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authorPavel Begunkov <asml.silence@gmail.com>2021-01-09 16:02:57 +0000
committerJens Axboe <axboe@kernel.dk>2021-01-25 08:58:24 -0700
commit0f1d344feb534555a0dcd0beafb7211a37c5355e (patch)
tree762d8e337b77776ae4f473d788de25f2709594a9 /fs/splice.c
parent684da7628d93bbdcfba9081b917d99f29ad04c23 (diff)
splice: don't generate zero-len segement bvecs
iter_file_splice_write() may spawn bvec segments with zero-length. In preparation for prohibiting them, filter out by hand at splice level. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/splice.c')
-rw-r--r--fs/splice.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/splice.c b/fs/splice.c
index 866d5c2367b2..474fb8b5562a 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -662,12 +662,14 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
/* build the vector */
left = sd.total_len;
- for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++, n++) {
+ for (n = 0; !pipe_empty(head, tail) && left && n < nbufs; tail++) {
struct pipe_buffer *buf = &pipe->bufs[tail & mask];
size_t this_len = buf->len;
- if (this_len > left)
- this_len = left;
+ /* zero-length bvecs are not supported, skip them */
+ if (!this_len)
+ continue;
+ this_len = min(this_len, left);
ret = pipe_buf_confirm(pipe, buf);
if (unlikely(ret)) {
@@ -680,6 +682,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
array[n].bv_len = this_len;
array[n].bv_offset = buf->offset;
left -= this_len;
+ n++;
}
iov_iter_bvec(&from, WRITE, array, n, sd.total_len - left);