Commit 936fcddb authored by unknown's avatar unknown
Browse files

Merge pchardin@bk-internal.mysql.com:/home/bk/mysql-5.1 

into  mysql.com:/home/cps/mysql/trees/5.1-team
parents e7d576ce 8c89c0d2

mysys/my_pread.c

+58 −12
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ uint my_pread(File Filedes, byte *Buffer, uint Count, my_off_t offset, 
	      myf MyFlags)

{

  uint readbytes;

  int error;

  int error= 0;

  DBUG_ENTER("my_pread");

  DBUG_PRINT("my",("Fd: %d  Seek: %lu  Buffer: 0x%lx  Count: %u  MyFlags: %d",

		   Filedes, (ulong) offset, Buffer, Count, MyFlags));
@@ -38,17 +38,40 @@ uint my_pread(File Filedes, byte *Buffer, uint Count, my_off_t offset, 
    errno=0;					/* Linux doesn't reset this */

#endif

#ifndef HAVE_PREAD

    off_t old_offset;



    pthread_mutex_lock(&my_file_info[Filedes].mutex);

    readbytes= (uint) -1;

    error= (lseek(Filedes, offset, MY_SEEK_SET) == -1L ||

	    (readbytes = (uint) read(Filedes, Buffer, Count)) != Count);

    /*

      As we cannot change the file pointer, we save the old position,

      before seeking to the given offset

    */



    error= (old_offset= lseek(Filedes, 0L, MY_SEEK_CUR)) == -1L ||

           lseek(Filedes, offset, MY_SEEK_SET) == -1L;



    if (!error)                                 /* Seek was successful */

    {

      if ((readbytes = (uint) read(Filedes, Buffer, Count)) == -1L)

        my_errno= errno;



      /*

        We should seek back, even if read failed. If this fails,

        we will return an error. If read failed as well, we will

        save the errno from read, not from lseek().

      */

      if ((error= (lseek(Filedes, old_offset, MY_SEEK_SET) == -1L)) &&

          readbytes != -1L)

        my_errno= errno;

    }



    pthread_mutex_unlock(&my_file_info[Filedes].mutex);

#else

    error=((readbytes = (uint) pread(Filedes, Buffer, Count, offset)) != Count);

    if ((error= ((readbytes =

                  (uint) pread(Filedes, Buffer, Count, offset)) != Count)))

      my_errno= errno;

#endif

    if (error)

    if (error || readbytes != Count)

    {

      my_errno=errno;

      DBUG_PRINT("warning",("Read only %ld bytes off %ld from %d, errno: %d",

			    readbytes,Count,Filedes,my_errno));

#ifdef THREAD
@@ -89,17 +112,41 @@ uint my_pwrite(int Filedes, const byte *Buffer, uint Count, my_off_t offset, 
  for (;;)

  {

#ifndef HAVE_PREAD

    int error;

    int error= 0;

    off_t old_offset;

    writenbytes= (uint) -1;

    pthread_mutex_lock(&my_file_info[Filedes].mutex);

    error=(lseek(Filedes, offset, MY_SEEK_SET) != -1L &&

	   (writenbytes = (uint) write(Filedes, Buffer, Count)) == Count);



    /*

      As we cannot change the file pointer, we save the old position,

      before seeking to the given offset

    */

    error= ((old_offset= lseek(Filedes, 0L, MY_SEEK_CUR)) == -1L ||

            lseek(Filedes, offset, MY_SEEK_SET) == -1L);



    if (!error)                                 /* Seek was successful */

    {

      if ((writenbytes = (uint) write(Filedes, Buffer, Count)) == -1L)

        my_errno= errno;



      /*

        We should seek back, even if write failed. If this fails,

        we will return an error. If write failed as well, we will

        save the errno from write, not from lseek().

      */

      if ((error= (lseek(Filedes, old_offset, MY_SEEK_SET) == -1L)) &&

          writenbytes != -1L)

        my_errno= errno;

    }

    pthread_mutex_unlock(&my_file_info[Filedes].mutex);

    if (error)



    if (!error && writenbytes == Count)

      break;

#else

    if ((writenbytes = (uint) pwrite(Filedes, Buffer, Count,offset)) == Count)

      break;

    else

      my_errno= errno;

#endif

    if ((int) writenbytes != -1)

    {					/* Safegueard */
@@ -108,7 +155,6 @@ uint my_pwrite(int Filedes, const byte *Buffer, uint Count, my_off_t offset, 
      Count-=writenbytes;

      offset+=writenbytes;

    }

    my_errno=errno;

    DBUG_PRINT("error",("Write only %d bytes",writenbytes));

#ifndef NO_BACKGROUND

#ifdef THREAD