ext4: Add statx support

Return enhanced file attributes from the Ext4 filesystem.  This includes
the following:

 (1) The inode creation time (i_crtime) as stx_btime, setting STATX_BTIME.

 (2) Certain FS_xxx_FL flags are mapped to stx_attribute flags.

This requires that all ext4 inodes have a getattr call, not just some of
them, so to this end, split the ext4_getattr() function and only call part
of it where appropriate.

Example output:

	[root@andromeda ~]# touch foo
	[root@andromeda ~]# chattr +ai foo
	[root@andromeda ~]# /tmp/test-statx foo
	statx(foo) = 0
	results=fff
	  Size: 0               Blocks: 0          IO Block: 4096    regular file
	Device: 08:12           Inode: 2101950     Links: 1
	Access: (0644/-rw-r--r--)  Uid:     0   Gid:     0
	Access: 2016-02-11 17:08:29.031795451+0000
	Modify: 2016-02-11 17:08:29.031795451+0000
	Change: 2016-02-11 17:11:11.987790114+0000
	 Birth: 2016-02-11 17:08:29.031795451+0000
	Attributes: 0000000000000030 (-------- -------- -------- -------- -------- -------- -------- --ai----)

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 32 insertions, 3 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4247d8d25687..5d02b922afa3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5390,11 +5390,40 @@ err_out:
 int ext4_getattr(const struct path *path, struct kstat *stat,
                  u32 request_mask, unsigned int query_flags)
 {
-        struct inode *inode;
-        unsigned long long delalloc_blocks;
+        struct inode *inode = d_inode(path->dentry);
+        struct ext4_inode *raw_inode;
+        struct ext4_inode_info *ei = EXT4_I(inode);
+        unsigned int flags;
+
+        if (EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) {
+                stat->result_mask |= STATX_BTIME;
+                stat->btime.tv_sec = ei->i_crtime.tv_sec;
+                stat->btime.tv_nsec = ei->i_crtime.tv_nsec;
+        }
+
+        flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
+        if (flags & EXT4_APPEND_FL)
+                stat->attributes |= STATX_ATTR_APPEND;
+        if (flags & EXT4_COMPR_FL)
+                stat->attributes |= STATX_ATTR_COMPRESSED;
+        if (flags & EXT4_ENCRYPT_FL)
+                stat->attributes |= STATX_ATTR_ENCRYPTED;
+        if (flags & EXT4_IMMUTABLE_FL)
+                stat->attributes |= STATX_ATTR_IMMUTABLE;
+        if (flags & EXT4_NODUMP_FL)
+                stat->attributes |= STATX_ATTR_NODUMP;
 
-        inode = d_inode(path->dentry);
         generic_fillattr(inode, stat);
+        return 0;
+}
+
+int ext4_file_getattr(const struct path *path, struct kstat *stat,
+                      u32 request_mask, unsigned int query_flags)
+{
+        struct inode *inode = d_inode(path->dentry);
+        u64 delalloc_blocks;
+
+        ext4_getattr(path, stat, request_mask, query_flags);
 
         /*
          * If there is inline data in the inode, the inode will normally not