[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, 1 insertions, 4 deletions

diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index 2e0a2ba92aa0..fdf58db44ae3 100644
--- a/fs/gfs2/glock.h
+++ b/fs/gfs2/glock.h
@@ -88,9 +88,6 @@ void gfs2_holder_uninit(struct gfs2_holder *gh);
 void gfs2_glock_xmote_th(struct gfs2_glock *gl, unsigned int state, int flags);
 void gfs2_glock_drop_th(struct gfs2_glock *gl);
 
-void gfs2_glmutex_lock(struct gfs2_glock *gl);
-void gfs2_glmutex_unlock(struct gfs2_glock *gl);
-
 int gfs2_glock_nq(struct gfs2_holder *gh);
 int gfs2_glock_poll(struct gfs2_holder *gh);
 int gfs2_glock_wait(struct gfs2_holder *gh);
@@ -110,6 +107,7 @@ void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs);
 void gfs2_glock_prefetch_num(struct gfs2_sbd *sdp, uint64_t number,
 			     struct gfs2_glock_operations *glops,
 			     unsigned int state, int flags);
+void gfs2_glock_inode_squish(struct inode *inode);
 
 /**
  * gfs2_glock_nq_init - intialize a holder and enqueue it on a glock
@@ -143,7 +141,6 @@ void gfs2_lvb_unhold(struct gfs2_glock *gl);
 
 void gfs2_glock_cb(lm_fsdata_t *fsdata, unsigned int type, void *data);
 
-void gfs2_try_toss_inode(struct gfs2_sbd *sdp, struct gfs2_inum *inum);
 void gfs2_iopen_go_callback(struct gfs2_glock *gl, unsigned int state);
 
 void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl);