Arnd Bergmann bb05b298af btrfs: zoned: bail out in btrfs_alloc_chunk for bad input
gcc complains that the ctl->max_chunk_size member might be used
uninitialized when none of the three conditions for initializing it in
init_alloc_chunk_ctl_policy_zoned() are true:

In function ‘init_alloc_chunk_ctl_policy_zoned’,
    inlined from ‘init_alloc_chunk_ctl’ at fs/btrfs/volumes.c:5023:3,
    inlined from ‘btrfs_alloc_chunk’ at fs/btrfs/volumes.c:5340:2:
include/linux/compiler-gcc.h:48:45: error: ‘ctl.max_chunk_size’ may be used uninitialized [-Werror=maybe-uninitialized]
 4998 |         ctl->max_chunk_size = min(limit, ctl->max_chunk_size);
      |                               ^~~
fs/btrfs/volumes.c: In function ‘btrfs_alloc_chunk’:
fs/btrfs/volumes.c:5316:32: note: ‘ctl’ declared here
 5316 |         struct alloc_chunk_ctl ctl;
      |                                ^~~

If we ever get into this condition, something is seriously
wrong, as validity is checked in the callers

  btrfs_alloc_chunk
    init_alloc_chunk_ctl
      init_alloc_chunk_ctl_policy_zoned

so the same logic as in init_alloc_chunk_ctl_policy_regular()
and a few other places should be applied. This avoids both further
data corruption, and the compile-time warning.

Fixes: 1cd6121f2a ("btrfs: zoned: implement zoned chunk allocator")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2021-04-19 17:25:17 +02:00
2021-01-24 14:27:20 +01:00
2021-04-16 16:10:37 -07:00
2021-04-09 14:54:23 -07:00
2021-02-26 09:41:03 -08:00
2021-04-18 14:45:32 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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