NetBSD-Bugs archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: kern/54504: -9/-current WAPBL panic: current transaction too big to flush

The following reply was made to PR kern/54504; it has been noted by GNATS.

From: Jason Thorpe <>
To: NetBSD Kernel Technical Discussion List <>
 "" <>
Subject: Re: kern/54504: -9/-current WAPBL panic: current transaction too big
 to flush
Date: Thu, 29 Aug 2019 08:38:00 -0700

 > On Aug 29, 2019, at 2:00 AM, wrote:
 > 	Workround (presumably): don't use WAPBL.
 > 	Fix: Change WAPBL logic to allow truncation/deletion of big =
 files aka avoid running into transaction size limitations.
 WAPBL is going to need some help with this -- but in all likelihood, the =
 WAPBL-using file system is going to have to participate, as well; i.e. =
 it's not just changes to WAPBL in order to solve this problem.
 The way some other file systems that I'm familiar with deal with this =
 situation is to move the file (or the file's extents / blocks) into a =
 "purgatory" (essentially, a hidden directory within the file system) -- =
 from the perspective of the original file, the operation is complete and =
 the file system consistent.  Then, a background task iterates on items =
 in the purgatory, operating in chunks that will fit within the =
 transaction size limitations.
 This sometimes means that space isn't freed immediately, but it works =
 pretty well in principle, and you can always add an escape valve that =
 boosts the priority of the purgatory task and blocks while it does its =
 work if you are desperate for space.
 -- thorpej

Home | Main Index | Thread Index | Old Index