Commit 097426f6 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds

[PATCH] md: fix possible problem in raid1/raid10 error overwriting

The code to overwrite/reread for addressing read errors in raid1/raid10
currently assumes that the read will not alter the buffer which could be used
to write to the next device.  This is not a safe assumption to make.

So we split the loops into a overwrite loop and a separate re-read loop, so
that the writing is complete before reading is attempted.

Cc: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 2604b703
......@@ -1253,6 +1253,7 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
} while (!success && d != r1_bio->read_disk);
if (success) {
int start = d;
/* write it back and re-read */
set_bit(R1BIO_Uptodate, &r1_bio->state);
while (d != r1_bio->read_disk) {
......@@ -1266,14 +1267,23 @@ static void sync_request_write(mddev_t *mddev, r1bio_t *r1_bio)
sect + rdev->data_offset,
s<<9,
bio->bi_io_vec[idx].bv_page,
WRITE) == 0 ||
sync_page_io(rdev->bdev,
WRITE) == 0)
md_error(mddev, rdev);
}
d = start;
while (d != r1_bio->read_disk) {
if (d == 0)
d = conf->raid_disks;
d--;
if (r1_bio->bios[d]->bi_end_io != end_sync_read)
continue;
rdev = conf->mirrors[d].rdev;
if (sync_page_io(rdev->bdev,
sect + rdev->data_offset,
s<<9,
bio->bi_io_vec[idx].bv_page,
READ) == 0) {
READ) == 0)
md_error(mddev, rdev);
}
}
} else {
char b[BDEVNAME_SIZE];
......@@ -1445,6 +1455,7 @@ static void raid1d(mddev_t *mddev)
if (success) {
/* write it back and re-read */
int start = d;
while (d != r1_bio->read_disk) {
if (d==0)
d = conf->raid_disks;
......@@ -1454,13 +1465,24 @@ static void raid1d(mddev_t *mddev)
test_bit(In_sync, &rdev->flags)) {
if (sync_page_io(rdev->bdev,
sect + rdev->data_offset,
s<<9, conf->tmppage, WRITE) == 0 ||
sync_page_io(rdev->bdev,
s<<9, conf->tmppage, WRITE) == 0)
/* Well, this device is dead */
md_error(mddev, rdev);
}
}
d = start;
while (d != r1_bio->read_disk) {
if (d==0)
d = conf->raid_disks;
d--;
rdev = conf->mirrors[d].rdev;
if (rdev &&
test_bit(In_sync, &rdev->flags)) {
if (sync_page_io(rdev->bdev,
sect + rdev->data_offset,
s<<9, conf->tmppage, READ) == 0) {
s<<9, conf->tmppage, READ) == 0)
/* Well, this device is dead */
md_error(mddev, rdev);
}
}
}
} else {
......
......@@ -1421,6 +1421,7 @@ static void raid10d(mddev_t *mddev)
} while (!success && sl != r10_bio->read_slot);
if (success) {
int start = sl;
/* write it back and re-read */
while (sl != r10_bio->read_slot) {
int d;
......@@ -1434,14 +1435,27 @@ static void raid10d(mddev_t *mddev)
if (sync_page_io(rdev->bdev,
r10_bio->devs[sl].addr +
sect + rdev->data_offset,
s<<9, conf->tmppage, WRITE) == 0 ||
sync_page_io(rdev->bdev,
s<<9, conf->tmppage, WRITE) == 0)
/* Well, this device is dead */
md_error(mddev, rdev);
}
}
sl = start;
while (sl != r10_bio->read_slot) {
int d;
if (sl==0)
sl = conf->copies;
sl--;
d = r10_bio->devs[sl].devnum;
rdev = conf->mirrors[d].rdev;
if (rdev &&
test_bit(In_sync, &rdev->flags)) {
if (sync_page_io(rdev->bdev,
r10_bio->devs[sl].addr +
sect + rdev->data_offset,
s<<9, conf->tmppage, READ) == 0) {
s<<9, conf->tmppage, READ) == 0)
/* Well, this device is dead */
md_error(mddev, rdev);
}
}
}
} else {
......
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