From fd7c092e711ebab55b2688d3859d95dfd0301f73 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Fri, 1 Mar 2013 22:45:44 +0000 Subject: dm: fix truncated status strings Avoid returning a truncated table or status string instead of setting the DM_BUFFER_FULL_FLAG when the last target of a table fills the buffer. When processing a table or status request, the function retrieve_status calls ti->type->status. If ti->type->status returns non-zero, retrieve_status assumes that the buffer overflowed and sets DM_BUFFER_FULL_FLAG. However, targets don't return non-zero values from their status method on overflow. Most targets returns always zero. If a buffer overflow happens in a target that is not the last in the table, it gets noticed during the next iteration of the loop in retrieve_status; but if a buffer overflow happens in the last target, it goes unnoticed and erroneously truncated data is returned. In the current code, the targets behave in the following way: * dm-crypt returns -ENOMEM if there is not enough space to store the key, but it returns 0 on all other overflows. * dm-thin returns errors from the status method if a disk error happened. This is incorrect because retrieve_status doesn't check the error code, it assumes that all non-zero values mean buffer overflow. * all the other targets always return 0. This patch changes the ti->type->status function to return void (because most targets don't use the return code). Overflow is detected in retrieve_status: if the status method fills up the remaining space completely, it is assumed that buffer overflow happened. Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- drivers/md/dm-raid.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'drivers/md/dm-raid.c') diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 9e58dbd8d8c..5a578d89da2 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -1201,8 +1201,8 @@ static int raid_map(struct dm_target *ti, struct bio *bio) return DM_MAPIO_SUBMITTED; } -static int raid_status(struct dm_target *ti, status_type_t type, - unsigned status_flags, char *result, unsigned maxlen) +static void raid_status(struct dm_target *ti, status_type_t type, + unsigned status_flags, char *result, unsigned maxlen) { struct raid_set *rs = ti->private; unsigned raid_param_cnt = 1; /* at least 1 for chunksize */ @@ -1344,8 +1344,6 @@ static int raid_status(struct dm_target *ti, status_type_t type, DMEMIT(" -"); } } - - return 0; } static int raid_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) @@ -1405,7 +1403,7 @@ static void raid_resume(struct dm_target *ti) static struct target_type raid_target = { .name = "raid", - .version = {1, 4, 1}, + .version = {1, 4, 2}, .module = THIS_MODULE, .ctr = raid_ctr, .dtr = raid_dtr, -- cgit v1.2.3-18-g5258 From 55a62eef8d1b50ceff3b7bf46851103bdcc7e5b0 Mon Sep 17 00:00:00 2001 From: Alasdair G Kergon Date: Fri, 1 Mar 2013 22:45:47 +0000 Subject: dm: rename request variables to bios Use 'bio' in the name of variables and functions that deal with bios rather than 'request' to avoid confusion with the normal block layer use of 'request'. No functional changes. Signed-off-by: Alasdair G Kergon --- drivers/md/dm-raid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/md/dm-raid.c') diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 5a578d89da2..9a01d1e4c78 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -1151,7 +1151,7 @@ static int raid_ctr(struct dm_target *ti, unsigned argc, char **argv) INIT_WORK(&rs->md.event_work, do_table_event); ti->private = rs; - ti->num_flush_requests = 1; + ti->num_flush_bios = 1; mutex_lock(&rs->md.reconfig_mutex); ret = md_run(&rs->md); -- cgit v1.2.3-18-g5258