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Message-ID: <20200831101313.168889-1-lihao2018.fnst@cn.fujitsu.com>
Date: Mon, 31 Aug 2020 18:13:13 +0800
From: Hao Li <lihao2018.fnst@...fujitsu.com>
To: <viro@...iv.linux.org.uk>
CC: <david@...morbit.com>, <ira.weiny@...el.com>,
<linux-fsdevel@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-xfs@...r.kernel.org>, <lihao2018.fnst@...fujitsu.com>,
<y-goto@...itsu.com>
Subject: [PATCH] fs: Handle I_DONTCACHE in iput_final() instead of generic_drop_inode()
If generic_drop_inode() returns true, it means iput_final() can evict
this inode regardless of whether it is dirty or not. If we check
I_DONTCACHE in generic_drop_inode(), any inode with this bit set will be
evicted unconditionally. This is not the desired behavior because
I_DONTCACHE only means the inode shouldn't be cached on the LRU list.
As for whether we need to evict this inode, this is what
generic_drop_inode() should do. This patch corrects the usage of
I_DONTCACHE.
This patch was proposed in [1].
[1]: https://lore.kernel.org/linux-fsdevel/20200831003407.GE12096@dread.disaster.area/
Signed-off-by: Hao Li <lihao2018.fnst@...fujitsu.com>
---
fs/inode.c | 3 ++-
include/linux/fs.h | 3 +--
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 72c4c347afb7..4e45d5ea3d0f 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1625,7 +1625,8 @@ static void iput_final(struct inode *inode)
else
drop = generic_drop_inode(inode);
- if (!drop && (sb->s_flags & SB_ACTIVE)) {
+ if (!drop && !(inode->i_state & I_DONTCACHE) &&
+ (sb->s_flags & SB_ACTIVE)) {
inode_add_lru(inode);
spin_unlock(&inode->i_lock);
return;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e019ea2f1347..93caee80ce47 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2922,8 +2922,7 @@ extern int inode_needs_sync(struct inode *inode);
extern int generic_delete_inode(struct inode *inode);
static inline int generic_drop_inode(struct inode *inode)
{
- return !inode->i_nlink || inode_unhashed(inode) ||
- (inode->i_state & I_DONTCACHE);
+ return !inode->i_nlink || inode_unhashed(inode);
}
extern void d_mark_dontcache(struct inode *inode);
--
2.28.0
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