linux.git/drivers/md/bcache/super.c, branch v5.6

bcache: Revert "bcache: shrink btree node cache after bch_btree_check()"

2020-02-13T15:53:49+00:00

This reverts commit 1df3877ff6a4810054237c3259d900ded4468969.

In my testing, sometimes even all the cached btree nodes are freed,
creating gc and allocator kernel threads may still fail. Finally it
turns out that kthread_run() may fail if there is pending signal for
current task. And the pending signal is sent from OOM killer which
is triggered by memory consuption in bch_btree_check().

Therefore explicitly shrinking bcache btree node here does not help,
and after the shrinker callback is improved, as well as pending signals
are ignored before creating kernel threads, now such operation is
unncessary anymore.

This patch reverts the commit 1df3877ff6a4 ("bcache: shrink btree node
cache after bch_btree_check()") because we have better improvement now.

Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: check return value of prio_read()

2020-02-01T14:55:39+00:00

Now if prio_read() failed during starting a cache set, we can print
out error message in run_cache_set() and handle the failure properly.

Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: use read_cache_page_gfp to read the superblock

2020-01-23T18:40:01+00:00

Avoid a pointless dependency on buffer heads in bcache by simply open
coding reading a single page.  Also add a SB_OFFSET define for the
byte offset of the superblock instead of using magic numbers.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: store a pointer to the on-disk sb in the cache and cached_dev structures

2020-01-23T18:40:01+00:00

This allows to properly build the superblock bio including the offset in
the page using the normal bio helpers.  This fixes writing the superblock
for page sizes larger than 4k where the sb write bio would need an offset
in the bio_vec.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: return a pointer to the on-disk sb from read_super

2020-01-23T18:40:01+00:00

Returning the properly typed actual data structure insteaf of the
containing struct page will save the callers some work going
forward.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: transfer the sb_page reference to register_{bdev,cache}

2020-01-23T18:40:01+00:00

Avoid an extra reference count roundtrip by transferring the sb_page
ownership to the lower level register helpers.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: fix use-after-free in register_bcache()

2020-01-23T18:40:01+00:00

The patch "bcache: rework error unwinding in register_bcache" introduces
a use-after-free regression in register_bcache(). Here are current code,
	2510 out_free_path:
	2511         kfree(path);
	2512 out_module_put:
	2513         module_put(THIS_MODULE);
	2514 out:
	2515         pr_info("error %s: %s", path, err);
	2516         return ret;
If some error happens and the above code path is executed, at line 2511
path is released, but referenced at line 2515. Then KASAN reports a use-
after-free error message.

This patch changes line 2515 in the following way to fix the problem,
	2515         pr_info("error %s: %s", path?path:"", err);

Signed-off-by: Coly Li 
Cc: Christoph Hellwig 
Signed-off-by: Jens Axboe

bcache: properly initialize 'path' and 'err' in register_bcache()

2020-01-23T18:40:01+00:00

Patch "bcache: rework error unwinding in register_bcache" from
Christoph Hellwig changes the local variables 'path' and 'err'
in undefined initial state. If the code in register_bcache() jumps
to label 'out:' or 'out_module_put:' by goto, these two variables
might be reference with undefined value by the following line,

	out_module_put:
	        module_put(THIS_MODULE);
	out:
	        pr_info("error %s: %s", path, err);
	        return ret;

Therefore this patch initializes these two local variables properly
in register_bcache() to avoid such issue.

Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: rework error unwinding in register_bcache

2020-01-23T18:40:01+00:00

Split the successful and error return path, and use one goto label for each
resource to unwind.  This also fixes some small errors like leaking the
module reference count in the reboot case (which seems entirely harmless)
or printing the wrong warning messages for early failures.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe

bcache: use a separate data structure for the on-disk super block

2020-01-23T18:40:00+00:00

Split out an on-disk version struct cache_sb with the proper endianness
annotations.  This fixes a fair chunk of sparse warnings, but there are
some left due to the way the checksum is defined.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe