ldiskfs/kernel_patches/patches/sles12sp2/ext4_s_max_ext_tree_depth.patch

   1 Fix ext4_ext_find_extent() to already pre-allocate ext4_ext_path[]
   2 array of the max depth instead of current depth.
   3 This will avoid racy cases of concurrent ext_depth() growth in
   4 current and unsafe implementation with ext4_ext_path[] array
   5 re-[sizing,allocation], even with more recent and related patches
   6 that will be integrated in more recent Kernels.
   7
   8 Index: linux-2.6.32-504.el6.x86_64/fs/ext4/ext4.h
   9 ===================================================================
  10 --- linux-2.6.32-504.el6.x86_64.orig/fs/ext4/ext4.h
  11 +++ linux-2.6.32-504.el6.x86_64/fs/ext4/ext4.h
  12 @@ -1147,6 +1147,9 @@
  13         unsigned long s_ext_extents;
  14  #endif
  15
  16 +       /* maximum possible extents tree depth, to be computed at mount time */
  17 +       unsigned int s_max_ext_tree_depth;
  18 +
  19         /* for buddy allocator */
  20         struct ext4_group_info ***s_group_info;
  21         struct inode *s_buddy_cache;
  22 Index: linux-2.6.32-504.el6.x86_64/fs/ext4/super.c
  23 ===================================================================
  24 --- linux-2.6.32-504.el6.x86_64.orig/fs/ext4/super.c
  25 +++ linux-2.6.32-504.el6.x86_64/fs/ext4/super.c
  26 @@ -4038,6 +4038,8 @@
  27                 if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
  28                         goto failed_mount3;
  29
  30 +       ext4_ext_init(sb); /* needed before using extent-mapped journal */
  31 +
  32         /*
  33          * The first inode we look at is the journal inode.  Don't try
  34          * root first: it may be modified in the journal!
  35 @@ -4200,7 +4202,6 @@
  36                 goto failed_mount4a;
  37         }
  38
  39 -       ext4_ext_init(sb);
  40         err = ext4_mb_init(sb);
  41         if (err) {
  42                 ext4_msg(sb, KERN_ERR, "failed to initialize mballoc (%d)",
  43 Index: linux-2.6.32-504.el6.x86_64/fs/ext4/extents.c
  44 ===================================================================
  45 --- linux-2.6.32-504.el6.x86_64.orig/fs/ext4/extents.c
  46 +++ linux-2.6.32-504.el6.x86_64/fs/ext4/extents.c
  47 @@ -699,8 +699,9 @@
  48
  49         if (!path) {
  50                 /* account possible depth increase */
  51 -               path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
  52 -                               GFP_NOFS);
  53 +               path = kzalloc(sizeof(struct ext4_ext_path) *
  54 +                              EXT4_SB(inode->i_sb)->s_max_ext_tree_depth,
  55 +                              GFP_NOFS);
  56                 if (unlikely(!path))
  57                         return ERR_PTR(-ENOMEM);
  58                 alloc = 1;
  59 @@ -2664,8 +2662,9 @@
  60                         path[k].p_block =
  61                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
  62         } else {
  63 -               path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
  64 -                              GFP_NOFS);
  65 +               path = kzalloc(sizeof(struct ext4_ext_path) *
  66 +                              EXT4_SB(inode->i_sb)->s_max_ext_tree_depth,
  67 +                              GFP_NOFS);
  68                 if (path == NULL) {
  69                         ext4_journal_stop(handle);
  70                         return -ENOMEM;
  71 @@ -3048,13 +3034,14 @@
  72   */
  73  void ext4_ext_init(struct super_block *sb)
  74  {
  75 +       ext4_fsblk_t maxblocks;
  76 +
  77         /*
  78          * possible initialization would be here
  79          */
  80
  81         if (ext4_has_feature_extents(sb)) {
  82 -#if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
  83 -               printk(KERN_INFO "EXT4-fs: file extents enabled"
  84 +               printk(KERN_INFO "EXT4-fs (%s): file extents enabled"
  85  #ifdef AGGRESSIVE_TEST
  86                        ", aggressive tests"
  87  #endif
  88 @@ -3064,8 +3051,31 @@
  89  #ifdef EXTENTS_STATS
  90                        ", stats"
  91  #endif
  92 -                      "\n");
  93 -#endif
  94 +                      , sb->s_id);
  95 +               EXT4_SB(sb)->s_max_ext_tree_depth = 1;
  96 +
  97 +               maxblocks = sb->s_maxbytes / sb->s_blocksize;
  98 +
  99 +               /* 1st/root level/node of extents tree stands in i_data and
 100 +                * entries stored in tree nodes can be of type ext4_extent
 101 +                * (leaf node) or ext4_extent_idx (internal node) */
 102 +               maxblocks /= (sizeof(((struct ext4_inode_info *)0x0)->i_data) -
 103 +                             sizeof(struct ext4_extent_header)) /
 104 +                            max(sizeof(struct ext4_extent),
 105 +                                sizeof(struct ext4_extent_idx));
 106 +
 107 +               /* compute maximum extents tree depth for a fully populated
 108 +                * file of max size made of only minimal/1-block extents */
 109 +               while (maxblocks > 0) {
 110 +                       maxblocks /= (sb->s_blocksize -
 111 +                                     sizeof(struct ext4_extent_header)) /
 112 +                                    max(sizeof(struct ext4_extent),
 113 +                                        sizeof(struct ext4_extent_idx));
 114 +                       EXT4_SB(sb)->s_max_ext_tree_depth++;
 115 +               }
 116 +
 117 +               printk(", maximum tree depth=%u\n",
 118 +                      EXT4_SB(sb)->s_max_ext_tree_depth);
 119  #ifdef EXTENTS_STATS
 120                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
 121                 EXT4_SB(sb)->s_ext_min = 1 << 30;