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authorAl Viro <viro@zeniv.linux.org.uk>2016-10-10 13:26:27 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2016-10-10 13:36:06 -0400
commitc3a690240423fc4eb8a0c3c7df025d13eadf140b (patch)
tree20f4a32910427c2aa4ccf8e33633d6e7194628bf
parenta949e63992469fed87aef197347960ced31701b8 (diff)
downloadlinux-c3a690240423fc4eb8a0c3c7df025d13eadf140b.tar.bz2
fix ITER_PIPE interaction with direct_IO
by making sure we call iov_iter_advance() on original iov_iter even if direct_IO (done on its copy) has returned 0. It's a no-op for old iov_iter flavours and does the right thing (== truncation of the stuff we'd allocated, but not filled) in ITER_PIPE case. Failures (e.g. -EIO) get caught and dealt with by cleanup in generic_file_read_iter(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/splice.c12
-rw-r--r--fs/xfs/xfs_file.c2
-rw-r--r--mm/filemap.c2
3 files changed, 5 insertions, 11 deletions
diff --git a/fs/splice.c b/fs/splice.c
index aa38901a4f10..153d4f3bd441 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -315,15 +315,9 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
*ppos = kiocb.ki_pos;
file_accessed(in);
} else if (ret < 0) {
- if (WARN_ON(to.idx != idx || to.iov_offset)) {
- /*
- * a bogus ->read_iter() has copied something and still
- * returned an error instead of a short read.
- */
- to.idx = idx;
- to.iov_offset = 0;
- iov_iter_advance(&to, 0); /* to free what was emitted */
- }
+ to.idx = idx;
+ to.iov_offset = 0;
+ iov_iter_advance(&to, 0); /* to free what was emitted */
/*
* callers of ->splice_read() expect -EAGAIN on
* "can't put anything in there", rather than -EFAULT.
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 92f16cfb81e8..26cf153e3714 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -317,7 +317,7 @@ xfs_file_dio_aio_read(
data = *to;
ret = __blockdev_direct_IO(iocb, inode, target->bt_bdev, &data,
xfs_get_blocks_direct, NULL, NULL, 0);
- if (ret > 0) {
+ if (ret >= 0) {
iocb->ki_pos += ret;
iov_iter_advance(to, ret);
}
diff --git a/mm/filemap.c b/mm/filemap.c
index 8a287dfc5372..6b965efe215e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1920,7 +1920,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
retval = mapping->a_ops->direct_IO(iocb, &data);
}
- if (retval > 0) {
+ if (retval >= 0) {
iocb->ki_pos += retval;
iov_iter_advance(iter, retval);
}