Skip to content

L
linux
Switch branch/tag
  1. 30 Oct, 2008 3 commits
    • Mikulas Patocka's avatar
      dm snapshot: wait for chunks in destructor · 879129d2
      Mikulas Patocka authored 
      If there are several snapshots sharing an origin and one is removed
while the origin is being written to, the snapshot's mempool may get
deleted while elements are still referenced.

Prior to dm-snapshot-use-per-device-mempools.patch the pending
exceptions may still have been referenced after the snapshot was
destroyed, but this was not a problem because the shared mempool
was still there.

This patch fixes the problem by tracking the number of mempool elements
in use.

The scenario:
- You have an origin and two snapshots 1 and 2.
- Someone writes to the origin.
- It creates two exceptions in the snapshots, snapshot 1 will be primary
exception, snapshot 2's pending_exception->primary_pe will point to the
exception in snapshot 1.
- The exceptions are being relocated, relocation of exception 1 finishes
(but it's pending_exception is still allocated, because it is referenced
by an exception from snapshot 2)
- The user lvremoves snapshot 1 --- it calls just suspend (does nothing)
and destructor. md->pending is zero (there is no I/O submitted to the
snapshot by md layer), so it won't help us.
- The destructor waits for kcopyd jobs to finish on snapshot 1 --- but
there are none.
- The destructor on snapshot 1 cleans up everything.
- The relocation of exception on snapshot 2 finishes, it drops reference
on primary_pe. This frees its primary_pe pointer. Primary_pe points to
pending exception created for snapshot 1. So it frees memory into
non-existing mempool.
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      879129d2
    • Mikulas Patocka's avatar
      dm snapshot: fix register_snapshot deadlock · 60c856c8
      Mikulas Patocka authored 
      register_snapshot() performs a GFP_KERNEL allocation while holding
_origins_lock for write, but that could write out dirty pages onto a
device that attempts to acquire _origins_lock for read, resulting in
deadlock.

So move the allocation up before taking the lock.

This path is not performance-critical, so it doesn't matter that we
allocate memory and free it if we find that we won't need it.
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      60c856c8
    • Ilpo Jarvinen's avatar
      dm raid1: fix do_failures · b34578a4
      Ilpo Jarvinen authored 
      Missing braces.  Commit 1f965b19 (dm raid1: separate region_hash interface
part1) broke it.
Signed-off-by: default avatarIlpo Jarvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
Cc: Heinz Mauelshagen <hjm@redhat.com>
      b34578a4
  3. 28 Oct, 2008 37 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7