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[ Upstream commit90be48bd9d] If a file has FI_COMPRESS_RELEASED, all writes for it should not be allowed. However, as of now, in case of compress_mode=user, writes triggered by IOCTLs like F2FS_IOC_DE/COMPRESS_FILE are allowed unexpectly, which could crash that file. To fix it, let's do not allow F2FS_IOC_DE/COMPRESS_IOCTL if a file already has FI_COMPRESS_RELEASED flag. This is the reproduction process: 1. $ touch ./file 2. $ chattr +c ./file 3. $ dd if=/dev/random of=./file bs=4096 count=30 conv=notrunc 4. $ dd if=/dev/zero of=./file bs=4096 count=34 seek=30 conv=notrunc 5. $ sync 6. $ do_compress ./file ; call F2FS_IOC_COMPRESS_FILE 7. $ get_compr_blocks ./file ; call F2FS_IOC_GET_COMPRESS_BLOCKS 8. $ release ./file ; call F2FS_IOC_RELEASE_COMPRESS_BLOCKS 9. $ do_compress ./file ; call F2FS_IOC_COMPRESS_FILE again 10. $ get_compr_blocks ./file ; call F2FS_IOC_GET_COMPRESS_BLOCKS again This reproduction process is tested in 128kb cluster size. You can find compr_blocks has a negative value. Fixes:5fdb322ff2("f2fs: add F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE") Signed-off-by: Junbeom Yeom <junbeom.yeom@samsung.com> Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com> Signed-off-by: Youngjin Gil <youngjin.gil@samsung.com> Signed-off-by: Jaewook Kim <jw5454.kim@samsung.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.