Windows presents files created within Linux as read-only, even when
permissions in Linux indicate the file should be writable.
UDF defines a slightly different set of basic file permissions than Linux.
Specifically, UDF has "delete" and "change attribute" permissions for each
access class (user/group/other). Linux has no equivalents for these.
When the Linux UDF driver creates a file (or directory), no UDF delete or
change attribute permissions are granted. The lack of delete permission
appears to cause Windows to mark an item read-only when its permissions
otherwise indicate that it should be read-write.
Fix this by granting UDF delete and change attribute permissions
to the owner when creating a new inode.
Reported by: Ty Young
Signed-off-by: Steven J. Magnani <steve@xxxxxxxxxxxxxxx>
---
--- a/fs/udf/udf_i.h 2019-08-14 07:24:05.029508342 -0500
+++ b/fs/udf/udf_i.h 2019-08-19 08:55:37.797394177 -0500
@@ -38,6 +38,7 @@ struct udf_inode_info {
__u32 i_next_alloc_block;
__u32 i_next_alloc_goal;
__u32 i_checkpoint;
+ __u32 i_extraPerms;
unsigned i_alloc_type : 3;
unsigned i_efe : 1; /* extendedFileEntry */
unsigned i_use : 1; /* unallocSpaceEntry */
--- a/fs/udf/ialloc.c 2019-08-14 07:24:05.029508342 -0500
+++ b/fs/udf/ialloc.c 2019-08-19 08:33:08.992422457 -0500
@@ -118,6 +118,7 @@ struct inode *udf_new_inode(struct inode
iinfo->i_lenAlloc = 0;
iinfo->i_use = 0;
iinfo->i_checkpoint = 1;
+ iinfo->i_extraPerms = FE_PERM_U_DELETE | FE_PERM_U_CHATTR;
if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_AD_IN_ICB))
iinfo->i_alloc_type = ICBTAG_FLAG_AD_IN_ICB;
else if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_SHORT_AD))
--- a/fs/udf/inode.c 2019-08-14 07:24:05.029508342 -0500
+++ b/fs/udf/inode.c 2019-08-19 08:42:46.537530051 -0500
@@ -45,6 +45,10 @@
#define EXTENT_MERGE_SIZE 5
+#define FE_MAPPED_PERMS (FE_PERM_U_READ | FE_PERM_U_WRITE | FE_PERM_U_EXEC | \
+ FE_PERM_G_READ | FE_PERM_G_WRITE | FE_PERM_G_EXEC | \
+ FE_PERM_O_READ | FE_PERM_O_WRITE | FE_PERM_O_EXEC)
+
static umode_t udf_convert_permissions(struct fileEntry *);
static int udf_update_inode(struct inode *, int);
static int udf_sync_inode(struct inode *inode);
@@ -1458,6 +1462,8 @@ reread:
else
inode->i_mode = udf_convert_permissions(fe);
inode->i_mode &= ~sbi->s_umask;
+ iinfo->i_extraPerms = le32_to_cpu(fe->permissions) & ~FE_MAPPED_PERMS;
+
read_unlock(&sbi->s_cred_lock);
link_count = le16_to_cpu(fe->fileLinkCount);
@@ -1691,10 +1697,7 @@ static int udf_update_inode(struct inode
((inode->i_mode & 0070) << 2) |
((inode->i_mode & 0700) << 4);
- udfperms |= (le32_to_cpu(fe->permissions) &
- (FE_PERM_O_DELETE | FE_PERM_O_CHATTR |
- FE_PERM_G_DELETE | FE_PERM_G_CHATTR |
- FE_PERM_U_DELETE | FE_PERM_U_CHATTR));
+ udfperms |= iinfo->i_extraPerms;
fe->permissions = cpu_to_le32(udfperms);
if (S_ISDIR(inode->i_mode) && inode->i_nlink > 0)
