ldiskfs/kernel_patches/patches/linux-5.4/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 diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
  11 index a1db7ce..b0291ed 100644
  12 --- a/fs/ext4/namei.c
  13 +++ b/fs/ext4/namei.c
  14 @@ -212,22 +212,13 @@ struct dx_entry
  15   * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
  16   */
  17
  18 -struct dx_root
  19 +struct dx_root_info
  20  {
  21 -       struct fake_dirent dot;
  22 -       char dot_name[4];
  23 -       struct fake_dirent dotdot;
  24 -       char dotdot_name[4];
  25 -       struct dx_root_info
  26 -       {
  27 -               __le32 reserved_zero;
  28 -               u8 hash_version;
  29 -               u8 info_length; /* 8 */
  30 -               u8 indirect_levels;
  31 -               u8 unused_flags;
  32 -       }
  33 -       info;
  34 -       struct dx_entry entries[0];
  35 +       __le32 reserved_zero;
  36 +       u8 hash_version;
  37 +       u8 info_length; /* 8 */
  38 +       u8 indirect_levels;
  39 +       u8 unused_flags;
  40  };
  41
  42  struct dx_node
  43 @@ -529,6 +520,16 @@ ext4_next_entry(struct ext4_dir_entry_2 *p, unsigned long blocksize)
  44   * Future: use high four bits of block for coalesce-on-delete flags
  45   * Mask them off for now.
  46   */
  47 +struct dx_root_info *dx_get_dx_info(struct ext4_dir_entry_2 *de)
  48 +{
  49 +       /* get dotdot first */
  50 +       de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(1));
  51 +
  52 +       /* dx root info is after dotdot entry */
  53 +       de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(2));
  54 +
  55 +       return (struct dx_root_info *)de;
  56 +}
  57
  58  static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
  59  {
  60 @@ -753,7 +754,7 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
  61  {
  62         unsigned count, indirect;
  63         struct dx_entry *at, *entries, *p, *q, *m;
  64 -       struct dx_root *root;
  65 +       struct dx_root_info *info;
  66         struct dx_frame *frame = frame_in;
  67         struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
  68         u32 hash;
  69 @@ -762,18 +763,17 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
  70         frame->bh = ext4_read_dirblock(dir, 0, INDEX);
  71         if (IS_ERR(frame->bh))
  72                 return (struct dx_frame *) frame->bh;
  73 -
  74 -       root = (struct dx_root *) frame->bh->b_data;
  75 -       if (root->info.hash_version != DX_HASH_TEA &&
  76 -           root->info.hash_version != DX_HASH_HALF_MD4 &&
  77 -           root->info.hash_version != DX_HASH_LEGACY) {
  78 -               ext4_warning_inode(dir, "Unrecognised inode hash code %u for directory "
  79 -                                  "%lu", root->info.hash_version, dir->i_ino);
  80 +       info = dx_get_dx_info((struct ext4_dir_entry_2 *)frame->bh->b_data);
  81 +        if (info->hash_version != DX_HASH_TEA &&
  82 +            info->hash_version != DX_HASH_HALF_MD4 &&
  83 +            info->hash_version != DX_HASH_LEGACY) {
  84 +               ext4_warning(dir->i_sb, "Unrecognised inode hash code %d for directory "
  85 +                             "#%lu", info->hash_version, dir->i_ino);
  86                 goto fail;
  87         }
  88         if (fname)
  89                 hinfo = &fname->hinfo;
  90 -       hinfo->hash_version = root->info.hash_version;
  91 +       hinfo->hash_version = info->hash_version;
  92         if (hinfo->hash_version <= DX_HASH_TEA)
  93                 hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
  94         hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
  95 @@ -781,13 +781,13 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
  96                 ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), hinfo);
  97         hash = hinfo->hash;
  98
  99 -       if (root->info.unused_flags & 1) {
 100 +       if (info->unused_flags & 1) {
 101                 ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
 102 -                                  root->info.unused_flags);
 103 +                                  info->unused_flags);
 104                 goto fail;
 105         }
 106
 107 -       indirect = root->info.indirect_levels;
 108 +       indirect = info->indirect_levels;
 109         if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
 110                 ext4_warning(dir->i_sb,
 111                              "Directory (ino: %lu) htree depth %#06x exceed"
 112 @@ -800,14 +800,13 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
 113                 goto fail;
 114         }
 115
 116 -       entries = (struct dx_entry *)(((char *)&root->info) +
 117 -                                     root->info.info_length);
 118 +       entries = (struct dx_entry *)(((char *)info) + info->info_length);
 119
 120         if (dx_get_limit(entries) != dx_root_limit(dir,
 121 -                                                  root->info.info_length)) {
 122 +                                                  info->info_length)) {
 123                 ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
 124                                    dx_get_limit(entries),
 125 -                                  dx_root_limit(dir, root->info.info_length));
 126 +                                  dx_root_limit(dir, info->info_length));
 127                 goto fail;
 128         }
 129
 130 @@ -892,7 +891,7 @@ static void dx_release(struct dx_frame *frames)
 131         if (frames[0].bh == NULL)
 132                 return;
 133
 134 -       info = &((struct dx_root *)frames[0].bh->b_data)->info;
 135 +       info = dx_get_dx_info((struct ext4_dir_entry_2 *)frames[0].bh->b_data);
 136         /* save local copy, "info" may be freed after brelse() */
 137         indirect_levels = info->indirect_levels;
 138         for (i = 0; i <= indirect_levels; i++) {
 139 @@ -2065,16 +2064,15 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
 140                             struct inode *inode, struct buffer_head *bh)
 141  {
 142         struct buffer_head *bh2;
 143 -       struct dx_root  *root;
 144         struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
 145         struct dx_entry *entries;
 146 -       struct ext4_dir_entry_2 *de, *de2;
 147 +       struct ext4_dir_entry_2 *de, *de2, *dot_de, *dotdot_de;
 148         char            *data2, *top;
 149         unsigned        len;
 150         int             retval;
 151         unsigned        blocksize;
 152         ext4_lblk_t  block;
 153 -       struct fake_dirent *fde;
 154 +       struct dx_root_info *dx_info;
 155         int csum_size = 0;
 156
 157         if (ext4_has_metadata_csum(inode->i_sb))
 158 @@ -2089,18 +2087,19 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
 159                 brelse(bh);
 160                 return retval;
 161         }
 162 -       root = (struct dx_root *) bh->b_data;
 163 +
 164 +       dot_de = (struct ext4_dir_entry_2 *)bh->b_data;
 165 +       dotdot_de = ext4_next_entry(dot_de, blocksize);
 166
 167         /* The 0th block becomes the root, move the dirents out */
 168 -       fde = &root->dotdot;
 169 -       de = (struct ext4_dir_entry_2 *)((char *)fde +
 170 -               ext4_rec_len_from_disk(fde->rec_len, blocksize));
 171 -       if ((char *) de >= (((char *) root) + blocksize)) {
 172 +       de = (struct ext4_dir_entry_2 *)((char *)dotdot_de +
 173 +               ext4_rec_len_from_disk(dotdot_de->rec_len, blocksize));
 174 +       if ((char *)de >= (((char *)dot_de) + blocksize)) {
 175                 EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
 176                 brelse(bh);
 177                 return -EFSCORRUPTED;
 178         }
 179 -       len = ((char *) root) + (blocksize - csum_size) - (char *) de;
 180 +       len = ((char *)dot_de) + (blocksize - csum_size) - (char *)de;
 181
 182         /* Allocate new block for the 0th block's dirents */
 183         bh2 = ext4_append(handle, dir, &block);
 184 @@ -2123,19 +2122,24 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
 185                 ext4_initialize_dirent_tail(bh2, blocksize);
 186
 187         /* Initialize the root; the dot dirents already exist */
 188 -       de = (struct ext4_dir_entry_2 *) (&root->dotdot);
 189 -       de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
 190 -                                          blocksize);
 191 -       memset (&root->info, 0, sizeof(root->info));
 192 -       root->info.info_length = sizeof(root->info);
 193 -       root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
 194 -       entries = root->entries;
 195 +       dotdot_de->rec_len =
 196 +               ext4_rec_len_to_disk(blocksize - le16_to_cpu(dot_de->rec_len),
 197 +                                    blocksize);
 198 +
 199 +       /* initialize hashing info */
 200 +       dx_info = dx_get_dx_info(dot_de);
 201 +       memset(dx_info, 0, sizeof(*dx_info));
 202 +       dx_info->info_length = sizeof(*dx_info);
 203 +       dx_info->hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
 204 +
 205 +       entries = (void *)dx_info + sizeof(*dx_info);
 206 +
 207         dx_set_block(entries, 1);
 208         dx_set_count(entries, 1);
 209 -       dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
 210 +       dx_set_limit(entries, dx_root_limit(dir, sizeof(*dx_info)));
 211
 212         /* Initialize as for dx_probe */
 213 -       fname->hinfo.hash_version = root->info.hash_version;
 214 +       fname->hinfo.hash_version = dx_info->hash_version;
 215         if (fname->hinfo.hash_version <= DX_HASH_TEA)
 216                 fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
 217         fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
 218 @@ -2488,7 +2492,7 @@ again:
 219                                 goto journal_error;
 220                         }
 221                 } else {
 222 -                       struct dx_root *dxroot;
 223 +                       struct dx_root_info *info;
 224                         memcpy((char *) entries2, (char *) entries,
 225                                icount * sizeof(struct dx_entry));
 226                         dx_set_limit(entries2, dx_node_limit(dir));
 227 @@ -2496,8 +2500,9 @@ again:
 228                         /* Set up root */
 229                         dx_set_count(entries, 1);
 230                         dx_set_block(entries + 0, newblock);
 231 -                       dxroot = (struct dx_root *)frames[0].bh->b_data;
 232 -                       dxroot->info.indirect_levels += 1;
 233 +                       info = dx_get_dx_info((struct ext4_dir_entry_2 *)
 234 +                                             frames[0].bh->b_data);
 235 +                       info->indirect_levels = 1;
 236                         dxtrace(printk(KERN_DEBUG
 237                                        "Creating %d level index...\n",
 238                                        dxroot->info.indirect_levels));
 239 --
 240 2.20.1
 241