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.ge12...@dread.disaster.area/ Signed-off-by: Hao Li <lihao2018.f...@cn.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
