kernel.git/drivers/mtd/ubi/eba.c, branch linux-4.3.y

UBI: Fastmap: Locking updates

2015-03-26T21:46:02Z

a) Rename ubi->fm_sem to ubi->fm_eba_sem as this semaphore protects EBA changes. b) Turn ubi->fm_mutex into a rw semaphore. It will still serialize fastmap writes but also ensures that ubi_wl_put_peb() is not interrupted by a fastmap write. We use a rw semaphore to allow ubi_wl_put_peb() still to be executed in parallel if no fastmap write is happening. Signed-off-by: Richard Weinberger

UBI: Fastmap: Fix race after ubi_wl_get_peb()

2015-03-26T21:46:01Z

ubi_wl_get_peb() returns a fresh PEB which can be used by user of UBI. Due to the pool logic fastmap will correctly map this PEB upon attach time because it will be scanned. If a new fastmap is written (due to heavy parallel io) while the before the fresh PEB is assigned to the EBA table it will not be scanned as it is no longer in the pool. So, the race window exists between ubi_wl_get_peb() and the EBA table assignment. We have to make sure that no new fastmap can be written while that. To ensure that ubi_wl_get_peb() will grab ubi->fm_sem in read mode and the user of ubi_wl_get_peb() has to release it after the PEB got assigned. Signed-off-by: Richard Weinberger

UBI: Fastmap: Fix race in ubi_eba_atomic_leb_change()

2015-03-26T21:45:58Z

This function a) requests a new PEB, b) writes data to it, c) returns the old PEB and d) registers the new PEB in the EBA table. For the non-fastmap case this works perfectly fine and is powercut safe. Is fastmap enabled this can lead to issues. If a new fastmap is written between a) and c) the freshly requested PEB is no longer in a pool and will not be scanned upon attaching. If now a powercut happens between c) and d) the freshly requested PEB will not be scanned and the old one got already scheduled for erase. After attaching the EBA table will point to a erased PEB. Fix this issue by swapping steps c) and d). Signed-off-by: Richard Weinberger

UBI: fix out of bounds write

2015-03-26T11:07:17Z

If aeb->len >= vol->reserved_pebs, we should not be writing aeb into the PEB->LEB mapping. Caught by Coverity, CID #711212. Cc: stable Signed-off-by: Brian Norris Signed-off-by: Richard Weinberger

UBI: fix missing brace control flow

2015-02-23T21:17:24Z

commit 0e707ae79ba3 ("UBI: do propagate positive error codes up") seems to have produced an unintended change in the control flow here. Completely untested, but it looks obvious. Caught by Coverity, which didn't like the indentation. CID 1271184. Signed-off-by: Brian Norris Cc: Dan Carpenter Signed-off-by: Richard Weinberger

UBI: do propagate positive error codes up

2015-01-28T15:09:25Z

UBI uses positive function return codes internally, and should not propagate them up, except in the place this path fixes. Here is the original bug report from Dan Carpenter: The problem is really in ubi_eba_read_leb(). drivers/mtd/ubi/eba.c 412 err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1); 413 if (err && err != UBI_IO_BITFLIPS) { 414 if (err > 0) { 415 /* 416 * The header is either absent or corrupted. 417 * The former case means there is a bug - 418 * switch to read-only mode just in case. 419 * The latter case means a real corruption - we 420 * may try to recover data. FIXME: but this is 421 * not implemented. 422 */ 423 if (err == UBI_IO_BAD_HDR_EBADMSG || 424 err == UBI_IO_BAD_HDR) { 425 ubi_warn("corrupted VID header at PEB %d, LEB %d:%d", 426 pnum, vol_id, lnum); 427 err = -EBADMSG; 428 } else 429 ubi_ro_mode(ubi); On this path we return UBI_IO_FF and UBI_IO_FF_BITFLIPS and it eventually gets passed to ERR_PTR(). We probably dereference the bad pointer and oops. At that point we've gone read only so it was already a bad situation... 430 } 431 goto out_free; 432 } else if (err == UBI_IO_BITFLIPS) 433 scrub = 1; 434 Reported-by: Dan Carpenter Signed-off-by: Artem Bityutskiy

UBI: Add initial support for scatter gather

2015-01-28T15:04:26Z

Adds a new set of functions to deal with scatter gather. ubi_eba_read_leb_sg() will read from a LEB into a scatter gather list. The new data structure struct ubi_sgl will be used within UBI to hold the scatter gather list itself and metadata to have a cursor within the list. Signed-off-by: Richard Weinberger Tested-by: Ezequiel Garcia Reviewed-by: Ezequiel Garcia

UBI: Extend UBI layer debug/messaging capabilities

2014-11-07T10:08:51Z

If there is more then one UBI device mounted, there is no way to distinguish between messages from different UBI devices. Add device number to all ubi layer message types. The R/O block driver messages were replaced by pr_* since ubi_device structure is not used by it. Amended a bit by Artem. Signed-off-by: Tanya Brokhman Signed-off-by: Artem Bityutskiy

UBI: ubi_eba_read_leb: Remove in vain variable assignment

2014-09-26T10:42:41Z

There is no need to set err, it will be overwritten in any case later at: if (scrub) err = ubi_wl_scrub_peb(ubi, pnum); Signed-off-by: Richard Weinberger Signed-off-by: Artem Bityutskiy

UBI: Wire-up ->fm_sem

2012-10-03T09:29:37Z

Fastmap uses ->fm_sem to stop EBA changes while writing a new fastmap. Signed-off-by: Richard Weinberger Signed-off-by: Artem Bityutskiy