bk commit into 4.1 tree (istruewing:1.2534) BUG#22119

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ChangeSet@stripped, 2006-10-25 13:39:40+02:00, istruewing@stripped +1 -0
  Bug#22119 - Changing MI_KEY_BLOCK_LENGTH makes a wrong myisamchk
  
  When compiling with a default key block size greater than the
  smallest key block size used in a table, checking that table
  failed with bogus errors. The table was marked corrupt. This
  affected myisamchk and the server.
  
  The problem was that the default key block size was used at
  some places where sizes less or equal to the block size of the
  index in check was required.
  
  We do now use the key block size of the particular index
  when checking.
  
  A test case is available for later versions only.

  myisam/mi_check.c@stripped, 2006-10-25 13:39:38+02:00, istruewing@stripped +72 -16
    Bug#22119 - Changing MI_KEY_BLOCK_LENGTH makes a wrong myisamchk
    Changed check_k_link() and chk_index_down() to use the block
    size of the index in check or MI_MIN_KEY_BLOCK_LENGTH where
    required. Formerly myisam_block_size or MYISAM_SHARE::blocksize
    was used wrongly.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	istruewing
# Host:	chilla.local
# Root:	/home/mydev/mysql-4.1-bug22119

--- 1.161/myisam/mi_check.c	2006-10-25 13:39:44 +02:00
+++ 1.162/myisam/mi_check.c	2006-10-25 13:39:44 +02:00
@@ -251,11 +251,12 @@ static int check_k_link(MI_CHECK *param,
   my_off_t next_link;
   uint block_size=(nr+1)*MI_MIN_KEY_BLOCK_LENGTH;
   ha_rows records;
-  char llbuff[21],*buff;
+  char llbuff[21], llbuff2[21], *buff;
   DBUG_ENTER("check_k_link");
+  DBUG_PRINT("enter", ("block_size: %u", block_size));
 
   if (param->testflag & T_VERBOSE)
-    printf("block_size %4d:",block_size);
+    printf("block_size %4u:", block_size); /* purecov: tested */
 
   next_link=info->s->state.key_del[nr];
   records= (ha_rows) (info->state->key_file_length / block_size);
@@ -265,14 +266,46 @@ static int check_k_link(MI_CHECK *param,
       DBUG_RETURN(1);
     if (param->testflag & T_VERBOSE)
       printf("%16s",llstr(next_link,llbuff));
-    if (next_link > info->state->key_file_length ||
-	next_link & (info->s->blocksize-1))
+
+    /* Key blocks must lay within the key file length entirely. */
+    if (next_link + block_size > info->state->key_file_length)
+    {
+      /* purecov: begin tested */
+      mi_check_print_error(param, "Invalid key block position: %s  "
+                           "key block size: %u  file_length: %s",
+                           llstr(next_link, llbuff), block_size,
+                           llstr(info->state->key_file_length, llbuff2));
       DBUG_RETURN(1);
+      /* purecov: end */
+    }
+
+    /* Key blocks must be aligned at MI_MIN_KEY_BLOCK_LENGTH. */
+    if (next_link & (MI_MIN_KEY_BLOCK_LENGTH - 1))
+    {
+      /* purecov: begin tested */
+      mi_check_print_error(param, "Mis-aligned key block: %s  "
+                           "minimum key block length: %u",
+                           llstr(next_link, llbuff), MI_MIN_KEY_BLOCK_LENGTH);
+      DBUG_RETURN(1);
+      /* purecov: end */
+    }
+
+    /*
+      Read the key block with MI_MIN_KEY_BLOCK_LENGTH to find next link.
+      If the key cache block size is smaller than block_size, we can so
+      avoid unecessary eviction of cache block.
+    */
     if (!(buff=key_cache_read(info->s->key_cache,
                               info->s->kfile, next_link, DFLT_INIT_HITS,
-                              (byte*) info->buff,
-			      myisam_block_size, block_size, 1)))
+                              (byte*) info->buff, MI_MIN_KEY_BLOCK_LENGTH,
+                              MI_MIN_KEY_BLOCK_LENGTH, 1)))
+    {
+      /* purecov: begin tested */
+      mi_check_print_error(param, "key cache read error for block: %s",
+			   llstr(next_link,llbuff));
       DBUG_RETURN(1);
+      /* purecov: end */
+    }
     next_link=mi_sizekorr(buff);
     records--;
     param->key_file_blocks+=block_size;
@@ -555,17 +588,37 @@ static int chk_index_down(MI_CHECK *para
                      ha_checksum *key_checksum, uint level)
 {
   char llbuff[22],llbuff2[22];
-  if (page > info->state->key_file_length || (page &
(info->s->blocksize -1)))
-  {
-    my_off_t max_length=my_seek(info->s->kfile,0L,MY_SEEK_END,MYF(0));
-    mi_check_print_error(param,"Wrong pagepointer: %s at page: %s",
-                llstr(page,llbuff),llstr(page,llbuff2));
+  DBUG_ENTER("chk_index_down");
 
-    if (page+info->s->blocksize > max_length)
+  /* Key blocks must lay within the key file length entirely. */
+  if (page + keyinfo->block_length > info->state->key_file_length)
+  {
+    /* purecov: begin tested */
+    /* Give it a chance to fit in the real file size. */
+    my_off_t max_length= my_seek(info->s->kfile, 0L, MY_SEEK_END, MYF(0));
+    mi_check_print_error(param, "Invalid key block position: %s  "
+                         "key block size: %u  file_length: %s",
+                         llstr(page, llbuff), keyinfo->block_length,
+                         llstr(info->state->key_file_length, llbuff2));
+    if (page + keyinfo->block_length > max_length)
       goto err;
-    info->state->key_file_length=(max_length &
-                                  ~ (my_off_t) (info->s->blocksize-1));
+    /* Fix the remebered key file length. */
+    info->state->key_file_length= (max_length &
+                                   ~ (my_off_t) (keyinfo->block_length - 1));
+    /* purecov: end */
   }
+
+  /* Key blocks must be aligned at MI_MIN_KEY_BLOCK_LENGTH. */
+  if (page & (MI_MIN_KEY_BLOCK_LENGTH - 1))
+  {
+    /* purecov: begin tested */
+    mi_check_print_error(param, "Mis-aligned key block: %s  "
+                         "minimum key block length: %u",
+                         llstr(page, llbuff), MI_MIN_KEY_BLOCK_LENGTH);
+    goto err;
+    /* purecov: end */
+  }
+
   if (!_mi_fetch_keypage(info,keyinfo,page, DFLT_INIT_HITS,buff,0))
   {
     mi_check_print_error(param,"Can't read key from filepos: %s",
@@ -576,9 +629,12 @@ static int chk_index_down(MI_CHECK *para
   if (chk_index(param,info,keyinfo,page,buff,keys,key_checksum,level))
     goto err;
 
-  return 0;
+  DBUG_RETURN(0);
+
+  /* purecov: begin tested */
 err:
-  return 1;
+  DBUG_RETURN(1);
+  /* purecov: end */
 }