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[Cluster-devel] Re: [GFS2] Simplify glops functions [53/70]



Hi,

On Fri, 2006-12-01 at 12:43 -0600, Russell Cattelan wrote:
> On Thu, 2006-11-30 at 12:21 +0000, Steven Whitehouse wrote:
> > >From 1a14d3a68f04527546121eb7b45187ff6af63151 Mon Sep 17 00:00:00 2001
> > From: Steven Whitehouse <swhiteho redhat com>
> > Date: Mon, 20 Nov 2006 10:37:45 -0500
> > Subject: [PATCH] [GFS2] Simplify glops functions
> > 
> > The go_sync callback took two flags, but one of them was set on every
> > call, so this patch removes once of the flags and makes the previously
> > conditional operations (on this flag), unconditional.
> > 
> > The go_inval callback took three flags, each of which was set on every
> > call to it. This patch removes the flags and makes the operations
> > unconditional, which makes the logic rather more obvious.
> 
> I get really nervous about making these type of interfaces changes
> until the problem is understood.
> 
The problem can by understood by the simple use of grep.

> Given the the rather non-function and incomplete state of GFS2 it
> seems premature to just remove flags states on the observation
> that they are not CURRENTLY used.
> 
I disagree, I don't want the code to be littered with functions
containing code which is never called as its very confusing,
particularly for those who are unable to devote their full time to
working on gfs2 but still need to understand the code.

If a use is ever found for this code (which I very much doubt) then we
can always put it back at that time. In the mean time, simpler code is
easier to debug,

Steve.

> > 
> > Two now unused flags are also removed from incore.h.
> > 
> > Signed-off-by: Steven Whitehouse <swhiteho redhat com>
> > ---
> >  fs/gfs2/glock.c  |   10 +++++-----
> >  fs/gfs2/glops.c  |   42 +++++++++++-------------------------------
> >  fs/gfs2/incore.h |   25 +++++++++++--------------
> >  fs/gfs2/super.c  |    2 +-
> >  4 files changed, 28 insertions(+), 51 deletions(-)
> > 
> > diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
> > index edc21c8..b8ba4d5 100644
> > --- a/fs/gfs2/glock.c
> > +++ b/fs/gfs2/glock.c
> > @@ -847,12 +847,12 @@ static void xmote_bh(struct gfs2_glock *
> >  
> >  	if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) {
> >  		if (glops->go_inval)
> > -			glops->go_inval(gl, DIO_METADATA | DIO_DATA);
> > +			glops->go_inval(gl, DIO_METADATA);
> >  	} else if (gl->gl_state == LM_ST_DEFERRED) {
> >  		/* We might not want to do this here.
> >  		   Look at moving to the inode glops. */
> >  		if (glops->go_inval)
> > -			glops->go_inval(gl, DIO_DATA);
> > +			glops->go_inval(gl, 0);
> >  	}
> >  
> >  	/*  Deal with each possible exit condition  */
> > @@ -954,7 +954,7 @@ void gfs2_glock_xmote_th(struct gfs2_glo
> >  	gfs2_assert_warn(sdp, state != gl->gl_state);
> >  
> >  	if (gl->gl_state == LM_ST_EXCLUSIVE && glops->go_sync)
> > -		glops->go_sync(gl, DIO_METADATA | DIO_DATA | DIO_RELEASE);
> > +		glops->go_sync(gl);
> >  
> >  	gfs2_glock_hold(gl);
> >  	gl->gl_req_bh = xmote_bh;
> > @@ -995,7 +995,7 @@ static void drop_bh(struct gfs2_glock *g
> >  	state_change(gl, LM_ST_UNLOCKED);
> >  
> >  	if (glops->go_inval)
> > -		glops->go_inval(gl, DIO_METADATA | DIO_DATA);
> > +		glops->go_inval(gl, DIO_METADATA);
> >  
> >  	if (gh) {
> >  		spin_lock(&gl->gl_spin);
> > @@ -1041,7 +1041,7 @@ void gfs2_glock_drop_th(struct gfs2_gloc
> >  	gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
> >  
> >  	if (gl->gl_state == LM_ST_EXCLUSIVE && glops->go_sync)
> > -		glops->go_sync(gl, DIO_METADATA | DIO_DATA | DIO_RELEASE);
> > +		glops->go_sync(gl);
> >  
> >  	gfs2_glock_hold(gl);
> >  	gl->gl_req_bh = drop_bh;
> > diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
> > index b92de0a..60561ca 100644
> > --- a/fs/gfs2/glops.c
> > +++ b/fs/gfs2/glops.c
> > @@ -173,23 +173,18 @@ static void gfs2_page_writeback(struct g
> >  /**
> >   * meta_go_sync - sync out the metadata for this glock
> >   * @gl: the glock
> > - * @flags: DIO_*
> >   *
> >   * Called when demoting or unlocking an EX glock.  We must flush
> >   * to disk all dirty buffers/pages relating to this glock, and must not
> >   * not return to caller to demote/unlock the glock until I/O is complete.
> >   */
> >  
> > -static void meta_go_sync(struct gfs2_glock *gl, int flags)
> > +static void meta_go_sync(struct gfs2_glock *gl)
> >  {
> > -	if (!(flags & DIO_METADATA))
> > -		return;
> > -
> >  	if (test_and_clear_bit(GLF_DIRTY, &gl->gl_flags)) {
> >  		gfs2_log_flush(gl->gl_sbd, gl);
> >  		gfs2_meta_sync(gl);
> > -		if (flags & DIO_RELEASE)
> > -			gfs2_ail_empty_gl(gl);
> > +		gfs2_ail_empty_gl(gl);
> >  	}
> >  
> >  }
> > @@ -264,31 +259,18 @@ static void inode_go_drop_th(struct gfs2
> >  /**
> >   * inode_go_sync - Sync the dirty data and/or metadata for an inode glock
> >   * @gl: the glock protecting the inode
> > - * @flags:
> >   *
> >   */
> >  
> > -static void inode_go_sync(struct gfs2_glock *gl, int flags)
> > +static void inode_go_sync(struct gfs2_glock *gl)
> >  {
> > -	int meta = (flags & DIO_METADATA);
> > -	int data = (flags & DIO_DATA);
> > -
> >  	if (test_bit(GLF_DIRTY, &gl->gl_flags)) {
> > -		if (meta && data) {
> > -			gfs2_page_writeback(gl);
> > -			gfs2_log_flush(gl->gl_sbd, gl);
> > -			gfs2_meta_sync(gl);
> > -			gfs2_page_wait(gl);
> > -			clear_bit(GLF_DIRTY, &gl->gl_flags);
> > -		} else if (meta) {
> > -			gfs2_log_flush(gl->gl_sbd, gl);
> > -			gfs2_meta_sync(gl);
> > -		} else if (data) {
> > -			gfs2_page_writeback(gl);
> > -			gfs2_page_wait(gl);
> > -		}
> > -		if (flags & DIO_RELEASE)
> > -			gfs2_ail_empty_gl(gl);
> > +		gfs2_page_writeback(gl);
> > +		gfs2_log_flush(gl->gl_sbd, gl);
> > +		gfs2_meta_sync(gl);
> > +		gfs2_page_wait(gl);
> > +		clear_bit(GLF_DIRTY, &gl->gl_flags);
> > +		gfs2_ail_empty_gl(gl);
> >  	}
> >  }
> >  
> > @@ -302,15 +284,13 @@ static void inode_go_sync(struct gfs2_gl
> >  static void inode_go_inval(struct gfs2_glock *gl, int flags)
> >  {
> >  	int meta = (flags & DIO_METADATA);
> > -	int data = (flags & DIO_DATA);
> >  
> >  	if (meta) {
> >  		struct gfs2_inode *ip = gl->gl_object;
> >  		gfs2_meta_inval(gl);
> >  		set_bit(GIF_INVALID, &ip->i_flags);
> >  	}
> > -	if (data)
> > -		gfs2_page_inval(gl);
> > +	gfs2_page_inval(gl);
> >  }
> >  
> >  /**
> > @@ -494,7 +474,7 @@ static void trans_go_xmote_bh(struct gfs
> >  	if (gl->gl_state != LM_ST_UNLOCKED &&
> >  	    test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
> >  		gfs2_meta_cache_flush(GFS2_I(sdp->sd_jdesc->jd_inode));
> > -		j_gl->gl_ops->go_inval(j_gl, DIO_METADATA | DIO_DATA);
> > +		j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);
> >  
> >  		error = gfs2_find_jhead(sdp->sd_jdesc, &head);
> >  		if (error)
> > diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
> > index 227a74d..734421e 100644
> > --- a/fs/gfs2/incore.h
> > +++ b/fs/gfs2/incore.h
> > @@ -14,8 +14,6 @@ #include <linux/fs.h>
> >  
> >  #define DIO_WAIT	0x00000010
> >  #define DIO_METADATA	0x00000020
> > -#define DIO_DATA	0x00000040
> > -#define DIO_RELEASE	0x00000080
> >  #define DIO_ALL		0x00000100
> >  
> >  struct gfs2_log_operations;
> > @@ -103,18 +101,17 @@ struct gfs2_bufdata {
> >  };
> >  
> >  struct gfs2_glock_operations {
> > -	void (*go_xmote_th) (struct gfs2_glock * gl, unsigned int state,
> > -			     int flags);
> > -	void (*go_xmote_bh) (struct gfs2_glock * gl);
> > -	void (*go_drop_th) (struct gfs2_glock * gl);
> > -	void (*go_drop_bh) (struct gfs2_glock * gl);
> > -	void (*go_sync) (struct gfs2_glock * gl, int flags);
> > -	void (*go_inval) (struct gfs2_glock * gl, int flags);
> > -	int (*go_demote_ok) (struct gfs2_glock * gl);
> > -	int (*go_lock) (struct gfs2_holder * gh);
> > -	void (*go_unlock) (struct gfs2_holder * gh);
> > -	void (*go_callback) (struct gfs2_glock * gl, unsigned int state);
> > -	void (*go_greedy) (struct gfs2_glock * gl);
> > +	void (*go_xmote_th) (struct gfs2_glock *gl, unsigned int state, int flags);
> > +	void (*go_xmote_bh) (struct gfs2_glock *gl);
> > +	void (*go_drop_th) (struct gfs2_glock *gl);
> > +	void (*go_drop_bh) (struct gfs2_glock *gl);
> > +	void (*go_sync) (struct gfs2_glock *gl);
> > +	void (*go_inval) (struct gfs2_glock *gl, int flags);
> > +	int (*go_demote_ok) (struct gfs2_glock *gl);
> > +	int (*go_lock) (struct gfs2_holder *gh);
> > +	void (*go_unlock) (struct gfs2_holder *gh);
> > +	void (*go_callback) (struct gfs2_glock *gl, unsigned int state);
> > +	void (*go_greedy) (struct gfs2_glock *gl);
> >  	const int go_type;
> >  };
> >  
> > diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
> > index 0ef8317..1408c5f 100644
> > --- a/fs/gfs2/super.c
> > +++ b/fs/gfs2/super.c
> > @@ -517,7 +517,7 @@ int gfs2_make_fs_rw(struct gfs2_sbd *sdp
> >  		return error;
> >  
> >  	gfs2_meta_cache_flush(ip);
> > -	j_gl->gl_ops->go_inval(j_gl, DIO_METADATA | DIO_DATA);
> > +	j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);
> >  
> >  	error = gfs2_find_jhead(sdp->sd_jdesc, &head);
> >  	if (error)


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