[Cluster-devel] [PATCH] GFS: write vfs inode attributes to disk

[Benjamin Marzinski]

GFS wasn't ever updating mtime during mmaps to a file.  This patch makes
gfs_write_inode write the vfs inode attributes out to disk if it can, so
that they get updated when the mmap data is written back to disk.
Unfortunately, gfs_write_inode can only do this if it was called with the
inode already exclusively locked, and not already in a transaction. The
patch also makes sure that the updated vfs timestamps don't get
overwritten by older gfs ones before they can be written out.

This patch is similar to my previous version, except that in now doesn't
do it's own locking.  This means it can only work when it happens to get
called with the glock already held.  This is necessary to preserve the
correct locking order. The down side is that it does not write out the
mtime in many of the cases where it should.

Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
---
 gfs-kernel/src/gfs/inode.c     | 15 +++++++++------
 gfs-kernel/src/gfs/ops_super.c | 31 +++++++++++++++++++++++++++++--
 2 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/gfs-kernel/src/gfs/inode.c b/gfs-kernel/src/gfs/inode.c
index 454366a..52b0819 100644
--- a/gfs-kernel/src/gfs/inode.c
+++ b/gfs-kernel/src/gfs/inode.c
@@ -46,7 +46,7 @@
  */
 
 static void
-inode_attr_in(struct gfs_inode *ip, struct inode *inode)
+inode_attr_in(struct gfs_inode *ip, struct inode *inode, int force)
 {
 	unsigned int mode;
 
@@ -93,9 +93,12 @@ inode_attr_in(struct gfs_inode *ip, struct inode *inode)
 	inode->i_uid = ip->i_di.di_uid;
 	inode->i_gid = ip->i_di.di_gid;
 	i_size_write(inode, ip->i_di.di_size);
-	inode->i_atime.tv_sec = ip->i_di.di_atime;
-	inode->i_mtime.tv_sec = ip->i_di.di_mtime;
-	inode->i_ctime.tv_sec = ip->i_di.di_ctime;
+	if (force || ip->i_di.di_atime > inode->i_atime.tv_sec)
+		inode->i_atime.tv_sec = ip->i_di.di_atime;
+	if (force || ip->i_di.di_mtime > inode->i_mtime.tv_sec)
+		inode->i_mtime.tv_sec = ip->i_di.di_mtime;
+	if (force || ip->i_di.di_ctime > inode->i_ctime.tv_sec)
+		inode->i_ctime.tv_sec = ip->i_di.di_ctime;
 	inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
 	inode->i_blocks = ip->i_di.di_blocks <<
 		(ip->i_sbd->sd_sb.sb_bsize_shift - GFS_BASIC_BLOCK_SHIFT);
@@ -125,7 +128,7 @@ gfs_inode_attr_in(struct gfs_inode *ip)
 
 	inode = gfs_iget(ip, NO_CREATE);
 	if (inode) {
-		inode_attr_in(ip, inode);
+		inode_attr_in(ip, inode, 0);
 		iput(inode);
 	}
 
@@ -185,7 +188,7 @@ gfs_iget(struct gfs_inode *ip, int create)
 	if (!tmp)
 		return NULL;
 
-	inode_attr_in(ip, tmp);
+	inode_attr_in(ip, tmp, 1);
 
 	/* Attach GFS-specific ops vectors */
 	if (ip->i_di.di_type == GFS_FILE_REG) {
diff --git a/gfs-kernel/src/gfs/ops_super.c b/gfs-kernel/src/gfs/ops_super.c
index c111a2e..bfb236b 100644
--- a/gfs-kernel/src/gfs/ops_super.c
+++ b/gfs-kernel/src/gfs/ops_super.c
@@ -39,6 +39,7 @@
 #include "super.h"
 #include "sys.h"
 #include "mount.h"
+#include "trans.h"
 
 /**
  * gfs_write_inode - Make sure the inode is stable on the disk
@@ -51,14 +52,40 @@
 static int
 gfs_write_inode(struct inode *inode, int sync)
 {
+	int ret = 0;
 	struct gfs_inode *ip = get_v2ip(inode);
+	struct buffer_head *dibh;
+	struct gfs_holder i_gh;
+
+	if (!ip)
+		return 0;
 
 	atomic_inc(&ip->i_sbd->sd_ops_super);
 
-	if (ip && sync)
+	if (current->flags & PF_MEMALLOC || get_transaction ||
+	    !gfs_glock_is_locked_by_me(ip->i_gl) || !gfs_glock_is_held_excl(ip->i_gl))
+		goto do_flush;
+	/* Trans may require:
+	   one dinode block. */
+	ret = gfs_trans_begin(ip->i_sbd, 1, 0);
+	if (ret)
+		goto do_flush;
+
+	ret = gfs_get_inode_buffer(ip, &dibh);
+	if (ret == 0) {
+		gfs_inode_attr_out(ip);
+		gfs_trans_add_bh(ip->i_gl, dibh);
+		gfs_dinode_out(&ip->i_di, dibh->b_data);
+		brelse(dibh);
+	}
+
+	gfs_trans_end(ip->i_sbd);
+
+do_flush:
+	if (sync)
 		gfs_log_flush_glock(ip->i_gl, 0);
 
-	return 0;
+	return ret;
 }
 
 /**
-- 
1.8.3.1