Merge tag 'pull-work.lseek' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs lseek updates from Al Viro:
 "Jason's lseek series.

  Saner handling of 'lseek should fail with ESPIPE' - this gets rid of
  the magical no_llseek thing and makes checks consistent.

  In particular, the ad-hoc "can we do splice via internal pipe" checks
  got saner (and somewhat more permissive, which is what Jason had been
  after, AFAICT)"

* tag 'pull-work.lseek' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: remove no_llseek
  fs: check FMODE_LSEEK to control internal pipe splicing
  vfio: do not set FMODE_LSEEK flag
  dma-buf: remove useless FMODE_LSEEK flag
  fs: do not compare against ->llseek
  fs: clear or set FMODE_LSEEK based on llseek function

6 files changed, 14 insertions, 24 deletions

diff --git a/fs/coredump.c b/fs/coredump.c
index ebc43f960b64..9f4aae202109 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -816,9 +816,9 @@ static int __dump_skip(struct coredump_params *cprm, size_t nr)
 {
 	static char zeroes[PAGE_SIZE];
 	struct file *file = cprm->file;
-	if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
+	if (file->f_mode & FMODE_LSEEK) {
 		if (dump_interrupted() ||
-		    file->f_op->llseek(file, nr, SEEK_CUR) < 0)
+		    vfs_llseek(file, nr, SEEK_CUR) < 0)
 			return 0;
 		cprm->pos += nr;
 		return 1;
diff --git a/fs/file_table.c b/fs/file_table.c
index 5424e3a8df5f..5727a63a7b67 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -235,6 +235,8 @@ static struct file *alloc_file(const struct path *path, int flags,
 	file->f_mapping = path->dentry->d_inode->i_mapping;
 	file->f_wb_err = filemap_sample_wb_err(file->f_mapping);
 	file->f_sb_err = file_sample_sb_err(file);
+	if (fop->llseek)
+		file->f_mode |= FMODE_LSEEK;
 	if ((file->f_mode & FMODE_READ) &&
 	     likely(fop->read || fop->read_iter))
 		file->f_mode |= FMODE_CAN_READ;
diff --git a/fs/open.c b/fs/open.c
index 2790aac66e58..1177e8d1cf83 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -888,6 +888,8 @@ static int do_dentry_open(struct file *f,
 	if ((f->f_mode & FMODE_WRITE) &&
 	     likely(f->f_op->write || f->f_op->write_iter))
 		f->f_mode |= FMODE_CAN_WRITE;
+	if ((f->f_mode & FMODE_LSEEK) && !f->f_op->llseek)
+		f->f_mode &= ~FMODE_LSEEK;
 	if (f->f_mapping->a_ops && f->f_mapping->a_ops->direct_IO)
 		f->f_mode |= FMODE_CAN_ODIRECT;
 
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 245e2cb62708..fdde6c56cc3d 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -226,8 +226,7 @@ static int ovl_copy_up_data(struct ovl_fs *ofs, struct path *old,
 	/* Couldn't clone, so now we try to copy the data */
 
 	/* Check if lower fs supports seek operation */
-	if (old_file->f_mode & FMODE_LSEEK &&
-	    old_file->f_op->llseek)
+	if (old_file->f_mode & FMODE_LSEEK)
 		skip_hole = true;
 
 	while (len) {
diff --git a/fs/read_write.c b/fs/read_write.c
index 0131d0df0476..ea59dd0095c2 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -227,12 +227,6 @@ loff_t noop_llseek(struct file *file, loff_t offset, int whence)
 }
 EXPORT_SYMBOL(noop_llseek);
 
-loff_t no_llseek(struct file *file, loff_t offset, int whence)
-{
-	return -ESPIPE;
-}
-EXPORT_SYMBOL(no_llseek);
-
 loff_t default_llseek(struct file *file, loff_t offset, int whence)
 {
 	struct inode *inode = file_inode(file);
@@ -290,14 +284,9 @@ EXPORT_SYMBOL(default_llseek);
 
 loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
 {
-	loff_t (*fn)(struct file *, loff_t, int);
-
-	fn = no_llseek;
-	if (file->f_mode & FMODE_LSEEK) {
-		if (file->f_op->llseek)
-			fn = file->f_op->llseek;
-	}
-	return fn(file, offset, whence);
+	if (!(file->f_mode & FMODE_LSEEK))
+		return -ESPIPE;
+	return file->f_op->llseek(file, offset, whence);
 }
 EXPORT_SYMBOL(vfs_llseek);
 
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;
 
 	/*