linux/drivers/mtd/ubi, branch v2.6.37

UBI: fix corrupted PEB detection for NOR flash

2010-12-03T13:49:21Z

My new shiny code for corrupted PEB detection has NOR specific bug. We tread PEB as corrupted and preserve it, if 1. EC header is OK. 2. VID header is corrupted. 3. data area is not "all 0xFFs" In case of NOR we have 'nor_erase_prepare()' quirk, which invalidates the headers before erasing the PEB. And we invalidate first the VID header, and then the EC header. So if a power cut happens after we have invalidated the VID header, but before we have invalidated the EC header, we end up with a PEB which satisfies the above 3 conditions, and the scanning code will treat it as corrupted, and will print scary warnings, wrongly. This patch fixes the issue by firt invalidating the EC header, then invalidating the VID header. In case of power cut inbetween, we still just lose the EC header, and UBI can deal with this situation gracefully. Thanks to Anatolij Gustschin for tracking this down. Signed-off-by: Artem Bityutskiy Reported-by: Anatolij Gustschin Tested-by: Anatolij Gustschin

UBI: release locks in check_corruption

2010-11-19T13:19:40Z

Commit 45aafd32996e27 "UBI: tighten the corrupted PEB criteria" introduced some return paths that didn't release the ubi->buf_mutex Signed-off-by: Dan Carpenter Signed-off-by: Artem Bityutskiy

Merge branch 'linux-next' of git://git.infradead.org/ubi-2.6

2010-10-22T23:34:23Z

* 'linux-next' of git://git.infradead.org/ubi-2.6: UBI: tighten the corrupted PEB criteria UBI: fix check_data_ff return code UBI: remember copy_flag while scanning UBI: preserve corrupted PEBs UBI: add truly corrupted PEBs to corrupted list UBI: introduce debugging helper function UBI: make check_pattern function non-static UBI: do not put eraseblocks to the corrupted list unnecessarily UBI: separate out corrupted list UBI: change cascade of ifs to switch statements UBI: rename a local variable UBI: handle bit-flips when no header found UBI: remove duplicate IO error codes UBI: rename IO error code UBI: fix small 80 characters limit style issue UBI: cleanup and simplify Kconfig

UBI: tighten the corrupted PEB criteria

2010-10-21T08:20:37Z

If we get a bit-flip of ECC error while reading the data area, do not add it to corrupted list, because it is possible that this is just unstable PEB with corruptions caused by unclean reboots. This patch also improves commentaries. Signed-off-by: Artem Bityutskiy

UBI: fix check_data_ff return code

2010-10-21T08:20:37Z

When the data does not contain all 0xFF bytes, 'check_data_ff()' should return 1, not -EINVAL; Also, the caller ('process_eb()') should not add the PEB to the "corrupted" list if there was a read error. Signed-off-by: Artem Bityutskiy

UBI: remember copy_flag while scanning

2010-10-21T08:20:36Z

While scanning the flash we read all VID headers and store some important information in 'struct ubi_scan_leb'. Store also the 'copy_flag' value there as it is needed when comparing LEBs. We do not increase memory consumption because this is just one bit and we have plenty of spare bits in 'struct ubi_scan_leb' (sizeof(struct ubi_scan_leb) is 48 both with and without this patch). Signed-off-by: Artem Bityutskiy

UBI: preserve corrupted PEBs

2010-10-19T14:19:57Z

Currently UBI erases all corrupted eraseblocks, irrespectively of the nature of corruption: corruption due to power cuts and non-power cut corruption. The former case is OK, but the latter is not, because UBI may destroy potentially important data. With this patch, during scanning, when UBI hits a PEB with corrupted VID header, it checks whether this PEB contains only 0xFF data. If yes, it is safe to erase this PEB and it is put to the 'erase' list. If not, this may be important data and it is better to avoid erasing this PEB. Instead, UBI puts it to the corr list and moves out of the pool of available PEB. IOW, UBI preserves this PEB. Such corrupted PEB lessen the amount of available PEBs. So the more of them we accumulate, the less PEBs are available. The maximum amount of non-power cut corrupted PEBs is 8. This patch is a response to UBIFS problem where reporter (Matthew L. Creech ) observes that UBIFS index points to an unmapped LEB. The theory is that corresponding PEB somehow got corrupted and UBI wiped it. This patch (actually a series of patches) tries to make sure such PEBs are preserved - this would make it is easier to analyze the corruption. Signed-off-by: Artem Bityutskiy

UBI: add truly corrupted PEBs to corrupted list

2010-10-19T14:19:57Z

Start using the 'corr' list and add there PEBs which look truly corrupted, which means they have corrupted VID header and the data which follows the corrupted header does not contain all 0xFF bytes. At the moment, this does not change UBI functionality much because these PEBs will be erase when scanning finishes. But the plan is to teach UBI preserving them. Signed-off-by: Artem Bityutskiy

UBI: introduce debugging helper function

2010-10-19T14:19:57Z

Introduce a helper function to print hexdump: 'ubi_dbg_print_hex_dump()'. It is compiled out if debugging is enabled. Will be used in the next patch. Signed-off-by: Artem Bityutskiy

UBI: make check_pattern function non-static

2010-10-19T14:19:57Z

This patch turns static function 'check_pattern()' into a non-static 'ubi_check_pattern()'. This is just a preparation for the chages which are coming in the next patches. Signed-off-by: Artem Bityutskiy