On Mon, 18 Jan 2010 23:06:08 GMT, bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > http://bugzilla.kernel.org/show_bug.cgi?id=15018 > > > Jan Kara <jack@xxxxxxx> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > CC| |jack@xxxxxxx, tytso@xxxxxxx > > > > > --- Comment #2 from Jan Kara <jack@xxxxxxx> 2010-01-18 23:06:07 --- > Ah, inlining and such stuff made reading this stack trace quite difficult. > Anyway, the problem is that we just should not call write_inode_now() in > ext4_da_reserve_space() when we have transaction already started. And as > Andreas correctly points out, the patch even introduces a deadlock because it > can call write_inode_now with wait==1. Moreover we hold page lock when holding > write_inode_now which introduces a plenty of nasty locking issues I believe. > The bug has been introduced by commit 0637c6f4135f592f094207c7c21e7c0fc5557834. > > Ted, I think that if we are failing to do the write because of ENOSPC, the only > reasonable non-deadlocky thing to do is to restart the write completely - i.e., > bail out up to ext4_da_write_begin, stop the transaction, drop the page, *do > some magic*, and start again... > How about the below. I am yet to test the change diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c818972..5af483a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1835,24 +1835,12 @@ repeat: * later. Real quota accounting is done at pages writeout * time. */ - if (vfs_dq_reserve_block(inode, md_needed + 1)) { - /* - * We tend to badly over-estimate the amount of - * metadata blocks which are needed, so if we have - * reserved any metadata blocks, try to force out the - * inode and see if we have any better luck. - */ - if (md_reserved && retries++ <= 3) - goto retry; + if (vfs_dq_reserve_block(inode, md_needed + 1)) return -EDQUOT; - } if (ext4_claim_free_blocks(sbi, md_needed + 1)) { vfs_dq_release_reservation_block(inode, md_needed + 1); if (ext4_should_retry_alloc(inode->i_sb, &retries)) { - retry: - if (md_reserved) - write_inode_now(inode, (retries == 3)); yield(); goto repeat; } @@ -3032,7 +3020,7 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { - int ret, retries = 0; + int ret, retries = 0, quota_retries = 0; struct page *page; pgoff_t index; unsigned from, to; @@ -3091,6 +3079,21 @@ retry: if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; + + if ((ret == -EDQUOT) && (quota_retries <= 3)) { + /* + * Since we do aggressive quota reservation may get no quota error + * even though we may be having quota. Forcing the inode write will + * free up the extra quota reserved. We do it only if we have + * meta data blocks reserved because we do aggressive reservation only + * for meta data blocks. + */ + if (EXT4_I(inode)->i_reserved_meta_blocks) { + write_inode_now(inode, (quota_retries == 3)); + quota_retries++; + goto retry; + } + } out: return ret; } -- 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
