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Linux kernel source tree
a7ddeeb079
When starting a transaction, with a non-zero number of items, we reserve metadata space for that number of items and for delayed refs by doing a call to btrfs_block_rsv_add(), with the transaction block reserve passed as the block reserve argument. This reserves metadata space and adds it to the transaction block reserve. Later we migrate the space we reserved for delayed references from the transaction block reserve into the delayed refs block reserve, by calling btrfs_migrate_to_delayed_refs_rsv(). btrfs_migrate_to_delayed_refs_rsv() decrements the number of bytes to migrate from the source block reserve, and this however may result in an underflow in case the space added to the transaction block reserve ended up being used by another task that has not reserved enough space for its own use - examples are tasks doing reflinks or hole punching because they end up calling btrfs_replace_file_extents() -> btrfs_drop_extents() and may need to modify/COW a variable number of leaves/paths, so they keep trying to use space from the transaction block reserve when they need to COW an extent buffer, and may end up trying to use more space then they have reserved (1 unit/path only for removing file extent items). This can be avoided by simply reserving space first without adding it to the transaction block reserve, then add the space for delayed refs to the delayed refs block reserve and finally add the remaining reserved space to the transaction block reserve. This also makes the code a bit shorter and simpler. So just do that. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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| 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.