On Thu, Jun 25, 2009 at 08:47:59AM -0400, Greg Freemyer wrote: > Aneesh, > > Can you provide the below requested info? > > Thanks > Greg > > On Tue, Jun 23, 2009 at 8:11 PM, Andreas Dilger<adilger@xxxxxxx> wrote: > > On Jun 23, 2009 20:02 -0400, Greg Freemyer wrote: > >> On Tue, Jun 23, 2009 at 7:19 PM, Andreas Dilger<adilger@xxxxxxx> wrote: > >> > On Jun 23, 2009 17:25 +0900, Akira Fujita wrote: > >> >> alloc_flag of ext4_alloc_rule structure is set as "mandatory" or "advisory". > >> >> Restricted blocks with "mandatory" are never used by block allocator. > >> >> But in "advisory" case, block allocator is allowed to use restricted blocks > >> >> when there are no free blocks on FS. > >> > > >> > Would it make more sense to implement the range protections via the > >> > existing preallocation ranges (PA)? An inode can have multiple > >> > PAs attached to it to have it prefer allocations from that range. > >> > > >> > We could also attach PAs to the superblock to prevent other files from > >> > allocating out of those ranges. This would work better with the existing > >> > allocation code instead of creating a second similar mechanism. > >> > >> Where can I find documentation about how PA works? Or is it just in > >> the source? If so, what are one or two calls that cause the PA ranges > >> to be set, etc. > > Mostly the source. Some of mballoc details are documented in the ols 2008 paper. Regarding some of the functions ext4_mb_use_preallocated -> allocate from PA ext4_mb_new_preallocation -> Create new PA. Source code also have some documentation that explains how mballoc use PA. -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
