delalloc-debug

   1 ext4: add delalloc debugging
   2
   3 This adds a file in /proc/fs/ext4/<dev> which when opened for reading,
   4 will trigger debugging code that dumps a lot of information about
   5 inodes subject to delayed allocation to the console.
   6
   7 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
   8 ---
   9  fs/ext4/sysfs.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  10  1 file changed, 69 insertions(+)
  11
  12 diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
  13 index 9d29723..507d33f 100644
  14 --- a/fs/ext4/sysfs.c
  15 +++ b/fs/ext4/sysfs.c
  16 @@ -371,6 +371,74 @@ static struct kobject ext4_feat = {
  17         .kset   = &ext4_kset,
  18  };
  19
  20 +#ifdef CONFIG_EXT4_DEBUG
  21 +static void print_inode_delalloc_info(struct inode *inode)
  22 +{
  23 +       if (!EXT4_I(inode)->i_reserved_data_blocks ||
  24 +           !EXT4_I(inode)->i_reserved_meta_blocks)
  25 +               return;
  26 +
  27 +       printk(KERN_DEBUG "ino %lu: %u %u\n", inode->i_ino,
  28 +              EXT4_I(inode)->i_reserved_data_blocks,
  29 +              EXT4_I(inode)->i_reserved_meta_blocks);
  30 +}
  31 +
  32 +static int debug_delalloc_show(struct seq_file *seq, void *offset)
  33 +{
  34 +       return 0;
  35 +}
  36 +
  37 +static int options_delalloc_debug_open_fs(struct inode *proc_inode,
  38 +                                         struct file *file)
  39 +{
  40 +       struct super_block *sb = PDE_DATA(proc_inode);
  41 +       struct ext4_sb_info *sbi = EXT4_SB(sb);
  42 +       struct inode *inode;
  43 +       extern spinlock_t inode_sb_list_lock;
  44 +
  45 +       printk(KERN_DEBUG "EXT4-fs debug delalloc of %s\n", sb->s_id);
  46 +       printk(KERN_DEBUG "EXT4-fs: dirty clusters %lld free clusters %lld\n",
  47 +              percpu_counter_sum(&sbi->s_dirtyclusters_counter),
  48 +              percpu_counter_sum(&sbi->s_freeclusters_counter));
  49 +
  50 +#ifndef MODULE
  51 +       spin_lock(&inode_sb_list_lock);
  52 +       if (!list_empty(&sb->s_bdi->wb.b_dirty)) {
  53 +               printk(KERN_DEBUG "s_bdi->wb.b_dirty list:\n");
  54 +               list_for_each_entry(inode, &sb->s_bdi->wb.b_dirty,
  55 +                                   i_io_list) {
  56 +                       print_inode_delalloc_info(inode);
  57 +               }
  58 +       }
  59 +       if (!list_empty(&sb->s_bdi->wb.b_io)) {
  60 +               printk(KERN_DEBUG "s_bdi->wb.b_io list:\n");
  61 +               list_for_each_entry(inode, &sb->s_bdi->wb.b_io,
  62 +                                   i_io_list) {
  63 +                       print_inode_delalloc_info(inode);
  64 +               }
  65 +       }
  66 +       if (!list_empty(&sb->s_bdi->wb.b_more_io)) {
  67 +               printk(KERN_DEBUG "s_bdi->wb.b_more_io list:\n");
  68 +               list_for_each_entry(inode, &sb->s_bdi->wb.b_more_io,
  69 +                                   i_io_list) {
  70 +                       print_inode_delalloc_info(inode);
  71 +               }
  72 +       }
  73 +       spin_unlock(&inode_sb_list_lock);
  74 +       printk(KERN_DEBUG "ext4 debug delalloc done\n");
  75 +#endif
  76 +       return single_open(file, debug_delalloc_show, sb);
  77 +}
  78 +
  79 +static const struct file_operations ext4_seq_delalloc_debug_fops = {
  80 +       .owner = THIS_MODULE,
  81 +       .open = options_delalloc_debug_open_fs,
  82 +       .read = seq_read,
  83 +       .llseek = seq_lseek,
  84 +       .release = single_release,
  85 +};
  86 +#endif
  87 +
  88  #define PROC_FILE_SHOW_DEFN(name) \
  89  static int name##_open(struct inode *inode, struct file *file) \
  90  { \
  91 @@ -398,6 +466,7 @@ static struct ext4_proc_files {
  92         PROC_FILE_LIST(options),
  93         PROC_FILE_LIST(es_shrinker_info),
  94         PROC_FILE_LIST(mb_groups),
  95 +       PROC_FILE_LIST(delalloc_debug),
  96         { NULL, NULL },
  97  };
  98