[PATCH v21 17/30] ecryptfs: Provide a splice-read stub

David Howells
2023-05-20T00:01:55Z

Provide a splice_read stub for ecryptfs to update the access time on the
lower file after the operation. Splicing from a direct I/O fd will update
the access time when ->read_iter() is called.

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: Tyler Hicks <code@tyhicks.com>
cc: ecryptfs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-mm@kvack.org
---
fs/ecryptfs/file.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 268b74499c28..284395587be0 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -44,6 +44,31 @@ static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
return rc;
}

+/*
+ * ecryptfs_splice_read_update_atime
+ *
+ * generic_file_splice_read updates the atime of upper layer inode. But, it
+ * doesn't give us a chance to update the atime of the lower layer inode. This
+ * function is a wrapper to generic_file_read. It updates the atime of the
+ * lower level inode if generic_file_read returns without any errors. This is
+ * to be used only for file reads. The function to be used for directory reads
+ * is ecryptfs_read.
+ */
+static ssize_t ecryptfs_splice_read_update_atime(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe,
+ size_t len, unsigned int flags)
+{
+ ssize_t rc;
+ const struct path *path;
+
+ rc = generic_file_splice_read(in, ppos, pipe, len, flags);
+ if (rc >= 0) {
+ path = ecryptfs_dentry_to_lower_path(in->f_path.dentry);
+ touch_atime(path);
+ }
+ return rc;
+}
+
struct ecryptfs_getdents_callback {
struct dir_context ctx;
struct dir_context *caller;
@@ -414,5 +439,5 @@ const struct file_operations ecryptfs_main_fops = {
.release = ecryptfs_release,
.fsync = ecryptfs_fsync,
.fasync = ecryptfs_fasync,
- .splice_read = generic_file_splice_read,
+ .splice_read = ecryptfs_splice_read_update_atime,
};