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由 J. Bruce Fields 提交于
In the loop in scatterwalk_copychunks(), if walk->offset is zero, then scatterwalk_pagedone rounds that up to the nearest page boundary: walk->offset += PAGE_SIZE - 1; walk->offset &= PAGE_MASK; which is a no-op in this case, so we don't advance to the next element of the scatterlist array: if (walk->offset >= walk->sg->offset + walk->sg->length) scatterwalk_start(walk, sg_next(walk->sg)); and we end up copying the same data twice. It appears that other callers of scatterwalk_{page}done first advance walk->offset, so I believe that's the correct thing to do here. This caused a bug in NFS when run with krb5p security, which would cause some writes to fail with permissions errors--for example, writes of less than 8 bytes (the des blocksize) at the start of a file. A git-bisect shows the bug was originally introduced by 5c64097a, first in 2.6.19-rc1. Signed-off-by: N"J. Bruce Fields" <bfields@citi.umich.edu> Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
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