Hi, It is quite a co-incidence - I have also spent some hours in the last few days rebasing the netgear derived patch set bit-rotting in my hard disk. I have a quick diff and it seems that you have drawn some ideas but yours is largely an independent effort. Anyway, here are a few things from where I am. - It appears that you don't treat the special files (catalog, etc) special? netgear's does; but i think there is a mistake in that they don't consider them ever getting fragmented, so they were not journaling those files properly. - I am still nowhere near figuring out what's the issue with just runing du on one funny volume i have. The driver gets confused after a few du's but the disk always fsck clean. - I see I still have one out-standing patch not yet submitted - the one about folder counts on case-sensitive volumes. I'll try to spend some time reading your patches and maybe even try them out. Will write again. Hin-tak ------------------------------ On Thu, Dec 26, 2013 09:41 GMT Vyacheslav Dubeyko wrote: >Hi, > >This patch implements journal replay functionality in HFS+ >file system driver. > >Technical Note TN1150: >"The purpose of the journal is to ensure that when a group of > related changes are being made, that either all of those changes > are actually made, or none of them are made. This is done by > gathering up all of the changes, and storing them in a separate > place (in the journal). Once the journal copy of the changes is > completely written to disk, the changes can actually be written > to their normal locations on disk. If a failure happens at that > time, the changes can simply be copied from the journal to their > normal locations. If a failure happens when the changes are being > written to the journal, but before they are marked complete, then > all of those changes are ignored." > >"A group of related changes is called a transaction. When all of > the changes of a transaction have been written to their normal > locations on disk, that transaction has been committed, and is > removed from the journal. The journal may contain several > transactions. Copying changes from all transactions to their > normal locations on disk is called replaying the journal." > >"In order to replay the journal, an implementation just loops > over the transactions, copying each individual block in the > transaction from the journal to its proper location on the > volume. Once those blocks have been flushed to the media > (not just the driver!), it may update the journal header to > remove the transactions." > >"Here are the steps to replay the journal: > 1. Read the volume header into variable vhb. The volume may > have an HFS wrapper; if so, you will need to use it to > determine the location of the volume header. > 2. Test the kHFSVolumeJournaledBit in the attributes field of > the volume header. If it is not set, there is no journal > to replay, and you are done. > 3. Read the journal info block from the allocation block number > vhb.journalInfoBlock, into variable jib. > 4. If kJIJournalNeedsInitMask is set in jib.flags, the journal > was never initialized, so there is no journal to replay. > 5. Verify that kJIJournalInFSMask is set and kJIJournalOnOtherDeviceMask > is clear in jib.flags. > 6. Read the journal header at jib.offset bytes from the start > of the volume, and place it in variable jhdr. > 7. If jhdr.start equals jhdr.end, the journal does not have > any transactions, so there is nothing to replay. > 8. Set the current offset in the journal (typically a local > variable) to the start of the journal buffer, jhdr.start. > 9. While jhdr.start does not equal jhdr.end, perform the > following steps: > 1. Read a block list header of jhdr.blhdr_size bytes from > the current offset in the journal into variable blhdr. > 2. For each block in bhdr.binfo[1] to bhdr.binfo[blhdr.num_blocks], > inclusive, copy bsize bytes from the current offset in > the journal to sector bnum on the volume (to byte offset > bnum*jdhr.jhdr_size). Remember that jhdr_size is the > size of a sector, in bytes. > 3. If bhdr.binfo[0].next is zero, you have completed the > last block list of the current transaction; set jhdr.start > to the current offset in the journal." > >With the best regards, >Vyacheslav Dubeyko. >--- > > Documentation/filesystems/hfsplus.txt | 4 + > fs/hfsplus/Makefile | 3 +- > fs/hfsplus/hfsplus_fs.h | 31 +- > fs/hfsplus/hfsplus_raw.h | 53 +- > fs/hfsplus/journal.c | 1207 +++++++++++++++++++++++++++++++++ > fs/hfsplus/options.c | 8 +- > fs/hfsplus/part_tbl.c | 4 +- > fs/hfsplus/super.c | 42 +- > fs/hfsplus/wrapper.c | 28 +- > 9 files changed, 1356 insertions(+), 24 deletions(-) >-- >1.7.9.5 > > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
