diff options
author | Jun'ichi Nomura <j-nomura@ce.jp.nec.com> | 2007-12-13 14:42:08 +0000 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-02-08 12:01:07 -0800 |
commit | 3fb754b906d44263625e8bbf4e53a694af181f0a (patch) | |
tree | 8d969114a6e51209059a667aeab55b60c5e62b39 /drivers | |
parent | 38fa6d004744d3794407fc1bd6992007e97e2abd (diff) |
dm: table detect io beyond device
Patch 512875bd9661368da6f993205a61213b79ba1df0 in mainline.
This patch fixes a panic on shrinking a DM device if there is
outstanding I/O to the part of the device that is being removed.
(Normally this doesn't happen - a filesystem would be resized first,
for example.)
The bug is that __clone_and_map() assumes dm_table_find_target()
always returns a valid pointer. It may fail if a bio arrives from the
block layer but its target sector is no longer included in the DM
btree.
This patch appends an empty entry to table->targets[] which will
be returned by a lookup beyond the end of the device.
After calling dm_table_find_target(), __clone_and_map() and target_message()
check for this condition using
dm_target_is_valid().
Sample test script to trigger oops:
#!/bin/bash
FILE=$(mktemp)
LODEV=$(losetup -f)
MAP=$(basename ${FILE})
SIZE=4M
dd if=/dev/zero of=${FILE} bs=${SIZE} count=1
losetup ${LODEV} ${FILE}
echo "0 $(blockdev --getsz ${LODEV}) linear ${LODEV} 0" |dmsetup create ${MAP}
dmsetup suspend ${MAP}
echo "0 1 linear ${LODEV} 0" |dmsetup load ${MAP}
dd if=/dev/zero of=/dev/mapper/${MAP} bs=${SIZE} count=1 &
echo "Wait til dd push some I/O"
sleep 5
dmsetup resume ${MAP}
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/md/dm-ioctl.c | 10 | ||||
-rw-r--r-- | drivers/md/dm-table.c | 7 | ||||
-rw-r--r-- | drivers/md/dm.c | 24 | ||||
-rw-r--r-- | drivers/md/dm.h | 5 |
4 files changed, 32 insertions, 14 deletions
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index b441d82c338a..8a4f63b13b27 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1250,21 +1250,17 @@ static int target_message(struct dm_ioctl *param, size_t param_size) if (!table) goto out_argv; - if (tmsg->sector >= dm_table_get_size(table)) { + ti = dm_table_find_target(table, tmsg->sector); + if (!dm_target_is_valid(ti)) { DMWARN("Target message sector outside device."); r = -EINVAL; - goto out_table; - } - - ti = dm_table_find_target(table, tmsg->sector); - if (ti->type->message) + } else if (ti->type->message) r = ti->type->message(ti, argc, argv); else { DMWARN("Target type does not support messages"); r = -EINVAL; } - out_table: dm_table_put(table); out_argv: kfree(argv); diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 2bcde5798b5a..72d2250e1575 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -187,8 +187,10 @@ static int alloc_targets(struct dm_table *t, unsigned int num) /* * Allocate both the target array and offset array at once. + * Append an empty entry to catch sectors beyond the end of + * the device. */ - n_highs = (sector_t *) dm_vcalloc(num, sizeof(struct dm_target) + + n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) + sizeof(sector_t)); if (!n_highs) return -ENOMEM; @@ -862,6 +864,9 @@ struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index) /* * Search the btree for the correct target. + * + * Caller should check returned pointer with dm_target_is_valid() + * to trap I/O beyond end of device. */ struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector) { diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 998d4502a039..fac09d52535a 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -663,13 +663,19 @@ static struct bio *clone_bio(struct bio *bio, sector_t sector, return clone; } -static void __clone_and_map(struct clone_info *ci) +static int __clone_and_map(struct clone_info *ci) { struct bio *clone, *bio = ci->bio; - struct dm_target *ti = dm_table_find_target(ci->map, ci->sector); - sector_t len = 0, max = max_io_len(ci->md, ci->sector, ti); + struct dm_target *ti; + sector_t len = 0, max; struct dm_target_io *tio; + ti = dm_table_find_target(ci->map, ci->sector); + if (!dm_target_is_valid(ti)) + return -EIO; + + max = max_io_len(ci->md, ci->sector, ti); + /* * Allocate a target io object. */ @@ -727,6 +733,9 @@ static void __clone_and_map(struct clone_info *ci) do { if (offset) { ti = dm_table_find_target(ci->map, ci->sector); + if (!dm_target_is_valid(ti)) + return -EIO; + max = max_io_len(ci->md, ci->sector, ti); tio = alloc_tio(ci->md); @@ -750,6 +759,8 @@ static void __clone_and_map(struct clone_info *ci) ci->idx++; } + + return 0; } /* @@ -758,6 +769,7 @@ static void __clone_and_map(struct clone_info *ci) static void __split_bio(struct mapped_device *md, struct bio *bio) { struct clone_info ci; + int error = 0; ci.map = dm_get_table(md); if (!ci.map) { @@ -777,11 +789,11 @@ static void __split_bio(struct mapped_device *md, struct bio *bio) ci.idx = bio->bi_idx; start_io_acct(ci.io); - while (ci.sector_count) - __clone_and_map(&ci); + while (ci.sector_count && !error) + error = __clone_and_map(&ci); /* drop the extra reference count */ - dec_pending(ci.io, 0); + dec_pending(ci.io, error); dm_table_put(ci.map); } /*----------------------------------------------------------------- diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 462ee652a890..07298a381d50 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -113,6 +113,11 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits); void dm_table_unplug_all(struct dm_table *t); int dm_table_flush_all(struct dm_table *t); +/* + * To check the return value from dm_table_find_target(). + */ +#define dm_target_is_valid(t) ((t)->table) + /*----------------------------------------------------------------- * A registry of target types. *---------------------------------------------------------------*/ |