[GFS2] bz 236008: Kernel gpf doing cat /debugfs/gfs2/xxx (lock dump)

This is for Bugzilla Bug 236008: Kernel gpf doing cat /debugfs/gfs2/xxx
(lock dump) seen at the "gfs2 summit".  This also fixes the bug that caused
garbage to be printed by the "initialized at" field.  I apologize for the
kludge, but that code will all be ripped out anyway when the official
sprint_symbol function becomes available in the Linux kernel.  I also
changed some formatting so that spaces are replaced by proper tabs.

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

1 files changed, 21 insertions, 8 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index d2e3094c40f8..b075f9359c60 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1765,15 +1765,20 @@ static void gfs2_print_symbol(struct glock_iter *gi, const char *fmt,
 {
 /* when sprint_symbol becomes available in the new kernel, replace this */
 /* function with:
-        char buffer[KSYM_SYMBOL_LEN];
+        char buffer[KSYM_SYMBOL_LEN];
 
-        sprint_symbol(buffer, address);
-        print_dbg(gi, fmt, buffer);
+        sprint_symbol(buffer, address);
+        print_dbg(gi, fmt, buffer);
 */
-        if (gi)
-                print_dbg(gi, fmt, address);
-        else
-                print_symbol(fmt, address);
+        char buffer[256];
+
+        if (gi) {
+                memset(buffer, 0, sizeof(buffer));
+                sprintf(buffer, "%p", address);
+                print_dbg(gi, fmt, buffer);
+        }
+        else
+                print_symbol(fmt, address);
 }
 
 /**
@@ -1993,14 +1998,19 @@ int __init gfs2_glock_init(void)
 
 static int gfs2_glock_iter_next(struct glock_iter *gi)
 {
+        read_lock(gl_lock_addr(gi->hash));
         while (1) {
                 if (!gi->hb_list) {  /* If we don't have a hash bucket yet */
                         gi->hb_list = &gl_hash_table[gi->hash].hb_list;
                         if (hlist_empty(gi->hb_list)) {
+                                read_unlock(gl_lock_addr(gi->hash));
                                 gi->hash++;
+                                read_lock(gl_lock_addr(gi->hash));
                                 gi->hb_list = NULL;
-                                if (gi->hash >= GFS2_GL_HASH_SIZE)
+                                if (gi->hash >= GFS2_GL_HASH_SIZE) {
+                                        read_unlock(gl_lock_addr(gi->hash));
                                         return 1;
+                                }
                                 else
                                         continue;
                         }
@@ -2011,7 +2021,9 @@ static int gfs2_glock_iter_next(struct glock_iter *gi)
                         }
                 } else {
                         if (gi->gl->gl_list.next == NULL) {
+                                read_unlock(gl_lock_addr(gi->hash));
                                 gi->hash++;
+                                read_lock(gl_lock_addr(gi->hash));
                                 gi->hb_list = NULL;
                                 continue;
                         }
@@ -2021,6 +2033,7 @@ static int gfs2_glock_iter_next(struct glock_iter *gi)
                 if (gi->gl)
                         break;
         }
+        read_unlock(gl_lock_addr(gi->hash));
         return 0;
 }