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ac13692844
If read() is done in an unbuffered manner, such that, say,
cifs_strict_readv() goes through cifs_user_readv() and thence
__cifs_readv(), it doesn't recognise the EOF and keeps indicating to
userspace that it returning full buffers of data.
This is due to ctx->iter being advanced in cifs_send_async_read() as the
buffer is split up amongst a number of rdata objects. The iterator count
is then used in collect_uncached_read_data() in the non-DIO case to set the
total length read - and thus the return value of sys_read(). But since the
iterator normally gets used up completely during splitting, ctx->total_len
gets overridden to the full amount.
However, prior to that in collect_uncached_read_data(), we've gone through
the list of rdatas and added up the amount of data we actually received
(which we then throw away).
Fix this by removing the bit that overrides the amount read in the non-DIO
case and just going with the total added up in the aforementioned loop.
This was observed by mounting a cifs share with multiple channels, e.g.:
mount //192.168.6.1/test /test/ -o user=shares,pass=...,max_channels=6
and then reading a 1MiB file on the share:
strace cat /xfstest.test/1M >/dev/null
Through strace, the same data can be seen being read again and again.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.