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dm snapshot: persistent fix dtr cleanup 

The persistent exception store destructor does not properly
account for all conditions in which it can be called.  If it
is called after 'ctr' but before 'read_metadata' (e.g. if
something else in 'snapshot_ctr' fails) then it will attempt
to free areas of memory that haven't been allocated yet.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Jonathan Brassow 2009-04-02 19:55:35 +01:00 committed by Alasdair G Kergon
parent 1e302a929e
commit a32079ce17
1 changed files with 15 additions and 5 deletions
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20
drivers/md/dm-snap-persistent.c
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@ -162,9 +162,12 @@ static int alloc_area(struct pstore *ps)
static void free_area(struct pstore *ps)
{
vfree(ps->area);
if (ps->area)
vfree(ps->area);
ps->area = NULL;
vfree(ps->zero_area);
if (ps->zero_area)
vfree(ps->zero_area);
ps->zero_area = NULL;
}
@ -482,9 +485,16 @@ static void persistent_dtr(struct dm_exception_store *store)
struct pstore *ps = get_info(store);
destroy_workqueue(ps->metadata_wq);
dm_io_client_destroy(ps->io_client);
vfree(ps->callbacks);
/* Created in read_header */
if (ps->io_client)
dm_io_client_destroy(ps->io_client);
free_area(ps);
/* Allocated in persistent_read_metadata */
if (ps->callbacks)
vfree(ps->callbacks);
kfree(ps);
}
@ -661,7 +671,7 @@ static int persistent_ctr(struct dm_exception_store *store,
struct pstore *ps;
/* allocate the pstore */
ps = kmalloc(sizeof(*ps), GFP_KERNEL);
ps = kzalloc(sizeof(*ps), GFP_KERNEL);
if (!ps)
return -ENOMEM;