Re: [PATCH] ovl: skip stale entries in merge dir cache iteration
From: Miklos Szeredi <miklos@szeredi.hu>
Date: 2021-07-20 04:21:55
On Mon, 19 Jul 2021 at 18:43, Amir Goldstein [off-list ref] wrote:
On Mon, Jul 19, 2021 at 6:24 PM Miklos Szeredi [off-list ref] wrote:quoted
On Fri, 4 Jun 2021 at 12:43, Amir Goldstein [off-list ref] wrote:quoted
On Mon, Apr 26, 2021 at 6:20 PM Amir Goldstein [off-list ref] wrote:quoted
On the first getdents call, ovl_iterate() populates the readdir cache with a list of entries, but for upper entries with origin lower inode, p->ino remains zero. Following getdents calls traverse the readdir cache list and call ovl_cache_update_ino() for entries with zero p->ino to lookup the entry in the overlay and return d_ino that is consistent with st_ino. If the upper file was unlinked between the first getdents call and the getdents call that lists the file entry, ovl_cache_update_ino() will not find the entry and fall back to setting d_ino to the upper real st_ino, which is inconsistent with how this object was presented to users. Instead of listing a stale entry with inconsistent d_ino, simply skip the stale entry, which is better for users.Miklos, I forgot to follow up on this patch. Upstream xfstest overlay/077 is failing without this patch.Can't reproduce (on ext4/xfs and "-oxino=on"). Is there some trick?Not sure. overlay/077 fails for me on v5.14.0-rc2 on ext4/xfs. QA output created by 077 +entry m100 has inconsistent d_ino (234 != 232) +entry f100 has inconsistent d_ino (335 != 16777542) Silence is golden Maybe you need to build src/t_dir_offset2?
root@kvm:/opt/xfstests-dev# git log -1 --pretty=%h 10f6b231 root@kvm:/opt/xfstests-dev# cat local.config export TEST_DEV=/dev/vdb1 export TEST_DIR=/test export SCRATCH_DEV=/dev/vdb2 export SCRATCH_MNT=/scratch export FSTYP=ext4 export OVERLAY_MOUNT_OPTIONS="-o xino=on" root@kvm:/opt/xfstests-dev# make src/t_dir_offset2 make: 'src/t_dir_offset2' is up to date. root@kvm:/opt/xfstests-dev# ./check -overlay overlay/077 FSTYP -- overlay PLATFORM -- Linux/x86_64 kvm 5.14.0-rc2 #276 SMP Tue Jul 20 05:54:44 CEST 2021 MKFS_OPTIONS -- /scratch MOUNT_OPTIONS -- -o xino=on /scratch /scratch/ovl-mnt overlay/077 1s ... 1s Ran: overlay/077 Passed all 1 tests root@kvm:/opt/xfstests-dev# cat results/overlay/077.full Create file in pure upper dir: getdents at offset 0 returned 192 bytes created entry p0 entry p0 found as expected Remove file in pure upper dir: getdents at offset 0 returned 192 bytes unlinked entry p100 entry p100 not found as expected Create file in impure upper dir: getdents at offset 0 returned 192 bytes created entry o0 entry o0 found as expected Remove file in impure upper dir: getdents at offset 0 returned 192 bytes unlinked entry o100 entry o100 not found as expected Create file in merge dir: getdents at offset 0 returned 192 bytes created entry m0 entry m0 found as expected Remove file in merge dir: getdents at offset 0 returned 192 bytes unlinked entry m100 entry m100 not found as expected Create file in former merge dir: getdents at offset 0 returned 192 bytes created entry f0 entry f0 found as expected Remove file in former merge dir: getdents at offset 0 returned 192 bytes unlinked entry f100 entry f100 not found as expected Ideas for further debugging why this test isn't failing for v4.12-rc2? Thanks, Miklos