At present, as discussed in this LKML thread, http://marc.info/?l=linux-kernel&m=117607695406580, when a dirty ext3 filesystem is mounted read-only it writes to the disk while replaying the journal log and cleaning up the orphan list. This behaviour may surprise users and can potentially cause data corruption/loss (e.g. if a system is suspended, booted into a different OS, then resumed). This patch series attempts to address this by using a block translation table instead of replaying the journal on a read-only filesystem. Patches 1-3 are independent cleanups/bug-fixes for things I came across while working on this. They could be submitted separately and are not required for following patches. Patch 4 is a refactoring change that simplifies the code prior to later substantive changes. Patch 5 introduces the translation table and support for a truly read-only journal into jbd. Patch 6 uses the facility introduced in patch 5 to add support for true read-only ext3. For testing I've been using qemu VMs to create and mount dirtied filesystems. I have a set of scripts that fully automates creating a dirty filesystem then checking mounting read-only and read-write produces consistent results. On my system it can get through around ~30 iteration overnight. If anyone is interested in the scripts please let me know. Any suggestions for additional tests or enhancements that could be made to the scripts would be gratefully received. TODO: * Add R/W remount support * Port to ext4 Cheers, Duane Griffin. > git diff --stat origin fs/ext3/balloc.c | 2 +- fs/ext3/ialloc.c | 2 +- fs/ext3/inode.c | 8 +- fs/ext3/resize.c | 2 +- fs/ext3/super.c | 123 ++++++++++----- fs/ext3/xattr.c | 8 +- fs/jbd/checkpoint.c | 2 +- fs/jbd/commit.c | 2 +- fs/jbd/journal.c | 68 +++++--- fs/jbd/recovery.c | 402 +++++++++++++++++++++++++++++++++-------------- fs/jbd/revoke.c | 133 ++++++---------- fs/ocfs2/journal.c | 4 +- include/linux/ext3_fs.h | 7 + include/linux/jbd.h | 41 +++++- 14 files changed, 516 insertions(+), 288 deletions(-) -- 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
