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>
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c4d831e164
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4ccdb95600
59
bitmap.c
59
bitmap.c
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@ -18,8 +18,6 @@
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include "mdadm.h"
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#define min(a,b) (((a) < (b)) ? (a) : (b))
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@ -118,10 +116,17 @@ unsigned long long bitmap_bits(unsigned long long array_size,
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bitmap_info_t *bitmap_fd_read(int fd, int brief)
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{
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/* Note: fd might be open O_DIRECT, so we must be
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* careful to align reads properly
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*/
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unsigned long long total_bits = 0, read_bits = 0, dirty_bits = 0;
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bitmap_info_t *info;
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char buf[512];
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int n;
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char *buf, *unaligned;
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int n, skip;
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unaligned = malloc(8192*2);
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buf = (char*) ((unsigned long)unaligned | 8191)+1;
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n = read(fd, buf, 8192);
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info = malloc(sizeof(*info));
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if (info == NULL) {
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@ -135,12 +140,15 @@ bitmap_info_t *bitmap_fd_read(int fd, int brief)
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return NULL;
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}
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if (read(fd, &info->sb, sizeof(info->sb)) != sizeof(info->sb)) {
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if (n < sizeof(info->sb)) {
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fprintf(stderr, Name ": failed to read superblock of bitmap "
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"file: %s\n", strerror(errno));
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free(info);
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free(unaligned);
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return NULL;
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}
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memcpy(&info->sb, buf, sizeof(info->sb));
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skip = sizeof(info->sb);
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sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
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@ -156,18 +164,22 @@ bitmap_info_t *bitmap_fd_read(int fd, int brief)
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*/
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total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
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while ((n = read(fd, buf, sizeof(buf))) > 0) {
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while(read_bits < total_bits) {
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unsigned long long remaining = total_bits - read_bits;
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if (remaining > sizeof(buf) * 8) /* we want the full buffer */
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remaining = sizeof(buf) * 8;
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if (remaining > n * 8) /* the file is truncated */
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remaining = n * 8;
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dirty_bits += count_dirty_bits(buf, remaining);
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if (n == 0) {
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n = read(fd, buf, 8192);
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skip = 0;
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if (n <= 0)
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break;
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}
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if (remaining > (n-skip) * 8) /* we want the full buffer */
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remaining = (n-skip) * 8;
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dirty_bits += count_dirty_bits(buf+skip, remaining);
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read_bits += remaining;
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if (read_bits >= total_bits) /* we've got what we want */
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break;
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n = 0;
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}
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if (read_bits < total_bits) { /* file truncated... */
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@ -189,14 +201,18 @@ bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **st
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struct stat stb;
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struct supertype *st = *stp;
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fd = open(filename, O_RDONLY);
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if (fd < 0) {
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fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
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filename, strerror(errno));
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if (stat(filename, &stb) < 0) {
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fprintf(stderr, Name ": failed to find file %s: %s\n",
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filename, strerror(errno));
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return NULL;
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}
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fstat(fd, &stb);
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if ((S_IFMT & stb.st_mode) == S_IFBLK) {
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fd = open(filename, O_RDONLY);
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if (fd < 0) {
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fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
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filename, strerror(errno));
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return NULL;
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}
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/* block device, so we are probably after an internal bitmap */
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if (!st) st = guess_super(fd);
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if (!st) {
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@ -207,6 +223,13 @@ bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **st
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}
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ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
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*stp = st;
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} else {
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fd = open(filename, O_RDONLY|O_DIRECT);
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if (fd < 0) {
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fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
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filename, strerror(errno));
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return NULL;
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}
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}
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info = bitmap_fd_read(fd, brief);
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2
config.c
2
config.c
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@ -273,7 +273,7 @@ void arrayline(char *line)
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mis.super_minor = UnSet;
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mis.level = UnSet;
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mis.raid_disks = UnSet;
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mis.spare_disks = UnSet;
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mis.spare_disks = 0;
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mis.devices = NULL;
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mis.devname = NULL;
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mis.spare_group = NULL;
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3
mdadm.h
3
mdadm.h
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@ -27,7 +27,7 @@
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* Australia
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*/
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#define __USE_LARGEFILE64
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#define _GNU_SOURCE
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#include <unistd.h>
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#ifndef __dietlibc__
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extern __off64_t lseek64 __P ((int __fd, __off64_t __offset, int __whence));
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@ -292,7 +292,6 @@ struct stat64;
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struct FTW {};
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# define FTW_PHYS 1
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#else
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# define __USE_XOPEN_EXTENDED
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# include <ftw.h>
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# ifdef __dietlibc__
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# define FTW_PHYS 1
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