Merge commit 'v2.6.39-rc3' into for-2.6.39

[pandora-kernel.git] / fs / ubifs / debug.c

diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
index 01c2b02..004d374 100644 (file)
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -818,7 +818,7 @@ void dbg_dump_leb(const struct ubifs_info *c, int lnum)
        printk(KERN_DEBUG "(pid %d) start dumping LEB %d\n",
               current->pid, lnum);
 
-       buf = __vmalloc(c->leb_size, GFP_KERNEL | GFP_NOFS, PAGE_KERNEL);
+       buf = __vmalloc(c->leb_size, GFP_NOFS, PAGE_KERNEL);
        if (!buf) {
                ubifs_err("cannot allocate memory for dumping LEB %d", lnum);
                return;
@@ -972,11 +972,39 @@ void dbg_dump_index(struct ubifs_info *c)
 void dbg_save_space_info(struct ubifs_info *c)
 {
        struct ubifs_debug_info *d = c->dbg;
-
-       ubifs_get_lp_stats(c, &d->saved_lst);
+       int freeable_cnt;
 
        spin_lock(&c->space_lock);
+       memcpy(&d->saved_lst, &c->lst, sizeof(struct ubifs_lp_stats));
+
+       /*
+        * We use a dirty hack here and zero out @c->freeable_cnt, because it
+        * affects the free space calculations, and UBIFS might not know about
+        * all freeable eraseblocks. Indeed, we know about freeable eraseblocks
+        * only when we read their lprops, and we do this only lazily, upon the
+        * need. So at any given point of time @c->freeable_cnt might be not
+        * exactly accurate.
+        *
+        * Just one example about the issue we hit when we did not zero
+        * @c->freeable_cnt.
+        * 1. The file-system is mounted R/O, c->freeable_cnt is %0. We save the
+        *    amount of free space in @d->saved_free
+        * 2. We re-mount R/W, which makes UBIFS to read the "lsave"
+        *    information from flash, where we cache LEBs from various
+        *    categories ('ubifs_remount_fs()' -> 'ubifs_lpt_init()'
+        *    -> 'lpt_init_wr()' -> 'read_lsave()' -> 'ubifs_lpt_lookup()'
+        *    -> 'ubifs_get_pnode()' -> 'update_cats()'
+        *    -> 'ubifs_add_to_cat()').
+        * 3. Lsave contains a freeable eraseblock, and @c->freeable_cnt
+        *    becomes %1.
+        * 4. We calculate the amount of free space when the re-mount is
+        *    finished in 'dbg_check_space_info()' and it does not match
+        *    @d->saved_free.
+        */
+       freeable_cnt = c->freeable_cnt;
+       c->freeable_cnt = 0;
        d->saved_free = ubifs_get_free_space_nolock(c);
+       c->freeable_cnt = freeable_cnt;
        spin_unlock(&c->space_lock);
 }
 
@@ -993,12 +1021,15 @@ int dbg_check_space_info(struct ubifs_info *c)
 {
        struct ubifs_debug_info *d = c->dbg;
        struct ubifs_lp_stats lst;
-       long long avail, free;
+       long long free;
+       int freeable_cnt;
 
        spin_lock(&c->space_lock);
-       avail = ubifs_calc_available(c, c->min_idx_lebs);
+       freeable_cnt = c->freeable_cnt;
+       c->freeable_cnt = 0;
+       free = ubifs_get_free_space_nolock(c);
+       c->freeable_cnt = freeable_cnt;
        spin_unlock(&c->space_lock);
-       free = ubifs_get_free_space(c);
 
        if (free != d->saved_free) {
                ubifs_err("free space changed from %lld to %lld",
@@ -2806,40 +2837,38 @@ int dbg_debugfs_init_fs(struct ubifs_info *c)
        struct ubifs_debug_info *d = c->dbg;
 
        sprintf(d->dfs_dir_name, "ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
-       d->dfs_dir = debugfs_create_dir(d->dfs_dir_name, dfs_rootdir);
-       if (IS_ERR(d->dfs_dir)) {
-               err = PTR_ERR(d->dfs_dir);
-               ubifs_err("cannot create \"%s\" debugfs directory, error %d\n",
-                         d->dfs_dir_name, err);
+       fname = d->dfs_dir_name;
+       dent = debugfs_create_dir(fname, dfs_rootdir);
+       if (IS_ERR_OR_NULL(dent))
                goto out;
-       }
+       d->dfs_dir = dent;
 
        fname = "dump_lprops";
        dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, c, &dfs_fops);
-       if (IS_ERR(dent))
+       if (IS_ERR_OR_NULL(dent))
                goto out_remove;
        d->dfs_dump_lprops = dent;
 
        fname = "dump_budg";
        dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, c, &dfs_fops);
-       if (IS_ERR(dent))
+       if (IS_ERR_OR_NULL(dent))
                goto out_remove;
        d->dfs_dump_budg = dent;
 
        fname = "dump_tnc";
        dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, c, &dfs_fops);
-       if (IS_ERR(dent))
+       if (IS_ERR_OR_NULL(dent))
                goto out_remove;
        d->dfs_dump_tnc = dent;
 
        return 0;
 
 out_remove:
-       err = PTR_ERR(dent);
-       ubifs_err("cannot create \"%s\" debugfs directory, error %d\n",
-                 fname, err);
        debugfs_remove_recursive(d->dfs_dir);
 out:
+       err = dent ? PTR_ERR(dent) : -ENODEV;
+       ubifs_err("cannot create \"%s\" debugfs directory, error %d\n",
+                 fname, err);
        return err;
 }