quota: clean up Q_XQUOTASYNC
Currently Q_XQUOTASYNC calls into the quota_sync method, but XFS does something
entirely different in it than the rest of the filesystems. xfs_quota which
calls Q_XQUOTASYNC expects an asynchronous data writeout to flush delayed
allocations, while the "VFS" quota support wants to flush changes to the quota
file.
So make Q_XQUOTASYNC call into the writeback code directly and make the
quota_sync method optional as XFS doesn't need in the sense expected by the
rest of the quota code.
GFS2 was using limited XFS-style quota and has a quota_sync method fitting
neither the style used by vfs_quota_sync nor xfs_fs_quota_sync. I left it
in for now as per discussion with Steve it expects to be called from the
sync path this way.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index d0efe30..3d31228 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -18,6 +18,7 @@
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/types.h>
+#include <linux/writeback.h>
#include <net/netlink.h>
#include <net/genetlink.h>
@@ -52,7 +53,7 @@
{
int cnt;
- if (!sb->s_qcop->quota_sync)
+ if (!sb->s_qcop || !sb->s_qcop->quota_sync)
return;
sb->s_qcop->quota_sync(sb, type);
@@ -318,9 +319,11 @@
case Q_XGETQUOTA:
return quota_getxquota(sb, type, id, addr);
case Q_XQUOTASYNC:
- if (!sb->s_qcop->quota_sync)
- return -ENOSYS;
- return sb->s_qcop->quota_sync(sb, type);
+ /* caller already holds s_umount */
+ if (sb->s_flags & MS_RDONLY)
+ return -EROFS;
+ writeback_inodes_sb(sb);
+ return 0;
default:
return -EINVAL;
}