Use O_DIRECT to read bitmap files.

A pending patch to the kernel causes bitmap file updates
to not go through the page cache, so O_DIRECT is needed to
ensure that we read current data.

Signed-off-by: Neil Brown <neilb@suse.de>

diff --git a/bitmap.c b/bitmap.c
index b044cd822d57aaedfd4fc79930ea6da1943a585b..33deab11bd829eff6d4ccf63c1c7819601613ee3 100644 (file)
--- a/bitmap.c
+++ b/bitmap.c
@@ -18,8 +18,6 @@
  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#include <sys/types.h>
-#include <sys/stat.h>
 #include "mdadm.h"
 
 #define min(a,b) (((a) < (b)) ? (a) : (b))
@@ -118,10 +116,17 @@ unsigned long long bitmap_bits(unsigned long long array_size,
 
 bitmap_info_t *bitmap_fd_read(int fd, int brief)
 {
+       /* Note: fd might be open O_DIRECT, so we must be
+        * careful to align reads properly
+        */
        unsigned long long total_bits = 0, read_bits = 0, dirty_bits = 0;
        bitmap_info_t *info;
-       char buf[512];
-       int n;
+       char *buf, *unaligned;
+       int n, skip;
+
+       unaligned = malloc(8192*2);
+       buf = (char*) ((unsigned long)unaligned | 8191)+1;
+       n = read(fd, buf, 8192);
 
        info = malloc(sizeof(*info));
        if (info == NULL) {
@@ -135,12 +140,15 @@ bitmap_info_t *bitmap_fd_read(int fd, int brief)
                return NULL;
        }
 
-       if (read(fd, &info->sb, sizeof(info->sb)) != sizeof(info->sb)) {
+       if (n < sizeof(info->sb)) {
                fprintf(stderr, Name ": failed to read superblock of bitmap "
                        "file: %s\n", strerror(errno));
                free(info);
+               free(unaligned);
                return NULL;
        }
+       memcpy(&info->sb, buf, sizeof(info->sb));
+       skip = sizeof(info->sb);
 
        sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
        
@@ -156,18 +164,22 @@ bitmap_info_t *bitmap_fd_read(int fd, int brief)
         */
        total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
 
-       while ((n = read(fd, buf, sizeof(buf))) > 0) {
+       while(read_bits < total_bits) {
                unsigned long long remaining = total_bits - read_bits;
 
-               if (remaining > sizeof(buf) * 8) /* we want the full buffer */
-                       remaining = sizeof(buf) * 8;
-               if (remaining > n * 8) /* the file is truncated */
-                       remaining = n * 8;
-               dirty_bits += count_dirty_bits(buf, remaining);
+               if (n == 0) {
+                       n = read(fd, buf, 8192);
+                       skip = 0;
+                       if (n <= 0)
+                               break;
+               }
+               if (remaining > (n-skip) * 8) /* we want the full buffer */
+                       remaining = (n-skip) * 8;
+
+               dirty_bits += count_dirty_bits(buf+skip, remaining);
 
                read_bits += remaining;
-               if (read_bits >= total_bits) /* we've got what we want */
-                       break;
+               n = 0;
        }
 
        if (read_bits < total_bits) { /* file truncated... */
@@ -189,14 +201,18 @@ bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **st
        struct stat stb;
        struct supertype *st = *stp;
 
-       fd = open(filename, O_RDONLY);
-       if (fd < 0) {
-               fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
-                               filename, strerror(errno));
+       if (stat(filename, &stb) < 0) {
+               fprintf(stderr, Name ": failed to find file %s: %s\n",
+                       filename, strerror(errno));
                return NULL;
        }
-       fstat(fd, &stb);
        if ((S_IFMT & stb.st_mode) == S_IFBLK) {
+               fd = open(filename, O_RDONLY);
+               if (fd < 0) {
+                       fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
+                               filename, strerror(errno));
+                       return NULL;
+               }
                /* block device, so we are probably after an internal bitmap */
                if (!st) st = guess_super(fd);
                if (!st) {
@@ -207,6 +223,13 @@ bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **st
                }
                ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
                *stp = st;
+       } else {
+               fd = open(filename, O_RDONLY|O_DIRECT);
+               if (fd < 0) {
+                       fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
+                               filename, strerror(errno));
+                       return NULL;
+               }
        }
 
        info = bitmap_fd_read(fd, brief);

diff --git a/config.c b/config.c
index bb22b0ebac2d2b4e76821f3dbb4df8b6429b30b6..70b798eb86535c5127f9d205b82ab7bfcfe23b54 100644 (file)
--- a/config.c
+++ b/config.c
@@ -273,7 +273,7 @@ void arrayline(char *line)
        mis.super_minor = UnSet;
        mis.level = UnSet;
        mis.raid_disks = UnSet;
-       mis.spare_disks = UnSet;
+       mis.spare_disks = 0;
        mis.devices = NULL;
        mis.devname = NULL;
        mis.spare_group = NULL;

diff --git a/mdadm.h b/mdadm.h
index 74672f7c683b201f6f1f65c1b20f8b798c4022fb..4ad4f9300ab0bd1d153e466e344d8fd0747d67cf 100644 (file)
--- a/mdadm.h
+++ b/mdadm.h
@@ -27,7 +27,7 @@
  *           Australia
  */
 
-#define        __USE_LARGEFILE64
+#define        _GNU_SOURCE
 #include       <unistd.h>
 #ifndef __dietlibc__
 extern __off64_t lseek64 __P ((int __fd, __off64_t __offset, int __whence));
@@ -292,7 +292,6 @@ struct stat64;
   struct FTW {};
 # define FTW_PHYS 1
 #else
-# define  __USE_XOPEN_EXTENDED
 # include <ftw.h>
 # ifdef __dietlibc__
 #  define FTW_PHYS 1