Make atomic writes general

- Atomic writes are enabled by default
- Automatically detect if device supports atomic write and use it if
  atomic writes are enabled
- Remove ATOMIC WRITE options from CREATE TABLE
  - Atomic write is a device option, not a table options as the table may
    crash if the media changes
- Add support for SHANNON SSD cards

1 files changed, 333 insertions, 0 deletions

diff --git a/mysys/my_atomic_writes.c b/mysys/my_atomic_writes.c
new file mode 100644
index 00000000000..0b54a207713
--- /dev/null
+++ b/mysys/my_atomic_writes.c
@@ -0,0 +1,333 @@
+/* Copyright (c) 2016, MariaDB Corporation
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
+
+#include "mysys_priv.h"
+
+my_bool my_may_have_atomic_write= 0;
+
+#ifdef __linux__
+
+my_bool has_shannon_atomic_write= 0, has_fusion_io_atomic_write= 0;
+
+#include <sys/ioctl.h>
+
+
+/***********************************************************************
+  FUSION_IO
+************************************************************************/
+
+/** FusionIO atomic write control info */
+#define DFS_IOCTL_ATOMIC_WRITE_SET      _IOW(0x95, 2, uint)
+
+
+/**
+   Check if the system has a funsion_io card
+   @return TRUE   Card exists
+*/
+
+static my_bool test_if_fusion_io_card_exists()
+{
+  /* Fusion card requires fallocate to exists */
+#ifndef HAVE_POSIX_FALLOCATE
+  return 0;
+#else
+  return (access("/dev/fcta", F_OK)) == 0;
+#endif
+}
+
+
+/**
+   Check if a file is on a Fusion_IO device and that it supports atomic_write
+   @param[in] file              OS file handle
+   @param[in] page_size         page size
+   @return TRUE                 Atomic write supported
+*/
+
+static my_bool fusion_io_has_atomic_write(File file, int page_size)
+{
+  int atomic= 1;
+  if (page_size <= 32768 &&
+      ioctl(file, DFS_IOCTL_ATOMIC_WRITE_SET, &atomic) != -1)
+    return(TRUE);
+  return(FALSE);
+}
+
+
+/***********************************************************************
+  SHANNON
+************************************************************************/
+
+#define SHANNON_IOMAGIC 'x'
+#define SHANNON_IOCQATOMIC_SIZE _IO(SHANNON_IOMAGIC, 22)
+
+#define SHANNON_MAX_DEVICES 32
+#define SHANNON_NO_ATOMIC_SIZE_YET -2
+
+struct shannon_dev
+{
+  char dev_name[32];
+  dev_t st_dev;
+  int atomic_size;
+};
+
+
+static struct shannon_dev shannon_devices[SHANNON_MAX_DEVICES+1];
+
+/**
+   Check if the system has a Shannon card
+   If card exists, record device numbers to allow us to later check if
+   a given file is on this device.
+   @return TRUE   Card exists
+*/
+
+static my_bool test_if_shannon_card_exists()
+{
+  uint shannon_found_devices= 0;
+  char dev_part;
+  uint dev_no;
+
+  if (access("/dev/scta", F_OK) < 0)
+    return 0;
+
+  /*
+    The Shannon devices are /dev/dfX, where X can be from a-z.
+    We have to check all of them as some may be missing if the user
+    removed one with the U.2 interface.
+  */
+
+  for (dev_part= 'a' ; dev_part < 'z' ; dev_part++)
+  {
+    char path[32];
+    struct stat stat_buff;
+
+    sprintf(path, "/dev/df%c", dev_part);
+#ifdef TEST_SHANNON
+    if (lstat(path, &stat_buff) < 0)
+    {
+      printf("%s(): lstat failed.\n", __func__);
+      break;
+    }
+#endif
+    shannon_devices[shannon_found_devices].st_dev= stat_buff.st_rdev;
+    sprintf(shannon_devices[shannon_found_devices].dev_name, "/dev/sct%c",
+            dev_part);
+
+#ifdef TEST_SHANNON
+    printf("%s(): i=%d, stat_buff.st_dev=0x%lx, stat_buff.st_rdev=0x%lx, st_rdev=0x%lx, dev_name=%s\n",
+           __func__,
+           shannon_found_devices,
+           (ulong) stat_buff.st_dev,
+           (ulong) stat_buff.st_rdev,
+           (ulong) shannon_devices[shannon_found_devices].st_dev,
+           shannon_devices[shannon_found_devices].dev_name);
+#endif
+
+    /*
+      The atomic size will be checked on first access. This is needed
+      as a normal user can't open the /dev/scta file
+    */
+    shannon_devices[shannon_found_devices].atomic_size=
+      SHANNON_NO_ATOMIC_SIZE_YET;
+    if (++shannon_found_devices== SHANNON_MAX_DEVICES)
+      goto end;
+
+    for (dev_no= 1 ; dev_no < 9 ; dev_no++)
+    {
+      sprintf(path, "/dev/df%c%d", dev_part, dev_no);
+      if (lstat(path, &stat_buff) < 0)
+        break;
+
+      shannon_devices[shannon_found_devices].st_dev= stat_buff.st_rdev;
+      sprintf(shannon_devices[shannon_found_devices].dev_name, "/dev/sct%c%d",
+              dev_part, dev_no);
+
+#ifdef TEST_SHANNON
+      printf("%s(): i=%d, st_dev=0x%lx, st_rdev=0x%lx, dev_name=%s\n",
+             __func__,
+             shannon_found_devices,
+             (ulong) stat_buff.st_dev,
+             (ulong) shannon_devices[shannon_found_devices].st_dev,
+             shannon_devices[shannon_found_devices].dev_name);
+#endif
+
+      /*
+        The atomic size will be checked on first access. This is needed
+        as a normal user can't open the /dev/scta file
+      */
+      shannon_devices[shannon_found_devices].atomic_size=
+        SHANNON_NO_ATOMIC_SIZE_YET;
+      if (++shannon_found_devices == SHANNON_MAX_DEVICES)
+        goto end;
+    }
+  }
+end:
+  shannon_devices[shannon_found_devices].st_dev= 0;
+  return shannon_found_devices > 0;
+}
+
+
+static my_bool shannon_dev_has_atomic_write(struct shannon_dev *dev,
+                                            int page_size)
+{
+#ifdef TEST_SHANNON
+  printf("%s: enter: page_size=%d, atomic_size=%d, dev_name=%s\n",
+          __func__,
+          page_size,
+          dev->atomic_size,
+          dev->dev_name);
+#endif
+  if (dev->atomic_size == SHANNON_NO_ATOMIC_SIZE_YET)
+  {
+    int fd= open(dev->dev_name, 0);
+    if (fd < 0)
+    {
+      perror("open() failed!");
+      dev->atomic_size= 0;                      /* Don't try again */
+      return FALSE;
+    }
+     dev->atomic_size= ioctl(fd, SHANNON_IOCQATOMIC_SIZE);
+     close(fd);
+  }
+
+#ifdef TEST_SHANNON
+  printf("%s: exit: page_size=%d, atomic_size=%d, dev_name=%s\n",
+          __func__,
+          page_size,
+          dev->atomic_size,
+          dev->dev_name);
+#endif
+  return (page_size <= dev->atomic_size);
+}
+
+
+/**
+   Check if a file is on a Shannon device and that it supports atomic_write
+   @param[in] file              OS file handle
+   @param[in] page_size         page size
+   @return TRUE                 Atomic write supported
+
+   @notes
+   This is called only at first open of a file.  In this case it's doesn't
+   matter so much that we loop over all cards.
+   We update the atomic size on first access.
+*/
+
+static my_bool shannon_has_atomic_write(File file, int page_size)
+{
+  struct shannon_dev *dev;
+  struct stat stat_buff;
+
+  if (fstat(file, &stat_buff) < 0)
+  {
+#ifdef TEST_SHANNON
+    printf("%s(): fstat failed\n", __func__);
+#endif
+    return 0;
+  }
+
+#ifdef TEST_SHANNON
+  printf("%s(): st_dev=0x%lx, st_rdev=0x%lx\n", __func__,
+         (ulong) stat_buff.st_dev, (ulong) stat_buff.st_rdev);
+#endif
+
+  for (dev= shannon_devices ; dev->st_dev; dev++)
+  {
+#ifdef TEST_SHANNON
+    printf("%s(): st_rdev=0x%lx\n", __func__, (ulong) dev->st_dev);
+#endif
+    if (stat_buff.st_dev == dev->st_dev)
+      return shannon_dev_has_atomic_write(dev, page_size);
+ }
+ return 0;
+}
+
+
+/***********************************************************************
+  Generic atomic write code
+************************************************************************/
+
+/*
+  Initalize automic write sub systems.
+  Checks if we have any devices that supports atomic write
+*/
+
+void my_init_atomic_write(void)
+{
+  if ((has_shannon_atomic_write=   test_if_shannon_card_exists()) ||
+      (has_fusion_io_atomic_write= test_if_fusion_io_card_exists()))
+  my_may_have_atomic_write= 1;
+#ifdef TEST_SHANNON
+  printf("%s(): has_shannon_atomic_write=%d, my_may_have_atomic_write=%d\n",
+          __func__,
+          has_shannon_atomic_write,
+          my_may_have_atomic_write);
+#endif
+}
+
+
+/**
+  Check if a file supports atomic write
+
+  @return FALSE   No atomic write support
+          TRUE    File supports atomic write
+*/
+
+my_bool my_test_if_atomic_write(File handle, int page_size)
+{
+#ifdef TEST_SHANNON
+  printf("%s(): has_shannon_atomic_write=%d, my_may_have_atomic_write=%d\n",
+          __func__,
+          has_shannon_atomic_write,
+          my_may_have_atomic_write);
+#endif
+  if (!my_may_have_atomic_write)
+    return 0;
+  if (has_shannon_atomic_write &&
+      shannon_has_atomic_write(handle, page_size))
+    return 1;
+
+  if (has_fusion_io_atomic_write &&
+      fusion_io_has_atomic_write(handle, page_size))
+    return 1;
+
+  return 0;
+}
+
+#ifdef TEST_SHANNON
+int main()
+{
+  int fd, ret;
+
+  my_init_atomic_write();
+  fd= open("/u01/1.file", O_RDWR);
+  ret= my_test_if_atomic_write(fd, 4096);
+  if (ret)
+    printf("support atomic_write\n");
+  else
+    printf("do not support atomic_write\n");
+  close(fd);
+  return 0;
+}
+#endif
+
+
+#else /* __linux__ */
+
+/* Dummy functions to provide the interfaces for other systems */
+
+void my_init_atomic_write(void)
+{
+}
+#endif /* __linux__ */