kernel.git/fs/ceph/super.c, branch linux-6.15.y

ceph: set superblock s_magic for IMA fsmagic matching

2025-06-27T10:13:02Z

commit 72386d5245b249f5a0a8fabb881df7ad947b8ea4 upstream. The CephFS kernel driver forgets to set the filesystem magic signature in its superblock. As a result, IMA policy rules based on fsmagic matching do not apply as intended. This causes a major performance regression in Talos Linux [1] when mounting CephFS volumes, such as when deploying Rook Ceph [2]. Talos Linux ships a hardened kernel with the following IMA policy (irrelevant lines omitted): [...] dont_measure fsmagic=0xc36400 # CEPH_SUPER_MAGIC [...] measure func=FILE_CHECK mask=^MAY_READ euid=0 measure func=FILE_CHECK mask=^MAY_READ uid=0 [...] Currently, IMA compares 0xc36400 == 0x0 for CephFS files, resulting in all files opened with O_RDONLY or O_RDWR getting measured with SHA512 on every open(2): 10 69990c87e8af323d47e2d6ae4... ima-ng sha512: /data/cephfs/test-file Since O_WRONLY is rare, this results in an order of magnitude lower performance than expected for practically all file operations. Properly setting CEPH_SUPER_MAGIC in the CephFS superblock resolves the regression. Tests performed on a 3x replicated Ceph v19.3.0 cluster across three i5-7200U nodes each equipped with one Micron 7400 MAX M.2 disk (BlueStore) and Gigabit ethernet, on Talos Linux v1.10.2: FS-Mark 3.3 Test: 500 Files, Empty Files/s > Higher Is Better 6.12.27-talos . 16.6 |==== +twelho patch . 208.4 |==================================================== FS-Mark 3.3 Test: 500 Files, 1KB Size Files/s > Higher Is Better 6.12.27-talos . 15.6 |======= +twelho patch . 118.6 |==================================================== FS-Mark 3.3 Test: 500 Files, 32 Sub Dirs, 1MB Size Files/s > Higher Is Better 6.12.27-talos . 12.7 |=============== +twelho patch . 44.7 |===================================================== IO500 [3] 2fcd6d6 results (benchmarks within variance omitted): | IO500 benchmark | 6.12.27-talos | +twelho patch | Speedup | |-------------------|----------------|----------------|-----------| | mdtest-easy-write | 0.018524 kIOPS | 1.135027 kIOPS | 6027.33 % | | mdtest-hard-write | 0.018498 kIOPS | 0.973312 kIOPS | 5161.71 % | | ior-easy-read | 0.064727 GiB/s | 0.155324 GiB/s | 139.97 % | | mdtest-hard-read | 0.018246 kIOPS | 0.780800 kIOPS | 4179.29 % | This applies outside of synthetic benchmarks as well, for example, the time to rsync a 55 MiB directory with ~12k of mostly small files drops from an unusable 10m5s to a reasonable 26s (23x the throughput). [1]: https://www.talos.dev/ [2]: https://www.talos.dev/v1.10/kubernetes-guides/configuration/ceph-with-rook/ [3]: https://github.com/IO500/io500 Cc: stable@vger.kernel.org Signed-off-by: Dennis Marttinen Reviewed-by: Viacheslav Dubeyko Signed-off-by: Ilya Dryomov Signed-off-by: Greg Kroah-Hartman

ceph: fix generic/421 test failure

2025-02-28T10:20:16Z

The generic/421 fails to finish because of the issue: Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.894678] INFO: task kworker/u48:0:11 blocked for more than 122 seconds. Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.895403] Not tainted 6.13.0-rc5+ #1 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.895867] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.896633] task:kworker/u48:0 state:D stack:0 pid:11 tgid:11 ppid:2 flags:0x00004000 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.896641] Workqueue: writeback wb_workfn (flush-ceph-24) Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897614] Call Trace: Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897620] Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897629] __schedule+0x443/0x16b0 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897637] schedule+0x2b/0x140 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897640] io_schedule+0x4c/0x80 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897643] folio_wait_bit_common+0x11b/0x310 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897646] ? _raw_spin_unlock_irq+0xe/0x50 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897652] ? __pfx_wake_page_function+0x10/0x10 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897655] __folio_lock+0x17/0x30 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897658] ceph_writepages_start+0xca9/0x1fb0 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897663] ? fsnotify_remove_queued_event+0x2f/0x40 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897668] do_writepages+0xd2/0x240 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897672] __writeback_single_inode+0x44/0x350 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897675] writeback_sb_inodes+0x25c/0x550 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897680] wb_writeback+0x89/0x310 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897683] ? finish_task_switch.isra.0+0x97/0x310 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897687] wb_workfn+0xb5/0x410 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897689] process_one_work+0x188/0x3d0 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897692] worker_thread+0x2b5/0x3c0 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897694] ? __pfx_worker_thread+0x10/0x10 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897696] kthread+0xe1/0x120 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897699] ? __pfx_kthread+0x10/0x10 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897701] ret_from_fork+0x43/0x70 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897705] ? __pfx_kthread+0x10/0x10 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897707] ret_from_fork_asm+0x1a/0x30 Jan 3 14:25:27 ceph-testing-0001 kernel: [ 369.897711] There are several issues here: (1) ceph_kill_sb() doesn't wait ending of flushing all dirty folios/pages because of racy nature of mdsc->stopping_blockers. As a result, mdsc->stopping becomes CEPH_MDSC_STOPPING_FLUSHED too early. (2) The ceph_inc_osd_stopping_blocker(fsc->mdsc) fails to increment mdsc->stopping_blockers. Finally, already locked folios/pages are never been unlocked and the logic tries to lock the same page second time. (3) The folio_batch with found dirty pages by filemap_get_folios_tag() is not processed properly. And this is why some number of dirty pages simply never processed and we have dirty folios/pages after unmount anyway. This patch fixes the issues by means of: (1) introducing dirty_folios counter and flush_end_wq waiting queue in struct ceph_mds_client; (2) ceph_dirty_folio() increments the dirty_folios counter; (3) writepages_finish() decrements the dirty_folios counter and wake up all waiters on the queue if dirty_folios counter is equal or lesser than zero; (4) adding in ceph_kill_sb() method the logic of checking the value of dirty_folios counter and waiting if it is bigger than zero; (5) adding ceph_inc_osd_stopping_blocker() call in the beginning of the ceph_writepages_start() and ceph_dec_osd_stopping_blocker() at the end of the ceph_writepages_start() with the goal to resolve the racy nature of mdsc->stopping_blockers. sudo ./check generic/421 FSTYP -- ceph PLATFORM -- Linux/x86_64 ceph-testing-0001 6.13.0+ #137 SMP PREEMPT_DYNAMIC Mon Feb 3 20:30:08 UTC 2025 MKFS_OPTIONS -- 127.0.0.1:40551:/scratch MOUNT_OPTIONS -- -o name=fs,secret=,ms_mode=crc,nowsync,copyfrom 127.0.0.1:40551:/scratch /mnt/scratch generic/421 7s ... 4s Ran: generic/421 Passed all 1 tests Signed-off-by: Viacheslav Dubeyko Link: https://lore.kernel.org/r/20250205000249.123054-5-slava@dubeyko.com Tested-by: David Howells Signed-off-by: Christian Brauner

ceph: validate snapdirname option length when mounting

2024-12-16T22:25:43Z

It becomes a path component, so it shouldn't exceed NAME_MAX characters. This was hardened in commit c152737be22b ("ceph: Use strscpy() instead of strcpy() in __get_snap_name()"), but no actual check was put in place. Cc: stable@vger.kernel.org Signed-off-by: Ilya Dryomov Reviewed-by: Alex Markuze

ceph: requalify some char pointers as const

2024-11-18T16:34:36Z

Signed-off-by: Patrick Donnelly Reviewed-by: Ilya Dryomov Signed-off-by: Ilya Dryomov

ceph: extract entity name from device id

2024-11-18T16:34:35Z

Previously, the "name" in the new device syntax "@." was ignored because (presumably) tests were done using mount.ceph which also passed the entity name using "-o name=foo". If mounting is done without the mount.ceph helper, the new device id syntax fails to set the name properly. Cc: stable@vger.kernel.org Link: https://tracker.ceph.com/issues/68516 Signed-off-by: Patrick Donnelly Reviewed-by: Ilya Dryomov Signed-off-by: Ilya Dryomov

ceph: flush all caps releases when syncing the whole filesystem

2024-09-24T20:51:28Z

We have hit a race between cap releases and cap revoke request that will cause the check_caps() to miss sending a cap revoke ack to MDS. And the client will depend on the cap release to release that revoking caps, which could be delayed for some unknown reasons. In Kclient we have figured out the RCA about race and we need a way to explictly trigger this manually could help to get rid of the caps revoke stuck issue. Link: https://tracker.ceph.com/issues/67221 Signed-off-by: Xiubo Li Reviewed-by: Ilya Dryomov Signed-off-by: Ilya Dryomov

ceph: fix incorrect kmalloc size of pagevec mempool

2024-07-23T08:01:57Z

The kmalloc size of pagevec mempool is incorrectly calculated. It misses the size of page pointer and only accounts the number for the array. Fixes: a0102bda5bc0 ("ceph: move sb->wb_pagevec_pool to be a global mempool") Signed-off-by: ethanwu Reviewed-by: Xiubo Li Signed-off-by: Ilya Dryomov

mm, slab: remove last vestiges of SLAB_MEM_SPREAD

2024-03-13T03:32:19Z

Yes, yes, I know the slab people were planning on going slow and letting every subsystem fight this thing on their own. But let's just rip off the band-aid and get it over and done with. I don't want to see a number of unnecessary pull requests just to get rid of a flag that no longer has any meaning. This was mainly done with a couple of 'sed' scripts and then some manual cleanup of the end result. Link: https://lore.kernel.org/all/CAHk-=wji0u+OOtmAOD-5JV3SXcRJF___k_+8XNKmak0yd5vW1Q@mail.gmail.com/ Signed-off-by: Linus Torvalds

ceph: allow idmapped mounts

2023-11-03T22:28:34Z

Now that we converted cephfs internally to account for idmapped mounts allow the creation of idmapped mounts on by setting the FS_ALLOW_IDMAP flag. Signed-off-by: Christian Brauner Signed-off-by: Alexander Mikhalitsyn Reviewed-by: Xiubo Li Signed-off-by: Ilya Dryomov

ceph: add enable_unsafe_idmap module parameter

2023-11-03T22:28:33Z

This parameter is used to decide if we allow to perform IO on idmapped mount in case when MDS lacks support of CEPHFS_FEATURE_HAS_OWNER_UIDGID feature. In this case we can't properly handle MDS permission checks and if UID/GID-based restrictions are enabled on the MDS side then IO requests which go through an idmapped mount may fail with -EACCESS/-EPERM. Fortunately, for most of users it's not a case and everything should work fine. But we put work "unsafe" in the module parameter name to warn users about possible problems with this feature and encourage update of cephfs MDS. Suggested-by: Stéphane Graber Signed-off-by: Alexander Mikhalitsyn Acked-by: Christian Brauner Reviewed-by: Xiubo Li Signed-off-by: Ilya Dryomov