Ocfs2 devel - Nov 2015 - [PATCH 1/1] ocfs2: return non-zero st_blocks for inline data

Hello All,

[Really sorry about this and I hope you're not getting fed up of
 multiple copies of this message but the list on oss.oracle.com really
 doesn't like me.]

Some programs, and programmers, assume that if a file is occupying
zero blocks (st_blocks == 0) then it contains no data and there's no
point in reading it.  Posix doesn't actually say anything about this,
but it seems to be something a lot of people expect. Indeed, ext4,
btrfs and ntfs-3d all seem to behave this way so that no one[1] has
any unpleasant surprises.

This patch is almost exactly the same as commit 9206c561554c ("ext4:
return non-zero st_blocks for inline data") although I couldn't bring
myself to include the typo in the comment :)

jch

[resend because rejected by list the first time.]
[1] tar, I'm looking at you, but you're not the only one.


John Haxby (1):
  ocfs2: return non-zero st_blocks for inline data

 fs/ocfs2/file.c | 8 ++++++++
 1 file changed, 8 insertions(+)

-- 
2.5.0

Some versions of tar assume that files with st_blocks == 0 do not
contain any data and will skip reading them entirely. See also
commit 9206c561554c ("ext4: return non-zero st_blocks for inline
data").

Signed-off-by: John Haxby <john.haxby at oracle.com>
---
 fs/ocfs2/file.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 0e5b451..d631279 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1302,6 +1302,14 @@ int ocfs2_getattr(struct vfsmount *mnt,
 	}
 
 	generic_fillattr(inode, stat);
+	/*
+	 * If there is inline data in the inode, the inode will normally not
+	 * have data blocks allocated (it may have an external xattr block).
+	 * Report at least one sector for such files, so tools like tar, rsync,
+	 * others don't incorrectly think the file is completely sparse.
+	 */
+	if (unlikely(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
+		stat->blocks += (stat->size + 511)>>9;
 
 	/* We set the blksize from the cluster size for performance */
 	stat->blksize = osb->s_clustersize;
-- 
2.5.0