This patch missed the fixes pull request(5.3-rc6), will it be in v5.3-rc7? -----邮件原件----- 发件人: Richard Weinberger [mailto:richard.weinberger@xxxxxxxxx] 发送时间: 2019年8月14日 5:38 收件人: chengzhihao <chengzhihao1@xxxxxxxxxx> 抄送: Richard Weinberger <richard@xxxxxx>; zhangyi (F) <yi.zhang@xxxxxxxxxx>; linux-mtd@xxxxxxxxxxxxxxxxxxx; LKML <linux-kernel@xxxxxxxxxxxxxxx> 主题: Re: [PATCH RFC v2] ubi: ubi_wl_get_peb: Increase the number of attempts while getting PEB On Sat, Aug 10, 2019 at 11:51 AM Zhihao Cheng <chengzhihao1@xxxxxxxxxx> wrote: > > Running stress test io_paral (A pressure ubi test in mtd-utils) on an > UBI device with fewer PEBs (fastmap enabled) may cause ENOSPC errors > and make UBI device read-only, but there are still free PEBs on the > UBI device. This problem can be easily reproduced by performing the > following steps on a 2-core machine: > $ modprobe nandsim first_id_byte=0x20 second_id_byte=0x33 parts=80 > $ modprobe ubi mtd="0,0" fm_autoconvert > $ ./io_paral /dev/ubi0 > > We may see the following verbose: > (output) > [io_paral] update_volume():108: failed to write 380 bytes at offset > 95920 of volume 2 > [io_paral] update_volume():109: update: 97088 bytes > [io_paral] write_thread():227: function pwrite() failed with error 28 > (No space left on device) > [io_paral] write_thread():229: cannot write 15872 bytes to offs 31744, > wrote -1 > (dmesg) > ubi0 error: ubi_wl_get_peb [ubi]: Unable to get a free PEB from user WL > pool > ubi0 warning: ubi_eba_write_leb [ubi]: switch to read-only mode > CPU: 0 PID: 2027 Comm: io_paral Not tainted 5.3.0-rc2-00001-g5986cd0 #9 > ubi0 warning: try_write_vid_and_data [ubi]: failed to write VID header > to LEB 2:5, PEB 18 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0 > -0-ga698c8995f-prebuilt.qemu.org 04/01/2014 > Call Trace: > dump_stack+0x85/0xba > ubi_eba_write_leb+0xa1e/0xa40 [ubi] > vol_cdev_write+0x307/0x520 [ubi] > vfs_write+0xfa/0x280 > ksys_pwrite64+0xc5/0xe0 > __x64_sys_pwrite64+0x22/0x30 > do_syscall_64+0xbf/0x440 > > In function ubi_wl_get_peb, the operation of filling the pool > (ubi_update_fastmap) with free PEBs and fetching a free PEB from the > pool is not atomic. After thread A filling the pool with free PEB, > free PEB may be taken away by thread B. When thread A checks the > expression again, the condition is still unsatisfactory. At this time, > there may still be free PEBs on UBI that can be filled into the pool. > > This patch increases the number of attempts to obtain PEB. An extreme > case (No free PEBs left after creating test volumes) has been tested > on different type of machines for 100 times. The biggest number of > attempts are shown below: > > x86_64 arm64 > 2-core 4 4 > 4-core 8 4 > 8-core 4 4 > > Signed-off-by: Zhihao Cheng <chengzhihao1@xxxxxxxxxx> Thanks for addressing this! I'll take this version. :-) -- Thanks, //richard ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/