On Thu, Nov 01, 2012 at 03:28:47AM -0400, George Spelvin wrote: > > Oh, so ... it's just nfsd that causes the linear fallback? Regular (i.e. > > non-nfs) users can see everything in the dir, no error messages? > > Yup. After it survived one e2fsck -D, I poked at the directory a bit > to see if I could cause the error. No success from local access. > > It's also probably an NFSv2 client. I wonder if it's doing something > odd with directory seeks that's causing problems; perhaps htree and the > 32-bit seek cookie limit are not friends? <shrug> I'm not nfs-wise, sadly. I _am_ wondering if an ftrace of this might be useful... or a gigantic glut of data that I'll never finish processing. Just from a quick read of ext4_find_entry() it looks like the only thing that results in fallback mode without a kernel message is ext4_bread() failing in dx_probe()? > >> I haven't observed it, no. But the nature of the symptoms suggests it > >> might be happening. > > > Hum. When linear scan happens on a hashed dir, it's scanning the same > > blocks that the hash scan sees. The htree block looks like a regular > > directory block with one huge "unused" dirent that wraps all the htree > > data. So, the linear scan should find the exact same files as a htree > > scan would. If it doesn't, something's wrong. But you say it isn't, > > so I imagine it's fine. > > Maybe I was wrong. I was worried that it was aborting the directory > scan due to the error and thus files would disappear. If that doesn't > happen, no worries. Oh well, it'll run slowly but at least it won't be throwing up errors. --D -- 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
