linux.git/fs/overlayfs/readdir.c, branch v5.2

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license version 2 as
  published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Enrico Weigelt 
Reviewed-by: Kate Stewart 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman

ovl: fix wrong use of impure dir cache in ovl_iterate()

2018-07-17T14:04:34+00:00

Only upper dir can be impure, but if we are in the middle of
iterating a lower real dir, dir could be copied up and marked
impure. We only want the impure cache if we started iterating
a real upper dir to begin with.

Aditya Kali reported that the following reproducer hits the
WARN_ON(!cache->refcount) in ovl_get_cache():

 docker run --rm drupal:8.5.4-fpm-alpine \
    sh -c 'cd /var/www/html/vendor/symfony && \
           chown -R www-data:www-data . && ls -l .'

Reported-by: Aditya Kali 
Tested-by: Aditya Kali 
Fixes: 4edb83bb1041 ('ovl: constant d_ino for non-merge dirs')
Cc:  # v4.14
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

ovl: consistent d_ino for non-samefs with xino

2018-04-12T10:04:50+00:00

When overlay layers are not all on the same fs, but all inode numbers
of underlying fs do not use the high 'xino' bits, overlay st_ino values
are constant and persistent.

In that case, relax non-samefs constraint for consistent d_ino and always
iterate non-merge dir using ovl_fill_real() actor so we can remap lower
inode numbers to unique lower fs range.

Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

ovl: whiteout orphan index entries on mount

2018-01-24T10:25:56+00:00

Orphan index entries are non-dir index entries whose union nlink count
dropped to zero. With index=on, orphan index entries are removed on
mount. With NFS export feature enabled, orphan index entries are replaced
with white out index entries to block future open by handle from opening
the lower file.

When dir index has a stale 'upper' xattr, we assume that the upper dir
was removed and we treat the dir index as orphan entry that needs to be
whited out or removed.

Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

ovl: simplify arguments to ovl_check_origin_fh()

2018-01-24T09:19:46+00:00

Pass the fs instance with lower_layers array instead of the dentry
lowerstack array to ovl_check_origin_fh(), because the dentry members
of lowerstack play no role in this helper.

This change simplifies the argument list of ovl_check_origin(),
ovl_cleanup_index() and ovl_verify_index().

Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

ovl: take mnt_want_write() for removing impure xattr

2018-01-19T16:43:24+00:00

The optimization in ovl_cache_get_impure() that tries to remove an
unneeded "impure" xattr needs to take mnt_want_write() on upper fs.

Fixes: 4edb83bb1041 ("ovl: constant d_ino for non-merge dirs")
Cc:  #v4.14
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

ovl: take lower dir inode mutex outside upper sb_writers lock

2018-01-19T16:43:23+00:00

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 
Signed-off-by: Miklos Szeredi

ovl: fix failure to fsync lower dir

2018-01-19T12:54:33+00:00

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 
Cc:  # v3.18
Signed-off-by: Amir Goldstein 
Tested-by: Raphaël Hertzog 
Signed-off-by: Miklos Szeredi

ovl: fix overlay: warning prefix

2017-12-14T10:14:52+00:00

Conform two stray warning messages to the standard overlayfs: prefix.

Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi

ovl: update ctx->pos on impure dir iteration

2017-12-11T10:28:11+00:00

This fixes a regression with readdir of impure dir in overlayfs
that is shared to VM via 9p fs.

Reported-by: Miguel Bernal Marin 
Fixes: 4edb83bb1041 ("ovl: constant d_ino for non-merge dirs")
Cc:  #4.14
Signed-off-by: Amir Goldstein 
Tested-by: Miguel Bernal Marin 
Signed-off-by: Miklos Szeredi