[PATCH 2/7] ksmbd: route stream FileDispositionInformation through stream delete flag

From: Gael Blivet <[email protected]>

set_file_disposition_info() calls ksmbd_set_inode_pending_delete() /
ksmbd_clear_inode_pending_delete() unconditionally, which always sets
S_DEL_PENDING on the whole inode (ci->m_flags), regardless of whether
the handle being closed is a regular file or an alternate data stream.

Requesting delete-pending on a single stream handle (e.g. deleting
just an alternate data stream some clients keep alongside a file)
would therefore incorrectly schedule deletion of the entire file's
data, not just the stream.

Add ksmbd_fd_set_delete_pending()/ksmbd_fd_clear_delete_pending(),
following the same stream-vs-whole-file routing pattern already used
by ksmbd_fd_set_delete_on_close() for the CREATE-time DeleteOnClose
option, and switch set_file_disposition_info() to use them.

Signed-off-by: Gael Blivet <[email protected]>
---
 fs/smb/server/smb2pdu.c   |  4 ++--
 fs/smb/server/vfs_cache.c | 32 ++++++++++++++++++++++++++++++++
 fs/smb/server/vfs_cache.h |  2 ++
 3 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index 39188bb84..e6d0f58d2 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -7117,9 +7117,9 @@ static int set_file_disposition_info(struct ksmbd_work *work,
 		    ksmbd_vfs_empty_dir(fp) == -ENOTEMPTY)
 			return -EBUSY;
 		smb_break_all_levII_oplock_for_delete(work, fp);
-		ksmbd_set_inode_pending_delete(fp);
+		ksmbd_fd_set_delete_pending(fp);
 	} else {
-		ksmbd_clear_inode_pending_delete(fp);
+		ksmbd_fd_clear_delete_pending(fp);
 	}
 	return 0;
 }
diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c
index d95c405ea..2543dd7e8 100644
--- a/fs/smb/server/vfs_cache.c
+++ b/fs/smb/server/vfs_cache.c
@@ -294,6 +294,38 @@ void ksmbd_fd_set_delete_on_close(struct ksmbd_file *fp,
 	up_write(&ci->m_lock);
 }
 
+/*
+ * FileDispositionInformation (SET_INFO) on a stream handle must only
+ * mark the stream for deletion, not the whole file -- otherwise
+ * deleting a single alternate data stream (e.g. AFP_AfpInfo) deletes
+ * the entire file's data along with it.
+ */
+void ksmbd_fd_set_delete_pending(struct ksmbd_file *fp)
+{
+	struct ksmbd_inode *ci = fp->f_ci;
+
+	if (ksmbd_stream_fd(fp)) {
+		down_write(&ci->m_lock);
+		ci->m_flags |= S_DEL_ON_CLS_STREAM;
+		up_write(&ci->m_lock);
+	} else {
+		ksmbd_set_inode_pending_delete(fp);
+	}
+}
+
+void ksmbd_fd_clear_delete_pending(struct ksmbd_file *fp)
+{
+	struct ksmbd_inode *ci = fp->f_ci;
+
+	if (ksmbd_stream_fd(fp)) {
+		down_write(&ci->m_lock);
+		ci->m_flags &= ~S_DEL_ON_CLS_STREAM;
+		up_write(&ci->m_lock);
+	} else {
+		ksmbd_clear_inode_pending_delete(fp);
+	}
+}
+
 static void ksmbd_inode_hash(struct ksmbd_inode *ci)
 {
 	struct hlist_head *b = inode_hashtable +
diff --git a/fs/smb/server/vfs_cache.h b/fs/smb/server/vfs_cache.h
index b9e27307a..111a4e315 100644
--- a/fs/smb/server/vfs_cache.h
+++ b/fs/smb/server/vfs_cache.h
@@ -214,6 +214,8 @@ void ksmbd_set_inode_pending_delete(struct ksmbd_file *fp);
 void ksmbd_clear_inode_pending_delete(struct ksmbd_file *fp);
 void ksmbd_fd_set_delete_on_close(struct ksmbd_file *fp,
 				  int file_info);
+void ksmbd_fd_set_delete_pending(struct ksmbd_file *fp);
+void ksmbd_fd_clear_delete_pending(struct ksmbd_file *fp);
 int ksmbd_reopen_durable_fd(struct ksmbd_work *work, struct ksmbd_file *fp);
 int ksmbd_validate_name_reconnect(struct ksmbd_share_config *share,
 				  struct ksmbd_file *fp, char *name);
-- 
2.43.0