[PATCH 4.9 8/8] ext4: avoid unnecessary stalls in ext4_evict_inode()

Lee Jones
2019-11-22T10:53:38Z

From: Jan Kara <jack@suse.cz>

[ Upstream commit 3abb1a0fc2871f2db52199e1748a1d48a54a3427 ]

These days inode reclaim calls evict_inode() only when it has no pages
in the mapping. In that case it is not necessary to wait for transaction
commit in ext4_evict_inode() as there can be no pages waiting to be
committed. So avoid unnecessary transaction waiting in that case.

We still have to keep the check for the case where ext4_evict_inode()
gets called from other paths (e.g. umount) where inode still can have
some page cache pages.

Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
fs/ext4/inode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index a73056e06bde..2ad48d166f32 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -212,7 +212,8 @@ void ext4_evict_inode(struct inode *inode)
*/
if (inode->i_ino != EXT4_JOURNAL_INO &&
ext4_should_journal_data(inode) &&
- (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) {
+ (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
+ inode->i_data.nrpages) {
journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;

--
2.24.0