The subject should have been [PATCH 00/27]... Sorry for the mistake. Honza On Mon 16-04-12 18:13:38, Jan Kara wrote: > Hello, > > here is the fifth iteration of my patches to improve filesystem freezing. > No serious changes since last time. Mostly I rebased patches and merged this > series with series moving file_update_time() to ->page_mkwrite() to simplify > testing and merging. > > Filesystem freezing is currently racy and thus we can end up with dirty data on > frozen filesystem (see changelog patch 13 for detailed race description). This > patch series aims at fixing this. > > To be able to block all places where inodes get dirtied, I've moved filesystem > file_update_time() call to ->page_mkwrite callback (patches 01-07) and put > freeze handling in mnt_want_write() / mnt_drop_write(). That however required > some code shuffling and changes to kern_path_create() (see patches 09-12). I > think the result is OK but opinions may differ ;). The advantage of this change > also is that all filesystems get freeze protection almost for free - even ext2 > can handle freezing well now. > > Another potential contention point might be patch 19. In that patch we make > freeze_super() refuse to freeze the filesystem when there are open but unlinked > files which may be impractical in some cases. The main reason for this is the > problem with handling of file deletion from fput() called with mmap_sem held > (e.g. from munmap(2)), and then there's the fact that we cannot really force > such filesystem into a consistent state... But if people think that freezing > with open but unlinked files should happen, then I have some possible > solutions in mind (maybe as a separate patchset since this is large enough). > > I'm not able to hit any deadlocks, lockdep warnings, or dirty data on frozen > filesystem despite beating it with fsstress and bash-shared-mapping while > freezing and unfreezing for several hours (using ext4 and xfs) so I'm > reasonably confident this could finally be the right solution. > > Changes since v4: > * added a couple of Acked-by's > * added some comments & doc update > * added patches from series "Push file_update_time() into .page_mkwrite" > since it doesn't make much sense to keep them separate anymore > * rebased on top of 3.4-rc2 > > Changes since v3: > * added third level of freezing for fs internal purposes - hooked some > filesystems to use it (XFS, nilfs2) > * removed racy i_size check from filemap_mkwrite() > > Changes since v2: > * completely rewritten > * freezing is now blocked at VFS entry points > * two stage freezing to handle both mmapped writes and other IO > > The biggest changes since v1: > * have two counters to provide safe state transitions for SB_FREEZE_WRITE > and SB_FREEZE_TRANS states > * use percpu counters instead of own percpu structure > * added documentation fixes from the old fs freezing series > * converted XFS to use SB_FREEZE_TRANS counter instead of its private > m_active_trans counter > > Honza > > CC: Alex Elder <elder@xxxxxxxxxx> > CC: Anton Altaparmakov <anton@xxxxxxxxxx> > CC: Ben Myers <bpm@xxxxxxx> > CC: Chris Mason <chris.mason@xxxxxxxxxx> > CC: cluster-devel@xxxxxxxxxx > CC: "David S. Miller" <davem@xxxxxxxxxxxxx> > CC: fuse-devel@xxxxxxxxxxxxxxxxxxxxx > CC: "J. Bruce Fields" <bfields@xxxxxxxxxxxx> > CC: Joel Becker <jlbec@xxxxxxxxxxxx> > CC: KONISHI Ryusuke <konishi.ryusuke@xxxxxxxxxxxxx> > CC: linux-btrfs@xxxxxxxxxxxxxxx > CC: linux-ext4@xxxxxxxxxxxxxxx > CC: linux-nfs@xxxxxxxxxxxxxxx > CC: linux-nilfs@xxxxxxxxxxxxxxx > CC: linux-ntfs-dev@xxxxxxxxxxxxxxxxxxxxx > CC: Mark Fasheh <mfasheh@xxxxxxxx> > CC: Miklos Szeredi <miklos@xxxxxxxxxx> > CC: ocfs2-devel@xxxxxxxxxxxxxx > CC: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> > CC: Steven Whitehouse <swhiteho@xxxxxxxxxx> > CC: "Theodore Ts'o" <tytso@xxxxxxx> > CC: xfs@xxxxxxxxxxx -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
