[GFS2] Add generation number

This adds a generation number for the eventual use of NFS to the
ondisk inode. Its backward compatible with the current code since
it doesn't really matter what the generation number is to start with,
and indeed since its set to zero, due to it being taken from padding
in both the inode and rgrp header, it should be fine.

The eventual plan is to use this rather than no_formal_ino in the
NFS filehandles. At that point no_formal_ino will be unused.

At the same time we also add a releasepages call back to the
"normal" address space for gfs2 inodes. Also I've removed a
one-linrer function thats not required any more.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 111 insertions, 0 deletions

diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
index 2c4ec5cf21f..031270ad55e 100644
--- a/fs/gfs2/ops_address.c
+++ b/fs/gfs2/ops_address.c
@@ -33,6 +33,7 @@
 #include "rgrp.h"
 #include "ops_file.h"
 #include "util.h"
+#include "glops.h"
 
 /**
  * gfs2_get_block - Fills in a buffer head with details about a block
@@ -659,6 +660,115 @@ static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 	return ret;
 }
 
+/**
+ * stuck_releasepage - We're stuck in gfs2_releasepage().  Print stuff out.
+ * @bh: the buffer we're stuck on
+ *
+ */
+
+static void stuck_releasepage(struct buffer_head *bh)
+{
+	struct inode *inode = bh->b_page->mapping->host;
+	struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
+	struct gfs2_bufdata *bd = bh->b_private;
+	struct gfs2_glock *gl;
+
+	fs_warn(sdp, "stuck in gfs2_releasepage() %p\n", inode);
+	fs_warn(sdp, "blkno = %llu, bh->b_count = %d\n",
+		(unsigned long long)bh->b_blocknr, atomic_read(&bh->b_count));
+	fs_warn(sdp, "pinned = %u\n", buffer_pinned(bh));
+	fs_warn(sdp, "bh->b_private = %s\n", (bd) ? "!NULL" : "NULL");
+
+	if (!bd)
+		return;
+
+	gl = bd->bd_gl;
+
+	fs_warn(sdp, "gl = (%u, %llu)\n", 
+		gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number);
+
+	fs_warn(sdp, "bd_list_tr = %s, bd_le.le_list = %s\n",
+		(list_empty(&bd->bd_list_tr)) ? "no" : "yes",
+		(list_empty(&bd->bd_le.le_list)) ? "no" : "yes");
+
+	if (gl->gl_ops == &gfs2_inode_glops) {
+		struct gfs2_inode *ip = gl->gl_object;
+		unsigned int x;
+
+		if (!ip)
+			return;
+
+		fs_warn(sdp, "ip = %llu %llu\n",
+			(unsigned long long)ip->i_num.no_formal_ino,
+			(unsigned long long)ip->i_num.no_addr);
+
+		for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
+			fs_warn(sdp, "ip->i_cache[%u] = %s\n",
+				x, (ip->i_cache[x]) ? "!NULL" : "NULL");
+	}
+}
+
+/**
+ * gfs2_aspace_releasepage - free the metadata associated with a page
+ * @page: the page that's being released
+ * @gfp_mask: passed from Linux VFS, ignored by us
+ *
+ * Call try_to_free_buffers() if the buffers in this page can be
+ * released.
+ *
+ * Returns: 0
+ */
+
+int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
+{
+	struct inode *aspace = page->mapping->host;
+	struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
+	struct buffer_head *bh, *head;
+	struct gfs2_bufdata *bd;
+	unsigned long t;
+
+	if (!page_has_buffers(page))
+		goto out;
+
+	head = bh = page_buffers(page);
+	do {
+		t = jiffies;
+
+		while (atomic_read(&bh->b_count)) {
+			if (atomic_read(&aspace->i_writecount)) {
+				if (time_after_eq(jiffies, t +
+				    gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
+					stuck_releasepage(bh);
+					t = jiffies;
+				}
+
+				yield();
+				continue;
+			}
+
+			return 0;
+		}
+
+		gfs2_assert_warn(sdp, !buffer_pinned(bh));
+
+		bd = bh->b_private;
+		if (bd) {
+			gfs2_assert_warn(sdp, bd->bd_bh == bh);
+			gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
+			gfs2_assert_warn(sdp, list_empty(&bd->bd_le.le_list));
+			gfs2_assert_warn(sdp, !bd->bd_ail);
+			kmem_cache_free(gfs2_bufdata_cachep, bd);
+			bh->b_private = NULL;
+		}
+
+		bh = bh->b_this_page;
+	}
+	while (bh != head);
+
+ out:
+	return try_to_free_buffers(page);
+}
+
 const struct address_space_operations gfs2_file_aops = {
 	.writepage = gfs2_writepage,
 	.readpage = gfs2_readpage,
@@ -668,6 +778,7 @@ const struct address_space_operations gfs2_file_aops = {
 	.commit_write = gfs2_commit_write,
 	.bmap = gfs2_bmap,
 	.invalidatepage = gfs2_invalidatepage,
+	.releasepage = gfs2_releasepage,
 	.direct_IO = gfs2_direct_IO,
 };