Dear all, I create a LVM snapshot from a mounted ext4 file system by: "lvcreate -kn --snapshot --name snap1 /dev/mapper/vg1/lv1" And after I mount this snapshot to another folder like: "mount -t ext4 /dev/mapper/vg1-snap1 /mnt/test" the following messages prompted in dmesg: [ 2445.480908] EXT4-fs (dm-6): orphan cleanup on readonly fs [ 2445.502317] EXT4-fs (dm-6): ext4_orphan_cleanup: deleting unreferenced inode 131180 [ 2445.502355] EXT4-fs (dm-6): ext4_orphan_cleanup: deleting unreferenced inode 131176 [ 2445.502360] EXT4-fs (dm-6): ext4_orphan_cleanup: deleting unreferenced inode 131175 [ 2445.502366] EXT4-fs (dm-6): ext4_orphan_cleanup: deleting unreferenced inode 131174 [ 2445.502372] EXT4-fs (dm-6): ext4_orphan_cleanup: deleting unreferenced inode 131173 [ 2445.502376] EXT4-fs (dm-6): 5 orphan inodes deleted To find out what the reason is, I use 'lsof' on lv1's mount point before I take the snapshot. Then I got some MySQL services that opened these temporary files which causes the orphan inodes in LVM snapshots: mysqld 26257 admin 7u REG 253,5 0 131173 /LV1/.system/tmp/ibTidhzb (deleted) mysqld 26257 admin 8u REG 253,5 0 131174 /LV1/.system/tmp/ibgWhCYc (deleted) mysqld 26257 admin 9u REG 253,5 0 131175 /LV1/.system/tmp/ibJE5pne (deleted) mysqld 26257 admin 10u REG 253,5 0 131176 /LV1/.system/tmp/ibsvL9hg (deleted) mysqld 26257 admin 14u REG 253,5 0 131180 /LV1/.system/tmp/ibcz1qOM (deleted) >From the above investigation, the problem gets solved if I disable the MySQL service before taking the LVM snapshot. However, I wonder if there's any other way to solve this issue. For example, can I just blindly remove these orphan inodes when ext4_freeze() is called? Thank you. - Wayne -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
