From c3b004460d77bf3f980d877be539016f2df4df12 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Wed, 23 Nov 2016 14:04:55 +0100 Subject: [PATCH] quota: Remove dqonoff_mutex The only places that were grabbing dqonoff_mutex are functions turning quotas on and off and these are properly serialized using s_umount semaphore. Remove dqonoff_mutex. Signed-off-by: Jan Kara --- fs/quota/dquot.c | 80 +++++++++++++------------------------------ fs/super.c | 1 - include/linux/quota.h | 1 - 3 files changed, 23 insertions(+), 59 deletions(-) diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index d91aecc939c9..550f78f2b7c7 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -119,8 +119,7 @@ * 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. + * s_umount > i_mutex > journal_lock > dquot->dq_lock > dqio_mutex */ static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dq_list_lock); @@ -933,7 +932,7 @@ static int dqinit_needed(struct inode *inode, int type) return 0; } -/* This routine is guarded by dqonoff_mutex mutex */ +/* This routine is guarded by s_umount semaphore */ static void add_dquot_ref(struct super_block *sb, int type) { struct inode *inode, *old_inode = NULL; @@ -2108,18 +2107,14 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags) 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); + if (!sb_any_quota_loaded(sb)) return 0; - } + for (cnt = 0; cnt < MAXQUOTAS; cnt++) { toputinode[cnt] = NULL; if (type != -1 && cnt != type) @@ -2173,7 +2168,6 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags) 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) @@ -2191,19 +2185,13 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags) * 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)) { - inode_lock(toputinode[cnt]); - toputinode[cnt]->i_flags &= ~(S_IMMUTABLE | + WARN_ON_ONCE(sb_has_quota_loaded(sb, cnt)); + inode_lock(toputinode[cnt]); + toputinode[cnt]->i_flags &= ~(S_IMMUTABLE | S_NOATIME | S_NOQUOTA); - truncate_inode_pages(&toputinode[cnt]->i_data, - 0); - inode_unlock(toputinode[cnt]); - mark_inode_dirty_sync(toputinode[cnt]); - } - mutex_unlock(&dqopt->dqonoff_mutex); + truncate_inode_pages(&toputinode[cnt]->i_data, 0); + inode_unlock(toputinode[cnt]); + mark_inode_dirty_sync(toputinode[cnt]); } if (sb->s_bdev) invalidate_bdev(sb->s_bdev); @@ -2275,6 +2263,10 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id, error = -EINVAL; goto out_fmt; } + if (sb_has_quota_loaded(sb, type)) { + error = -EBUSY; + goto out_fmt; + } if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) { /* As we bypass the pagecache we must now flush all the @@ -2286,11 +2278,6 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id, 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 @@ -2311,7 +2298,7 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id, error = -EIO; dqopt->files[type] = igrab(inode); if (!dqopt->files[type]) - goto out_lock; + goto out_file_flags; error = -EINVAL; if (!fmt->qf_ops->check_quota_file(sb, type)) goto out_file_init; @@ -2334,14 +2321,13 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id, 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: +out_file_flags: if (oldflags != -1) { inode_lock(inode); /* Set the flags back (in the case of accidental quotaon() @@ -2350,7 +2336,6 @@ out_lock: inode->i_flags |= oldflags; inode_unlock(inode); } - mutex_unlock(&dqopt->dqonoff_mutex); out_fmt: put_quota_format(fmt); @@ -2372,12 +2357,9 @@ int dquot_resume(struct super_block *sb, int type) 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); + if (!sb_has_quota_suspended(sb, cnt)) continue; - } + inode = dqopt->files[cnt]; dqopt->files[cnt] = NULL; spin_lock(&dq_state_lock); @@ -2386,7 +2368,6 @@ int dquot_resume(struct super_block *sb, int type) 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, @@ -2422,9 +2403,7 @@ EXPORT_SYMBOL(dquot_quota_on); 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); @@ -2436,31 +2415,18 @@ int dquot_enable(struct inode *inode, int type, int format_id, 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; - } + sb_has_quota_usage_enabled(sb, type)) + return -EBUSY; if (flags & DQUOT_LIMITS_ENABLED && - sb_has_quota_limits_enabled(sb, type)) { - ret = -EBUSY; - goto out_lock; - } + sb_has_quota_limits_enabled(sb, type)) + return -EBUSY; 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; + return 0; } -load_quota: return vfs_load_quota_inode(inode, type, format_id, flags); } EXPORT_SYMBOL(dquot_enable); diff --git a/fs/super.c b/fs/super.c index f7f724230e2b..1709ed029a2c 100644 --- a/fs/super.c +++ b/fs/super.c @@ -244,7 +244,6 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags, mutex_init(&s->s_vfs_rename_mutex); lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key); mutex_init(&s->s_dquot.dqio_mutex); - mutex_init(&s->s_dquot.dqonoff_mutex); s->s_maxbytes = MAX_NON_LFS; s->s_op = &default_op; s->s_time_gran = 1000000000; diff --git a/include/linux/quota.h b/include/linux/quota.h index 55107a8ff887..b281d198ee5b 100644 --- a/include/linux/quota.h +++ b/include/linux/quota.h @@ -520,7 +520,6 @@ static inline void quota_send_warning(struct kqid qid, dev_t dev, struct quota_info { unsigned int flags; /* Flags for diskquotas on this device */ struct mutex dqio_mutex; /* lock device while I/O in progress */ - struct mutex dqonoff_mutex; /* Serialize quotaon & quotaoff */ struct inode *files[MAXQUOTAS]; /* inodes of quotafiles */ struct mem_dqinfo info[MAXQUOTAS]; /* Information for each quota type */ const struct quota_format_ops *ops[MAXQUOTAS]; /* Operations for each type */ -- 2.20.1