Commit Graph

362 Commits

Author SHA1 Message Date
Amir Goldstein
f81678173c ovl: fix another overlay: warning prefix
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-19 17:43:24 +01:00
Amir Goldstein
6d0a8a90a5 ovl: take lower dir inode mutex outside upper sb_writers lock
The functions ovl_lower_positive() and ovl_check_empty_dir() both take
inode mutex on the real lower dir under ovl_want_write() which takes
the upper_mnt sb_writers lock.

While this is not a clear locking order or layering violation, it creates
an undesired lock dependency between two unrelated layers for no good
reason.

This lock dependency materializes to a false(?) positive lockdep warning
when calling rmdir() on a nested overlayfs, where both nested and
underlying overlayfs both use the same fs type as upper layer.

rmdir() on the nested overlayfs creates the lock chain:
  sb_writers of upper_mnt (e.g. tmpfs) in ovl_do_remove()
  ovl_i_mutex_dir_key[] of lower overlay dir in ovl_lower_positive()

rmdir() on the underlying overlayfs creates the lock chain in
reverse order:
  ovl_i_mutex_dir_key[] of lower overlay dir in vfs_rmdir()
  sb_writers of nested upper_mnt (e.g. tmpfs) in ovl_do_remove()

To rid of the unneeded locking dependency, move both ovl_lower_positive()
and ovl_check_empty_dir() to before ovl_want_write() in rmdir() and
rename() implementation.

This change spreads the pieces of ovl_check_empty_and_clear() directly
inside the rmdir()/rename() implementations so the helper is no longer
needed and removed.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-19 17:43:23 +01:00
Amir Goldstein
d796e77f1d ovl: fix failure to fsync lower dir
As a writable mount, it is not expected for overlayfs to return
EINVAL/EROFS for fsync, even if dir/file is not changed.

This commit fixes the case of fsync of directory, which is easier to
address, because overlayfs already implements fsync file operation for
directories.

The problem reported by Raphael is that new PostgreSQL 10.0 with a
database in overlayfs where lower layer in squashfs fails to start.
The failure is due to fsync error, when PostgreSQL does fsync on all
existing db directories on startup and a specific directory exists
lower layer with no changes.

Reported-by: Raphael Hertzog <raphael@ouaza.com>
Cc: <stable@vger.kernel.org> # v3.18
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Tested-by: Raphaël Hertzog <hertzog@debian.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-01-19 13:54:33 +01:00
Amir Goldstein
31747eda41 ovl: hash directory inodes for fsnotify
fsnotify pins a watched directory inode in cache, but if directory dentry
is released, new lookup will allocate a new dentry and a new inode.
Directory events will be notified on the new inode, while fsnotify listener
is watching the old pinned inode.

Hash all directory inodes to reuse the pinned inode on lookup. Pure upper
dirs are hashes by real upper inode, merge and lower dirs are hashed by
real lower inode.

The reference to lower inode was being held by the lower dentry object
in the overlay dentry (oe->lowerstack[0]). Releasing the overlay dentry
may drop lower inode refcount to zero. Add a refcount on behalf of the
overlay inode to prevent that.

As a by-product, hashing directory inodes also detects multiple
redirected dirs to the same lower dir and uncovered redirected dir
target on and returns -ESTALE on lookup.

The reported issue dates back to initial version of overlayfs, but this
patch depends on ovl_inode code that was introduced in kernel v4.13.

Cc: <stable@vger.kernel.org> #v4.13
Reported-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Tested-by: Niklas Cassel <niklas.cassel@axis.com>
2018-01-19 13:54:33 +01:00
Amir Goldstein
da2e6b7eed ovl: fix overlay: warning prefix
Conform two stray warning messages to the standard overlayfs: prefix.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-12-14 11:14:52 +01:00
Vasyl Gomonovych
7879cb43f9 ovl: Use PTR_ERR_OR_ZERO()
Fix ptr_ret.cocci warnings:
fs/overlayfs/overlayfs.h:179:11-17: WARNING: PTR_ERR_OR_ZERO can be used

Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR

Generated by: scripts/coccinelle/api/ptr_ret.cocci

Signed-off-by: Vasyl Gomonovych <gomonovych@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-12-11 11:28:11 +01:00
Chengguang Xu
e8d4bfe3a7 ovl: Sync upper dirty data when syncing overlayfs
When executing filesystem sync or umount on overlayfs,
dirty data does not get synced as expected on upper filesystem.
This patch fixes sync filesystem method to keep data consistency
for overlayfs.

Signed-off-by: Chengguang Xu <cgxu@mykernel.net>
Fixes: e593b2bf51 ("ovl: properly implement sync_filesystem()")
Cc: <stable@vger.kernel.org> #4.11
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-12-11 11:28:11 +01:00
Amir Goldstein
b02a16e641 ovl: update ctx->pos on impure dir iteration
This fixes a regression with readdir of impure dir in overlayfs
that is shared to VM via 9p fs.

Reported-by: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
Fixes: 4edb83bb10 ("ovl: constant d_ino for non-merge dirs")
Cc: <stable@vger.kernel.org> #4.14
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Tested-by: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-12-11 11:28:11 +01:00
Vivek Goyal
08d8f8a5b0 ovl: Pass ovl_get_nlink() parameters in right order
Right now we seem to be passing index as "lowerdentry" and origin.dentry
as "upperdentry". IIUC, we should pass these parameters in reversed order
and this looks like a bug.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Amir Goldstein <amir73il@gmail.com>
Fixes: caf70cb2ba ("ovl: cleanup orphan index entries")
Cc: <stable@vger.kernel.org> #v4.13
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-12-11 11:28:10 +01:00
Miklos Szeredi
438c84c2f0 ovl: don't follow redirects if redirect_dir=off
Overlayfs is following redirects even when redirects are disabled. If this
is unintentional (probably the majority of cases) then this can be a
problem.  E.g. upper layer comes from untrusted USB drive, and attacker
crafts a redirect to enable read access to otherwise unreadable
directories.

If "redirect_dir=off", then turn off following as well as creation of
redirects.  If "redirect_dir=follow", then turn on following, but turn off
creation of redirects (which is what "redirect_dir=off" does now).

This is a backward incompatible change, so make it dependent on a config
option.

Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-12-11 11:28:10 +01:00
Linus Torvalds
1751e8a6cb Rename superblock flags (MS_xyz -> SB_xyz)
This is a pure automated search-and-replace of the internal kernel
superblock flags.

The s_flags are now called SB_*, with the names and the values for the
moment mirroring the MS_* flags that they're equivalent to.

Note how the MS_xyz flags are the ones passed to the mount system call,
while the SB_xyz flags are what we then use in sb->s_flags.

The script to do this was:

    # places to look in; re security/*: it generally should *not* be
    # touched (that stuff parses mount(2) arguments directly), but
    # there are two places where we really deal with superblock flags.
    FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
            include/linux/fs.h include/uapi/linux/bfs_fs.h \
            security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
    # the list of MS_... constants
    SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
          DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
          POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
          I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
          ACTIVE NOUSER"

    SED_PROG=
    for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done

    # we want files that contain at least one of MS_...,
    # with fs/namespace.c and fs/pnode.c excluded.
    L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')

    for f in $L; do sed -i $f $SED_PROG; done

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-27 13:05:09 -08:00
Linus Torvalds
b04a23421b Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi:

 - Report constant st_ino values across copy-up even if underlying
   layers are on different filesystems, but using different st_dev
   values for each layer.

   Ideally we'd report the same st_dev across the overlay, and it's
   possible to do for filesystems that use only 32bits for st_ino by
   unifying the inum space. It would be nice if it wasn't a choice of 32
   or 64, rather filesystems could report their current maximum (that
   could change on resize, so it wouldn't be set in stone).

 - miscellaneus fixes and a cleanup of ovl_fill_super(), that was long
   overdue.

 - created a path_put_init() helper that clears out the pointers after
   putting the ref.

   I think this could be useful elsewhere, so added it to <linux/path.h>

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (30 commits)
  ovl: remove unneeded arg from ovl_verify_origin()
  ovl: Put upperdentry if ovl_check_origin() fails
  ovl: rename ufs to ofs
  ovl: clean up getting lower layers
  ovl: clean up workdir creation
  ovl: clean up getting upper layer
  ovl: move ovl_get_workdir() and ovl_get_lower_layers()
  ovl: reduce the number of arguments for ovl_workdir_create()
  ovl: change order of setup in ovl_fill_super()
  ovl: factor out ovl_free_fs() helper
  ovl: grab reference to workbasedir early
  ovl: split out ovl_get_indexdir() from ovl_fill_super()
  ovl: split out ovl_get_lower_layers() from ovl_fill_super()
  ovl: split out ovl_get_workdir() from ovl_fill_super()
  ovl: split out ovl_get_upper() from ovl_fill_super()
  ovl: split out ovl_get_lowerstack() from ovl_fill_super()
  ovl: split out ovl_get_workpath() from ovl_fill_super()
  ovl: split out ovl_get_upperpath() from ovl_fill_super()
  ovl: use path_put_init() in error paths for ovl_fill_super()
  vfs: add path_put_init()
  ...
2017-11-17 13:36:59 -08:00
Amir Goldstein
d976807606 ovl: remove unneeded arg from ovl_verify_origin()
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-10 09:39:16 +01:00
Vivek Goyal
5455f92b54 ovl: Put upperdentry if ovl_check_origin() fails
If ovl_check_origin() fails, we should put upperdentry. We have a reference
on it by now. So goto out_put_upper instead of out.

Fixes: a9d019573e ("ovl: lookup non-dir copy-up-origin by file handle")
Cc: <stable@vger.kernel.org> #4.12
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-10 09:39:16 +01:00
Miklos Szeredi
ad204488d3 ovl: rename ufs to ofs
Rename all "struct ovl_fs" pointers to "ofs".  The "ufs" name is historical
and can only be found in overlayfs/super.c.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-10 09:39:16 +01:00
Miklos Szeredi
4155c10a03 ovl: clean up getting lower layers
Move calling ovl_get_lower_layers() into ovl_get_lowerstack().

ovl_get_lowerstack() now returns the root dentry's filled in ovl_entry.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-10 09:39:15 +01:00
Miklos Szeredi
bca44b52f8 ovl: clean up workdir creation
Move calling ovl_get_workdir() into ovl_get_workpath().

Rename ovl_get_workdir() to ovl_make_workdir() and ovl_get_workpath() to
ovl_get_workdir().

Workpath is now not needed outside ovl_get_workdir().

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-10 09:39:15 +01:00
Miklos Szeredi
5064975e7f ovl: clean up getting upper layer
Merge ovl_get_upper() and ovl_get_upperpath().

The resulting function is named ovl_get_upper(), though it still returns
upperpath as well.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-10 09:39:15 +01:00
Miklos Szeredi
520d7c867f ovl: move ovl_get_workdir() and ovl_get_lower_layers()
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-10 09:39:15 +01:00
Miklos Szeredi
6e88256e19 ovl: reduce the number of arguments for ovl_workdir_create()
Remove "sb" and "dentry" arguments of ovl_workdir_create() and related
functions.  Move setting MS_RDONLY flag to callers.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-10 09:39:15 +01:00
Miklos Szeredi
c6fe625493 ovl: change order of setup in ovl_fill_super()
Move ovl_get_upper() immediately after ovl_get_upperpath(),
ovl_get_workdir() immediately after ovl_get_workdir() and
ovl_get_lower_layers() immediately after ovl_get_lowerstack().

Also move prepare_creds() up to where other allocations are happening.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-10 09:39:15 +01:00
Miklos Szeredi
a9075cdb46 ovl: factor out ovl_free_fs() helper
This can be called both from ovl_put_super() and in the error cleanup path
from ovl_fill_super().

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-10 09:39:15 +01:00
Miklos Szeredi
95e6d4177c ovl: grab reference to workbasedir early
and related cleanups.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:29 +01:00
Miklos Szeredi
f7e3a7d947 ovl: split out ovl_get_indexdir() from ovl_fill_super()
It's okay to get rid of the intermediate error label due to ufs being
zeroed on allocation.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:28 +01:00
Miklos Szeredi
c0d91fb910 ovl: split out ovl_get_lower_layers() from ovl_fill_super()
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:28 +01:00
Miklos Szeredi
8ed61dc37e ovl: split out ovl_get_workdir() from ovl_fill_super()
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:28 +01:00
Miklos Szeredi
21a3b317a6 ovl: split out ovl_get_upper() from ovl_fill_super()
And don't clobber ufs->upper_mnt on error.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:28 +01:00
Miklos Szeredi
53dbb0b478 ovl: split out ovl_get_lowerstack() from ovl_fill_super()
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:28 +01:00
Miklos Szeredi
87ad447a9d ovl: split out ovl_get_workpath() from ovl_fill_super()
It's okay to get rid of the intermediate error label due to ufs being
zeroed on allocation.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:28 +01:00
Miklos Szeredi
6ee8acf0f7 ovl: split out ovl_get_upperpath() from ovl_fill_super()
It's okay to get rid of the intermediate error label due to ufs being
zeroed on allocation.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:28 +01:00
Miklos Szeredi
8aafcb593d ovl: use path_put_init() in error paths for ovl_fill_super()
This allows simplifying the error cleanup later.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:28 +01:00
Amir Goldstein
f30536f0f9 ovl: update cache version of impure parent on rename
ovl_rename() updates dir cache version for impure old parent if an entry
with copy up origin is moved into old parent, but it did not update
cache version if the entry moved out of old parent has a copy up origin.

[SzM] Same for new dir: we updated the version if an entry with origin was
moved in, but not if an entry with origin was moved out.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:27 +01:00
Amir Goldstein
a0c5ad307a ovl: relax same fs constraint for constant st_ino
For the case of all layers not on the same fs, return the copy up origin
inode st_dev/st_ino for non-dir from stat(2).

This guaranties constant st_dev/st_ino for non-dir across copy up.
Like the same fs case, st_ino of non-dir is also persistent.

If the st_dev/st_ino for copied up object would have been the same as
that of the real underlying lower file, running diff on underlying lower
file and overlay copied up file would result in diff reporting that the
two files are equal when in fact, they may have different content.

Therefore, unlike the same fs case, st_dev is not persistent because it
uses the unique anonymous bdev allocated for the lower layer.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:27 +01:00
Chandan Rajendra
ba1e563cdc ovl: return anonymous st_dev for lower inodes
For non-samefs setup, to make sure that st_dev/st_ino pair is unique
across the system, we return a unique anonymous st_dev for stat(2)
of lower layer inode.

A following patch is going to fix constant st_dev/st_ino across copy up
by returning origin st_dev/st_ino for copied up objects.

If the st_dev/st_ino for copied up object would have been the same as
that of the real underlying lower file, running diff on underlying lower
file and overlay copied up file would result in diff reporting that the
2 files are equal when in fact, they may have different content.

[amir: simplify ovl_get_pseudo_dev()
       split from allocate anonymous bdev patch]

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:27 +01:00
Chandan Rajendra
2a9c6d066e ovl: allocate anonymous devs for lowerdirs
Generate unique values of st_dev per lower layer for non-samefs
overlay mount. The unique values are obtained by allocating anonymous
bdevs for each of the lowerdirs in the overlayfs instance.

The anonymous bdev is going to be returned by stat(2) for lowerdir
non-dir entries in non-samefs case.

[amir: split from ovl_getattr() and re-structure patches]

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:27 +01:00
Chandan Rajendra
b93436320c ovl: re-structure overlay lower layers in-memory
Define new structures to represent overlay instance lower layers and
overlay merge dir lower layers to make room for storing more per layer
information in-memory.

Instead of keeping the fs instance lower layers in an array of struct
vfsmount, keep them in an array of new struct ovl_layer, that has a
pointer to struct vfsmount.

Instead of keeping the dentry lower layers in an array of struct path,
keep them in an array of new struct ovl_path, that has a pointer to
struct dentry and to struct ovl_layer.

Add a small helper to find the fs layer id that correspopnds to a lower
struct ovl_path and use it in ovl_lookup().

[amir: split re-structure from anonymous bdev patch]

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:27 +01:00
Amir Goldstein
ee023c30d7 ovl: move include of ovl_entry.h into overlayfs.h
Most overlayfs c files already explicitly include ovl_entry.h
to use overlay entry struct definitions and upcoming changes
are going to require even more c files to include this header.

All overlayfs c files include overlayfs.h and overlayfs.h itself
refers to some structs defined in ovl_entry.h, so it seems more
logic to include ovl_entry.h from overlayfs.h than from c files.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:27 +01:00
zhangyi (F)
07f6fff148 ovl: fix rmdir problem on non-merge dir with origin xattr
An "origin && non-merge" upper dir may have leftover whiteouts that
were created in past mount. overlayfs does no clear this dir when we
delete it, which may lead to rmdir fail or temp file left in workdir.

Simple reproducer:
  mkdir lower upper work merge
  mkdir -p lower/dir
  touch lower/dir/a
  mount -t overlay overlay -olowerdir=lower,upperdir=upper,\
    workdir=work merge
  rm merge/dir/a
  umount merge
  rm -rf lower/*
  touch lower/dir  (*)
  mount -t overlay overlay -olowerdir=lower,upperdir=upper,\
    workdir=work merge
  rm -rf merge/dir

Syslog dump:
  overlayfs: cleanup of 'work/#7' failed (-39)

(*): if we do not create the regular file, the result is different:
  rm: cannot remove "dir/": Directory not empty

This patch adds a check for the case of non-merge dir that may contain
whiteouts, and calls ovl_check_empty_dir() to check and clear whiteouts
from upper dir when an empty dir is being deleted.

[amir: split patch from ovl_check_empty_dir() cleanup
       rename ovl_is_origin() to ovl_may_have_whiteouts()
       check OVL_WHITEOUTS flag instead of checking origin xattr]

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:27 +01:00
zhangyi (F)
95e598e7ac ovl: simplify ovl_check_empty_and_clear()
Filter out non-whiteout non-upper entries from list of merge dir entries
while checking if merge dir is empty in ovl_check_empty_dir().
The remaining work for ovl_clear_empty() is to clear all entries on the
list.

[amir: split patch from rmdir bug fix]

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:27 +01:00
Amir Goldstein
b79e05aaa1 ovl: no direct iteration for dir with origin xattr
If a non-merge dir in an overlay mount has an overlay.origin xattr, it
means it was once an upper merge dir, which may contain whiteouts and
then the lower dir was removed under it.

Do not iterate real dir directly in this case to avoid exposing whiteouts.

[SzM] Set OVL_WHITEOUT for all merge directories as well.

[amir] A directory that was just copied up does not have the OVL_WHITEOUTS
flag. We need to set it to fix merge dir iteration.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:26 +01:00
Amir Goldstein
4eae06de48 ovl: lockdep annotate of nested OVL_I(inode)->lock
This fixes a lockdep splat when mounting a nested overlayfs.

Fixes: a015dafcaf ("ovl: use ovl_inode mutex to synchronize...")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-11-09 10:23:26 +01:00
Ingo Molnar
8c5db92a70 Merge branch 'linus' into locking/core, to resolve conflicts
Conflicts:
	include/linux/compiler-clang.h
	include/linux/compiler-gcc.h
	include/linux/compiler-intel.h
	include/uapi/linux/stddef.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-07 10:32:44 +01:00
Amir Goldstein
fa0096e3ba ovl: do not cleanup unsupported index entries
With index=on, ovl_indexdir_cleanup() tries to cleanup invalid index
entries (e.g. bad index name). This behavior could result in cleaning of
entries created by newer kernels and is therefore undesirable.
Instead, abort mount if such entries are encountered. We still cleanup
'stale' entries and 'orphan' entries, both those cases can be a result
of offline changes to lower and upper dirs.

When encoutering an index entry of type directory or whiteout, kernel
was supposed to fallback to read-only mount, but the fill_super()
operation returns EROFS in this case instead of returning success with
read-only mount flag, so mount fails when encoutering directory or
whiteout index entries. Bless this behavior by returning -EINVAL on
directory and whiteout index entries as we do for all unsupported index
entries.

Fixes: 61b674710c ("ovl: do not cleanup directory and whiteout index..")
Cc: <stable@vger.kernel.org> # v4.13
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2017-10-24 16:06:17 +02:00
Amir Goldstein
7937a56fdf ovl: handle ENOENT on index lookup
Treat ENOENT from index entry lookup the same way as treating a returned
negative dentry. Apparently, either could be returned if file is not
found, depending on the underlying file system.

Fixes: 359f392ca5 ("ovl: lookup index entry for copy up origin")
Cc: <stable@vger.kernel.org> # v4.13
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
2017-10-24 16:06:17 +02:00
Amir Goldstein
6eaf011144 ovl: fix EIO from lookup of non-indexed upper
Commit fbaf94ee3c ("ovl: don't set origin on broken lower hardlink")
attempt to avoid the condition of non-indexed upper inode with lower
hardlink as origin. If this condition is found, lookup returns EIO.

The protection of commit mentioned above does not cover the case of lower
that is not a hardlink when it is copied up (with either index=off/on)
and then lower is hardlinked while overlay is offline.

Changes to lower layer while overlayfs is offline should not result in
unexpected behavior, so a permanent EIO error after creating a link in
lower layer should not be considered as correct behavior.

This fix replaces EIO error with success in cases where upper has origin
but no index is found, or index is found that does not match upper
inode. In those cases, lookup will not fail and the returned overlay inode
will be hashed by upper inode instead of by lower origin inode.

Fixes: 359f392ca5 ("ovl: lookup index entry for copy up origin")
Cc: <stable@vger.kernel.org> # v4.13
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-10-24 16:06:16 +02:00
Will Deacon
506458efaf locking/barriers: Convert users of lockless_dereference() to READ_ONCE()
READ_ONCE() now has an implicit smp_read_barrier_depends() call, so it
can be used instead of lockless_dereference() without any change in
semantics.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1508840570-22169-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-24 13:17:33 +02:00
Dan Carpenter
0ce5cdc9d7 ovl: Return -ENOMEM if an allocation fails ovl_lookup()
The error code is missing here so it means we return ERR_PTR(0) or NULL.
The other error paths all return an error code so this probably should
as well.

Fixes: 02b69b284c ("ovl: lookup redirects")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-10-19 16:19:52 +02:00
Hirofumi Nakagawa
b3885bd6ed ovl: add NULL check in ovl_alloc_inode
This was detected by fault injection test

Signed-off-by: Hirofumi Nakagawa <nklabs@gmail.com>
Fixes: 13cf199d00 ("ovl: allocate an ovl_inode struct")
Cc: <stable@vger.kernel.org> # v4.13
2017-10-19 16:19:51 +02:00
Amir Goldstein
85fdee1eef ovl: fix regression caused by exclusive upper/work dir protection
Enforcing exclusive ownership on upper/work dirs caused a docker
regression: https://github.com/moby/moby/issues/34672.

Euan spotted the regression and pointed to the offending commit.
Vivek has brought the regression to my attention and provided this
reproducer:

Terminal 1:

  mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none
        merged/

Terminal 2:

  unshare -m

Terminal 1:

  umount merged
  mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none
        merged/
  mount: /root/overlay-testing/merged: none already mounted or mount point
         busy

To fix the regression, I replaced the error with an alarming warning.
With index feature enabled, mount does fail, but logs a suggestion to
override exclusive dir protection by disabling index.
Note that index=off mount does take the inuse locks, so a concurrent
index=off will issue the warning and a concurrent index=on mount will fail.

Documentation was updated to reflect this change.

Fixes: 2cac0c00a6 ("ovl: get exclusive ownership on upper/work dirs")
Cc: <stable@vger.kernel.org> # v4.13
Reported-by: Euan Kemp <euank@euank.com>
Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-10-05 15:53:18 +02:00
Amir Goldstein
5820dc0888 ovl: fix missing unlock_rename() in ovl_do_copy_up()
Use the ovl_lock_rename_workdir() helper which requires
unlock_rename() only on lock success.

Fixes: ("fd210b7d67ee ovl: move copy up lock out")
Cc: <stable@vger.kernel.org> # v4.13
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-10-05 15:53:18 +02:00