linux-toradex.git/fs/ceph/mds_client.h, branch v7.0-rc2

ceph: fix race condition validating r_parent before applying state

2025-09-09T10:57:02+00:00

Add validation to ensure the cached parent directory inode matches the
directory info in MDS replies. This prevents client-side race conditions
where concurrent operations (e.g. rename) cause r_parent to become stale
between request initiation and reply processing, which could lead to
applying state changes to incorrect directory inodes.

[ idryomov: folded a kerneldoc fixup and a follow-up fix from Alex to
  move CEPH_CAP_PIN reference when r_parent is updated:

  When the parent directory lock is not held, req->r_parent can become
  stale and is updated to point to the correct inode.  However, the
  associated CEPH_CAP_PIN reference was not being adjusted.  The
  CEPH_CAP_PIN is a reference on an inode that is tracked for
  accounting purposes.  Moving this pin is important to keep the
  accounting balanced. When the pin was not moved from the old parent
  to the new one, it created two problems: The reference on the old,
  stale parent was never released, causing a reference leak.
  A reference for the new parent was never acquired, creating the risk
  of a reference underflow later in ceph_mdsc_release_request().  This
  patch corrects the logic by releasing the pin from the old parent and
  acquiring it for the new parent when r_parent is switched.  This
  ensures reference accounting stays balanced. ]

Cc: stable@vger.kernel.org
Signed-off-by: Alex Markuze 
Reviewed-by: Viacheslav Dubeyko 
Signed-off-by: Ilya Dryomov

ceph: fix generic/421 test failure

2025-02-28T10:20:16+00:00

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_d_revalidate(): propagate stable name down into request encoding

2025-01-28T00:25:23+00:00

Currently get_fscrypt_altname() requires ->r_dentry->d_name to be stable
and it gets that in almost all cases.  The only exception is ->d_revalidate(),
where we have a stable name, but it's passed separately - dentry->d_name
is not stable there.

Propagate it down to get_fscrypt_altname() as a new field of struct
ceph_mds_request - ->r_dname, to be used instead ->r_dentry->d_name
when non-NULL.

Reviewed-by: Jeff Layton 
Signed-off-by: Al Viro

ceph: Remove fs/ceph deadcode

2024-11-18T16:34:35+00:00

ceph_caps_revoking() has been unused since 2017's commit
3fb99d483e61 ("ceph: nuke startsync op")

ceph_mdsc_open_export_target_sessions() has been unused since 2013's
commit 11df2dfb610d ("ceph: add imported caps when handling cap export message")

Remove them.

Signed-off-by: Dr. David Alan Gilbert 
Reviewed-by: Ilya Dryomov 
Signed-off-by: Ilya Dryomov

ceph: rename ceph_flush_cap_releases() to ceph_flush_session_cap_releases()

2024-09-24T20:51:19+00:00

Prepare for adding a helper to flush the cap releases for all
sessions.

Signed-off-by: Xiubo Li 
Reviewed-by: Ilya Dryomov 
Signed-off-by: Ilya Dryomov

ceph: Remove unused declarations

2024-08-27T07:28:48+00:00

These functions is never implemented and used.

Signed-off-by: Yue Haibing 
Reviewed-by: Jeff Layton 
Signed-off-by: Ilya Dryomov

ceph: use cap_wait_list only if debugfs is enabled

2024-07-23T08:01:57+00:00

Only debugfs uses this list.  By omitting it, we save some memory and
reduce lock contention on `caps_list_lock`.

Signed-off-by: Max Kellermann 
Reviewed-by: Xiubo Li 
Signed-off-by: Ilya Dryomov

ceph: add CEPHFS_FEATURE_MDS_AUTH_CAPS_CHECK feature bit

2024-05-23T08:35:47+00:00

Since we have support checking the mds auth cap in kclient, just
set the feature bit.

Link: https://tracker.ceph.com/issues/61333
Signed-off-by: Xiubo Li 
Reviewed-by: Milind Changire 
Signed-off-by: Ilya Dryomov

ceph: add ceph_mds_check_access() helper

2024-05-23T08:35:46+00:00

This will help check the mds auth access in client side. Always
insert the server path in front of the target path when matching
the paths.

[ idryomov: use u32 instead of uint32_t ]

Link: https://tracker.ceph.com/issues/61333
Signed-off-by: Xiubo Li 
Reviewed-by: Milind Changire 
Signed-off-by: Ilya Dryomov

ceph: save cap_auths in MDS client when session is opened

2024-05-23T08:35:46+00:00

Save the cap_auths, which have been parsed by the MDS, in the opened
session.

[ idryomov: use s64 and u32 instead of int64_t and uint32_t, switch to
            bool for root_squash, readable and writeable ]

Link: https://tracker.ceph.com/issues/61333
Signed-off-by: Xiubo Li 
Reviewed-by: Milind Changire 
Signed-off-by: Ilya Dryomov