module_names[qm].qm_mod_name)) return NULL; spin_lock(&dq_list_lock); for (actqf = quota_formats; actqf && actqf->qf_fmt_id != id; actqf = actqf->qf_next); if (actqf && !try_module_get(actqf->qf_owner)) actqf = NULL; } spin_unlock(&dq_list_lock); return actqf; } static void put_quota_format(struct quota_format_type *fmt) { module_put(fmt->qf_owner); } /* * Dquot List Management: * The quota code uses three lists for dquot management: the inuse_list, * free_dquots, and dquot_hash[] array. A single dquot structure may be * on all three lists, depending on its current state. * * All dquots are placed to the end of inuse_list when first created, and this * list is used for invalidate operation, which must look at every dquot. * * Unused dquots (dq_count == 0) are added to the free_dquots list when freed, * and this list is searched whenever we need an available dquot. Dquots are * removed from the list as soon as they are used again, and * dqstats.free_dquots gives the number of dquots on the list. When * dquot is invalidated it's completely released from memory. * * Dquots with a specific identity (device, type and id) are placed on * one of the dquot_hash[] hash chains. The provides an efficient search * mechanism to locate a specific dquot. */ static LIST_HEAD(inuse_list); static LIST_HEAD(free_dquots); static unsigned int dq_hash_bits, dq_hash_mask; static struct hlist_head *dquot_hash; struct dqstats dqstats; static void dqput(struct dquot *dquot); static inline unsigned int hashfn(const struct super_block *sb, unsigned int id, int type) { unsigned long tmp; tmp = (((unsigned long)sb>>L1_CACHE_SHIFT) ^ id) * (MAXQUOTAS - type); return (tmp + (tmp >> dq_hash_bits)) & dq_hash_mask; } /* * Following list functions expect dq_list_lock to be held */ static inline void insert_dquot_hash(struct dquot *dquot) { struct hlist_head *head = dquot_hash + hashfn(dquot->dq_sb, dquot->dq_id, dquot->dq_type); hlist_add_head(&dquot->dq_hash, head); } static inline void remove_dquot_hash(struct dquot *dquot) { hlist_del_init(&dquot->dq_hash); } static inline struct dquot *find_dquot(unsigned int hashent, struct super_block *sb, unsigned int id, int type) { struct hlist_node *node; struct dquot *dquot; hlist_for_each (node, dquot_hash+hashent) { dquot = hlist_entry(node, struct dquot, dq_hash); if (dquot->dq_sb == sb && dquot->dq_id == id && dquot->dq_type == type) return dquot; } return NODQUOT; } /* Add a dquot to the tail of the free list */ static inline void put_dquot_last(struct dquot *dquot) { list_add(&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) { mutex_lock(&dquot->dq_lock); mutex_unlock(&dquot->dq_lock); } #define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot)) int dquot_mark_dquot_dirty(struct dquot *dquot) { spin_lock(&dq_list_lock); if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags)) list_add(&dquot->dq_dirty, &sb_dqopt(dquot->dq_sb)-> info[dquot->dq_type].dqi_dirty_list); spin_unlock(&dq_list_lock); return 0; } /* This function needs dq_list_lock */ static inline int clear_dquot_dirty(struct dquot *dquot) { if (!test_and_clear_bit(DQ_MOD_B, &dquot->dq_flags)) return 0; list_del_init(&dquot->dq_dirty); return 1; } void mark_info_dirty(struct super_block *sb, int type) { set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags); } EXPORT_SYMBOL(mark_info_dirty); /* * Read dquot from disk and alloc space for it */ int dquot_acquire(struct dquot *dquot) { int ret = 0, ret2 = 0; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); mutex_lock(&dquot->dq_lock); mutex_lock(&dqopt->dqio_mutex); if (!test_bit(DQ_READ_B, &dquot->dq_flags)) ret = dqopt->ops[dquot->dq_type]->read_dqblk(dquot); if (ret < 0) goto out_iolock; set_bit(DQ_READ_B, &dquot->dq_flags); /* Instantiate dquot if needed */ if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && !dquot->dq_off) { ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot); /* Write the info if needed */ if (info_dirty(&dqopt->info[dquot->dq_type])) ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type); if (ret < 0) goto out_iolock; if (ret2 < 0) { ret = ret2; goto out_iolock; } } set_bit(DQ_ACTIVE_B, &dquot->dq_flags); out_iolock: mutex_unlock(&dqopt->dqio_mutex); mutex_unlock(&dquot->dq_lock); return ret; } /* * Write dquot to disk */ int dquot_commit(struct dquot *dquot) { int ret = 0, ret2 = 0; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); mutex_lock(&dqopt->dqio_mutex); spin_lock(&dq_list_lock); if (!clear_dquot_dirty(dquot)) { spin_unlock(&dq_list_lock); goto out_sem; } spin_unlock(&dq_list_lock); /* Inactive dquot can be only if there was error during read/init * => we have better not writing it */ if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) { ret = dqopt->ops[dquot->dq_type]->commit_dqblk(dquot); if (info_dirty(&dqopt->info[dquot->dq_type])) ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type); if (ret >= 0) ret = ret2; } out_sem: mutex_unlock(&dqopt->dqio_mutex); return ret; } /* * Release dquot */ int dquot_release(struct dquot *dquot) { int ret = 0, ret2 = 0; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); mutex_lock(&dquot->dq_lock); /* Check whether we are not racing with some other dqget() */ if (atomic_read(&dquot->dq_count) > 1) goto out_dqlock; mutex_lock(&dqopt->dqio_mutex); if (dqopt->ops[dquot->dq_type]->release_dqblk) { ret = dqopt->ops[dquot->dq_type]->release_dqblk(dquot); /* Write the info */ if (info_dirty(&dqopt->info[dquot->dq_type])) ret2 = dqopt->ops[dquot->dq_type]->write_file_info(dquot->dq_sb, dquot->dq_type); if (ret >= 0) ret = ret2; } clear_bit(DQ_ACTIVE_B, &dquot->dq_flags); mutex_unlock(&dqopt->dqio_mutex); out_dqlock: mutex_unlock(&dquot->dq_lock); return ret; } /* Invalidate all dquots on the list. Note that this function is called after * quota is disabled and pointers from inodes removed so there cannot be new * quota users. There can still be some users of quotas due to inodes being * just deleted or pruned by prune_icache() (those are not attached to any * list). We have to wait for such users. */ static void invalidate_dquots(struct super_block *sb, int type) { struct dquot *dquot, *tmp; restart: spin_lock(&dq_list_lock); list_for_each_entry_safe(dquot, tmp, &inuse_list, dq_inuse) { if (dquot->dq_sb != sb) continue; if (dquot->dq_type != type) continue; /* Wait for dquot users */ if (atomic_read(&dquot->dq_count)) { DEFINE_WAIT(wait); atomic_inc(&dquot->dq_count); prepare_to_wait(&dquot->dq_wait_unused, &wait, TASK_UNINTERRUPTIBLE); spin_unlock(&dq_list_lock); /* Once dqput() wakes us up, we know it's time to free * the dquot. * IMPORTANT: we rely on the fact that there is always * at most one process waiting for dquot to free. * Otherwise dq_count would be > 1 and we would never * wake up. */ if (atomic_read(&dquot->dq_count) > 1) schedule(); finish_wait(&dquot->dq_wait_unused, &wait); dqput(dquot); /* At this moment dquot() need not exist (it could be * reclaimed by prune_dqcache(). Hence we must * restart. */ goto restart; } /* * Quota now has no users and it has been written on last * dqput() */ remove_dquot_hash(dquot); remove_free_dquot(dquot); remove_inuse(dquot); kmem_cache_free(dquot_cachep, dquot); } spin_unlock(&dq_list_lock); } int vfs_quota_sync(struct super_block *sb, int type) { struct list_head *dirty; struct dquot *dquot; struct quota_info *dqopt = sb_dqopt(sb); int cnt; mutex_lock(&dqopt->dqonoff_mutex); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (type != -1 && cnt != type) continue; if (!sb_has_quota_enabled(sb, cnt)) continue; spin_lock(&dq_list_lock); dirty = &dqopt->info[cnt].dqi_dirty_list; while (!list_empty(dirty)) { dquot = list_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); mutex_unlock(&dqopt->dqonoff_mutex); return 0; } /* Free unused dquots from cache */ static void prune_dqcache(int count) { struct list_head *head; struct dquot *dquot; head = free_dquots.prev; while (head != &free_dquots && count) { dquot = list_entry(head, struct dquot, dq_free); remove_dquot_hash(dquot); remove_free_dquot(dquot); remove_inuse(dquot); kmem_cache_free(dquot_cachep, dquot); count--; head = free_dquots.prev; } } /* * This is called from kswapd when we think we need some * more memory */ static int shrink_dqcache_memory(int nr, gfp_t gfp_mask) { if (nr) { spin_lock(&dq_list_lock); prune_dqcache(nr); spin_unlock(&dq_list_lock); } return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure; } /* * Put reference to dquot * NOTE: If you change this function please check whether dqput_blocks() works right... * MUST be called with either dqptr_sem or dqonoff_mutex held */ static void dqput(struct dquot *dquot) { if (!dquot) return; #ifdef __DQUOT_PARANOIA if (!atomic_read(&dquot->dq_count)) { printk("VFS: dqput: trying to free free dquot\n"); printk("VFS: device %s, dquot of %s %d\n", dquot->dq_sb->s_id, quotatypes[dquot->dq_type], dquot->dq_id); BUG(); } #endif spin_lock(&dq_list_lock); dqstats.drops++; spin_unlock(&dq_list_lock); we_slept: spin_lock(&dq_list_lock); if (atomic_read(&dquot->dq_count) > 1) { /* We have more than one user... nothing to do */ atomic_dec(&dquot->dq_count); /* Releasing dquot during quotaoff phase? */ if (!sb_has_quota_enabled(dquot->dq_sb, dquot->dq_type) && atomic_read(&dquot->dq_count) == 1) wake_up(&dquot->dq_wait_unused); spin_unlock(&dq_list_lock); return; } /* Need to release dquot? */ if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) { spin_unlock(&dq_list_lock); /* Commit dquot before releasing */ dquot->dq_sb->dq_op->write_dquot(dquot); goto we_slept; } /* Clear flag in case dquot was inactive (something bad happened) */ clear_dquot_dirty(dquot); if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) { spin_unlock(&dq_list_lock); dquot->dq_sb->dq_op->release_dquot(dquot); goto we_slept; } atomic_dec(&dquot->dq_count); #ifdef __DQUOT_PARANOIA /* sanity check */ BUG_ON(!list_empty(&dquot->dq_free)); #endif put_dquot_last(dquot); spin_unlock(&dq_list_lock); } static struct dquot *get_empty_dquot(struct super_block *sb, int type) { struct dquot *dquot; dquot = kmem_cache_alloc(dquot_cachep, SLAB_NOFS); if(!dquot) return NODQUOT; memset((caddr_t)dquot, 0, sizeof(struct dquot)); mutex_init(&dquot->dq_lock); INIT_LIST_HEAD(&dquot->dq_free); INIT_LIST_HEAD(&dquot->dq_inuse); INIT_HLIST_NODE(&dquot->dq_hash); INIT_LIST_HEAD(&dquot->dq_dirty); init_waitqueue_head(&dquot->dq_wait_unused); dquot->dq_sb = sb; dquot->dq_type = type; atomic_set(&dquot->dq_count, 1); return dquot; } /* * Get reference to dquot * MUST be called with either dqptr_sem or dqonoff_mutex held */ static struct dquot *dqget(struct super_block *sb, unsigned int id, int type) { unsigned int hashent = hashfn(sb, id, type); struct dquot *dquot, *empty = NODQUOT; if (!sb_has_quota_enabled(sb, type)) return NODQUOT; we_slept: spin_lock(&dq_list_lock); if ((dquot = find_dquot(hashent, sb, id, type)) == NODQUOT) { if (empty == NODQUOT) { spin_unlock(&dq_list_lock); if ((empty = get_empty_dquot(sb, type)) == NODQUOT) schedule(); /* Try to wait for a moment... */ goto we_slept; } dquot = empty; dquot->dq_id = id; /* all dquots go on the inuse_list */ put_inuse(dquot); /* hash it first so it can be found */ insert_dquot_hash(dquot); dqstats.lookups++; spin_unlock(&dq_list_lock); } else { if (!atomic_read(&dquot->dq_count)) remove_free_dquot(dquot); atomic_inc(&dquot->dq_count); dqstats.cache_hits++; dqstats.lookups++; spin_unlock(&dq_list_lock); if (empty) kmem_cache_free(dquot_cachep, empty); } /* Wait for dq_lock - after this we know that either dquot_release() is already * finished or it will be canceled due to dq_count > 1 test */ wait_on_dquot(dquot); /* Read the dquot and instantiate it (everything done only if needed) */ if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && sb->dq_op->acquire_dquot(dquot) < 0) { dqput(dquot); return NODQUOT; } #ifdef __DQUOT_PARANOIA BUG_ON(!dquot->dq_sb); /* Has somebody invalidated entry under us? */ #endif return dquot; } static int dqinit_needed(struct inode *inode, int type) { int cnt; if (IS_NOQUOTA(inode)) return 0; if (type != -1) return inode->i_dquot[type] == NODQUOT; for (cnt = 0; cnt < MAXQUOTAS; cnt++) if (inode->i_dquot[cnt] == NODQUOT) return 1; return 0; } /* This routine is guarded by dqonoff_mutex mutex */ static void add_dquot_ref(struct super_block *sb, int type) { struct 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); down_write(&sb_dqopt(sb)->dqptr_sem); remove_dquot_ref(sb, type, &tofree_head); up_write(&sb_dqopt(sb)->dqptr_sem); put_dquot_list(&tofree_head); } static inline void dquot_incr_inodes(struct dquot *dquot, unsigned long number) { dquot->dq_dqb.dqb_curinodes += number; } static inline void dquot_incr_space(struct dquot *dquot, qsize_t number) { dquot->dq_dqb.dqb_curspace += number; } static inline void dquot_decr_inodes(struct dquot *dquot, unsigned long number) { if (dquot->dq_dqb.dqb_curinodes > number) dquot->dq_dqb.dqb_curinodes -= number; else dquot->dq_dqb.dqb_curinodes = 0; if (dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit) dquot->dq_dqb.dqb_itime = (time_t) 0; clear_bit(DQ_INODES_B, &dquot->dq_flags); } static inline void dquot_decr_space(struct dquot *dquot, qsize_t number) { if (dquot->dq_dqb.dqb_curspace > number) dquot->dq_dqb.dqb_curspace -= number; else dquot->dq_dqb.dqb_curspace = 0; if (toqb(dquot->dq_dqb.dqb_curspace) <= dquot->dq_dqb.dqb_bsoftlimit) dquot->dq_dqb.dqb_btime = (time_t) 0; clear_bit(DQ_BLKS_B, &dquot->dq_flags); } static int 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 mutex - solves deadlocks when we * re-enter the quota code and are already holding the mutex */ if (IS_NOQUOTA(inode)) return 0; down_write(&sb_dqopt(inode->i_sb)->dqptr_sem); /* Having dqptr_sem we know NOQUOTA flags can't be altered... */ if (IS_NOQUOTA(inode)) goto out_err; for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (type != -1 && cnt != type) continue; if (inode->i_dquot[cnt] == NODQUOT) { switch (cnt) { case USRQUOTA: id = inode->i_uid; break; case GRPQUOTA: id = inode->i_gid; break; } inode->i_dquot[cnt] = dqget(inode->i_sb, id, cnt); } } out_err: up_write(&sb_dqopt(inode->i_sb)->dqptr_sem); return ret; } /* * Release all quotas referenced by inode * Transaction must be started at an entry */ int dquot_drop(struct inode *inode) { int cnt; down_write(&sb_dqopt(inode->i_sb)->dqptr_sem); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (inode->i_dquot[cnt] != NODQUOT) { dqput(inode->i_dquot[cnt]); inode->i_dquot[cnt] = NODQUOT; } } up_write(&sb_dqopt(inode->i_sb)->dqptr_sem); return 0; } /* * Following four functions update i_blocks+i_bytes fields and * quota information (together with appropriate checks) * NOTE: We absolutely rely on the fact that caller dirties * the inode (usually macros in quotaops.h care about this) and * holds a handle for the current transaction so that dquot write and * inode write go into the same transaction. */ /* * This operation can block, but only after everything is updated */ int dquot_alloc_space(struct inode *inode, qsize_t number, int warn) { int cnt, ret = NO_QUOTA; char warntype[MAXQUOTAS]; /* First test before acquiring mutex - solves deadlocks when we * re-enter the quota code and are already holding the mutex */ if (IS_NOQUOTA(inode)) { out_add: inode_add_bytes(inode, number); return QUOTA_OK; } for (cnt = 0; cnt < MAXQUOTAS; cnt++) warntype[cnt] = NOWARN; down_read(&sb_dqopt(inode->i_sb)->dqptr_sem); if (IS_NOQUOTA(inode)) { /* Now we can do reliable test... */ up_read(&sb_dqopt(inode->i_sb)->dqptr_sem); goto out_add; } spin_lock(&dq_data_lock); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (inode->i_dquot[cnt] == NODQUOT) continue; if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt) == NO_QUOTA) goto warn_put_all; } for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (inode->i_dquot[cnt] == NODQUOT) continue; dquot_incr_space(inode->i_dquot[cnt], number); } inode_add_bytes(inode, number); ret = QUOTA_OK; warn_put_all: spin_unlock(&dq_data_lock); if (ret == QUOTA_OK) /* Dirtify all the dquots - this can block when journalling */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) if (inode->i_dquot[cnt]) mark_dquot_dirty(inode->i_dquot[cnt]); flush_warnings(inode->i_dquot, warntype); up_read(&sb_dqopt(inode->i_sb)->dqptr_sem); return ret; } /* * This operation can block, but only after everything is updated */ int dquot_alloc_inode(const struct inode *inode, unsigned long number) { int cnt, ret = NO_QUOTA; char warntype[MAXQUOTAS]; /* First test before acquiring mutex - solves deadlocks when we * re-enter the quota code and are already holding the mutex */ if (IS_NOQUOTA(inode)) return QUOTA_OK; for (cnt = 0; cnt < MAXQUOTAS; cnt++) warntype[cnt] = NOWARN; down_read(&sb_dqopt(inode->i_sb)->dqptr_sem); if (IS_NOQUOTA(inode)) { up_read(&sb_dqopt(inode->i_sb)->dqptr_sem); return QUOTA_OK; } spin_lock(&dq_data_lock); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (inode->i_dquot[cnt] == NODQUOT) continue; if (check_idq(inode->i_dquot[cnt], number, warntype+cnt) == NO_QUOTA) goto warn_put_all; } for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (inode->i_dquot[cnt] == NODQUOT) continue; dquot_incr_inodes(inode->i_dquot[cnt], number); } ret = QUOTA_OK; warn_put_all: spin_unlock(&dq_data_lock); if (ret == QUOTA_OK) /* Dirtify all the dquots - this can block when journalling */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) if (inode->i_dquot[cnt]) mark_dquot_dirty(inode->i_dquot[cnt]); flush_warnings((struct dquot **)inode->i_dquot, warntype); up_read(&sb_dqopt(inode->i_sb)->dqptr_sem); return ret; } /* * This operation can block, but only after everything is updated */ int dquot_free_space(struct inode *inode, qsize_t number) { unsigned int cnt; /* First test before acquiring mutex - solves deadlocks when we * re-enter the quota code and are already holding the mutex */ if (IS_NOQUOTA(inode)) { out_sub: inode_sub_bytes(inode, number); return QUOTA_OK; } down_read(&sb_dqopt(inode->i_sb)->dqptr_sem); /* Now recheck reliably when holding dqptr_sem */ if (IS_NOQUOTA(inode)) { up_read(&sb_dqopt(inode->i_sb)->dqptr_sem); goto out_sub; } spin_lock(&dq_data_lock); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (inode->i_dquot[cnt] == NODQUOT) continue; dquot_decr_space(inode->i_dquot[cnt], number); } inode_sub_bytes(inode, number); spin_unlock(&dq_data_lock); /* Dirtify all the dquots - this can block when journalling */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) if (inode->i_dquot[cnt]) mark_dquot_dirty(inode->i_dquot[cnt]); up_read(&sb_dqopt(inode->i_sb)->dqptr_sem); return QUOTA_OK; } /* * This operation can block, but only after everything is updated */ int dquot_free_inode(const struct inode *inode, unsigned long number) { unsigned int cnt; /* First test before acquiring mutex - solves deadlocks when we * re-enter the quota code and are already holding the mutex */ if (IS_NOQUOTA(inode)) return QUOTA_OK; down_read(&sb_dqopt(inode->i_sb)->dqptr_sem); /* Now recheck reliably when holding dqptr_sem */ if (IS_NOQUOTA(inode)) { up_read(&sb_dqopt(inode->i_sb)->dqptr_sem); return QUOTA_OK; } spin_lock(&dq_data_lock); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (inode->i_dquot[cnt] == NODQUOT) continue; dquot_decr_inodes(inode->i_dquot[cnt], number); } spin_unlock(&dq_data_lock); /* Dirtify all the dquots - this can block when journalling */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) if (inode->i_dquot[cnt]) mark_dquot_dirty(inode->i_dquot[cnt]); up_read(&sb_dqopt(inode->i_sb)->dqptr_sem); return QUOTA_OK; } /* * Transfer the number of inode and blocks from one diskquota to an other. * * This operation can block, but only after everything is updated * A transaction must be started when entering this function. */ int dquot_transfer(struct inode *inode, struct iattr *iattr) { qsize_t space; struct dquot *transfer_from[MAXQUOTAS]; struct dquot *transfer_to[MAXQUOTAS]; int cnt, ret = NO_QUOTA, chuid = (iattr->ia_valid & ATTR_UID) && inode->i_uid != iattr->ia_uid, chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid; char warntype[MAXQUOTAS]; /* First test before acquiring mutex - solves deadlocks when we * re-enter the quota code and are already holding the mutex */ if (IS_NOQUOTA(inode)) return QUOTA_OK; /* Clear the arrays */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) { transfer_to[cnt] = transfer_from[cnt] = NODQUOT; warntype[cnt] = NOWARN; } down_write(&sb_dqopt(inode->i_sb)->dqptr_sem); /* Now recheck reliably when holding dqptr_sem */ if (IS_NOQUOTA(inode)) { /* File without quota accounting? */ up_write(&sb_dqopt(inode->i_sb)->dqptr_sem); return QUOTA_OK; } /* First build the transfer_to list - here we can block on * reading/instantiating of dquots. We know that the transaction for * us was already started so we don't violate lock ranking here */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) { switch (cnt) { case USRQUOTA: if (!chuid) continue; transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_uid, cnt); break; case GRPQUOTA: if (!chgid) continue; transfer_to[cnt] = dqget(inode->i_sb, iattr->ia_gid, cnt); break; } } spin_lock(&dq_data_lock); space = inode_get_bytes(inode); /* Build the transfer_from list and check the limits */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (transfer_to[cnt] == NODQUOT) continue; transfer_from[cnt] = inode->i_dquot[cnt]; if (check_idq(transfer_to[cnt], 1, warntype+cnt) == NO_QUOTA || check_bdq(transfer_to[cnt], space, 0, warntype+cnt) == NO_QUOTA) goto warn_put_all; } /* * Finally perform the needed transfer from transfer_from to transfer_to */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) { /* * Skip changes for same uid or gid or for turned off quota-type. */ if (transfer_to[cnt] == NODQUOT) continue; /* Due to IO error we might not have transfer_from[] structure */ if (transfer_from[cnt]) { dquot_decr_inodes(transfer_from[cnt], 1); dquot_decr_space(transfer_from[cnt], space); } dquot_incr_inodes(transfer_to[cnt], 1); dquot_incr_space(transfer_to[cnt], space); inode->i_dquot[cnt] = transfer_to[cnt]; } ret = QUOTA_OK; warn_put_all: spin_unlock(&dq_data_lock); /* Dirtify all the dquots - this can block when journalling */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (transfer_from[cnt]) mark_dquot_dirty(transfer_from[cnt]); if (transfer_to[cnt]) mark_dquot_dirty(transfer_to[cnt]); } flush_warnings(transfer_to, warntype); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (ret == QUOTA_OK && transfer_from[cnt] != NODQUOT) dqput(transfer_from[cnt]); if (ret == NO_QUOTA && transfer_to[cnt] != NODQUOT) dqput(transfer_to[cnt]); } up_write(&sb_dqopt(inode->i_sb)->dqptr_sem); return ret; } /* * Write info of quota file to disk */ int dquot_commit_info(struct super_block *sb, int type) { int ret; struct quota_info *dqopt = sb_dqopt(sb); mutex_lock(&dqopt->dqio_mutex); ret = dqopt->ops[type]->write_file_info(sb, type); mutex_unlock(&dqopt->dqio_mutex); return ret; } /* * Definitions of diskquota operations. */ struct dquot_operations dquot_operations = { .initialize = dquot_initialize, .drop = dquot_drop, .alloc_space = dquot_alloc_space, .alloc_inode = dquot_alloc_inode, .free_space = dquot_free_space, .free_inode = dquot_free_inode, .transfer = dquot_transfer, .write_dquot = dquot_commit, .acquire_dquot = dquot_acquire, .release_dquot = dquot_release, .mark_dirty = dquot_mark_dquot_dirty, .write_info = dquot_commit_info }; static inline void set_enable_flags(struct quota_info *dqopt, int type) { switch (type) { case USRQUOTA: dqopt->flags |= DQUOT_USR_ENABLED; break; case GRPQUOTA: dqopt->flags |= DQUOT_GRP_ENABLED; break; } } static inline void reset_enable_flags(struct quota_info *dqopt, int type) { switch (type) { case USRQUOTA: dqopt->flags &= ~DQUOT_USR_ENABLED; break; case GRPQUOTA: dqopt->flags &= ~DQUOT_GRP_ENABLED; break; } } /* * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount) */ int vfs_quota_off(struct super_block *sb, int type) { int cnt; struct quota_info *dqopt = sb_dqopt(sb); struct inode *toputinode[MAXQUOTAS]; /* We need to serialize quota_off() for device */ mutex_lock(&dqopt->dqonoff_mutex); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { toputinode[cnt] = NULL; if (type != -1 && cnt != type) continue; if (!sb_has_quota_enabled(sb, cnt)) continue; reset_enable_flags(dqopt, cnt); /* Note: these are blocking operations */ drop_dquot_ref(sb, cnt); invalidate_dquots(sb, cnt); /* * Now all dquots should be invalidated, all writes done so we should be only * users of the info. No locks needed. */ if (info_dirty(&dqopt->info[cnt])) sb->dq_op->write_info(sb, cnt); if (dqopt->ops[cnt]->free_file_info) dqopt->ops[cnt]->free_file_info(sb, cnt); put_quota_format(dqopt->info[cnt].dqi_format); toputinode[cnt] = dqopt->files[cnt]; dqopt->files[cnt] = NULL; dqopt->info[cnt].dqi_flags = 0; dqopt->info[cnt].dqi_igrace = 0; dqopt->info[cnt].dqi_bgrace = 0; dqopt->ops[cnt] = NULL; } mutex_unlock(&dqopt->dqonoff_mutex); /* Sync the superblock so that buffers with quota data are written to * disk (and so userspace sees correct data afterwards). */ if (sb->s_op->sync_fs) sb->s_op->sync_fs(sb, 1); sync_blockdev(sb->s_bdev); /* Now the quota files are just ordinary files and we can set the * inode flags back. Moreover we discard the pagecache so that * userspace sees the writes we did bypassing the pagecache. We * must also discard the blockdev buffers so that we see the * changes done by userspace on the next quotaon() */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) if (toputinode[cnt]) { mutex_lock(&dqopt->dqonoff_mutex); /* If quota was reenabled in the meantime, we have


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