From: Eric Sandeen <sandeen@redhat.com>
To: linux-fsdevel@vger.kernel.org
Cc: viro@zeniv.linux.org.uk
Subject: [PATCH 1/2] fs: avoid softlockups in s_inodes iterators
Date: Thu, 7 Nov 2019 14:52:33 -0600 [thread overview]
Message-ID: <1573159954-27846-2-git-send-email-sandeen@redhat.com> (raw)
In-Reply-To: <1573159954-27846-1-git-send-email-sandeen@redhat.com>
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 <sandeen@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
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(-)
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index d31b6c7..dc1a1d5 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 fef457a..96d62d9 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -676,6 +676,7 @@ 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);
@@ -698,6 +699,12 @@ 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 2ecef61..ac9eb27 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -77,6 +77,7 @@ static 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 6e826b4..4a085b3 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -985,6 +985,7 @@ 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);
--
1.8.3.1
next prev parent reply other threads:[~2019-11-07 20:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-07 20:52 [PATCH 0/2 V2] avoid softlockups in various s_inodes iterators Eric Sandeen
2019-11-07 20:52 ` Eric Sandeen [this message]
2019-11-07 20:52 ` [PATCH 2/2] fs: call fsnotify_sb_delete after evict_inodes Eric Sandeen
2019-11-13 23:26 ` Al Viro
2019-11-15 13:47 ` [PATCH 2/2 V2] " Eric Sandeen
2019-11-13 22:07 ` [PATCH 0/2 V2] avoid softlockups in various s_inodes iterators Eric Sandeen
-- strict thread matches above, loose matches on Subject: below --
2019-11-07 19:42 [PATCH 0/2] " Eric Sandeen
2019-11-07 19:47 ` [PATCH 1/2] fs: avoid softlockups in " Eric Sandeen
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