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authorPali Rohár <pali@kernel.org>2024-09-18 00:28:25 +0200
committerSteve French <stfrench@microsoft.com>2025-02-19 10:42:27 -0600
commitb587fd128660d48cd2122f870f720ff8e2b4abb3 (patch)
tree09f4fbda0c8ea9b3e7beee75dcb145e7800bd9f8
parentcad3fc0a4c8cef07b07ceddc137f582267577250 (diff)
cifs: Treat unhandled directory name surrogate reparse points as mount directory nodes
If the reparse point was not handled (indicated by the -EOPNOTSUPP from ops->parse_reparse_point() call) but reparse tag is of type name surrogate directory type, then treat is as a new mount point. Name surrogate reparse point represents another named entity in the system. From SMB client point of view, this another entity is resolved on the SMB server, and server serves its content automatically. Therefore from Linux client point of view, this name surrogate reparse point of directory type crosses mount point. Signed-off-by: Pali Rohár <pali@kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
-rw-r--r--fs/smb/client/inode.c13
-rw-r--r--fs/smb/common/smbfsctl.h3
2 files changed, 16 insertions, 0 deletions
diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
index 3261190e6f90..616149c7f0a5 100644
--- a/fs/smb/client/inode.c
+++ b/fs/smb/client/inode.c
@@ -1215,6 +1215,19 @@ static int reparse_info_to_fattr(struct cifs_open_info_data *data,
rc = server->ops->parse_reparse_point(cifs_sb,
full_path,
iov, data);
+ /*
+ * If the reparse point was not handled but it is the
+ * name surrogate which points to directory, then treat
+ * is as a new mount point. Name surrogate reparse point
+ * represents another named entity in the system.
+ */
+ if (rc == -EOPNOTSUPP &&
+ IS_REPARSE_TAG_NAME_SURROGATE(data->reparse.tag) &&
+ (le32_to_cpu(data->fi.Attributes) & ATTR_DIRECTORY)) {
+ rc = 0;
+ cifs_create_junction_fattr(fattr, sb);
+ goto out;
+ }
}
if (data->reparse.tag == IO_REPARSE_TAG_SYMLINK && !rc) {
diff --git a/fs/smb/common/smbfsctl.h b/fs/smb/common/smbfsctl.h
index 4b379e84c46b..3253a18ecb5c 100644
--- a/fs/smb/common/smbfsctl.h
+++ b/fs/smb/common/smbfsctl.h
@@ -159,6 +159,9 @@
#define IO_REPARSE_TAG_LX_CHR 0x80000025
#define IO_REPARSE_TAG_LX_BLK 0x80000026
+/* If Name Surrogate Bit is set, the file or directory represents another named entity in the system. */
+#define IS_REPARSE_TAG_NAME_SURROGATE(tag) (!!((tag) & 0x20000000))
+
/* fsctl flags */
/* If Flags is set to this value, the request is an FSCTL not ioctl request */
#define SMB2_0_IOCTL_IS_FSCTL 0x00000001