On Tue 14-01-25 07:01:08, Guenter Roeck wrote: > On 1/14/25 05:19, Jan Kara wrote: > > On Mon 13-01-25 15:05:25, Guenter Roeck wrote: > > > On Thu, Nov 21, 2024 at 06:05:39PM +0800, Jim Zhao wrote: > > > > Address the feedback from "mm/page-writeback: raise wb_thresh to prevent > > > > write blocking with strictlimit"(39ac99852fca98ca44d52716d792dfaf24981f53). > > > > The wb_thresh bumping logic is scattered across wb_position_ratio, > > > > __wb_calc_thresh, and wb_update_dirty_ratelimit. For consistency, > > > > consolidate all wb_thresh bumping logic into __wb_calc_thresh. > > > > > > > > Reviewed-by: Jan Kara <jack@xxxxxxx> > > > > Signed-off-by: Jim Zhao <jimzhao.ai@xxxxxxxxx> > > > > > > This patch triggers a boot failure with one of my 'sheb' boot tests. > > > It is seen when trying to boot from flash (mtd). The log says > > > > > > ... > > > Starting network: 8139cp 0000:00:02.0 eth0: link down > > > udhcpc: started, v1.33.0 > > > EXT2-fs (mtdblock3): error: ext2_check_folio: bad entry in directory #363: : directory entry across blocks - offset=0, inode=27393, rec_len=3072, name_len=2 > > > udhcpc: sending discover > > > udhcpc: sending discover > > > udhcpc: sending discover > > > EXT2-fs (mtdblock3): error: ext2_check_folio: bad entry in directory #363: : directory entry across blocks - offset=0, inode=27393, rec_len=3072, name_len=2 > > > > Thanks for report! Uh, I have to say I'm very confused by this. It is clear > > than when ext2 detects the directory corruption (we fail checking directory > > inode 363 which is likely /etc/init.d/), the boot fails in interesting > > ways. What is unclear is how the commit can possibly cause ext2 directory > > corruption. If you didn't verify reverting the commit fixes the issue, I'd > > be suspecting bad bisection but that obviously isn't the case :-) > > > > Ext2 is storing directory data in the page cache so at least it uses the > > subsystem which the patch impacts but how writeback throttling can cause > > ext2 directory corruption is beyond me. BTW, do you recreate the root > > filesystem before each boot? How exactly? > > I use pre-built root file systems. For sheb, they are at > https://github.com/groeck/linux-build-test/tree/master/rootfs/sheb Thanks. So the problematic directory is /usr/share/udhcpc/ where we read apparently bogus metadata at the beginning of that directory. > I don't think this is related to ext2 itself. Booting an ext2 image from > ata/ide drive works. Interesting this is specific to mtd. I'll read the patch carefully again if something rings a bell. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
