kernel/linux.git/drivers/mtd/ubi/ubi.h, branch linux-4.4.y

ubi: Be more paranoid while seaching for the most recent Fastmap

2018-07-25T08:18:32+00:00

commit 74f2c6e9a47cf4e508198c8594626cc82906a13d upstream. Since PEB erasure is asynchornous it can happen that there is more than one Fastmap on the MTD. This is fine because the attach logic will pick the Fastmap data structure with the highest sequence number. On a not so well configured MTD stack spurious ECC errors are common. Causes can be different, bad hardware, wrong operating modes, etc... If the most current Fastmap renders bad due to ECC errors UBI might pick an older Fastmap to attach from. While this can only happen on an anyway broken setup it will show completely different sympthoms and makes finding the root cause much more difficult. So, be debug friendly and fall back to scanning mode of we're facing an ECC error while scanning for Fastmap. Cc: Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

ubi: Rework Fastmap attach base code

2018-07-25T08:18:32+00:00

commit fdf10ed710c0aa177e8dfcd84e65e4e5e8e0956b upstream. Introduce a new list to the UBI attach information object to be able to deal better with old and corrupted Fastmap eraseblocks. Also move more Fastmap specific code into fastmap.c. Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

ubi: Introduce vol_ignored()

2018-07-25T08:18:32+00:00

commit 243a4f8126fcf7facb04b324dbb7c85d10b11ce9 upstream. This makes the logic more easy to follow. Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

UBI: Fix static volume checks when Fastmap is used

2016-06-01T19:15:54+00:00

commit 1900149c835ab5b48bea31a823ea5e5a401fb560 upstream. Ezequiel reported that he's facing UBI going into read-only mode after power cut. It turned out that this behavior happens only when updating a static volume is interrupted and Fastmap is used. A possible trace can look like: ubi0 warning: ubi_io_read_vid_hdr [ubi]: no VID header found at PEB 2323, only 0xFF bytes ubi0 warning: ubi_eba_read_leb [ubi]: switch to read-only mode CPU: 0 PID: 833 Comm: ubiupdatevol Not tainted 4.6.0-rc2-ARCH #4 Hardware name: SAMSUNG ELECTRONICS CO., LTD. 300E4C/300E5C/300E7C/NP300E5C-AD8AR, BIOS P04RAP 10/15/2012 0000000000000286 00000000eba949bd ffff8800c45a7b38 ffffffff8140d841 ffff8801964be000 ffff88018eaa4800 ffff8800c45a7bb8 ffffffffa003abf6 ffffffff850e2ac0 8000000000000163 ffff8801850e2ac0 ffff8801850e2ac0 Call Trace: [] dump_stack+0x63/0x82 [] ubi_eba_read_leb+0x486/0x4a0 [ubi] [] ubi_check_volume+0x83/0xf0 [ubi] [] ubi_open_volume+0x177/0x350 [ubi] [] vol_cdev_open+0x58/0xb0 [ubi] [] chrdev_open+0xae/0x1d0 [] do_dentry_open+0x1ff/0x300 [] ? cdev_put+0x30/0x30 [] vfs_open+0x56/0x60 [] path_openat+0x4f4/0x1190 [] do_filp_open+0x91/0x100 [] ? __alloc_fd+0xc7/0x190 [] do_sys_open+0x13f/0x210 [] SyS_open+0x1e/0x20 [] entry_SYSCALL_64_fastpath+0x1a/0xa4 UBI checks static volumes for data consistency and reads the whole volume upon first open. If the volume is found erroneous users of UBI cannot read from it, but another volume update is possible to fix it. The check is performed by running ubi_eba_read_leb() on every allocated LEB of the volume. For static volumes ubi_eba_read_leb() computes the checksum of all data stored in a LEB. To verify the computed checksum it has to read the LEB's volume header which stores the original checksum. If the volume header is not found UBI treats this as fatal internal error and switches to RO mode. If the UBI device was attached via a full scan the assumption is correct, the volume header has to be present as it had to be there while scanning to get known as mapped. If the attach operation happened via Fastmap the assumption is no longer correct. When attaching via Fastmap UBI learns the mapping table from Fastmap's snapshot of the system state and not via a full scan. It can happen that a LEB got unmapped after a Fastmap was written to the flash. Then UBI can learn the LEB still as mapped and accessing it returns only 0xFF bytes. As UBI is not a FTL it is allowed to have mappings to empty PEBs, it assumes that the layer above takes care of LEB accounting and referencing. UBIFS does so using the LEB property tree (LPT). For static volumes UBI blindly assumes that all LEBs are present and therefore special actions have to be taken. The described situation can happen when updating a static volume is interrupted, either by a user or a power cut. The volume update code first unmaps all LEBs of a volume and then writes LEB by LEB. If the sequence of operations is interrupted UBI detects this either by the absence of LEBs, no volume header present at scan time, or corrupted payload, detected via checksum. In the Fastmap case the former method won't trigger as no scan happened and UBI automatically thinks all LEBs are present. Only by reading data from a LEB it detects that the volume header is missing and incorrectly treats this as fatal error. To deal with the situation ubi_eba_read_leb() from now on checks whether we attached via Fastmap and handles the absence of a volume header like a data corruption error. This way interrupted static volume updates will correctly get detected also when Fastmap is used. Reported-by: Ezequiel Garcia Tested-by: Ezequiel Garcia Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

UBI: Use static class and attribute groups

2015-06-02T11:16:25+00:00

This patch cleans up the manual device_create_file() or class_create_file() calls by replacing with static attribute groups. It simplifies the code and also avoids the possible races between the device/class registration and sysfs creations. For the simplification, also make ubi_class a static instance with initializers, too. Amend a bit by Hujianyang. Signed-off-by: Takashi Iwai Tested-by: Sheng Yong Signed-off-by: hujianyang Signed-off-by: Richard Weinberger

UBI: power cut emulation for testing

2015-04-13T19:05:17+00:00

Emulate random power cuts by switching device to ro after a number of writes to allow simple power cut testing with nand-sim. Maximum and minimum number of successful writes before power cut and what kind of writes (EC header, VID header or none) to interrupt configurable via debugfs. Signed-off-by: David Oberhollenzer Signed-off-by: Richard Weinberger

UBI: Add accessor functions for WL data structures

2015-03-26T21:47:35+00:00

Fastmap need access to various WL data structures as fastmap tightly depends on WL. To make the access less invasive add accessor functions. Signed-off-by: Richard Weinberger

UBI: Add initial support for fastmap self checks

2015-03-26T21:46:03+00:00

Using this debugfs knob fastmap self checks can be controlled. Signed-off-by: Richard Weinberger Reviewed-by: Tanya Brokhman

UBI: Fastmap: Locking updates

2015-03-26T21:46:02+00:00

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: Wrap fastmap specific function in a ifdef

2015-03-26T21:45:56+00:00

...such that we can implement NOP variants of some functions. This will help to reduce fastmap specific ifdefs in other c files. Signed-off-by: Richard Weinberger Reviewed-by: Tanya Brokhman