Qu WenruoandDavid Sterba ec1f3a207c btrfs: scrub: update device stats when an error is detected
[BUG]
Since the migration to the new scrub_stripe interface, scrub no longer
updates the device stats when hitting an error, no matter if it's a read
or checksum mismatch error. E.g:

  BTRFS info (device dm-2): scrub: started on devid 1
  BTRFS error (device dm-2): unable to fixup (regular) error at logical 13631488 on dev /dev/mapper/test-scratch1 physical 13631488
  BTRFS warning (device dm-2): checksum error at logical 13631488 on dev /dev/mapper/test-scratch1, physical 13631488, root 5, inode 257, offset 0, length 4096, links 1 (path: file)
  BTRFS error (device dm-2): unable to fixup (regular) error at logical 13631488 on dev /dev/mapper/test-scratch1 physical 13631488
  BTRFS warning (device dm-2): checksum error at logical 13631488 on dev /dev/mapper/test-scratch1, physical 13631488, root 5, inode 257, offset 0, length 4096, links 1 (path: file)
  BTRFS info (device dm-2): scrub: finished on devid 1 with status: 0

Note there is no line showing the device stats error update.

[CAUSE]
In the migration to the new scrub_stripe interface, we no longer call
btrfs_dev_stat_inc_and_print().

[FIX]
- Introduce a new bitmap for metadata generation errors
  * A new bitmap
    @meta_gen_error_bitmap is introduced to record which blocks have
    metadata generation mismatch errors.

  * A new counter for that bitmap
    @init_nr_meta_gen_errors, is also introduced to store the number of
    generation mismatch errors that are found during the initial read.

    This is for the error reporting at scrub_stripe_report_errors().

  * New dedicated error message for unrepaired generation mismatches

  * Update @meta_gen_error_bitmap if a transid mismatch is hit

- Add btrfs_dev_stat_inc_and_print() calls to the following call sites
  * scrub_stripe_report_errors()
  * scrub_write_endio()
    This is only for the write errors.

This means there is a minor behavior change:

- The timing of device stats error message
  Since we concentrate the error messages at
  scrub_stripe_report_errors(), the device stats error messages will all
  show up in one go, after the detailed scrub error messages:

   BTRFS error (device dm-2): unable to fixup (regular) error at logical 13631488 on dev /dev/mapper/test-scratch1 physical 13631488
   BTRFS warning (device dm-2): checksum error at logical 13631488 on dev /dev/mapper/test-scratch1, physical 13631488, root 5, inode 257, offset 0, length 4096, links 1 (path: file)
   BTRFS error (device dm-2): unable to fixup (regular) error at logical 13631488 on dev /dev/mapper/test-scratch1 physical 13631488
   BTRFS warning (device dm-2): checksum error at logical 13631488 on dev /dev/mapper/test-scratch1, physical 13631488, root 5, inode 257, offset 0, length 4096, links 1 (path: file)
   BTRFS error (device dm-2): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0
   BTRFS error (device dm-2): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 2, gen 0

Fixes: e02ee89baa ("btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2025-05-15 14:30:54 +02:00
2025-02-19 14:53:27 -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 reStructuredText 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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