[PATCH 3/3] smb/client: decode reparse metadata using its payload type

cifs_open_info_data stores FILE_ALL_INFORMATION and SMB3 POSIX query
information in a union. reparse_info_to_fattr() selects a union member
from the mount mode, while several directory checks always read
fi.Attributes.

The metadata can instead come from an SMB2 CREATE response on a POSIX
mount, or from a POSIX query while processing a reparse point. In those
cases the mount mode and hard-coded fi accesses select the wrong union
member.

See the procedures below:

  cifs_nt_open
    smb2_open_file
      SMB2_open
        data->fi = SMB2 CREATE response
        data->contains_posix_file_info = false
    cifs_get_inode_info
      reparse_info_to_fattr
        if (tcon->posix_extensions) // true
          smb311_posix_info_to_fattr
            data->posix_fi // wrong union member

  smb311_posix_get_fattr
    smb2_query_path_info
      smb2_compound_op
        data->posix_fi = SMB3 POSIX query response
        data->contains_posix_file_info = true
    reparse_info_to_fattr
      data->fi.Attributes // wrong union member

Add a common DOS attribute accessor and use contains_posix_file_info
both for attribute reads and for the final fattr conversion.

Signed-off-by: Ze Tan <[email protected]>
---
 fs/smb/client/inode.c     |  9 +++++----
 fs/smb/client/reparse.h   | 17 ++++++++++-------
 fs/smb/client/smb2inode.c |  6 ++++--
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
index 0afff761aab9..e7ef50b74378 100644
--- a/fs/smb/client/inode.c
+++ b/fs/smb/client/inode.c
@@ -1215,7 +1215,7 @@ static int reparse_info_to_fattr(struct cifs_open_info_data *data,
 		break;
 	case IO_REPARSE_TAG_INTERNAL:
 		rc = 0;
-		if (le32_to_cpu(data->fi.Attributes) & ATTR_DIRECTORY) {
+		if (cifs_open_data_attrs(data) & ATTR_DIRECTORY) {
 			cifs_create_junction_fattr(fattr, sb);
 			goto out;
 		}
@@ -1239,7 +1239,7 @@ static int reparse_info_to_fattr(struct cifs_open_info_data *data,
 			 */
 			if (rc == -EOPNOTSUPP &&
 			    IS_REPARSE_TAG_NAME_SURROGATE(data->reparse.tag) &&
-			    (le32_to_cpu(data->fi.Attributes) & ATTR_DIRECTORY)) {
+			    (cifs_open_data_attrs(data) & ATTR_DIRECTORY)) {
 				rc = 0;
 				cifs_create_junction_fattr(fattr, sb);
 				goto out;
@@ -1257,13 +1257,14 @@ static int reparse_info_to_fattr(struct cifs_open_info_data *data,
 		}
 
 		if (data->reparse.tag == IO_REPARSE_TAG_SYMLINK && !rc) {
-			bool directory = le32_to_cpu(data->fi.Attributes) & ATTR_DIRECTORY;
+			bool directory = cifs_open_data_attrs(data) & ATTR_DIRECTORY;
+
 			rc = smb2_fix_symlink_target_type(&data->symlink_target, directory, cifs_sb);
 		}
 		break;
 	}
 
-	if (tcon->posix_extensions)
+	if (data->contains_posix_file_info)
 		smb311_posix_info_to_fattr(fattr, data, sb);
 	else
 		cifs_open_info_to_fattr(fattr, data, sb);
diff --git a/fs/smb/client/reparse.h b/fs/smb/client/reparse.h
index 0164dc47bdfd..49efd85b1e94 100644
--- a/fs/smb/client/reparse.h
+++ b/fs/smb/client/reparse.h
@@ -98,15 +98,21 @@ static inline bool reparse_inode_match(struct inode *inode,
 		timespec64_equal(&ctime, &fattr->cf_ctime);
 }
 
+static inline u32 cifs_open_data_attrs(const struct cifs_open_info_data *data)
+{
+	if (data->contains_posix_file_info)
+		return le32_to_cpu(data->posix_fi.DosAttributes);
+
+	return le32_to_cpu(data->fi.Attributes);
+}
+
 static inline bool cifs_open_data_reparse(struct cifs_open_info_data *data)
 {
-	u32 attrs;
-	bool ret;
+	u32 attrs = cifs_open_data_attrs(data);
 
 	if (data->contains_posix_file_info) {
 		struct smb311_posix_qinfo *fi = &data->posix_fi;
 
-		attrs = le32_to_cpu(fi->DosAttributes);
 		if (data->reparse_point) {
 			attrs |= ATTR_REPARSE_POINT;
 			fi->DosAttributes = cpu_to_le32(attrs);
@@ -115,16 +121,13 @@ static inline bool cifs_open_data_reparse(struct cifs_open_info_data *data)
 	} else {
 		struct smb2_file_all_info *fi = &data->fi;
 
-		attrs = le32_to_cpu(fi->Attributes);
 		if (data->reparse_point) {
 			attrs |= ATTR_REPARSE_POINT;
 			fi->Attributes = cpu_to_le32(attrs);
 		}
 	}
 
-	ret = attrs & ATTR_REPARSE_POINT;
-
-	return ret;
+	return attrs & ATTR_REPARSE_POINT;
 }
 
 bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb,
diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index 058b05f7a3e5..bcaa44814b71 100644
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -22,6 +22,7 @@
 #include "smb2glob.h"
 #include "smb2proto.h"
 #include "cached_dir.h"
+#include "reparse.h"
 #include "../common/smb2status.h"
 #include "../common/smbfsctl.h"
 
@@ -1002,12 +1003,13 @@ int smb2_query_path_info(const unsigned int xid,
 		/*
 		 * If the symlink was already parsed in create response then it is needed to fix
 		 * its type now (after the second call with OPEN_REPARSE_POINT which filled the
-		 * data->fi.Attributes). If the symlink was not parsed in create response then
+		 * metadata attributes). If the symlink was not parsed in create response then
 		 * the data->symlink_target was not filled yet and then the type will be fixed
 		 * later after data->symlink_target is filled.
 		 */
 		if (data->reparse.tag == IO_REPARSE_TAG_SYMLINK && !rc && data->symlink_target) {
-			bool directory = le32_to_cpu(data->fi.Attributes) & ATTR_DIRECTORY;
+			bool directory = cifs_open_data_attrs(data) & ATTR_DIRECTORY;
+
 			rc = smb2_fix_symlink_target_type(&data->symlink_target, directory, cifs_sb);
 		}
 		break;
-- 
2.43.0