Eric Lee / smarc-fsl-linux-kernel

22 Jun, 2015

1 commit

  • cdb672795   ovl: lookup whiteouts outside iterate_dir() ... Browse Code »

    If jffs2 can deadlock on overlayfs readdir because it takes the same lock
    on ->iterate() as in ->lookup().

    Fix by moving whiteout checking outside iterate_dir(). Optimized by
    collecting potential whiteouts (DT_CHR) in a temporary list and if
    non-empty iterating throug these and checking for a 0/0 chardev.

    Signed-off-by: Miklos Szeredi
    Fixes: 49c21e1cacd7 ("ovl: check whiteout while reading directory")
    Reported-by: Roman Yeryomin

    Miklos Szeredi
     

20 Feb, 2015

1 commit

09 Jan, 2015

1 commit

  • 4330397e4   ovl: discard independent cursor in readdir() ... Browse Code »

    Since the ovl_dir_cache is stable during a directory reading, the cursor
    of struct ovl_dir_file don't need to be an independent entry in the list
    of a merged directory.

    This patch changes *cursor* to a pointer which points to the entry in the
    ovl_dir_cache. After this, we don't need to check *is_cursor* either.

    Signed-off-by: hujianyang
    Signed-off-by: Miklos Szeredi

    hujianyang
     

13 Dec, 2014

4 commits

  • 3e01cee3b   ovl: check whiteout on lowest layer as well ... Browse Code »

    Not checking whiteouts on lowest layer was an optimization (there's nothing
    to white out there), but it could result in inconsitent behavior when a
    layer previously used as upper/middle is later used as lowest.

    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     
  • 9d7459d83   ovl: multi-layer readdir ... Browse Code »

    If multiple lower layers exist, merge them as well in readdir according to
    the same rules as merging upper with lower. I.e. take whiteouts and opaque
    directories into account on all but the lowers layer.

    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     
  • 1afaba1ec   ovl: make path-type a bitmap ... Browse Code »

    OVL_PATH_PURE_UPPER -> __OVL_PATH_UPPER | __OVL_PATH_PURE
    OVL_PATH_UPPER -> __OVL_PATH_UPPER
    OVL_PATH_MERGE -> __OVL_PATH_UPPER | __OVL_PATH_MERGE
    OVL_PATH_LOWER -> 0

    Multiple R/O layers will allow __OVL_PATH_MERGE without __OVL_PATH_UPPER.

    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     
  • 49c21e1ca   ovl: check whiteout while reading directory ... Browse Code »

    Don't make a separate pass for checking whiteouts, since we can do it while
    reading the upper directory.

    This will make it easier to handle multiple layers.

    Signed-off-by: Miklos Szeredi

    Miklos Szeredi
     

09 Dec, 2014

1 commit

20 Nov, 2014

2 commits

05 Nov, 2014

1 commit

  • 3f822c626   ovl: don't poison cursor ... Browse Code »

    ovl_cache_put() can be called from ovl_dir_reset() if the cache needs to be
    rebuilt. We did list_del() on the cursor, which results in an Oops on the
    poisoned pointer in ovl_seek_cursor().

    Reported-by: Jordi Pujol Palomer
    Signed-off-by: Miklos Szeredi
    Tested-by: Jordi Pujol Palomer
    Signed-off-by: Al Viro

    Miklos Szeredi
     

01 Nov, 2014

2 commits

29 Oct, 2014

3 commits

  • d1b72cc6d   overlayfs: fix lockdep misannotation ... Browse Code »

    In an overlay directory that shadows an empty lower directory, say
    /mnt/a/empty102, do:

    touch /mnt/a/empty102/x
    unlink /mnt/a/empty102/x
    rmdir /mnt/a/empty102

    It's actually harmless, but needs another level of nesting between
    I_MUTEX_CHILD and I_MUTEX_NORMAL.

    Signed-off-by: Miklos Szeredi
    Tested-by: David Howells
    Signed-off-by: Al Viro

    Miklos Szeredi
     
  • c2096537d   ovl: fix check for cursor ... Browse Code »

    ovl_cache_entry.name is now an array not a pointer, so it makes no sense
    test for it being NULL.

    Detected by coverity.

    From: Miklos Szeredi
    Fixes: 68bf8611076a ("overlayfs: make ovl_cache_entry->name an array instead of
    +pointer")
    Signed-off-by: Miklos Szeredi
    Signed-off-by: Al Viro

    Miklos Szeredi
     
  • d45f00ae4   overlayfs: barriers for opening upper-layer directory ... Browse Code »

    make sure that
    a) all stores done by opening struct file don't leak past storing
    the reference in od->upperfile
    b) the lockless side has read dependency barrier

    Signed-off-by: Al Viro

    Al Viro
     

25 Oct, 2014

4 commits

24 Oct, 2014

1 commit

  • e9be9d5e7   overlay filesystem ... Browse Code »

    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 :
    - minimal remount support
    - use correct seek function for directories
    - initialise is_real before use
    - rename ovl_fill_cache to ovl_dir_read

    Felix Fietkau :
    - fix a deadlock in ovl_dir_read_merged
    - fix a deadlock in ovl_remove_whiteouts

    Erez Zadok
    - fix cleanup after WARN_ON

    Sedat Dilek
    - fix up permission to confirm to new API

    Robin Dong
    - fix possible leak in ovl_new_inode
    - create new inode in ovl_link

    Andy Whitcroft
    - 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
    Andy Whitcroft
    Michal Suchanek
    Felix Fietkau
    Erez Zadok
    Randy Dunlap

    Signed-off-by: Miklos Szeredi

    Miklos Szeredi