GFS2: Improve journal allocation via sysfs

Recently a feature was added to GFS2 to allow journal id allocation
via sysfs. This patch builds upon that so that a negative journal id
will be treated as an error code to be passed back as the return code
from mount. This allows termination of the mount process if there is
a failure.

Also, the process has been updated so that the kernel will wait
for a journal id, even in the "spectator" case. This is required
in order to avoid mounting a filesystem in case there is an error
while joining the cluster. In the spectator case, 0 is written into
the file to indicate that all is well, and that mount should continue.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 6f6ff8aba99a1a2abae412cc703ebe620fa99061..764fbb49efc8e3adbdeda7f83f178b0fd6ea70f8 100644 (file)
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -494,7 +494,7 @@ struct gfs2_sb_host {
  */
 
 struct lm_lockstruct {
-       unsigned int ls_jid;
+       int ls_jid;
        unsigned int ls_first;
        unsigned int ls_first_done;
        unsigned int ls_nodir;

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 5b11f37681445f391310e484dc965c4d1fc7f55b..aeafc233dc897fdb102df29bf052fc040b61faef 100644 (file)
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1056,8 +1056,6 @@ static int gfs2_journalid_wait(void *word)
 
 static int wait_on_journal(struct gfs2_sbd *sdp)
 {
-       if (sdp->sd_args.ar_spectator)
-               return 0;
        if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
                return 0;
 
@@ -1160,6 +1158,20 @@ static int fill_super(struct super_block *sb, struct gfs2_args *args, int silent
        if (error)
                goto fail_sb;
 
+       /*
+        * If user space has failed to join the cluster or some similar
+        * failure has occurred, then the journal id will contain a
+        * negative (error) number. This will then be returned to the
+        * caller (of the mount syscall). We do this even for spectator
+        * mounts (which just write a jid of 0 to indicate "ok" even though
+        * the jid is unused in the spectator case)
+        */
+       if (sdp->sd_lockstruct.ls_jid < 0) {
+               error = sdp->sd_lockstruct.ls_jid;
+               sdp->sd_lockstruct.ls_jid = 0;
+               goto fail_sb;
+       }
+
        error = init_inodes(sdp, DO);
        if (error)
                goto fail_sb;

diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c
index ccacffd2faaa6d65d1f116b9b2788ee732786f3f..64082a5feae136bf608afcac8edf27ac4f81a095 100644 (file)
--- a/fs/gfs2/sys.c
+++ b/fs/gfs2/sys.c
@@ -399,31 +399,32 @@ static ssize_t recover_status_show(struct gfs2_sbd *sdp, char *buf)
 
 static ssize_t jid_show(struct gfs2_sbd *sdp, char *buf)
 {
-       return sprintf(buf, "%u\n", sdp->sd_lockstruct.ls_jid);
+       return sprintf(buf, "%d\n", sdp->sd_lockstruct.ls_jid);
 }
 
 static ssize_t jid_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
 {
-        unsigned jid;
+        int jid;
        int rv;
 
-       rv = sscanf(buf, "%u", &jid);
+       rv = sscanf(buf, "%d", &jid);
        if (rv != 1)
                return -EINVAL;
 
        spin_lock(&sdp->sd_jindex_spin);
        rv = -EINVAL;
-       if (sdp->sd_args.ar_spectator)
-               goto out;
        if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
                goto out;
        rv = -EBUSY;
-       if (test_and_clear_bit(SDF_NOJOURNALID, &sdp->sd_flags) == 0)
+       if (test_bit(SDF_NOJOURNALID, &sdp->sd_flags) == 0)
                goto out;
+       rv = 0;
+       if (sdp->sd_args.ar_spectator && jid > 0)
+               rv = jid = -EINVAL;
        sdp->sd_lockstruct.ls_jid = jid;
+       clear_bit(SDF_NOJOURNALID, &sdp->sd_flags);
        smp_mb__after_clear_bit();
        wake_up_bit(&sdp->sd_flags, SDF_NOJOURNALID);
-       rv = 0;
 out:
        spin_unlock(&sdp->sd_jindex_spin);
        return rv ? rv : len;
@@ -617,7 +618,7 @@ static int gfs2_uevent(struct kset *kset, struct kobject *kobj,
        add_uevent_var(env, "LOCKTABLE=%s", sdp->sd_table_name);
        add_uevent_var(env, "LOCKPROTO=%s", sdp->sd_proto_name);
        if (!test_bit(SDF_NOJOURNALID, &sdp->sd_flags))
-               add_uevent_var(env, "JOURNALID=%u", sdp->sd_lockstruct.ls_jid);
+               add_uevent_var(env, "JOURNALID=%d", sdp->sd_lockstruct.ls_jid);
        if (gfs2_uuid_valid(uuid))
                add_uevent_var(env, "UUID=%pUB", uuid);
        return 0;