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ubi: Fix races around ubi_refill_pools()

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When writing a new Fastmap the first thing that happens
is refilling the pools in memory.
At this stage it is possible that new PEBs from the new pools
get already claimed and written with data.
If this happens before the new Fastmap data structure hits the
flash and we face power cut the freshly written PEB will not
scanned and unnoticed.

Solve the issue by locking the pools until Fastmap is written.

Cc: <stable@vger.kernel.org>
Fixes: dbb7d2a88d ("UBI: Add fastmap core")
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Richard Weinberger
2016-08-24 14:36:14 +02:00
parent 2365418879
commit 2e8f08deab
4 changed files with 30 additions and 14 deletions
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4
drivers/mtd/ubi/eba.c
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@@ -1210,6 +1210,8 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
struct ubi_volume *vol;
uint32_t crc;
ubi_assert(rwsem_is_locked(&ubi->fm_eba_sem));
vol_id = be32_to_cpu(vid_hdr->vol_id);
lnum = be32_to_cpu(vid_hdr->lnum);
@@ -1352,9 +1354,7 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
}
ubi_assert(vol->eba_tbl->entries[lnum].pnum == from);
down_read(&ubi->fm_eba_sem);
vol->eba_tbl->entries[lnum].pnum = to;
up_read(&ubi->fm_eba_sem);
out_unlock_buf:
mutex_unlock(&ubi->buf_mutex);