From 61855d6805ae078ae6bba561e6e76715436d776d Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Fri, 6 Dec 2019 10:54:23 -0600 Subject: fs: avoid softlockups in s_inodes iterators [ Upstream commit 04646aebd30b99f2cfa0182435a2ec252fcb16d0 ] Anything that walks all inodes on sb->s_inodes list without rescheduling risks softlockups. Previous efforts were made in 2 functions, see: c27d82f fs/drop_caches.c: avoid softlockups in drop_pagecache_sb() ac05fbb inode: don't softlockup when evicting inodes but there hasn't been an audit of all walkers, so do that now. This also consistently moves the cond_resched() calls to the bottom of each loop in cases where it already exists. One loop remains: remove_dquot_ref(), because I'm not quite sure how to deal with that one w/o taking the i_lock. Signed-off-by: Eric Sandeen Reviewed-by: Jan Kara Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- fs/drop_caches.c | 2 +- fs/inode.c | 7 +++++++ fs/notify/fsnotify.c | 1 + fs/quota/dquot.c | 1 + 4 files changed, 10 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/drop_caches.c b/fs/drop_caches.c index d31b6c72b476..dc1a1d5d825b 100644 --- a/fs/drop_caches.c +++ b/fs/drop_caches.c @@ -35,11 +35,11 @@ static void drop_pagecache_sb(struct super_block *sb, void *unused) spin_unlock(&inode->i_lock); spin_unlock(&sb->s_inode_list_lock); - cond_resched(); invalidate_mapping_pages(inode->i_mapping, 0, -1); iput(toput_inode); toput_inode = inode; + cond_resched(); spin_lock(&sb->s_inode_list_lock); } spin_unlock(&sb->s_inode_list_lock); diff --git a/fs/inode.c b/fs/inode.c index 76f7535fe754..d2a700c5efce 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -656,6 +656,7 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty) struct inode *inode, *next; LIST_HEAD(dispose); +again: spin_lock(&sb->s_inode_list_lock); list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { spin_lock(&inode->i_lock); @@ -678,6 +679,12 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty) inode_lru_list_del(inode); spin_unlock(&inode->i_lock); list_add(&inode->i_lru, &dispose); + if (need_resched()) { + spin_unlock(&sb->s_inode_list_lock); + cond_resched(); + dispose_list(&dispose); + goto again; + } } spin_unlock(&sb->s_inode_list_lock); diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 506da82ff3f1..a308f7a7e577 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -90,6 +90,7 @@ void fsnotify_unmount_inodes(struct super_block *sb) iput_inode = inode; + cond_resched(); spin_lock(&sb->s_inode_list_lock); } spin_unlock(&sb->s_inode_list_lock); diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index 3fdbdd29702b..30f5da8f4aff 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -976,6 +976,7 @@ static int add_dquot_ref(struct super_block *sb, int type) * later. */ old_inode = inode; + cond_resched(); spin_lock(&sb->s_inode_list_lock); } spin_unlock(&sb->s_inode_list_lock); -- cgit v1.2.3