ceph: fix duplicate increment of opened_inodes metric

[ Upstream commit 973e5245637accc4002843f6b888495a6a7762bc ]

opened_inodes is incremented twice when the same inode is opened twice
with O_RDONLY and O_WRONLY respectively.

To reproduce, run this python script, then check the metrics:

import os
for _ in range(10000):
    fd_r = os.open('a', os.O_RDONLY)
    fd_w = os.open('a', os.O_WRONLY)
    os.close(fd_r)
    os.close(fd_w)

Fixes: 1dd8d4708136 ("ceph: metrics for opened files, pinned caps and opened inodes")
Signed-off-by: Hu Weiwen <sehuww@mail.scut.edu.cn>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 676f551..d3f6727 100644 (file)
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -4359,7 +4359,7 @@ void ceph_get_fmode(struct ceph_inode_info *ci, int fmode, int count)
 {
        struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(ci->vfs_inode.i_sb);
        int bits = (fmode << 1) | 1;
-       bool is_opened = false;
+       bool already_opened = false;
        int i;
 
        if (count == 1)
@@ -4367,19 +4367,19 @@ void ceph_get_fmode(struct ceph_inode_info *ci, int fmode, int count)
 
        spin_lock(&ci->i_ceph_lock);
        for (i = 0; i < CEPH_FILE_MODE_BITS; i++) {
-               if (bits & (1 << i))
-                       ci->i_nr_by_mode[i] += count;
-
                /*
-                * If any of the mode ref is larger than 1,
+                * If any of the mode ref is larger than 0,
                 * that means it has been already opened by
                 * others. Just skip checking the PIN ref.
                 */
-               if (i && ci->i_nr_by_mode[i] > 1)
-                       is_opened = true;
+               if (i && ci->i_nr_by_mode[i])
+                       already_opened = true;
+
+               if (bits & (1 << i))
+                       ci->i_nr_by_mode[i] += count;
        }
 
-       if (!is_opened)
+       if (!already_opened)
                percpu_counter_inc(&mdsc->metric.opened_inodes);
        spin_unlock(&ci->i_ceph_lock);
 }