[GFS2] Clean up the glock core
This patch implements a number of cleanups to the core of the
GFS2 glock code. As a result a lot of code is removed. It looks
like a really big change, but actually a large part of this patch
is either removing or moving existing code.
There are some new bits too though, such as the new run_queue()
function which is considerably streamlined. Highlights of this
patch include:
o Fixes a cluster coherency bug during SH -> EX lock conversions
o Removes the "glmutex" code in favour of a single bit lock
o Removes the ->go_xmote_bh() for inodes since it was duplicating
->go_lock()
o We now only use the ->lm_lock() function for both locks and
unlocks (i.e. unlock is a lock with target mode LM_ST_UNLOCKED)
o The fast path is considerably shortly, giving performance gains
especially with lock_nolock
o The glock_workqueue is now used for all the callbacks from the DLM
which allows us to simplify the lock_dlm module (see following patch)
o The way is now open to make further changes such as eliminating the two
threads (gfs2_glockd and gfs2_scand) in favour of a more efficient
scheme.
This patch has undergone extensive testing with various test suites
so it should be pretty stable by now.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>
diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
index f55394e..2b556dd 100644
--- a/fs/gfs2/ops_address.c
+++ b/fs/gfs2/ops_address.c
@@ -507,26 +507,23 @@
static int gfs2_readpage(struct file *file, struct page *page)
{
struct gfs2_inode *ip = GFS2_I(page->mapping->host);
- struct gfs2_holder *gh;
+ struct gfs2_holder gh;
int error;
- gh = gfs2_glock_is_locked_by_me(ip->i_gl);
- if (!gh) {
- gh = kmalloc(sizeof(struct gfs2_holder), GFP_NOFS);
- if (!gh)
- return -ENOBUFS;
- gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, gh);
+ gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|LM_FLAG_TRY_1CB, &gh);
+ error = gfs2_glock_nq_atime(&gh);
+ if (unlikely(error)) {
unlock_page(page);
- error = gfs2_glock_nq_atime(gh);
- if (likely(error != 0))
- goto out;
- return AOP_TRUNCATED_PAGE;
+ goto out;
}
error = __gfs2_readpage(file, page);
- gfs2_glock_dq(gh);
+ gfs2_glock_dq(&gh);
out:
- gfs2_holder_uninit(gh);
- kfree(gh);
+ gfs2_holder_uninit(&gh);
+ if (error == GLR_TRYFAILED) {
+ yield();
+ return AOP_TRUNCATED_PAGE;
+ }
return error;
}