[PATCH v21 21/30] ntfs3: Provide a splice-read stub

David Howells
2023-05-20T00:02:04Z

Provide a splice_read stub for NTFS3 to perform various checks before
allowing the operation to proceed.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
cc: ntfs3@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-mm@kvack.org
---
fs/ntfs3/file.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index 9a3d55c367d9..667c9dc68b58 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -744,6 +744,35 @@ static ssize_t ntfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
return generic_file_read_iter(iocb, iter);
}

+static ssize_t ntfs_file_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe,
+ size_t len, unsigned int flags)
+{
+ struct inode *inode = in->f_mapping->host;
+ struct ntfs_inode *ni = ntfs_i(inode);
+
+ if (is_encrypted(ni)) {
+ ntfs_inode_warn(inode, "encrypted i/o not supported");
+ return -EOPNOTSUPP;
+ }
+
+#ifndef CONFIG_NTFS3_LZX_XPRESS
+ if (ni->ni_flags & NI_FLAG_COMPRESSED_MASK) {
+ ntfs_inode_warn(
+ inode,
+ "activate CONFIG_NTFS3_LZX_XPRESS to read external compressed files");
+ return -EOPNOTSUPP;
+ }
+#endif
+
+ if (is_dedup(ni)) {
+ ntfs_inode_warn(inode, "read deduplicated not supported");
+ return -EOPNOTSUPP;
+ }
+
+ return generic_file_splice_read(in, ppos, pipe, len, flags);
+}
+
/*
* ntfs_get_frame_pages
*
@@ -1159,7 +1188,7 @@ const struct file_operations ntfs_file_operations = {
#ifdef CONFIG_COMPAT
.compat_ioctl = ntfs_compat_ioctl,
#endif
- .splice_read = generic_file_splice_read,
+ .splice_read = ntfs_file_splice_read,
.mmap = ntfs_file_mmap,
.open = ntfs_file_open,
.fsync = generic_file_fsync,