nilfs2: support nanosecond timestamp

After a review of user's feedback for finding out other compatibility
issues, I found nilfs improperly initializes timestamps in inode;
CURRENT_TIME was used there instead of CURRENT_TIME_SEC even though nilfs
didn't have nanosecond timestamps on disk.  A few users gave us the report
that the tar program sometimes failed to expand symbolic links on nilfs,
and it turned out to be the cause.

Instead of applying the above displacement, I've decided to support
nanosecond timestamps on this occation.  Fortunetaly, a needless 64-bit
field was in the nilfs_inode struct, and I found it's available for this
purpose without impact for the users.

So, this will do the enhancement and resolve the tar problem.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 7 deletions

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index a1922b17662c..49ab4a49bb4f 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -306,7 +306,6 @@ struct inode *nilfs_new_inode(struct inode *dir, int mode)
 
 	/* ii->i_file_acl = 0; */
 	/* ii->i_dir_acl = 0; */
-	ii->i_dtime = 0;
 	ii->i_dir_start_lookup = 0;
 #ifdef CONFIG_NILFS_FS_POSIX_ACL
 	ii->i_acl = NULL;
@@ -390,11 +389,10 @@ int nilfs_read_inode_common(struct inode *inode,
 	inode->i_atime.tv_sec = le64_to_cpu(raw_inode->i_mtime);
 	inode->i_ctime.tv_sec = le64_to_cpu(raw_inode->i_ctime);
 	inode->i_mtime.tv_sec = le64_to_cpu(raw_inode->i_mtime);
-	inode->i_atime.tv_nsec = 0;
-	inode->i_ctime.tv_nsec = 0;
-	inode->i_mtime.tv_nsec = 0;
-	ii->i_dtime = le64_to_cpu(raw_inode->i_dtime);
-	if (inode->i_nlink == 0 && (inode->i_mode == 0 || ii->i_dtime))
+	inode->i_atime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);
+	inode->i_ctime.tv_nsec = le32_to_cpu(raw_inode->i_ctime_nsec);
+	inode->i_mtime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);
+	if (inode->i_nlink == 0 && inode->i_mode == 0)
 		return -EINVAL; /* this inode is deleted */
 
 	inode->i_blocks = le64_to_cpu(raw_inode->i_blocks);
@@ -505,9 +503,10 @@ void nilfs_write_inode_common(struct inode *inode,
 	raw_inode->i_size = cpu_to_le64(inode->i_size);
 	raw_inode->i_ctime = cpu_to_le64(inode->i_ctime.tv_sec);
 	raw_inode->i_mtime = cpu_to_le64(inode->i_mtime.tv_sec);
+	raw_inode->i_ctime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);
+	raw_inode->i_mtime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
 	raw_inode->i_blocks = cpu_to_le64(inode->i_blocks);
 
-	raw_inode->i_dtime = cpu_to_le64(ii->i_dtime);
 	raw_inode->i_flags = cpu_to_le32(ii->i_flags);
 	raw_inode->i_generation = cpu_to_le32(inode->i_generation);