Hi, Here is the V7 of the patches. These patches apply on top of overlayfs-next branch of miklos's tree. I have taken care of most of the comments from previous iteration. These patches are very lightly tested. First I want to make sure that I have addressed all design concerns. Once that is done, will do more extensive testing. Following are changes from V6. - Cherry picked Amir's patch to disable redirect_dir and index feature if upper does not support xattr. - Disable metacopy if upper does not support xattr. - Merged encryption and compression patch. - Merged barriers patch into core patch. - Now OVL_UPPERDATA is set for all kind of dentries. Read side of OVL_UPPERDATA first checks whether dentry in question should have this flag set or not. - Now smp_rmb() is called only when checking OVL_UPPERDATA from lockless path. - Miscellaneous code cleanus as asked by Amir. Original Description -------------------- In one of the recent converstions, people mentioned that chown/chmod lead to copy up files as well as data. We could optimize it so that only metadata is copied up during chown/chmod and data is copied up when file is opened for WRITE. This optimization potentially could be useful with containers and user namespaces. In popular scenario, people end up doing chown() on whole image directory tree based on container mappings. And this chown copies up everything, breaking sharing of page cache between containers. With these patches, only metadat is copied up during chown() and if file is opened for READ, d_real() returns lower dentry/inode. That way, different containers can still continue to use page cache. That's the use case I have in mind. Basically, I am relying on storing OVL_XATTR_ORIGIN in upper inode during copy up. I use that information to get to lower inode later and do data copy up when necessary. I also store OVL_XATTR_METACOPY in upper inode to mark that only metadata has been copied up and data copy up still might be required. Any feedback is helpful. Thanks Vivek Amir Goldstein (1): ovl: disable redirect_dir and index when no xattr support Vivek Goyal (13): ovl: ovl_check_setxattr() get rid of redundant -EOPNOTSUPP check ovl: Create origin xattr on copy up for all files ovl: Provide a mount option metacopy=on/off for metadata copyup ovl: During copy up, first copy up metadata and then data ovl: Move couple of copy up functions in copy_up.c ovl: Copy up only metadata during copy up where it makes sense ovl: Add helper ovl_already_copied_up() ovl: A new xattr OVL_XATTR_METACOPY for file on upper ovl: Fix ovl_getattr() to get number of blocks from lower ovl: Set OVL_UPPERDATA flag during ovl_lookup() ovl: Do not expose metacopy only upper dentry from d_real() ovl: Fix encryption/compression status of a metacopy only file ovl: Enable metadata only feature fs/overlayfs/Kconfig | 8 +++ fs/overlayfs/copy_up.c | 161 ++++++++++++++++++++++++++++++++++------------- fs/overlayfs/dir.c | 1 + fs/overlayfs/inode.c | 58 ++++++++--------- fs/overlayfs/namei.c | 40 ++++++++++++ fs/overlayfs/overlayfs.h | 9 ++- fs/overlayfs/ovl_entry.h | 1 + fs/overlayfs/super.c | 61 ++++++++++++++++-- fs/overlayfs/util.c | 107 +++++++++++++++++++++++++++---- 9 files changed, 352 insertions(+), 94 deletions(-) -- 2.13.6 -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
