splice: fix sendfile() issue with relay

Splice isn't always incrementing the ppos correctly, which broke
relay splice.

Signed-off-by: Tom Zanussi <zanussi@comcast.net>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/fs/splice.c b/fs/splice.c
index 7815003..a048ad2 100644 (file)
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -983,7 +983,7 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
 
        while (len) {
                size_t read_len;
-               loff_t pos = sd->pos;
+               loff_t pos = sd->pos, prev_pos = pos;
 
                ret = do_splice_to(in, &pos, pipe, len, flags);
                if (unlikely(ret <= 0))
@@ -998,15 +998,19 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
                 * could get stuck data in the internal pipe:
                 */
                ret = actor(pipe, sd);
-               if (unlikely(ret <= 0))
+               if (unlikely(ret <= 0)) {
+                       sd->pos = prev_pos;
                        goto out_release;
+               }
 
                bytes += ret;
                len -= ret;
                sd->pos = pos;
 
-               if (ret < read_len)
+               if (ret < read_len) {
+                       sd->pos = prev_pos + ret;
                        goto out_release;
+               }
        }
 
 done:
@@ -1072,7 +1076,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
 
        ret = splice_direct_to_actor(in, &sd, direct_splice_actor);
        if (ret > 0)
-               *ppos += ret;
+               *ppos = sd.pos;
 
        return ret;
 }

diff --git a/kernel/relay.c b/kernel/relay.c
index bc24dcd..7de644c 100644 (file)
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -1191,7 +1191,7 @@ static ssize_t relay_file_splice_read(struct file *in,
        ret = 0;
        spliced = 0;
 
-       while (len) {
+       while (len && !spliced) {
                ret = subbuf_splice_actor(in, ppos, pipe, len, flags, &nonpad_ret);
                if (ret < 0)
                        break;