bk commit into 4.1 tree (thek:1.2543) BUG#22828

[kpettersson]

Below is the list of changes that have just been committed into a local
4.1 repository of thek. When thek does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
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see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet@stripped, 2006-10-24 20:09:26+02:00, thek@stripped +4 -0
  Bug#22828 _my_b_read() ignores return values for my_seek() calls
  - Because my_seek actually is capable of returning an error code we should
    exploit that in the best possible way.
  - There might be kernel errors or other errors we can't predict and capturing
    the return value of all system calls gives us better understanding of
    possible errors.

  mysys/mf_iocache.c@stripped, 2006-10-24 20:09:24+02:00, thek@stripped +46 -10
    - Added check on rturn value for my_seek
    - Added comments

  mysys/my_chsize.c@stripped, 2006-10-24 20:09:24+02:00, thek@stripped +5 -1
    - Added check on rturn value for my_seek
    - Added comments

  mysys/my_lock.c@stripped, 2006-10-24 20:09:24+02:00, thek@stripped +23 -6
    - Added check on rturn value for my_seek
    - Added comments

  mysys/my_seek.c@stripped, 2006-10-24 20:09:24+02:00, thek@stripped +24 -2
    - Added comments

# 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:	thek
# Host:	kpdesk.mysql.com
# Root:	/home/thek/dev/bug22828/my41-bug22828

--- 1.48/mysys/mf_iocache.c	2006-10-24 20:09:30 +02:00
+++ 1.49/mysys/mf_iocache.c	2006-10-24 20:09:30 +02:00
@@ -440,11 +440,23 @@ int _my_b_read(register IO_CACHE *info, 
 
   /* pos_in_file always point on where info->buffer was read */
   pos_in_file=info->pos_in_file+(uint) (info->read_end - info->buffer);
+
+  /* 
+    Check the seek_not_done trigger. If this is true
+    our file has been touched and we need to do a seek.
+    Capture any error while we seek and send it to the
+    caller as error code 1.
+  */
   if (info->seek_not_done)
-  {					/* File touched, do seek */
-    VOID(my_seek(info->file,pos_in_file,MY_SEEK_SET,MYF(0)));
+  {
+    if (my_seek(info->file,pos_in_file,MY_SEEK_SET,MYF(0) == MY_FILEPOS_ERROR )
+	DBUG_RETURN(1);
+    /*
+      Seek is done; reet the trigger
+    */
     info->seek_not_done=0;
   }
+
   diff_length=(uint) (pos_in_file & (IO_SIZE-1));
   if (Count >= (uint) (IO_SIZE+(IO_SIZE-diff_length)))
   {					/* Fill first intern buffer */
@@ -633,8 +645,16 @@ int _my_b_read_r(register IO_CACHE *info
     if (lock_io_cache(info, pos_in_file))
     {
       info->share->active=info;
-      if (info->seek_not_done)             /* File touched, do seek */
-        VOID(my_seek(info->file,pos_in_file,MY_SEEK_SET,MYF(0)));
+      /*
+        Check if the seek_not_done trigger is set.
+        Capture any error while seeking in the file
+        and return error code 1.
+      */
+      if (info->seek_not_done)
+      {
+        if( my_seek(info->file,pos_in_file,MY_SEEK_SET,MYF(0)) == MY_FILEPOS_ERROR )
+          DBUG_RETURN(1);
+      }
       len=(int)my_read(info->file,info->buffer, length, info->myflags);
       info->read_end=info->buffer + (len == -1 ? 0 : len);
       info->error=(len == (int)length ? 0 : len);
@@ -668,11 +688,16 @@ int _my_b_read_r(register IO_CACHE *info
 
 
 /*
-  Do sequential read from the SEQ_READ_APPEND cache
-  we do this in three stages:
+  Do sequential read from the SEQ_READ_APPEND cache.
+  
+  We do this in three stages:
    - first read from info->buffer
    - then if there are still data to read, try the file descriptor
    - afterwards, if there are still data to read, try append buffer
+
+  RETURNS
+    0  Success
+    1  Failed to read
 */
 
 int _my_b_seq_read(register IO_CACHE *info, byte *Buffer, uint Count)
@@ -700,7 +725,8 @@ int _my_b_seq_read(register IO_CACHE *in
     With read-append cache we must always do a seek before we read,
     because the write could have moved the file pointer astray
   */
-  VOID(my_seek(info->file,pos_in_file,MY_SEEK_SET,MYF(0)));
+  if( my_seek(info->file,pos_in_file,MY_SEEK_SET,MYF(0)) == MY_FILEPOS_ERROR )
+	DBUG_RETURN(1);
   info->seek_not_done=0;
 
   diff_length=(uint) (pos_in_file & (IO_SIZE-1));
@@ -906,7 +932,10 @@ int _my_b_async_read(register IO_CACHE *
       info->error=(int) (read_length+left_length);
       return 1;
     }
-    VOID(my_seek(info->file,next_pos_in_file,MY_SEEK_SET,MYF(0)));
+    
+    if( my_seek(info->file,next_pos_in_file,MY_SEEK_SET,MYF(0)) == MY_FILEPOS_ERROR )
+      DBUG_RETURN(1);
+
     read_length=IO_SIZE*2- (uint) (next_pos_in_file & (IO_SIZE-1));
     if (Count < read_length)
     {					/* Small block, read to cache */
@@ -999,7 +1028,13 @@ int _my_b_get(IO_CACHE *info)
   return (int) (uchar) buff;
 }
 
-	/* Returns != 0 if error on write */
+/* 
+   Write a byte buffer to disk
+
+   Returns 
+    1 On error on write
+    0 On success
+*/
 
 int _my_b_write(register IO_CACHE *info, const byte *Buffer, uint Count)
 {
@@ -1023,7 +1058,8 @@ int _my_b_write(register IO_CACHE *info,
     length=Count & (uint) ~(IO_SIZE-1);
     if (info->seek_not_done)
     {					/* File touched, do seek */
-      VOID(my_seek(info->file,info->pos_in_file,MY_SEEK_SET,MYF(0)));
+      if( my_seek(info->file,info->pos_in_file,MY_SEEK_SET,MYF(0)) )
+        DBUG_RETURN(1);
       info->seek_not_done=0;
     }
     if (my_write(info->file,Buffer,(uint) length,info->myflags | MY_NABP))

--- 1.15/mysys/my_chsize.c	2006-10-24 20:09:30 +02:00
+++ 1.16/mysys/my_chsize.c	2006-10-24 20:09:30 +02:00
@@ -88,7 +88,11 @@ int my_chsize(File fd, my_off_t newlengt
       Fill space between requested length and true length with 'filler'
       We should never come here on any modern machine
     */
-    VOID(my_seek(fd, newlength, MY_SEEK_SET, MYF(MY_WME+MY_FAE)));
+    if( my_seek(fd, newlength, MY_SEEK_SET, MYF(MY_WME+MY_FAE)) == MY_FILEPOS_ERROR )
+    {
+      my_errno= errno= EINVAL;
+      goto err;
+    }
     swap_variables(my_off_t, newlength, oldsize);
   }
 #endif

--- 1.12/mysys/my_lock.c	2006-10-24 20:09:30 +02:00
+++ 1.13/mysys/my_lock.c	2006-10-24 20:09:30 +02:00
@@ -35,7 +35,13 @@
 #include <nks/fsio.h>
 #endif
 
-	/* Lock a part of a file */
+/* 
+  Lock a part of a file 
+
+  RETURN VALUE
+    0   Success
+    -1  An error has occured.
+*/
 
 int my_lock(File fd, int locktype, my_off_t start, my_off_t length,
 	    myf MyFlags)
@@ -106,9 +112,15 @@ int my_lock(File fd, int locktype, my_of
   {
     my_bool error;
     pthread_mutex_lock(&my_file_info[fd].mutex);
-    if (MyFlags & MY_SEEK_NOT_DONE)
-      VOID(my_seek(fd,start,MY_SEEK_SET,MYF(MyFlags & ~MY_SEEK_NOT_DONE)));
-    error= locking(fd,locktype,(ulong) length) && errno != EINVAL;
+    if (MyFlags & MY_SEEK_NOT_DONE) 
+    {
+      if( my_seek(fd,start,MY_SEEK_SET,MYF(MyFlags & ~MY_SEEK_NOT_DONE)) ==
MY_FILEPOS_ERROR ) {
+        error= true;
+        errno= EINVAL;
+      }
+    }
+    if( !error )
+      error= locking(fd,locktype,(ulong) length) && errno != EINVAL;
     pthread_mutex_unlock(&my_file_info[fd].mutex);
     if (!error)
       DBUG_RETURN(0);
@@ -144,8 +156,13 @@ int my_lock(File fd, int locktype, my_of
       DBUG_RETURN(0);
   }
 #else
-  if (MyFlags & MY_SEEK_NOT_DONE)
-    VOID(my_seek(fd,start,MY_SEEK_SET,MYF(MyFlags & ~MY_SEEK_NOT_DONE)));
+  if (MyFlags & MY_SEEK_NOT_DONE) 
+  {
+    if( my_seek(fd,start,MY_SEEK_SET,MYF(MyFlags & ~MY_SEEK_NOT_DONE)) ==
MY_FILEPOS_ERROR ) {
+      error= true;
+      errno= EINVAL;
+    }
+  }
   if (lockf(fd,locktype,length) != -1)
     DBUG_RETURN(0);
 #endif /* HAVE_FCNTL */

--- 1.11/mysys/my_seek.c	2006-10-24 20:09:30 +02:00
+++ 1.12/mysys/my_seek.c	2006-10-24 20:09:30 +02:00
@@ -16,8 +16,30 @@
 
 #include "mysys_priv.h"
 
-	/* Seek to position in file */
-	/*ARGSUSED*/
+/* 
+  Seek to a position in a file.
+
+  ARGUMENTS
+  File fd          The file descriptor
+  my_off_t pos     The expected position (absolute or relative)
+  int whence       A direction parameter and one of 
+                   {SEEK_SET, SEEK_CUR, SEEK_END}
+  myf MyFlags      Not used.
+
+  DESCRIPTION
+    The my_seek  function  is a wrapper around the system call lseek and
+    repositions  the  offset of the file descriptor fd to the argument 
+    offset according to the directive whence as follows:
+      SEEK_SET    The offset is set to offset bytes.
+      SEEK_CUR    The offset is set to its current location plus offset bytes
+      SEEK_END    The offset is set to the size of the file plus offset bytes
+
+  
+  RETURN VALUE
+    my_off_t newpos  - The new position in the file.
+    MY_FILEPOS_ERROR - An error was encountered while performing 
+                     the seek.     
+*/
 
 my_off_t my_seek(File fd, my_off_t pos, int whence,
 		 myf MyFlags __attribute__((unused)))