diff options
author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2011-06-10 13:30:23 -0400 |
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committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2011-06-21 11:54:06 -0400 |
commit | 19982ba8562e33083cb5bbb59a74855d8a9624ea (patch) | |
tree | 51656f4ff6252a0207a0f42feea147c736474171 /fs/nfs/pnfs.c | |
parent | 8f7d5efbef8718a774ac5e347b4ec069f17fd9b4 (diff) |
NFSv4.1: Fix an off-by-one error in pnfs_generic_pg_test
And document what is going on there...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/pnfs.c')
-rw-r--r-- | fs/nfs/pnfs.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 0f42e02436ee..29c0ca7fc347 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -1078,11 +1078,22 @@ pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev, return true; } - if (req_offset(req) > end_offset(pgio->pg_lseg->pls_range.offset, - pgio->pg_lseg->pls_range.length)) - return false; - - return true; + /* + * Test if a nfs_page is fully contained in the pnfs_layout_range. + * Note that this test makes several assumptions: + * - that the previous nfs_page in the struct nfs_pageio_descriptor + * is known to lie within the range. + * - that the nfs_page being tested is known to be contiguous with the + * previous nfs_page. + * - Layout ranges are page aligned, so we only have to test the + * start offset of the request. + * + * Please also note that 'end_offset' is actually the offset of the + * first byte that lies outside the pnfs_layout_range. FIXME? + * + */ + return req_offset(req) < end_offset(pgio->pg_lseg->pls_range.offset, + pgio->pg_lseg->pls_range.length); } EXPORT_SYMBOL_GPL(pnfs_generic_pg_test); |