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Currently getbmap uses xfs_bmapi_read to query the extent map, and then fixes up various bits that are eventually reported to userspace. This patch instead rewrites it to use xfs_iext_lookup_extent and xfs_iext_get_extent to iteratively process the extent map. This not only avoids the need to allocate a map for the returned xfs_bmbt_irec structures but also greatly simplified the code. There are two intentional behavior changes compared to the old code: - the current code reports unwritten extents that don't directly border a written one as unwritten even when not passing the BMV_IF_PREALLOC option, contrary to the documentation. The new code requires the BMV_IF_PREALLOC flag to report the unwrittent extent bit. - The new code does never merges consecutive extents, unlike the old code that sometimes does it based on the boundaries of the xfs_bmapi_read calls. Note that the extent merging behavior was entirely undocumented. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. 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.