[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, 9 insertions, 23 deletions

diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index 5ef21317b2f6..30cfcc10beb2 100644
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -27,32 +27,20 @@ static inline int gfs2_is_dir(struct gfs2_inode *ip)
 
 void gfs2_inode_attr_in(struct gfs2_inode *ip);
 void gfs2_inode_attr_out(struct gfs2_inode *ip);
-struct inode *gfs2_ip2v_lookup(struct gfs2_inode *ip);
-struct inode *gfs2_ip2v(struct gfs2_inode *ip);
-struct inode *gfs2_iget(struct super_block *sb, struct gfs2_inum *inum);
+struct inode *gfs2_inode_lookup(struct super_block *sb, struct gfs2_inum *inum, unsigned type);
+struct inode *gfs2_ilookup(struct super_block *sb, struct gfs2_inum *inum);
 
-void gfs2_inode_min_init(struct gfs2_inode *ip, unsigned int type);
 int gfs2_inode_refresh(struct gfs2_inode *ip);
 
-int gfs2_inode_get(struct gfs2_glock *i_gl,
-                   const struct gfs2_inum *inum, int create,
-                   struct gfs2_inode **ipp);
-void gfs2_inode_hold(struct gfs2_inode *ip);
-void gfs2_inode_put(struct gfs2_inode *ip);
-void gfs2_inode_destroy(struct gfs2_inode *ip, int unlock);
-
-int gfs2_inode_dealloc(struct gfs2_sbd *sdp, struct gfs2_unlinked *ul);
-
+int gfs2_dinode_dealloc(struct gfs2_inode *inode);
 int gfs2_change_nlink(struct gfs2_inode *ip, int diff);
-struct inode *gfs2_lookupi(struct inode *dir, struct qstr *name, int is_root,
-                           struct nameidata *nd);
-struct inode *gfs2_createi(struct gfs2_holder *ghs, struct qstr *name,
+struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name, 
+                           int is_root, struct nameidata *nd);
+struct inode *gfs2_createi(struct gfs2_holder *ghs, const struct qstr *name,
                            unsigned int mode);
-int gfs2_unlinki(struct gfs2_inode *dip, struct qstr *name,
-                 struct gfs2_inode *ip, struct gfs2_unlinked *ul);
-int gfs2_rmdiri(struct gfs2_inode *dip, struct qstr *name,
-                struct gfs2_inode *ip, struct gfs2_unlinked *ul);
-int gfs2_unlink_ok(struct gfs2_inode *dip, struct qstr *name,
+int gfs2_rmdiri(struct gfs2_inode *dip, const struct qstr *name,
+                struct gfs2_inode *ip);
+int gfs2_unlink_ok(struct gfs2_inode *dip, const struct qstr *name,
                    struct gfs2_inode *ip);
 int gfs2_ok_to_move(struct gfs2_inode *this, struct gfs2_inode *to);
 int gfs2_readlinki(struct gfs2_inode *ip, char **buf, unsigned int *len);
@@ -60,8 +48,6 @@ int gfs2_readlinki(struct gfs2_inode *ip, char **buf, unsigned int *len);
 int gfs2_glock_nq_atime(struct gfs2_holder *gh);
 int gfs2_glock_nq_m_atime(unsigned int num_gh, struct gfs2_holder *ghs);
 
-void gfs2_try_toss_vnode(struct gfs2_inode *ip);
-
 int gfs2_setattr_simple(struct gfs2_inode *ip, struct iattr *attr);
 
 int gfs2_repermission(struct inode *inode, int mask, struct nameidata *nd);