3fa750dcf2
write_cache_pages() is used in both background and integrity writeback scenarios by various filesystems. Background writeback is mostly concerned with cleaning a certain number of dirty pages based on various mm heuristics. It may not write the full set of dirty pages or wait for I/O to complete. Integrity writeback is responsible for persisting a set of dirty pages before the writeback job completes. For example, an fsync() call must perform integrity writeback to ensure data is on disk before the call returns. write_cache_pages() unconditionally breaks out of its processing loop in the event of a ->writepage() error. This is fine for background writeback, which had no strict requirements and will eventually come around again. This can cause problems for integrity writeback on filesystems that might need to clean up state associated with failed page writeouts. For example, XFS performs internal delayed allocation accounting before returning a ->writepage() error, where applicable. If the current writeback happens to be associated with an unmount and write_cache_pages() completes the writeback prematurely due to error, the filesystem is unmounted in an inconsistent state if dirty+delalloc pages still exist. To handle this problem, update write_cache_pages() to always process the full set of pages for integrity writeback regardless of ->writepage() errors. Save the first encountered error and return it to the caller once complete. This facilitates XFS (or any other fs that expects integrity writeback to process the entire set of dirty pages) to clean up its internal state completely in the event of persistent mapping errors. Background writeback continues to exit on the first error encountered. [akpm@linux-foundation.org: fix typo in comment] Link: http://lkml.kernel.org/r/20181116134304.32440-1-bfoster@redhat.com Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
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| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
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| README | ||
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.