On Fri, Dec 12, 2008 at 09:56:09AM -0500, Theodore Tso wrote: > On Tue, Dec 09, 2008 at 04:11:22PM +0530, Aneesh Kumar K.V wrote: > > The problem is due to remove-do_blk_alloc patch. > > > > The patch below should fix the crash. > > > > - EXT4_I(inode)->i_allocated_meta_blocks += *count; > > + EXT4_I(inode)->i_allocated_meta_blocks += ar.len; > > > Good catch, thanks. I'll add it to the patch queue. > > > I have one question regarding the patch. What about blocks allocated for > > directories for the ext3 format. With extent format we are not > > setting EXT4_MB_HINT_DATA for non regular files. So i guess we also > > need the below patch . > > One of the good things about getting rid of too many layers of > abstractions is that it makes bugs like this easier to spot. We've > been sending allocating directory and symlinks using EXT4_MB_HINT_DATA > if extents haven't been enabled, and no one noticed before we > simplified out things.... We had always sent the directory allocation request with EXT4_MB_HINT_DATA not set. With Linus kernel I have this 671 static ext4_fsblk_t do_blk_alloc(handle_t *handle, struct inode *inode, ..... .... 686 if (S_ISREG(inode->i_mode) && !(flags & EXT4_META_BLOCK)) 687 /* enable in-core preallocation for data block allocation */ 688 ar.flags = EXT4_MB_HINT_DATA; 689 else 690 /* disable in-core preallocation for non-regular files */ 691 ar.flags = 0; That means if the request for block allocation is not on regular files set ar.flags = 0; For regular files if the request is for meta-data blocks set ar.glags = 0. > > Actually, I wonder if maybe we should set EXT4_MB_HINT_DATA for > directories as well. Making directories contiguous does speed up > certain workloads, and it does speed up fsck. It may be though that > the mballoc algorithms should be tuned specifically for directories, > and what we should do is to define a new flag, EXT4_MB_HINT_DIRECTORY, > and pass it in for that case. > > Some experimentation is clearly called for, here.... > True. But with the changes to do do_blk_alloc I guess we need to make sure we request directories with EXT4_MB_HINT_DATA not set. -aneesh -- 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
