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4f3d1e4533
Before this patch, the call stack in ext4_run_li_request is as follows: /* * nr = no. of BGs we want to fetch (=s_mb_prefetch) * prefetch_ios = no. of BGs not uptodate after * ext4_read_block_bitmap_nowait() */ next_group = ext4_mb_prefetch(sb, group, nr, prefetch_ios); ext4_mb_prefetch_fini(sb, next_group prefetch_ios); ext4_mb_prefetch_fini() will only try to initialize buddies for BGs in range [next_group - prefetch_ios, next_group). This is incorrect since sometimes (prefetch_ios < nr), which causes ext4_mb_prefetch_fini() to incorrectly ignore some of the BGs that might need initialization. This issue is more notable now with the previous patch enabling "fetching" of BLOCK_UNINIT BGs which are marked buffer_uptodate by default. Fix this by passing nr to ext4_mb_prefetch_fini() instead of prefetch_ios so that it considers the right range of groups. Similarly, make sure we don't pass nr=0 to ext4_mb_prefetch_fini() in ext4_mb_regular_allocator() since we might have prefetched BLOCK_UNINIT groups that would need buddy initialization. Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/05e648ae04ec5b754207032823e9c1de9a54f87a.1685449706.git.ojaswin@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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.