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authorChristoph Hellwig <hch@lst.de>2014-08-21 11:09:17 -0500
committerTrond Myklebust <trond.myklebust@primarydata.com>2014-09-10 12:47:01 -0700
commit2e11f8296d22134c4fca7eb022eea2b09facd307 (patch)
treef80b3d375c399f31091ebe58d5fb7883dcbc8098
parentbc7d4b8fd0917b4b84a8911185d34a97c696f219 (diff)
nfs: cap request size to fit a kmalloced page array
pNFS servers may return arbitrarily large layouts. Trim back the I/O size to one that we can at least allocate the page array for. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
-rw-r--r--fs/nfs/pagelist.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index be7cbce6e4c7..94e16ec88312 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -481,6 +481,14 @@ size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
return 0;
}
+ /*
+ * Limit the request size so that we can still allocate a page array
+ * for it without upsetting the slab allocator.
+ */
+ if (((desc->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
+ sizeof(struct page) > PAGE_SIZE)
+ return 0;
+
return min(desc->pg_bsize - desc->pg_count, (size_t)req->wb_bytes);
}
EXPORT_SYMBOL_GPL(nfs_generic_pg_test);