Speed up consecutive hostdisk operations on the same device.

* util/hostdisk.c (struct grub_util_biosdisk_data): New structure.
(grub_util_biosdisk_open): Initialise disk->data.
(struct linux_partition_cache): New structure.
(linux_find_partition): Cache partition start positions; these are
expensive to compute on every read and write.
(open_device): Cache open file descriptor in disk->data, so that we
don't have to reopen it and flush the buffer cache for consecutive
operations on the same device.
(grub_util_biosdisk_close): New function.
(grub_util_biosdisk_dev): Set `close' member.

* conf/common.rmk (grub_probe_SOURCES): Add kern/list.c.
* conf/i386-efi.rmk (grub_setup_SOURCES): Likewise.
* conf/i386-pc.rmk (grub_setup_SOURCES): Likewise.
* conf/sparc64-ieee1275.rmk (grub_setup_SOURCES): Likewise.
* conf/x86_64-efi.rmk (grub_setup_SOURCES): Likewise.

ChangeLog

@@ -1,3 +1,24 @@
+2010-03-14  Colin Watson  <cjwatson@ubuntu.com>
+
+	Speed up consecutive hostdisk operations on the same device.
+
+	* util/hostdisk.c (struct grub_util_biosdisk_data): New structure.
+	(grub_util_biosdisk_open): Initialise disk->data.
+	(struct linux_partition_cache): New structure.
+	(linux_find_partition): Cache partition start positions; these are
+	expensive to compute on every read and write.
+	(open_device): Cache open file descriptor in disk->data, so that we
+	don't have to reopen it and flush the buffer cache for consecutive
+	operations on the same device.
+	(grub_util_biosdisk_close): New function.
+	(grub_util_biosdisk_dev): Set `close' member.
+
+	* conf/common.rmk (grub_probe_SOURCES): Add kern/list.c.
+	* conf/i386-efi.rmk (grub_setup_SOURCES): Likewise.
+	* conf/i386-pc.rmk (grub_setup_SOURCES): Likewise.
+	* conf/sparc64-ieee1275.rmk (grub_setup_SOURCES): Likewise.
+	* conf/x86_64-efi.rmk (grub_setup_SOURCES): Likewise.
+
 2010-03-14  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	Compile parts of grub-emu as modules.

conf/common.rmk

@@ -24,7 +24,7 @@ util/grub-probe.c_DEPENDENCIES = grub_probe_init.h
 grub_probe_SOURCES = gnulib/progname.c util/grub-probe.c	\
 	util/hostdisk.c	util/misc.c util/getroot.c		\
 	kern/device.c kern/disk.c kern/err.c kern/misc.c	\
-	kern/parser.c kern/partition.c kern/file.c		\
+	kern/parser.c kern/partition.c kern/file.c kern/list.c	\
 	\
 	fs/affs.c fs/cpio.c fs/fat.c fs/ext2.c fs/hfs.c		\
 	fs/hfsplus.c fs/iso9660.c fs/udf.c fs/jfs.c fs/minix.c	\

conf/i386-efi.rmk

@@ -21,7 +21,7 @@ util/i386/efi/grub-mkimage.c_DEPENDENCIES = Makefile
 #	kern/err.c kern/misc.c fs/fat.c fs/ext2.c fs/xfs.c fs/affs.c	\
 #	fs/sfs.c kern/parser.c kern/partition.c partmap/msdos.c		\
 #	fs/ufs.c fs/ufs2.c fs/minix.c fs/hfs.c fs/jfs.c fs/hfsplus.c kern/file.c	\
-#	kern/fs.c kern/env.c fs/fshelp.c
+#	kern/fs.c kern/env.c kern/list.c fs/fshelp.c
 
 # Scripts.
 sbin_SCRIPTS = grub-install

conf/i386-pc.rmk

@@ -96,7 +96,8 @@ grub_setup_SOURCES = gnulib/progname.c \
 	util/i386/pc/grub-setup.c util/hostdisk.c	\
 	util/misc.c util/getroot.c kern/device.c kern/disk.c	\
 	kern/err.c kern/misc.c kern/parser.c kern/partition.c	\
-	kern/file.c kern/fs.c kern/env.c fs/fshelp.c		\
+	kern/file.c kern/fs.c kern/env.c kern/list.c		\
+	fs/fshelp.c						\
 	\
 	fs/affs.c fs/cpio.c fs/ext2.c fs/fat.c fs/hfs.c		\
 	fs/hfsplus.c fs/iso9660.c fs/udf.c fs/jfs.c fs/minix.c	\

conf/sparc64-ieee1275.rmk

@@ -70,7 +70,8 @@ util/sparc64/ieee1275/grub-setup.c_DEPENDENCIES = grub_setup_init.h
 grub_setup_SOURCES = util/sparc64/ieee1275/grub-setup.c util/hostdisk.c	\
 	util/misc.c util/getroot.c kern/device.c kern/disk.c	\
 	kern/err.c kern/misc.c kern/parser.c kern/partition.c	\
-	kern/file.c kern/fs.c kern/env.c fs/fshelp.c		\
+	kern/file.c kern/fs.c kern/env.c kern/list.c		\
+	fs/fshelp.c						\
 	\
 	fs/affs.c fs/cpio.c fs/ext2.c fs/fat.c fs/hfs.c		\
 	fs/hfsplus.c fs/iso9660.c fs/udf.c fs/jfs.c fs/minix.c	\

conf/x86_64-efi.rmk

@@ -20,7 +20,7 @@ grub_mkimage_SOURCES = gnulib/progname.c util/i386/efi/grub-mkimage.c \
 #	kern/err.c kern/misc.c fs/fat.c fs/ext2.c fs/xfs.c fs/affs.c	\
 #	fs/sfs.c kern/parser.c kern/partition.c partmap/msdos.c		\
 #	fs/ufs.c fs/ufs2.c fs/minix.c fs/hfs.c fs/jfs.c fs/hfsplus.c kern/file.c	\
-#	kern/fs.c kern/env.c fs/fshelp.c
+#	kern/fs.c kern/env.c kern/list.c fs/fshelp.c
 
 # Scripts.
 sbin_SCRIPTS = grub-install

util/hostdisk.c

@@ -26,6 +26,7 @@
 #include <grub/util/hostdisk.h>
 #include <grub/misc.h>
 #include <grub/i18n.h>
+#include <grub/list.h>
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -103,6 +104,13 @@ struct
   char *device;
 } map[256];
 
+struct grub_util_biosdisk_data
+{
+  char *dev;
+  int access_mode;
+  int fd;
+};
+
 #ifdef __linux__
 /* Check if we have devfs support.  */
 static int
@@ -165,6 +173,7 @@ grub_util_biosdisk_open (const char *name, grub_disk_t disk)
 {
   int drive;
   struct stat st;
+  struct grub_util_biosdisk_data *data;
 
   drive = find_grub_drive (name);
   if (drive < 0)
@@ -173,6 +182,10 @@ grub_util_biosdisk_open (const char *name, grub_disk_t disk)
 
   disk->has_partitions = 1;
   disk->id = drive;
+  disk->data = data = xmalloc (sizeof (struct grub_util_biosdisk_data));
+  data->dev = NULL;
+  data->access_mode = 0;
+  data->fd = -1;
 
   /* Get the size.  */
 #if defined(__MINGW32__)
@@ -254,6 +267,17 @@ grub_util_biosdisk_open (const char *name, grub_disk_t disk)
 }
 
 #ifdef __linux__
+/* Cache of partition start sectors for each disk.  */
+struct linux_partition_cache
+{
+  struct linux_partition_cache *next;
+  char *dev;
+  unsigned long start;
+  int partno;
+};
+
+struct linux_partition_cache *linux_partition_cache_list;
+
 static int
 linux_find_partition (char *dev, unsigned long sector)
 {
@@ -262,6 +286,7 @@ linux_find_partition (char *dev, unsigned long sector)
   char *p;
   int i;
   char real_dev[PATH_MAX];
+  struct linux_partition_cache *cache;
 
   strcpy(real_dev, dev);
 
@@ -281,6 +306,16 @@ linux_find_partition (char *dev, unsigned long sector)
       format = "%d";
     }
 
+  for (cache = linux_partition_cache_list; cache; cache = cache->next)
+    {
+      if (strcmp (cache->dev, dev) == 0 && cache->start == sector)
+	{
+	  sprintf (p, format, cache->partno);
+	  strcpy (dev, real_dev);
+	  return 1;
+	}
+    }
+
   for (i = 1; i < 10000; i++)
     {
       int fd;
@@ -301,6 +336,15 @@ linux_find_partition (char *dev, unsigned long sector)
 
       if (hdg.start == sector)
 	{
+	  struct linux_partition_cache *new_cache_item;
+
+	  new_cache_item = xmalloc (sizeof *new_cache_item);
+	  new_cache_item->dev = xstrdup (dev);
+	  new_cache_item->start = hdg.start;
+	  new_cache_item->partno = i;
+	  grub_list_push (GRUB_AS_LIST_P (&linux_partition_cache_list),
+			  GRUB_AS_LIST (new_cache_item));
+
 	  strcpy (dev, real_dev);
 	  return 1;
 	}
@@ -314,6 +358,7 @@ static int
 open_device (const grub_disk_t disk, grub_disk_addr_t sector, int flags)
 {
   int fd;
+  struct grub_util_biosdisk_data *data = disk->data;
 
 #ifdef O_LARGEFILE
   flags |= O_LARGEFILE;
@@ -340,18 +385,35 @@ open_device (const grub_disk_t disk, grub_disk_addr_t sector, int flags)
 	&& strncmp (map[disk->id].device, "/dev/", 5) == 0)
       is_partition = linux_find_partition (dev, disk->partition->start);
 
-    /* Open the partition.  */
+    if (data->dev && strcmp (data->dev, dev) == 0 &&
-    grub_dprintf ("hostdisk", "opening the device `%s' in open_device()\n", dev);
+	data->access_mode == (flags & O_ACCMODE))
-    fd = open (dev, flags);
-    if (fd < 0)
       {
-	grub_error (GRUB_ERR_BAD_DEVICE, "cannot open `%s'", dev);
+	grub_dprintf ("hostdisk", "reusing open device `%s'\n", dev);
-	return -1;
+	fd = data->fd;
       }
+    else
+      {
+	free (data->dev);
+	if (data->fd != -1)
+	  close (data->fd);
 
-    /* Flush the buffer cache to the physical disk.
+	/* Open the partition.  */
-       XXX: This also empties the buffer cache.  */
+	grub_dprintf ("hostdisk", "opening the device `%s' in open_device()\n", dev);
-    ioctl (fd, BLKFLSBUF, 0);
+	fd = open (dev, flags);
+	if (fd < 0)
+	  {
+	    grub_error (GRUB_ERR_BAD_DEVICE, "cannot open `%s'", dev);
+	    return -1;
+	  }
+
+	/* Flush the buffer cache to the physical disk.
+	   XXX: This also empties the buffer cache.  */
+	ioctl (fd, BLKFLSBUF, 0);
+
+	data->dev = xstrdup (dev);
+	data->access_mode = (flags & O_ACCMODE);
+	data->fd = fd;
+      }
 
     if (is_partition)
       sector -= disk->partition->start;
@@ -375,7 +437,26 @@ open_device (const grub_disk_t disk, grub_disk_addr_t sector, int flags)
     }
 #endif
 
-  fd = open (map[disk->id].device, flags);
+  if (data->dev && strcmp (data->dev, map[disk->id].device) == 0 &&
+      data->access_mode == (flags & O_ACCMODE))
+    {
+      grub_dprintf ("hostdisk", "reusing open device `%s'\n", data->dev);
+      fd = data->fd;
+    }
+  else
+    {
+      free (data->dev);
+      if (data->fd != -1)
+	close (data->fd);
+
+      fd = open (map[disk->id].device, flags);
+      if (fd >= 0)
+	{
+	  data->dev = xstrdup (map[disk->id].device);
+	  data->access_mode = (flags & O_ACCMODE);
+	  data->fd = fd;
+	}
+    }
 
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
   if (! (sysctl_oldflags & 0x10)
@@ -535,7 +616,6 @@ grub_util_biosdisk_read (grub_disk_t disk, grub_disk_addr_t sector,
       != (ssize_t) (size << GRUB_DISK_SECTOR_BITS))
     grub_error (GRUB_ERR_READ_ERROR, "cannot read from `%s'", map[disk->id].device);
 
-  close (fd);
   return grub_errno;
 }
 
@@ -570,17 +650,27 @@ grub_util_biosdisk_write (grub_disk_t disk, grub_disk_addr_t sector,
       != (ssize_t) (size << GRUB_DISK_SECTOR_BITS))
     grub_error (GRUB_ERR_WRITE_ERROR, "cannot write to `%s'", map[disk->id].device);
 
-  close (fd);
   return grub_errno;
 }
 
+static void
+grub_util_biosdisk_close (struct grub_disk *disk)
+{
+  struct grub_util_biosdisk_data *data = disk->data;
+
+  free (data->dev);
+  if (data->fd != -1)
+    close (data->fd);
+  free (data);
+}
+
 static struct grub_disk_dev grub_util_biosdisk_dev =
   {
     .name = "biosdisk",
     .id = GRUB_DISK_DEVICE_BIOSDISK_ID,
     .iterate = grub_util_biosdisk_iterate,
     .open = grub_util_biosdisk_open,
-    .close = 0,
+    .close = grub_util_biosdisk_close,
     .read = grub_util_biosdisk_read,
     .write = grub_util_biosdisk_write,
     .next = 0