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Ilya Dryomov
3e1f941dd9
Commitceaa762527("block: move direct_IO into our own read_iter handler") introduced several regressions for bdev DIO: 1. read spanning EOF always returns 0 instead of the number of bytes read. This is because "count" is assigned early and isn't updated when the iterator is truncated: $ lsblk -o name,size /dev/vdb NAME SIZE vdb 1G $ xfs_io -d -c 'pread -b 4M 1021M 4M' /dev/vdb read 0/4194304 bytes at offset 1070596096 0.000000 bytes, 0 ops; 0.0007 sec (0.000000 bytes/sec and 0.0000 ops/sec) instead of $ xfs_io -d -c 'pread -b 4M 1021M 4M' /dev/vdb read 3145728/4194304 bytes at offset 1070596096 3 MiB, 1 ops; 0.0007 sec (3.865 GiB/sec and 1319.2612 ops/sec) 2. truncated iterator isn't reexpanded 3. iterator isn't reverted on blkdev_direct_IO() error 4. zero size read no longer skips atime update Fixes:ceaa762527("block: move direct_IO into our own read_iter handler") Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220201100420.25875-1-idryomov@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.