diff options
| author |   Jason A. Donenfeld <Jason@zx2c4.com> | 2022-06-29 15:06:58 +0200 |
|---|---|---|
| committer |   Al Viro <viro@zeniv.linux.org.uk> | 2022-07-16 09:19:16 -0400 |
| commit | 97ef77c52b789ec1411d360ed99dca1efe4b2c81 (patch) | |
| tree | c17483d04296da08c6a68d745dcf499005f4e7ec | |
| parent | vfio: do not set FMODE_LSEEK flag (diff) | |
| download | linux-dev-97ef77c52b789ec1411d360ed99dca1efe4b2c81.tar.xz linux-dev-97ef77c52b789ec1411d360ed99dca1efe4b2c81.zip | |
fs: check FMODE_LSEEK to control internal pipe splicing
The original direct splicing mechanism from Jens required the input to
be a regular file because it was avoiding the special socket case. It
also recognized blkdevs as being close enough to a regular file. But it
forgot about chardevs, which behave the same way and work fine here.
This is an okayish heuristic, but it doesn't totally work. For example,
a few chardevs should be spliceable here. And a few regular files
shouldn't. This patch fixes this by instead checking whether FMODE_LSEEK
is set, which represents decently enough what we need rewinding for when
splicing to internal pipes.
Fixes: b92ce5589374 ("[PATCH] splice: add direct fd <-> fd splicing support")
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/splice.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/fs/splice.c b/fs/splice.c index 047b79db8eb5..93a2c9bf6249 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -814,17 +814,15 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, { struct pipe_inode_info *pipe; long ret, bytes; - umode_t i_mode; size_t len; int i, flags, more; /* - * We require the input being a regular file, as we don't want to - * randomly drop data for eg socket -> socket splicing. Use the - * piped splicing for that! + * We require the input to be seekable, as we don't want to randomly + * drop data for eg socket -> socket splicing. Use the piped splicing + * for that! */ - i_mode = file_inode(in)->i_mode; - if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode))) + if (unlikely(!(in->f_mode & FMODE_LSEEK))) return -EINVAL; /* |