1. 19 Nov, 2014 17 commits
  2. 03 Nov, 2014 2 commits
  3. 31 Oct, 2014 5 commits
  4. 28 Oct, 2014 4 commits
  5. 25 Oct, 2014 4 commits
  6. 24 Oct, 2014 1 commit
    • Al Viro's avatar
      fix inode leaks on d_splice_alias() failure exits · 51486b90
      Al Viro authored
      
      
      d_splice_alias() callers expect it to either stash the inode reference
      into a new alias, or drop the inode reference.  That makes it possible
      to just return d_splice_alias() result from ->lookup() instance, without
      any extra housekeeping required.
      
      Unfortunately, that should include the failure exits.  If d_splice_alias()
      returns an error, it leaves the dentry it has been given negative and
      thus it *must* drop the inode reference.  Easily fixed, but it goes way
      back and will need backporting.
      
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      51486b90
  7. 23 Oct, 2014 7 commits
    • Miklos Szeredi's avatar
      fs: limit filesystem stacking depth · 69c433ed
      Miklos Szeredi authored
      
      
      Add a simple read-only counter to super_block that indicates how deep this
      is in the stack of filesystems.  Previously ecryptfs was the only stackable
      filesystem and it explicitly disallowed multiple layers of itself.
      
      Overlayfs, however, can be stacked recursively and also may be stacked
      on top of ecryptfs or vice versa.
      
      To limit the kernel stack usage we must limit the depth of the
      filesystem stack.  Initially the limit is set to 2.
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
      69c433ed
    • Erez Zadok's avatar
      overlayfs: implement show_options · f45827e8
      Erez Zadok authored
      
      
      This is useful because of the stacking nature of overlayfs.  Users like to
      find out (via /proc/mounts) which lower/upper directory were used at mount
      time.
      
      AV: even failing ovl_parse_opt() could've done some kstrdup()
      AV: failure of ovl_alloc_entry() should end up with ENOMEM, not EINVAL
      Signed-off-by: default avatarErez Zadok <ezk@cs.sunysb.edu>
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
      f45827e8
    • Andy Whitcroft's avatar
      overlayfs: add statfs support · cc259639
      Andy Whitcroft authored
      
      
      Add support for statfs to the overlayfs filesystem.  As the upper layer
      is the target of all write operations assume that the space in that
      filesystem is the space in the overlayfs.  There will be some inaccuracy as
      overwriting a file will copy it up and consume space we were not expecting,
      but it is better than nothing.
      
      Use the upper layer dentry and mount from the overlayfs root inode,
      passing the statfs call to that filesystem.
      Signed-off-by: default avatarAndy Whitcroft <apw@canonical.com>
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
      cc259639
    • Miklos Szeredi's avatar
      overlay filesystem · e9be9d5e
      Miklos Szeredi authored
      
      
      Overlayfs allows one, usually read-write, directory tree to be
      overlaid onto another, read-only directory tree.  All modifications
      go to the upper, writable layer.
      
      This type of mechanism is most often used for live CDs but there's a
      wide variety of other uses.
      
      The implementation differs from other "union filesystem"
      implementations in that after a file is opened all operations go
      directly to the underlying, lower or upper, filesystems.  This
      simplifies the implementation and allows native performance in these
      cases.
      
      The dentry tree is duplicated from the underlying filesystems, this
      enables fast cached lookups without adding special support into the
      VFS.  This uses slightly more memory than union mounts, but dentries
      are relatively small.
      
      Currently inodes are duplicated as well, but it is a possible
      optimization to share inodes for non-directories.
      
      Opening non directories results in the open forwarded to the
      underlying filesystem.  This makes the behavior very similar to union
      mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file
      descriptors).
      
      Usage:
      
        mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay
      
      The following cotributions have been folded into this patch:
      
      Neil Brown <neilb@suse.de>:
       - minimal remount support
       - use correct seek function for directories
       - initialise is_real before use
       - rename ovl_fill_cache to ovl_dir_read
      
      Felix Fietkau <nbd@openwrt.org>:
       - fix a deadlock in ovl_dir_read_merged
       - fix a deadlock in ovl_remove_whiteouts
      
      Erez Zadok <ezk@fsl.cs.sunysb.edu>
       - fix cleanup after WARN_ON
      
      Sedat Dilek <sedat.dilek@googlemail.com>
       - fix up permission to confirm to new API
      
      Robin Dong <hao.bigrat@gmail.com>
       - fix possible leak in ovl_new_inode
       - create new inode in ovl_link
      
      Andy Whitcroft <apw@canonical.com>
       - switch to __inode_permission()
       - copy up i_uid/i_gid from the underlying inode
      
      AV:
       - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits
       - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(),
         lack of check for udir being the parent of upper, dropping and regaining
         the lock on udir (which would require _another_ check for parent being
         right).
       - bogus d_drop() in copyup and rename [fix from your mail]
       - copyup/remove and copyup/rename races [fix from your mail]
       - ovl_dir_fsync() leaving ERR_PTR() in ->realfile
       - ovl_entry_free() is pointless - it's just a kfree_rcu()
       - fold ovl_do_lookup() into ovl_lookup()
       - manually assigning ->d_op is wrong.  Just use ->s_d_op.
       [patches picked from Miklos]:
       * copyup/remove and copyup/rename races
       * bogus d_drop() in copyup and rename
      
      Also thanks to the following people for testing and reporting bugs:
      
        Jordi Pujol <jordipujolp@gmail.com>
        Andy Whitcroft <apw@canonical.com>
        Michal Suchanek <hramrach@centrum.cz>
        Felix Fietkau <nbd@openwrt.org>
        Erez Zadok <ezk@fsl.cs.sunysb.edu>
        Randy Dunlap <rdunlap@xenotime.net>
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
      e9be9d5e
    • Miklos Szeredi's avatar
      ext4: support RENAME_WHITEOUT · cd808dec
      Miklos Szeredi authored
      
      
      Add whiteout support to ext4_rename().  A whiteout inode (chrdev/0,0) is
      created before the rename takes place.  The whiteout inode is added to the
      old entry instead of deleting it.
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
      cd808dec
    • Miklos Szeredi's avatar
      vfs: add RENAME_WHITEOUT · 0d7a8555
      Miklos Szeredi authored
      
      
      This adds a new RENAME_WHITEOUT flag.  This flag makes rename() create a
      whiteout of source.  The whiteout creation is atomic relative to the
      rename.
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
      0d7a8555
    • Miklos Szeredi's avatar
      vfs: add whiteout support · 787fb6bc
      Miklos Szeredi authored
      
      
      Whiteout isn't actually a new file type, but is represented as a char
      device (Linus's idea) with 0/0 device number.
      
      This has several advantages compared to introducing a new whiteout file
      type:
      
       - no userspace API changes (e.g. trivial to make backups of upper layer
         filesystem, without losing whiteouts)
      
       - no fs image format changes (you can boot an old kernel/fsck without
         whiteout support and things won't break)
      
       - implementation is trivial
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
      787fb6bc