mainlining shenanigans
0eb79294db
iomap dio will run generic_write_sync() for us if the iocb is DSYNC. This is problematic for us because of 2 reasons: 1. we hold the inode_lock() during this operation, and we take it in generic_write_sync() 2. we hold a read lock on the dio_sem but take the write lock in fsync Since we don't want to rip out this code right now, but reworking the locking is a bit much to do at this point, work around this problem with this masterpiece of a patch. First, we clear DSYNC on the iocb so that the iomap stuff doesn't know that it needs to handle the sync. We save this fact in current->journal_info, because we need to see do special things once we're in iomap_begin, and we have no way to pass private information into iomap_dio_rw(). Next we specify a separate iomap_dio_ops for sync, which implements an ->end_io() callback that gets called when the dio completes. This is important for AIO, because we really do need to run generic_write_sync() if we complete asynchronously. However if we're still in the submitting context when we enter ->end_io() we clear the flag so that the submitter knows they're the ones that needs to run generic_write_sync(). This is meant to be temporary. We need to work out how to eliminate the inode_lock() and the dio_sem in our fsync and use another mechanism to protect these operations. Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| 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.