ldiskfs/kernel_patches/patches/linux-5.8/ext4-kill-dx-root.patch

   1 From aa282f628e4ad75eea7f8ee1b26dea920c238241 Mon Sep 17 00:00:00 2001
   2 From: Shaun Tancheff <stancheff@cray.com>
   3 Date: Tue, 6 Aug 2019 17:00:55 -0500
   4 Subject: [PATCH] + linux-5.3/ext4-kill-dx-root
   5
   6 ---
   7  fs/ext4/namei.c |  111 +++++++++++++++++++++++++++++---------------------------
   8  1 file changed, 58 insertions(+), 53 deletions(-)
   9
  10 --- a/fs/ext4/namei.c
  11 +++ b/fs/ext4/namei.c
  12 @@ -219,22 +219,13 @@ struct dx_entry
  13   * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
  14   */
  15
  16 -struct dx_root
  17 +struct dx_root_info
  18  {
  19 -       struct fake_dirent dot;
  20 -       char dot_name[4];
  21 -       struct fake_dirent dotdot;
  22 -       char dotdot_name[4];
  23 -       struct dx_root_info
  24 -       {
  25 -               __le32 reserved_zero;
  26 -               u8 hash_version;
  27 -               u8 info_length; /* 8 */
  28 -               u8 indirect_levels;
  29 -               u8 unused_flags;
  30 -       }
  31 -       info;
  32 -       struct dx_entry entries[];
  33 +       __le32 reserved_zero;
  34 +       u8 hash_version;
  35 +       u8 info_length; /* 8 */
  36 +       u8 indirect_levels;
  37 +       u8 unused_flags;
  38  };
  39
  40  struct dx_node
  41 @@ -536,6 +527,16 @@ ext4_next_entry(struct ext4_dir_entry_2
  42   * Future: use high four bits of block for coalesce-on-delete flags
  43   * Mask them off for now.
  44   */
  45 +struct dx_root_info *dx_get_dx_info(struct ext4_dir_entry_2 *de)
  46 +{
  47 +       /* get dotdot first */
  48 +       de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(1));
  49 +
  50 +       /* dx root info is after dotdot entry */
  51 +       de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(2));
  52 +
  53 +       return (struct dx_root_info *)de;
  54 +}
  55
  56  static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
  57  {
  58 @@ -760,7 +761,7 @@ dx_probe(struct ext4_filename *fname, st
  59  {
  60         unsigned count, indirect;
  61         struct dx_entry *at, *entries, *p, *q, *m;
  62 -       struct dx_root *root;
  63 +       struct dx_root_info *info;
  64         struct dx_frame *frame = frame_in;
  65         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
  66         u32 hash;
  67 @@ -769,18 +770,17 @@ dx_probe(struct ext4_filename *fname, st
  68         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
  69         if (IS_ERR(frame->bh))
  70                 return (struct dx_frame *) frame->bh;
  71 -
  72 -       root = (struct dx_root *) frame->bh->b_data;
  73 -       if (root->info.hash_version != DX_HASH_TEA &&
  74 -           root->info.hash_version != DX_HASH_HALF_MD4 &&
  75 -           root->info.hash_version != DX_HASH_LEGACY) {
  76 -               ext4_warning_inode(dir, "Unrecognised inode hash code %u for directory "
  77 -                                  "%lu", root->info.hash_version, dir->i_ino);
  78 +       info = dx_get_dx_info((struct ext4_dir_entry_2 *)frame->bh->b_data);
  79 +        if (info->hash_version != DX_HASH_TEA &&
  80 +            info->hash_version != DX_HASH_HALF_MD4 &&
  81 +            info->hash_version != DX_HASH_LEGACY) {
  82 +               ext4_warning(dir->i_sb, "Unrecognised inode hash code %d for directory "
  83 +                             "#%lu", info->hash_version, dir->i_ino);
  84                 goto fail;
  85         }
  86         if (fname)
  87                 hinfo = &fname->hinfo;
  88 -       hinfo->hash_version = root->info.hash_version;
  89 +       hinfo->hash_version = info->hash_version;
  90         if (hinfo->hash_version <= DX_HASH_TEA)
  91                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
  92         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
  93 @@ -788,13 +788,13 @@ dx_probe(struct ext4_filename *fname, st
  94                 ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), hinfo);
  95         hash = hinfo->hash;
  96
  97 -       if (root->info.unused_flags & 1) {
  98 +       if (info->unused_flags & 1) {
  99                 ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
 100 -                                  root->info.unused_flags);
 101 +                                  info->unused_flags);
 102                 goto fail;
 103         }
 104
 105 -       indirect = root->info.indirect_levels;
 106 +       indirect = info->indirect_levels;
 107         if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
 108                 ext4_warning(dir->i_sb,
 109                              "Directory (ino: %lu) htree depth %#06x exceed"
 110 @@ -807,14 +807,13 @@ dx_probe(struct ext4_filename *fname, st
 111                 goto fail;
 112         }
 113
 114 -       entries = (struct dx_entry *)(((char *)&root->info) +
 115 -                                     root->info.info_length);
 116 +       entries = (struct dx_entry *)(((char *)info) + info->info_length);
 117
 118         if (dx_get_limit(entries) != dx_root_limit(dir,
 119 -                                                  root->info.info_length)) {
 120 +                                                  info->info_length)) {
 121                 ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
 122                                    dx_get_limit(entries),
 123 -                                  dx_root_limit(dir, root->info.info_length));
 124 +                                  dx_root_limit(dir, info->info_length));
 125                 goto fail;
 126         }
 127
 128 @@ -899,7 +898,7 @@ static void dx_release(struct dx_frame *
 129         if (frames[0].bh == NULL)
 130                 return;
 131
 132 -       info = &((struct dx_root *)frames[0].bh->b_data)->info;
 133 +       info = dx_get_dx_info((struct ext4_dir_entry_2 *)frames[0].bh->b_data);
 134         /* save local copy, "info" may be freed after brelse() */
 135         indirect_levels = info->indirect_levels;
 136         for (i = 0; i <= indirect_levels; i++) {
 137 @@ -2072,16 +2071,15 @@ static int make_indexed_dir(handle_t *ha
 138                             struct inode *inode, struct buffer_head *bh)
 139  {
 140         struct buffer_head *bh2;
 141 -       struct dx_root  *root;
 142         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
 143         struct dx_entry *entries;
 144 -       struct ext4_dir_entry_2 *de, *de2;
 145 +       struct ext4_dir_entry_2 *de, *de2, *dot_de, *dotdot_de;
 146         char            *data2, *top;
 147         unsigned        len;
 148         int             retval;
 149         unsigned        blocksize;
 150         ext4_lblk_t  block;
 151 -       struct fake_dirent *fde;
 152 +       struct dx_root_info *dx_info;
 153         int csum_size = 0;
 154
 155         if (ext4_has_metadata_csum(inode->i_sb))
 156 @@ -2096,18 +2094,19 @@ static int make_indexed_dir(handle_t *ha
 157                 brelse(bh);
 158                 return retval;
 159         }
 160 -       root = (struct dx_root *) bh->b_data;
 161 +
 162 +       dot_de = (struct ext4_dir_entry_2 *)bh->b_data;
 163 +       dotdot_de = ext4_next_entry(dot_de, blocksize);
 164
 165         /* The 0th block becomes the root, move the dirents out */
 166 -       fde = &root->dotdot;
 167 -       de = (struct ext4_dir_entry_2 *)((char *)fde +
 168 -               ext4_rec_len_from_disk(fde->rec_len, blocksize));
 169 -       if ((char *) de >= (((char *) root) + blocksize)) {
 170 +       de = (struct ext4_dir_entry_2 *)((char *)dotdot_de +
 171 +               ext4_rec_len_from_disk(dotdot_de->rec_len, blocksize));
 172 +       if ((char *)de >= (((char *)dot_de) + blocksize)) {
 173                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
 174                 brelse(bh);
 175                 return -EFSCORRUPTED;
 176         }
 177 -       len = ((char *) root) + (blocksize - csum_size) - (char *) de;
 178 +       len = ((char *)dot_de) + (blocksize - csum_size) - (char *)de;
 179
 180         /* Allocate new block for the 0th block's dirents */
 181         bh2 = ext4_append(handle, dir, &block);
 182 @@ -2130,19 +2129,24 @@ static int make_indexed_dir(handle_t *ha
 183                 ext4_initialize_dirent_tail(bh2, blocksize);
 184
 185         /* Initialize the root; the dot dirents already exist */
 186 -       de = (struct ext4_dir_entry_2 *) (&root->dotdot);
 187 -       de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
 188 -                                          blocksize);
 189 -       memset (&root->info, 0, sizeof(root->info));
 190 -       root->info.info_length = sizeof(root->info);
 191 -       root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
 192 -       entries = root->entries;
 193 +       dotdot_de->rec_len =
 194 +               ext4_rec_len_to_disk(blocksize - le16_to_cpu(dot_de->rec_len),
 195 +                                    blocksize);
 196 +
 197 +       /* initialize hashing info */
 198 +       dx_info = dx_get_dx_info(dot_de);
 199 +       memset(dx_info, 0, sizeof(*dx_info));
 200 +       dx_info->info_length = sizeof(*dx_info);
 201 +       dx_info->hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
 202 +
 203 +       entries = (void *)dx_info + sizeof(*dx_info);
 204 +
 205         dx_set_block(entries, 1);
 206         dx_set_count(entries, 1);
 207 -       dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
 208 +       dx_set_limit(entries, dx_root_limit(dir, sizeof(*dx_info)));
 209
 210         /* Initialize as for dx_probe */
 211 -       fname->hinfo.hash_version = root->info.hash_version;
 212 +       fname->hinfo.hash_version = dx_info->hash_version;
 213         if (fname->hinfo.hash_version <= DX_HASH_TEA)
 214                 fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
 215         fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 216 @@ -2506,7 +2510,7 @@ again:
 217                                 goto journal_error;
 218                         }
 219                 } else {
 220 -                       struct dx_root *dxroot;
 221 +                       struct dx_root_info *info;
 222                         memcpy((char *) entries2, (char *) entries,
 223                                icount * sizeof(struct dx_entry));
 224                         dx_set_limit(entries2, dx_node_limit(dir));
 225 @@ -2514,8 +2518,9 @@ again:
 226                         /* Set up root */
 227                         dx_set_count(entries, 1);
 228                         dx_set_block(entries + 0, newblock);
 229 -                       dxroot = (struct dx_root *)frames[0].bh->b_data;
 230 -                       dxroot->info.indirect_levels += 1;
 231 +                       info = dx_get_dx_info((struct ext4_dir_entry_2 *)
 232 +                                             frames[0].bh->b_data);
 233 +                       info->indirect_levels += 1;
 234                         dxtrace(printk(KERN_DEBUG
 235                                        "Creating %d level index...\n",
 236                                        dxroot->info.indirect_levels));