[PATCH v4 1/8] md/r5cache: Check array size in r5l_init_log
From: Song Liu <hidden>
Date: 2016-10-11 00:24:39
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
Currently, r5l_write_stripe checks meta size for each stripe write, which is not necessary. With this patch, r5l_init_log checks maximal meta size of the array, which is (r5l_meta_block + raid_disks x r5l_payload_data_parity). If this is too big to fit in one page, r5l_init_log aborts. With current meta data, r5l_log support raid_disks up to 203. Signed-off-by: Song Liu <redacted> --- drivers/md/raid5-cache.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-)
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 1b1ab4a..7557791b 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c@@ -441,7 +441,6 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) { int write_disks = 0; int data_pages, parity_pages; - int meta_size; int reserve; int i; int ret = 0;
@@ -473,15 +472,6 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) parity_pages = 1 + !!(sh->qd_idx >= 0); data_pages = write_disks - parity_pages; - meta_size = - ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32)) - * data_pages) + - sizeof(struct r5l_payload_data_parity) + - sizeof(__le32) * parity_pages; - /* Doesn't work with very big raid array */ - if (meta_size + sizeof(struct r5l_meta_block) > PAGE_SIZE) - return -EINVAL; - set_bit(STRIPE_LOG_TRAPPED, &sh->state); /* * The stripe must enter state machine again to finish the write, so
@@ -1184,6 +1174,22 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) if (PAGE_SIZE != 4096) return -EINVAL; + + /* + * The PAGE_SIZE must be big enough to hold 1 r5l_meta_block and + * raid_disks r5l_payload_data_parity. + * + * Write journal and cache does not work for very big array + * (raid_disks > 203) + */ + if (sizeof(struct r5l_meta_block) + + ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32)) * + conf->raid_disks) > PAGE_SIZE) { + pr_err("md/raid:%s: write journal/cache doesn't work for array with %d disks\n", + mdname(conf->mddev), conf->raid_disks); + return -EINVAL; + } + log = kzalloc(sizeof(*log), GFP_KERNEL); if (!log) return -ENOMEM;
--
2.9.3