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Filipe Manana
7ed586d0a8
Btrfs: fix assertion on fsync of regular file when using no-holes feature
When using the NO_HOLES feature and logging a regular file, we were expecting that if we find an inline extent, that either its size in RAM (uncompressed and unenconded) matches the size of the file or if it does not, that it matches the sector size and it represents compressed data. This assertion does not cover a case where the length of the inline extent is smaller than the sector size and also smaller the file's size, such case is possible through fallocate. Example: $ mkfs.btrfs -f -O no-holes /dev/sdb $ mount /dev/sdb /mnt $ xfs_io -f -c "pwrite -S 0xb60 0 21" /mnt/foobar $ xfs_io -c "falloc 40 40" /mnt/foobar $ xfs_io -c "fsync" /mnt/foobar In the above example we trigger the assertion because the inline extent's length is 21 bytes while the file size is 80 bytes. The fallocate() call merely updated the file's size and did not touch the existing inline extent, as expected. So fix this by adjusting the assertion so that an inline extent length smaller than the file size is valid if the file size is smaller than the filesystem's sector size. A test case for fstests follows soon. Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> Fixes: a89ca6f24ffe ("Btrfs: fix fsync after truncate when no_holes feature is enabled") CC: stable@vger.kernel.org # 4.14+ Link: https://lore.kernel.org/linux-btrfs/CAE5jQCfRSBC7n4pUTFJcmHh109=gwyT9mFkCOL+NKfzswmR=_Q@mail.gmail.com/ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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.
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