[GFS2] Fix unlinked file handling

This patch fixes the way we have been dealing with unlinked,
but still open files. It removes all limits (other than memory
for inodes, as per every other filesystem) on numbers of these
which we can support on GFS2. It also means that (like other
fs) its the responsibility of the last process to close the file
to deallocate the storage, rather than the person who did the
unlinking. Note that with GFS2, those two events might take place
on different nodes.

Also there are a number of other changes:

 o We use the Linux inode subsystem as it was intended to be
used, wrt allocating GFS2 inodes
 o The Linux inode cache is now the point which we use for
local enforcement of only holding one copy of the inode in
core at once (previous to this we used the glock layer).
 o We no longer use the unlinked "special" file. We just ignore it
completely. This makes unlinking more efficient.
 o We now use the 4th block allocation state. The previously unused
state is used to track unlinked but still open inodes.
 o gfs2_inoded is no longer needed
 o Several fields are now no longer needed (and removed) from the in
core struct gfs2_inode
 o Several fields are no longer needed (and removed) from the in core
superblock

There are a number of future possible optimisations and clean ups
which have been made possible by this patch.

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

1 files changed, 4 insertions, 8 deletions

diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index c785172..2523d42 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -91,9 +91,6 @@ static void stuck_releasepage(struct buffer_head *bh)
 		fs_warn(sdp, "ip = %llu %llu\n",
 			(unsigned long long)ip->i_num.no_formal_ino,
 			(unsigned long long)ip->i_num.no_addr);
-		fs_warn(sdp, "ip->i_count = %d, ip->i_vnode = %s\n",
-			atomic_read(&ip->i_count),
-			(ip->i_vnode) ? "!NULL" : "NULL");
 
 		for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
 			fs_warn(sdp, "ip->i_cache[%u] = %s\n",
@@ -567,7 +564,6 @@ void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
 
 	bd = kmem_cache_alloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL),
 	memset(bd, 0, sizeof(struct gfs2_bufdata));
-
 	bd->bd_bh = bh;
 	bd->bd_gl = gl;
 
@@ -664,7 +660,7 @@ void gfs2_unpin(struct gfs2_sbd *sdp, struct buffer_head *bh,
 
 void gfs2_meta_wipe(struct gfs2_inode *ip, uint64_t bstart, uint32_t blen)
 {
-	struct gfs2_sbd *sdp = ip->i_sbd;
+	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
 	struct inode *aspace = ip->i_gl->gl_aspace;
 	struct buffer_head *bh;
 
@@ -770,7 +766,7 @@ int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, uint64_t num,
 		if (new)
 			meta_prep_new(bh);
 		else {
-			error = gfs2_meta_reread(ip->i_sbd, bh,
+			error = gfs2_meta_reread(GFS2_SB(&ip->i_inode), bh,
 						 DIO_START | DIO_WAIT);
 			if (error) {
 				brelse(bh);
@@ -797,7 +793,7 @@ int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, uint64_t num,
 	}
 
 	if (new) {
-		if (gfs2_assert_warn(ip->i_sbd, height)) {
+		if (gfs2_assert_warn(GFS2_SB(&ip->i_inode), height)) {
 			brelse(bh);
 			return -EIO;
 		}
@@ -805,7 +801,7 @@ int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, uint64_t num,
 		gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
 		gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
 
-	} else if (gfs2_metatype_check(ip->i_sbd, bh,
+	} else if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh,
 			     (height) ? GFS2_METATYPE_IN : GFS2_METATYPE_DI)) {
 		brelse(bh);
 		return -EIO;