Hello once more. I have one concern against the patch: If the situation is triggered again and again, the patch would produce lots of output. Maybe it's better to use WARN_ONCE. Cheers, Martin -----Original Message----- From: Jan Kara [mailto:jack@xxxxxxx] Sent: Mittwoch, 4. Mai 2011 23:55 To: Zielinski, Martin Cc: tytso@xxxxxxx; jack@xxxxxxx; linux-ext4@xxxxxxxxxxxxxxx Subject: Re: [PATCH 2/2] jbd: fix fsync() tid wraparound bug On Wed 04-05-11 09:21:04, Martin_Zielinski@xxxxxxxxxx wrote: > Here's an update. > In my first post I was not aware of the implementation of tid_gt. > I agree that 2 and a half billion commits on an SD card are - hmph - > unlikely <snip> > gdb) p *journal > $4 = {j_flags = 16, j_errno = 0, j_sb_buffer = 0xffff88031f156dc8, > j_superblock = 0xffff88031f876000, j_format_version = 2, j_state_lock = {raw_lock = { > slock = 2874125135}}, j_barrier_count = 0, j_barrier = {count = {counter = 1}, wait_lock = { > raw_lock = {slock = 0}}, wait_list = {next = 0xffff88031e6c4638, > prev = 0xffff88031e6c4638}, owner = 0x0}, j_running_transaction = 0x0, > j_committing_transaction = 0x0, j_checkpoint_transactions = 0xffff88031bd16b40, > ... > j_tail_sequence = 2288011385, j_transaction_sequence = 2288014068, > j_commit_sequence = 2288014067, j_commit_request = 140530417, > ... > j_wbuf = 0xffff88031de98000, j_wbufsize = 512, j_last_sync_writer = 4568, > j_average_commit_time = 69247, j_private = 0xffff88031fd49400} <snip> > (gdb) p ((struct ext3_inode_info*)(0xffff88031f0c0758-0xd0))->i_sync_tid > $5 = {counter = -2006954411} > (gdb) p ((struct ext3_inode_info*)(0xffff88031f0c0758-0xd0))->i_datasync_tid > $3 = {counter = 140530417} > > > j_commit_request = 140530417 > > So it *is* a datasync from sqlite. And your fix will catch it. > I still don't understand, where this number comes from. Ok, so i_datasync_tid got corrupted. But look at the numbers in hex: i_datasync_tid==140530417==0x86052F1 and i_commit_sequence==2288014067==0x886052F3 So it's a single bit error - we lost the highest bit of the number. Are you getting the cores from different machines? Otherwise I'd suspect the HW. If it's not HW I'm at loss what can cause it... You can try moving i_datasync_tid to a different place in struct ext3_inode_info so that we can rule out / confirm whether some code external to i_datasync_tid handling is just causing random memory corruption... Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
