Messages in this thread | | | Subject | Re: [PATCH] ext4: properly check for dirty state in ext4_inode_datasync_dirty() | From | Ritesh Harjani <> | Date | Wed, 28 Oct 2020 08:57:03 +0530 |
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On 10/27/20 3:58 AM, harshad shirwadkar wrote: > Thanks Andrea for catching and sending out a fix for this. > > On Sat, Oct 24, 2020 at 7:01 AM Andrea Righi <andrea.righi@canonical.com> wrote: >> >> ext4_inode_datasync_dirty() needs to return 'true' if the inode is >> dirty, 'false' otherwise, but the logic seems to be incorrectly changed >> by commit aa75f4d3daae ("ext4: main fast-commit commit path"). >> >> This introduces a problem with swap files that are always failing to be >> activated, showing this error in dmesg: >> >> [ 34.406479] swapon: file is not committed >>
Well, I too noticed this yesterday while I was testing xfstests -g swap. Those tests were returning _notrun, hence that could be the reason why it didn't get notice in XFSTESTing from Ted.
- I did notice that this code was introduced in v10 only. This wasn't there in v9 though.
>> Simple test case to reproduce the problem: >> >> # fallocate -l 8G swapfile >> # chmod 0600 swapfile >> # mkswap swapfile >> # swapon swapfile >> >> Fix the logic to return the proper state of the inode. >> >> Link: https://lore.kernel.org/lkml/20201024131333.GA32124@xps-13-7390 >> Fixes: aa75f4d3daae ("ext4: main fast-commit commit path") >> Signed-off-by: Andrea Righi <andrea.righi@canonical.com> >> --- >> fs/ext4/inode.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c >> index 03c2253005f0..a890a17ab7e1 100644 >> --- a/fs/ext4/inode.c >> +++ b/fs/ext4/inode.c >> @@ -3308,8 +3308,8 @@ static bool ext4_inode_datasync_dirty(struct inode *inode) >> if (journal) { >> if (jbd2_transaction_committed(journal, >> EXT4_I(inode)->i_datasync_tid)) >> - return true; >> - return atomic_read(&EXT4_SB(inode->i_sb)->s_fc_subtid) >= >> + return false; >> + return atomic_read(&EXT4_SB(inode->i_sb)->s_fc_subtid) < >> EXT4_I(inode)->i_fc_committed_subtid; > In addition, the above condition should only be checked if fast > commits are enabled. So, in effect this overall condition will look > like this: > > if (journal) { > if (jbd2_transaction_committed(journal, EXT4_I(inode)->i_datasync_tid)) > return false; > if (test_opt2(sb, JOURNAL_FAST_COMMIT)) > return atomic_read(&EXT4_SB(inode->i_sb)->s_fc_subtid) < > EXT4_I(inode)->i_fc_committed_subtid; > return true; > }
Yup - I too had made a similar patch. But then I also noticed that below condition will always remain false. Since we never update "i_fc_committed_subtid" other than at these 2 places (one during init where we set it to 0 and other during ext4_fc_commit() where we set it to sbi->s_fc_subtid).
<condition> atomic_read(&EXT4_SB(inode->i_sb)->s_fc_subtid < EXT4_I(inode)->i_fc_committed_subtid
Maybe I need more reading around this.
-ritesh
> > Thanks, > Harshad > >> } >> >> -- >> 2.27.0 >>
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