deprecate-max_writeback_sb_bump-sysfs-attribute

   1 ext4: deprecate max_writeback_mb_bump sysfs attribute
   2
   3 From: Jan Kara <jack@suse.cz>
   4
   5 This attribute is now unused so deprecate it.  We still show the old
   6 default value to keep some compatibility but we don't allow writing to
   7 that attribute anymore.
   8
   9 Signed-off-by: Jan Kara <jack@suse.cz>
  10 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  11 ---
  12  fs/ext4/ext4.h  |  1 -
  13  fs/ext4/super.c | 30 ++++++++++++++++++++++++------
  14  2 files changed, 24 insertions(+), 7 deletions(-)
  15
  16 diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
  17 index 0aabb34..d260fb7 100644
  18 --- a/fs/ext4/ext4.h
  19 +++ b/fs/ext4/ext4.h
  20 @@ -1246,7 +1246,6 @@ struct ext4_sb_info {
  21         unsigned int s_mb_stats;
  22         unsigned int s_mb_order2_reqs;
  23         unsigned int s_mb_group_prealloc;
  24 -       unsigned int s_max_writeback_mb_bump;
  25         unsigned int s_max_dir_size_kb;
  26         /* where last allocation was done - for stream allocation */
  27         unsigned long s_mb_last_group;
  28 diff --git a/fs/ext4/super.c b/fs/ext4/super.c
  29 index 94cc84d..18bd6dd 100644
  30 --- a/fs/ext4/super.c
  31 +++ b/fs/ext4/super.c
  32 @@ -2377,7 +2377,10 @@ struct ext4_attr {
  33         ssize_t (*show)(struct ext4_attr *, struct ext4_sb_info *, char *);
  34         ssize_t (*store)(struct ext4_attr *, struct ext4_sb_info *,
  35                          const char *, size_t);
  36 -       int offset;
  37 +       union {
  38 +               int offset;
  39 +               int deprecated_val;
  40 +       } u;
  41  };
  42
  43  static int parse_strtoull(const char *buf,
  44 @@ -2446,7 +2449,7 @@ static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
  45  static ssize_t sbi_ui_show(struct ext4_attr *a,
  46                            struct ext4_sb_info *sbi, char *buf)
  47  {
  48 -       unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
  49 +       unsigned int *ui = (unsigned int *) (((char *) sbi) + a->u.offset);
  50
  51         return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
  52  }
  53 @@ -2455,7 +2458,7 @@ static ssize_t sbi_ui_store(struct ext4_attr *a,
  54                             struct ext4_sb_info *sbi,
  55                             const char *buf, size_t count)
  56  {
  57 -       unsigned int *ui = (unsigned int *) (((char *) sbi) + a->offset);
  58 +       unsigned int *ui = (unsigned int *) (((char *) sbi) + a->u.offset);
  59         unsigned long t;
  60         int ret;
  61
  62 @@ -2504,12 +2507,20 @@ static ssize_t trigger_test_error(struct ext4_attr *a,
  63         return count;
  64  }
  65
  66 +static ssize_t sbi_deprecated_show(struct ext4_attr *a,
  67 +                                  struct ext4_sb_info *sbi, char *buf)
  68 +{
  69 +       return snprintf(buf, PAGE_SIZE, "%d\n", a->u.deprecated_val);
  70 +}
  71 +
  72  #define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \
  73  static struct ext4_attr ext4_attr_##_name = {                  \
  74         .attr = {.name = __stringify(_name), .mode = _mode },   \
  75         .show   = _show,                                        \
  76         .store  = _store,                                       \
  77 -       .offset = offsetof(struct ext4_sb_info, _elname),       \
  78 +       .u = {                                                  \
  79 +               .offset = offsetof(struct ext4_sb_info, _elname),\
  80 +       },                                                      \
  81  }
  82  #define EXT4_ATTR(name, mode, show, store) \
  83  static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
  84 @@ -2520,6 +2531,14 @@ static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
  85  #define EXT4_RW_ATTR_SBI_UI(name, elname)      \
  86         EXT4_ATTR_OFFSET(name, 0644, sbi_ui_show, sbi_ui_store, elname)
  87  #define ATTR_LIST(name) &ext4_attr_##name.attr
  88 +#define EXT4_DEPRECATED_ATTR(_name, _val)      \
  89 +static struct ext4_attr ext4_attr_##_name = {                  \
  90 +       .attr = {.name = __stringify(_name), .mode = 0444 },    \
  91 +       .show   = sbi_deprecated_show,                          \
  92 +       .u = {                                                  \
  93 +               .deprecated_val = _val,                         \
  94 +       },                                                      \
  95 +}
  96
  97  EXT4_RO_ATTR(delayed_allocation_blocks);
  98  EXT4_RO_ATTR(session_write_kbytes);
  99 @@ -2534,7 +2553,7 @@ EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
 100  EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
 101  EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
 102  EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
 103 -EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);
 104 +EXT4_DEPRECATED_ATTR(max_writeback_mb_bump, 128);
 105  EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
 106  EXT4_ATTR(trigger_fs_error, 0200, NULL, trigger_test_error);
 107
 108 @@ -3787,7 +3806,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 109         }
 110
 111         sbi->s_stripe = ext4_get_stripe_size(sbi);
 112 -       sbi->s_max_writeback_mb_bump = 128;
 113         sbi->s_extent_max_zeroout_kb = 32;
 114
 115         /*
 116 --
 117 1.8.1.4
 118
 119