22d3151c2c
When doing an incremental send, if we have a file in the parent snapshot that has prealloc extents beyond EOF and in the send snapshot it got a hole punch that partially covers the prealloc extents, the send stream, when replayed by a receiver, can result in a file that has a size bigger than it should and filled with zeroes past the correct EOF. For example: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "falloc -k 0 4M" /mnt/foobar $ xfs_io -c "pwrite -S 0xea 0 1M" /mnt/foobar $ btrfs subvolume snapshot -r /mnt /mnt/snap1 $ btrfs send -f /tmp/1.send /mnt/snap1 $ xfs_io -c "fpunch 1M 2M" /mnt/foobar $ btrfs subvolume snapshot -r /mnt /mnt/snap2 $ btrfs send -f /tmp/2.send -p /mnt/snap1 /mnt/snap2 $ stat --format %s /mnt/snap2/foobar 1048576 $ md5sum /mnt/snap2/foobar d31659e82e87798acd4669a1e0a19d4f /mnt/snap2/foobar $ umount /mnt $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt $ btrfs receive -f /mnt/1.snap /mnt $ btrfs receive -f /mnt/2.snap /mnt $ stat --format %s /mnt/snap2/foobar 3145728 # --> should be 1Mb and not 3Mb (which was the end offset of hole # punch operation) $ md5sum /mnt/snap2/foobar 117baf295297c2a995f92da725b0b651 /mnt/snap2/foobar # --> should be d31659e82e87798acd4669a1e0a19d4f as in the original fs This issue actually happens only since commit |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| 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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.