diff options
Diffstat (limited to 'fs/dquot.c')
| -rw-r--r-- | fs/dquot.c | 167 |
1 files changed, 97 insertions, 70 deletions
@@ -103,12 +103,12 @@ * (these locking rules also apply for S_NOQUOTA flag in the inode - note that * for altering the flag i_mutex is also needed). If operation is holding * reference to dquot in other way (e.g. quotactl ops) it must be guarded by - * dqonoff_sem. + * 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 semaphore. Locked dquots might not be referenced + * 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 @@ -118,9 +118,9 @@ * spinlock to internal buffers before writing. * * Lock ordering (including related VFS locks) is the following: - * i_mutex > dqonoff_sem > iprune_sem > journal_lock > dqptr_sem > - * > dquot->dq_lock > dqio_sem - * i_mutex on quota files is special (it's below dqio_sem) + * 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); @@ -281,8 +281,8 @@ static inline void remove_inuse(struct dquot *dquot) static void wait_on_dquot(struct dquot *dquot) { - down(&dquot->dq_lock); - up(&dquot->dq_lock); + mutex_lock(&dquot->dq_lock); + mutex_unlock(&dquot->dq_lock); } #define mark_dquot_dirty(dquot) ((dquot)->dq_sb->dq_op->mark_dirty(dquot)) @@ -321,8 +321,8 @@ int dquot_acquire(struct dquot *dquot) int ret = 0, ret2 = 0; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); - down(&dquot->dq_lock); - down(&dqopt->dqio_sem); + 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) @@ -343,8 +343,8 @@ int dquot_acquire(struct dquot *dquot) } set_bit(DQ_ACTIVE_B, &dquot->dq_flags); out_iolock: - up(&dqopt->dqio_sem); - up(&dquot->dq_lock); + mutex_unlock(&dqopt->dqio_mutex); + mutex_unlock(&dquot->dq_lock); return ret; } @@ -356,7 +356,7 @@ int dquot_commit(struct dquot *dquot) int ret = 0, ret2 = 0; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); - down(&dqopt->dqio_sem); + mutex_lock(&dqopt->dqio_mutex); spin_lock(&dq_list_lock); if (!clear_dquot_dirty(dquot)) { spin_unlock(&dq_list_lock); @@ -373,7 +373,7 @@ int dquot_commit(struct dquot *dquot) ret = ret2; } out_sem: - up(&dqopt->dqio_sem); + mutex_unlock(&dqopt->dqio_mutex); return ret; } @@ -385,11 +385,11 @@ int dquot_release(struct dquot *dquot) int ret = 0, ret2 = 0; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb); - down(&dquot->dq_lock); + 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; - down(&dqopt->dqio_sem); + 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 */ @@ -399,31 +399,57 @@ int dquot_release(struct dquot *dquot) ret = ret2; } clear_bit(DQ_ACTIVE_B, &dquot->dq_flags); - up(&dqopt->dqio_sem); + mutex_unlock(&dqopt->dqio_mutex); out_dqlock: - up(&dquot->dq_lock); + 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. Also because we hold dqonoff_sem there can be no quota users - * for this sb+type at all. */ + * 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; -#ifdef __DQUOT_PARANOIA - if (atomic_read(&dquot->dq_count)) - BUG(); -#endif - /* Quota now has no users and it has been written on last dqput() */ + /* 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); @@ -439,7 +465,7 @@ int vfs_quota_sync(struct super_block *sb, int type) struct quota_info *dqopt = sb_dqopt(sb); int cnt; - down(&dqopt->dqonoff_sem); + mutex_lock(&dqopt->dqonoff_mutex); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { if (type != -1 && cnt != type) continue; @@ -474,7 +500,7 @@ int vfs_quota_sync(struct super_block *sb, int type) spin_lock(&dq_list_lock); dqstats.syncs++; spin_unlock(&dq_list_lock); - up(&dqopt->dqonoff_sem); + mutex_unlock(&dqopt->dqonoff_mutex); return 0; } @@ -515,7 +541,7 @@ static int shrink_dqcache_memory(int nr, gfp_t gfp_mask) /* * Put reference to dquot * NOTE: If you change this function please check whether dqput_blocks() works right... - * MUST be called with either dqptr_sem or dqonoff_sem held + * MUST be called with either dqptr_sem or dqonoff_mutex held */ static void dqput(struct dquot *dquot) { @@ -540,6 +566,10 @@ we_slept: 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; } @@ -576,11 +606,12 @@ static struct dquot *get_empty_dquot(struct super_block *sb, int type) return NODQUOT; memset((caddr_t)dquot, 0, sizeof(struct dquot)); - sema_init(&dquot->dq_lock, 1); + 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); @@ -590,7 +621,7 @@ static struct dquot *get_empty_dquot(struct super_block *sb, int type) /* * Get reference to dquot - * MUST be called with either dqptr_sem or dqonoff_sem held + * MUST be called with either dqptr_sem or dqonoff_mutex held */ static struct dquot *dqget(struct super_block *sb, unsigned int id, int type) { @@ -656,7 +687,7 @@ static int dqinit_needed(struct inode *inode, int type) return 0; } -/* This routine is guarded by dqonoff_sem semaphore */ +/* This routine is guarded by dqonoff_mutex mutex */ static void add_dquot_ref(struct super_block *sb, int type) { struct list_head *p; @@ -732,13 +763,9 @@ static void drop_dquot_ref(struct super_block *sb, int type) { LIST_HEAD(tofree_head); - /* We need to be guarded against prune_icache to reach all the - * inodes - otherwise some can be on the local list of prune_icache */ - down(&iprune_sem); down_write(&sb_dqopt(sb)->dqptr_sem); remove_dquot_ref(sb, type, &tofree_head); up_write(&sb_dqopt(sb)->dqptr_sem); - up(&iprune_sem); put_dquot_list(&tofree_head); } @@ -938,8 +965,8 @@ int dquot_initialize(struct inode *inode, int type) unsigned int id = 0; int cnt, ret = 0; - /* First test before acquiring semaphore - solves deadlocks when we - * re-enter the quota code and are already holding the semaphore */ + /* 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); @@ -1002,8 +1029,8 @@ int dquot_alloc_space(struct inode *inode, qsize_t number, int warn) int cnt, ret = NO_QUOTA; char warntype[MAXQUOTAS]; - /* First test before acquiring semaphore - solves deadlocks when we - * re-enter the quota code and are already holding the semaphore */ + /* 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); @@ -1051,8 +1078,8 @@ int dquot_alloc_inode(const struct inode *inode, unsigned long number) int cnt, ret = NO_QUOTA; char warntype[MAXQUOTAS]; - /* First test before acquiring semaphore - solves deadlocks when we - * re-enter the quota code and are already holding the semaphore */ + /* 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++) @@ -1095,8 +1122,8 @@ int dquot_free_space(struct inode *inode, qsize_t number) { unsigned int cnt; - /* First test before acquiring semaphore - solves deadlocks when we - * re-enter the quota code and are already holding the semaphore */ + /* 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); @@ -1131,8 +1158,8 @@ int dquot_free_inode(const struct inode *inode, unsigned long number) { unsigned int cnt; - /* First test before acquiring semaphore - solves deadlocks when we - * re-enter the quota code and are already holding the semaphore */ + /* 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); @@ -1171,8 +1198,8 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr) chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid; char warntype[MAXQUOTAS]; - /* First test before acquiring semaphore - solves deadlocks when we - * re-enter the quota code and are already holding the semaphore */ + /* 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 */ @@ -1266,9 +1293,9 @@ int dquot_commit_info(struct super_block *sb, int type) int ret; struct quota_info *dqopt = sb_dqopt(sb); - down(&dqopt->dqio_sem); + mutex_lock(&dqopt->dqio_mutex); ret = dqopt->ops[type]->write_file_info(sb, type); - up(&dqopt->dqio_sem); + mutex_unlock(&dqopt->dqio_mutex); return ret; } @@ -1324,7 +1351,7 @@ int vfs_quota_off(struct super_block *sb, int type) struct inode *toputinode[MAXQUOTAS]; /* We need to serialize quota_off() for device */ - down(&dqopt->dqonoff_sem); + mutex_lock(&dqopt->dqonoff_mutex); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { toputinode[cnt] = NULL; if (type != -1 && cnt != type) @@ -1353,7 +1380,7 @@ int vfs_quota_off(struct super_block *sb, int type) dqopt->info[cnt].dqi_bgrace = 0; dqopt->ops[cnt] = NULL; } - up(&dqopt->dqonoff_sem); + 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) @@ -1366,7 +1393,7 @@ int vfs_quota_off(struct super_block *sb, int type) * changes done by userspace on the next quotaon() */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) if (toputinode[cnt]) { - down(&dqopt->dqonoff_sem); + mutex_lock(&dqopt->dqonoff_mutex); /* If quota was reenabled in the meantime, we have * nothing to do */ if (!sb_has_quota_enabled(sb, cnt)) { @@ -1378,7 +1405,7 @@ int vfs_quota_off(struct super_block *sb, int type) mark_inode_dirty(toputinode[cnt]); iput(toputinode[cnt]); } - up(&dqopt->dqonoff_sem); + mutex_unlock(&dqopt->dqonoff_mutex); } if (sb->s_bdev) invalidate_bdev(sb->s_bdev, 0); @@ -1419,7 +1446,7 @@ static int vfs_quota_on_inode(struct inode *inode, int type, int format_id) /* And now flush the block cache so that kernel sees the changes */ invalidate_bdev(sb->s_bdev, 0); mutex_lock(&inode->i_mutex); - down(&dqopt->dqonoff_sem); + mutex_lock(&dqopt->dqonoff_mutex); if (sb_has_quota_enabled(sb, type)) { error = -EBUSY; goto out_lock; @@ -1444,17 +1471,17 @@ static int vfs_quota_on_inode(struct inode *inode, int type, int format_id) dqopt->ops[type] = fmt->qf_ops; dqopt->info[type].dqi_format = fmt; INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list); - down(&dqopt->dqio_sem); + mutex_lock(&dqopt->dqio_mutex); if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) { - up(&dqopt->dqio_sem); + mutex_unlock(&dqopt->dqio_mutex); goto out_file_init; } - up(&dqopt->dqio_sem); + mutex_unlock(&dqopt->dqio_mutex); mutex_unlock(&inode->i_mutex); set_enable_flags(dqopt, type); add_dquot_ref(sb, type); - up(&dqopt->dqonoff_sem); + mutex_unlock(&dqopt->dqonoff_mutex); return 0; @@ -1462,7 +1489,7 @@ out_file_init: dqopt->files[type] = NULL; iput(inode); out_lock: - up(&dqopt->dqonoff_sem); + mutex_unlock(&dqopt->dqonoff_mutex); if (oldflags != -1) { down_write(&dqopt->dqptr_sem); /* Set the flags back (in the case of accidental quotaon() @@ -1550,14 +1577,14 @@ int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *d { struct dquot *dquot; - down(&sb_dqopt(sb)->dqonoff_sem); + mutex_lock(&sb_dqopt(sb)->dqonoff_mutex); if (!(dquot = dqget(sb, id, type))) { - up(&sb_dqopt(sb)->dqonoff_sem); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); return -ESRCH; } do_get_dqblk(dquot, di); dqput(dquot); - up(&sb_dqopt(sb)->dqonoff_sem); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); return 0; } @@ -1619,14 +1646,14 @@ int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *d { struct dquot *dquot; - down(&sb_dqopt(sb)->dqonoff_sem); + mutex_lock(&sb_dqopt(sb)->dqonoff_mutex); if (!(dquot = dqget(sb, id, type))) { - up(&sb_dqopt(sb)->dqonoff_sem); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); return -ESRCH; } do_set_dqblk(dquot, di); dqput(dquot); - up(&sb_dqopt(sb)->dqonoff_sem); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); return 0; } @@ -1635,9 +1662,9 @@ int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii) { struct mem_dqinfo *mi; - down(&sb_dqopt(sb)->dqonoff_sem); + mutex_lock(&sb_dqopt(sb)->dqonoff_mutex); if (!sb_has_quota_enabled(sb, type)) { - up(&sb_dqopt(sb)->dqonoff_sem); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); return -ESRCH; } mi = sb_dqopt(sb)->info + type; @@ -1647,7 +1674,7 @@ int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii) ii->dqi_flags = mi->dqi_flags & DQF_MASK; ii->dqi_valid = IIF_ALL; spin_unlock(&dq_data_lock); - up(&sb_dqopt(sb)->dqonoff_sem); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); return 0; } @@ -1656,9 +1683,9 @@ int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii) { struct mem_dqinfo *mi; - down(&sb_dqopt(sb)->dqonoff_sem); + mutex_lock(&sb_dqopt(sb)->dqonoff_mutex); if (!sb_has_quota_enabled(sb, type)) { - up(&sb_dqopt(sb)->dqonoff_sem); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); return -ESRCH; } mi = sb_dqopt(sb)->info + type; @@ -1673,7 +1700,7 @@ int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii) mark_info_dirty(sb, type); /* Force write to disk */ sb->dq_op->write_info(sb, type); - up(&sb_dqopt(sb)->dqonoff_sem); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); return 0; } |
