[XFS] Invalidate dentry in unlink/rmdir if in case-insensitive mode

The vfs_unlink/d_delete functionality in the Linux VFS make the
dentry negative if it is the only inode being referenced. Case-insensitive
mode doesn't work with negative dentries, so if using CI-mode, invalidate
the dentry on unlink/rmdir.

SGI-PV: 983102
SGI-Modid: xfs-linux-melb:xfs-kern:31308a

Signed-off-by: Barry Naujok <bnaujok@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>

fs/xfs/linux-2.6/xfs_iops.c

@@ -475,6 +475,13 @@ xfs_vn_unlink(
 	if (likely(!error)) {
 		xfs_validate_fields(dir);	/* size needs update */
 		xfs_validate_fields(inode);
+		/*
+		 * With unlink, the VFS makes the dentry "negative": no inode,
+		 * but still hashed. This is incompatible with case-insensitive
+		 * mode, so invalidate (unhash) the dentry in CI-mode.
+		 */
+		if (xfs_sb_version_hasasciici(&XFS_M(dir->i_sb)->m_sb))
+			d_invalidate(dentry);
 	}
 	return -error;
 }
@@ -531,6 +538,13 @@ xfs_vn_rmdir(
 	if (likely(!error)) {
 		xfs_validate_fields(inode);
 		xfs_validate_fields(dir);
+		/*
+		 * With rmdir, the VFS makes the dentry "negative": no inode,
+		 * but still hashed. This is incompatible with case-insensitive
+		 * mode, so invalidate (unhash) the dentry in CI-mode.
+		 */
+		if (xfs_sb_version_hasasciici(&XFS_M(dir->i_sb)->m_sb))
+			d_invalidate(dentry);
 	}
 	return -error;
 }