GFS2: Merge lock_dlm module into GFS2
This is the big patch that I've been working on for some time
now. There are many reasons for wanting to make this change
such as:
o Reducing overhead by eliminating duplicated fields between structures
o Simplifcation of the code (reduces the code size by a fair bit)
o The locking interface is now the DLM interface itself as proposed
some time ago.
o Fewer lookups of glocks when processing replies from the DLM
o Fewer memory allocations/deallocations for each glock
o Scope to do further optimisations in the future (but this patch is
more than big enough for now!)
Please note that (a) this patch relates to the lock_dlm module and
not the DLM itself, that is still a separate module; and (b) that
we retain the ability to build GFS2 as a standalone single node
filesystem with out requiring the DLM.
This patch needs a lot of testing, hence my keeping it I restarted
my -git tree after the last merge window. That way, this has the maximum
exposure before its merged. This is (modulo a few minor bug fixes) the
same patch that I've been posting on and off the the last three months
and its passed a number of different tests so far.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/lock_dlm.c b/fs/gfs2/lock_dlm.c
new file mode 100644
index 0000000..a0bb7d2
--- /dev/null
+++ b/fs/gfs2/lock_dlm.c
@@ -0,0 +1,240 @@
+/*
+ * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
+ * Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU General Public License version 2.
+ */
+
+#include <linux/fs.h>
+#include <linux/dlm.h>
+#include <linux/types.h>
+#include <linux/gfs2_ondisk.h>
+
+#include "incore.h"
+#include "glock.h"
+#include "util.h"
+
+
+static void gdlm_ast(void *arg)
+{
+ struct gfs2_glock *gl = arg;
+ unsigned ret = gl->gl_state;
+
+ BUG_ON(gl->gl_lksb.sb_flags & DLM_SBF_DEMOTED);
+
+ if (gl->gl_lksb.sb_flags & DLM_SBF_VALNOTVALID)
+ memset(gl->gl_lvb, 0, GDLM_LVB_SIZE);
+
+ switch (gl->gl_lksb.sb_status) {
+ case -DLM_EUNLOCK: /* Unlocked, so glock can be freed */
+ kmem_cache_free(gfs2_glock_cachep, gl);
+ return;
+ case -DLM_ECANCEL: /* Cancel while getting lock */
+ ret |= LM_OUT_CANCELED;
+ goto out;
+ case -EAGAIN: /* Try lock fails */
+ goto out;
+ case -EINVAL: /* Invalid */
+ case -ENOMEM: /* Out of memory */
+ ret |= LM_OUT_ERROR;
+ goto out;
+ case 0: /* Success */
+ break;
+ default: /* Something unexpected */
+ BUG();
+ }
+
+ ret = gl->gl_target;
+ if (gl->gl_lksb.sb_flags & DLM_SBF_ALTMODE) {
+ if (gl->gl_target == LM_ST_SHARED)
+ ret = LM_ST_DEFERRED;
+ else if (gl->gl_target == LM_ST_DEFERRED)
+ ret = LM_ST_SHARED;
+ else
+ BUG();
+ }
+
+ set_bit(GLF_INITIAL, &gl->gl_flags);
+ gfs2_glock_complete(gl, ret);
+ return;
+out:
+ if (!test_bit(GLF_INITIAL, &gl->gl_flags))
+ gl->gl_lksb.sb_lkid = 0;
+ gfs2_glock_complete(gl, ret);
+}
+
+static void gdlm_bast(void *arg, int mode)
+{
+ struct gfs2_glock *gl = arg;
+
+ switch (mode) {
+ case DLM_LOCK_EX:
+ gfs2_glock_cb(gl, LM_ST_UNLOCKED);
+ break;
+ case DLM_LOCK_CW:
+ gfs2_glock_cb(gl, LM_ST_DEFERRED);
+ break;
+ case DLM_LOCK_PR:
+ gfs2_glock_cb(gl, LM_ST_SHARED);
+ break;
+ default:
+ printk(KERN_ERR "unknown bast mode %d", mode);
+ BUG();
+ }
+}
+
+/* convert gfs lock-state to dlm lock-mode */
+
+static int make_mode(const unsigned int lmstate)
+{
+ switch (lmstate) {
+ case LM_ST_UNLOCKED:
+ return DLM_LOCK_NL;
+ case LM_ST_EXCLUSIVE:
+ return DLM_LOCK_EX;
+ case LM_ST_DEFERRED:
+ return DLM_LOCK_CW;
+ case LM_ST_SHARED:
+ return DLM_LOCK_PR;
+ }
+ printk(KERN_ERR "unknown LM state %d", lmstate);
+ BUG();
+ return -1;
+}
+
+static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
+ const int req)
+{
+ u32 lkf = 0;
+
+ if (gfs_flags & LM_FLAG_TRY)
+ lkf |= DLM_LKF_NOQUEUE;
+
+ if (gfs_flags & LM_FLAG_TRY_1CB) {
+ lkf |= DLM_LKF_NOQUEUE;
+ lkf |= DLM_LKF_NOQUEUEBAST;
+ }
+
+ if (gfs_flags & LM_FLAG_PRIORITY) {
+ lkf |= DLM_LKF_NOORDER;
+ lkf |= DLM_LKF_HEADQUE;
+ }
+
+ if (gfs_flags & LM_FLAG_ANY) {
+ if (req == DLM_LOCK_PR)
+ lkf |= DLM_LKF_ALTCW;
+ else if (req == DLM_LOCK_CW)
+ lkf |= DLM_LKF_ALTPR;
+ else
+ BUG();
+ }
+
+ if (lkid != 0)
+ lkf |= DLM_LKF_CONVERT;
+
+ lkf |= DLM_LKF_VALBLK;
+
+ return lkf;
+}
+
+static unsigned int gdlm_lock(struct gfs2_glock *gl,
+ unsigned int req_state, unsigned int flags)
+{
+ struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
+ int error;
+ int req;
+ u32 lkf;
+
+ req = make_mode(req_state);
+ lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);
+
+ /*
+ * Submit the actual lock request.
+ */
+
+ error = dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, gl->gl_strname,
+ GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl, gdlm_bast);
+ if (error == -EAGAIN)
+ return 0;
+ if (error)
+ return LM_OUT_ERROR;
+ return LM_OUT_ASYNC;
+}
+
+static void gdlm_put_lock(struct kmem_cache *cachep, void *ptr)
+{
+ struct gfs2_glock *gl = ptr;
+ struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
+ int error;
+
+ if (gl->gl_lksb.sb_lkid == 0) {
+ kmem_cache_free(cachep, gl);
+ return;
+ }
+
+ error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_VALBLK,
+ NULL, gl);
+ if (error) {
+ printk(KERN_ERR "gdlm_unlock %x,%llx err=%d\n",
+ gl->gl_name.ln_type,
+ (unsigned long long)gl->gl_name.ln_number, error);
+ return;
+ }
+}
+
+static void gdlm_cancel(struct gfs2_glock *gl)
+{
+ struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
+ dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_CANCEL, NULL, gl);
+}
+
+static int gdlm_mount(struct gfs2_sbd *sdp, const char *fsname)
+{
+ struct lm_lockstruct *ls = &sdp->sd_lockstruct;
+ int error;
+
+ if (fsname == NULL) {
+ fs_info(sdp, "no fsname found\n");
+ return -EINVAL;
+ }
+
+ error = dlm_new_lockspace(fsname, strlen(fsname), &ls->ls_dlm,
+ DLM_LSFL_FS | DLM_LSFL_NEWEXCL |
+ (ls->ls_nodir ? DLM_LSFL_NODIR : 0),
+ GDLM_LVB_SIZE);
+ if (error)
+ printk(KERN_ERR "dlm_new_lockspace error %d", error);
+
+ return error;
+}
+
+static void gdlm_unmount(struct gfs2_sbd *sdp)
+{
+ struct lm_lockstruct *ls = &sdp->sd_lockstruct;
+
+ if (ls->ls_dlm) {
+ dlm_release_lockspace(ls->ls_dlm, 2);
+ ls->ls_dlm = NULL;
+ }
+}
+
+static const match_table_t dlm_tokens = {
+ { Opt_jid, "jid=%d"},
+ { Opt_id, "id=%d"},
+ { Opt_first, "first=%d"},
+ { Opt_nodir, "nodir=%d"},
+ { Opt_err, NULL },
+};
+
+const struct lm_lockops gfs2_dlm_ops = {
+ .lm_proto_name = "lock_dlm",
+ .lm_mount = gdlm_mount,
+ .lm_unmount = gdlm_unmount,
+ .lm_put_lock = gdlm_put_lock,
+ .lm_lock = gdlm_lock,
+ .lm_cancel = gdlm_cancel,
+ .lm_tokens = &dlm_tokens,
+};
+