src/patches/U-Boot-v2-fs-fat-read-fix-fat16-ls-read-issue.patch

   1 diff --git a/fs/fat/fat.c b/fs/fat/fat.c
   2 index 04a51db..bccc3e3 100644
   3 --- a/fs/fat/fat.c
   4 +++ b/fs/fat/fat.c
   5 @@ -823,8 +823,11 @@ int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
   6         int ret = -1;
   7         int firsttime;
   8         __u32 root_cluster = 0;
   9 +       __u32 read_blk;
  10         int rootdir_size = 0;
  11 -       int j;
  12 +       int buffer_blk_cnt;
  13 +       int do_read;
  14 +       __u8 *dir_ptr;
  15
  16         if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
  17                 debug("Error: reading boot sector\n");
  18 @@ -909,24 +912,54 @@ int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
  19                 isdir = 1;
  20         }
  21
  22 -       j = 0;
  23 +       buffer_blk_cnt = 0;
  24 +       firsttime = 1;
  25         while (1) {
  26                 int i;
  27
  28 -               if (j == 0) {
  29 -                       debug("FAT read sect=%d, clust_size=%d, DIRENTSPERBLOCK=%zd\n",
  30 -                               cursect, mydata->clust_size, DIRENTSPERBLOCK);
  31 +               if (mydata->fatsize == 32 || firsttime) {
  32 +                       dir_ptr = do_fat_read_at_block;
  33 +                       firsttime = 0;
  34 +               } else {
  35 +                       /**
  36 +                        * FAT16 sector buffer modification:
  37 +                        * Each loop, the second buffered block is moved to
  38 +                        * the buffer begin, and two next sectors are read
  39 +                        * next to the previously moved one. So the sector
  40 +                        * buffer keeps always 3 sectors for fat16.
  41 +                        * And the current sector is the buffer second sector
  42 +                        * beside the "firsttime" read, when it is the first one.
  43 +                        *
  44 +                        * PREFETCH_BLOCKS is 2 for FAT16 == loop[0:1]
  45 +                        * n = computed root dir sector
  46 +                        * loop |  cursect-1  | cursect    | cursect+1  |
  47 +                        *   0  |  sector n+0 | sector n+1 | none       |
  48 +                        *   1  |  none       | sector n+0 | sector n+1 |
  49 +                        *   0  |  sector n+1 | sector n+2 | sector n+3 |
  50 +                        *   1  |  sector n+3 | ...
  51 +                       */
  52 +                       dir_ptr = (do_fat_read_at_block + mydata->sect_size);
  53 +                       memcpy(do_fat_read_at_block, dir_ptr, mydata->sect_size);
  54 +               }
  55 +
  56 +               do_read = 1;
  57 +
  58 +               if (mydata->fatsize == 32 && buffer_blk_cnt)
  59 +                       do_read = 0;
  60 +
  61 +               if (do_read) {
  62 +                       read_blk = (mydata->fatsize == 32) ?
  63 +                                   mydata->clust_size : PREFETCH_BLOCKS;
  64 +
  65 +                       debug("FAT read(sect=%d, cnt:%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
  66 +                               cursect, read_blk, mydata->clust_size, DIRENTSPERBLOCK);
  67
  68 -                       if (disk_read(cursect,
  69 -                                       (mydata->fatsize == 32) ?
  70 -                                       (mydata->clust_size) :
  71 -                                       PREFETCH_BLOCKS,
  72 -                                       do_fat_read_at_block) < 0) {
  73 +                       if (disk_read(cursect, read_blk, dir_ptr) < 0) {
  74                                 debug("Error: reading rootdir block\n");
  75                                 goto exit;
  76                         }
  77
  78 -                       dentptr = (dir_entry *) do_fat_read_at_block;
  79 +                       dentptr = (dir_entry *)dir_ptr;
  80                 }
  81
  82                 for (i = 0; i < DIRENTSPERBLOCK; i++) {
  83 @@ -951,7 +984,7 @@ int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
  84
  85                                         get_vfatname(mydata,
  86                                                      root_cluster,
  87 -                                                    do_fat_read_at_block,
  88 +                                                    dir_ptr,
  89                                                      dentptr, l_name);
  90
  91                                         if (dols == LS_ROOT) {
  92 @@ -1062,7 +1095,7 @@ int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
  93
  94                         goto rootdir_done;      /* We got a match */
  95                 }
  96 -               debug("END LOOP: j=%d   clust_size=%d\n", j,
  97 +               debug("END LOOP: buffer_blk_cnt=%d   clust_size=%d\n", buffer_blk_cnt,
  98                        mydata->clust_size);
  99
 100                 /*
 101 @@ -1070,10 +1103,10 @@ int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
 102                  * root directory clusters when a cluster has been
 103                  * completely processed.
 104                  */
 105 -               ++j;
 106 +               ++buffer_blk_cnt;
 107                 int rootdir_end = 0;
 108                 if (mydata->fatsize == 32) {
 109 -                       if (j == mydata->clust_size) {
 110 +                       if (buffer_blk_cnt == mydata->clust_size) {
 111                                 int nxtsect = 0;
 112                                 int nxt_clust = 0;
 113
 114 @@ -1086,11 +1119,11 @@ int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
 115                                 root_cluster = nxt_clust;
 116
 117                                 cursect = nxtsect;
 118 -                               j = 0;
 119 +                               buffer_blk_cnt = 0;
 120                         }
 121                 } else {
 122 -                       if (j == PREFETCH_BLOCKS)
 123 -                               j = 0;
 124 +                       if (buffer_blk_cnt == PREFETCH_BLOCKS)
 125 +                               buffer_blk_cnt = 0;
 126
 127                         rootdir_end = (++cursect - mydata->rootdir_sect >=
 128                                        rootdir_size);