NFS: nfs_set_pgio_error sometimes misses errors

PATCH New Trond Myklebust 1 participant 1 message Aug 17, 2015

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Trond Myklebust

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2015-08-17 18:03 UTC #0 lore raw

PATCH 1/1 NFS: nfs_set_pgio_error sometimes misses errors

We should ensure that we always set the pgio_header's error field if a READ or WRITE RPC call returns an error. The current code depends on 'hdr->good_bytes' always being initialised to a large value, which is not always done correctly by callers.
When this happens, applications may end up missing important errors.

Cc [email protected]

Signed-off-by Trond Myklebust <[email protected]>

---
 fs/nfs/pagelist.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

fs/nfs/pagelist.c +2 -2

index 4984bbe55ff1..7c5718ba625e 100644
@@ -77,8 +77,8 @@ EXPORT_SYMBOL_GPL(nfs_pgheader_init);
 void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
 {
 	spin_lock(&hdr->lock);
-	if (pos < hdr->io_start + hdr->good_bytes) {
-		set_bit(NFS_IOHDR_ERROR, &hdr->flags);
+	if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags)
+	    || pos < hdr->io_start + hdr->good_bytes) {
 		clear_bit(NFS_IOHDR_EOF, &hdr->flags);
 		hdr->good_bytes = pos - hdr->io_start;
 		hdr->error = error;

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