4eaaec24c0
All callers of btrfs_free_reserved_extent (respectively __btrfs_free_reserved_extent with in set to 0) pass in extents which have only been reserved but not yet written to. Namely, * in cow_file_range that function is called only if create_io_em fails or btrfs_add_ordered_extent fail, both of which happen _before_ any IO is submitted to the newly reserved range * in submit_compressed_extents the code flow is similar - out_free_reserve can be called only before btrfs_submit_compressed_write which is where any writes to the range could occur * btrfs_new_extent_direct also calls btrfs_free_reserved_extent only if extent_map fails, before any IO is issued * __btrfs_prealloc_file_range also calls btrfs_free_reserved_extent in case insertion of the metadata fails * btrfs_alloc_tree_block again can only be called in case in-memory operations fail, before any IO is submitted * btrfs_finish_ordered_io - this is the only caller where discarding the extent could have a material effect, since it can be called for an extent which was partially written. With this change the submission of discards is optimised since discards are now not being created for extents which are known to not have been touched on disk. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| 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 | ||
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.