Commit graph

653 commits

Author SHA1 Message Date
Amir Goldstein
be4df0cea0 ovl: use generic vfs_ioc_setflags_prepare() helper
Canonalize to ioctl FS_* flags instead of inode S_* flags.

Note that we do not call the helper vfs_ioc_fssetxattr_check()
for FS_IOC_FSSETXATTR ioctl. The reason is that underlying filesystem
will perform all the checks. We only need to perform the capability
check before overriding credentials.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-10-06 15:38:15 +02:00
Amir Goldstein
61536bed21 ovl: support [S|G]ETFLAGS and FS[S|G]ETXATTR ioctls for directories
[S|G]ETFLAGS and FS[S|G]ETXATTR ioctls are applicable to both files and
directories, so add ioctl operations to dir as well.

We teach ovl_real_fdget() to get the realfile of directories which use
a different type of file->private_data.

Ifdef away compat ioctl implementation to conform to standard practice.

With this change, xfstest generic/079 which tests these ioctls on files
and directories passes.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-10-06 15:38:14 +02:00
Miklos Szeredi
8f6ee74c27 ovl: rearrange ovl_can_list()
ovl_can_list() should return false for overlay private xattrs.  Since
currently these use the "trusted.overlay." prefix, they will always match
the "trusted." prefix as well, hence the test for being non-trusted will
not trigger.

Prepare for using the "user.overlay." namespace by moving the test for
private xattr before the test for non-trusted.

This patch doesn't change behavior.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:49 +02:00
Miklos Szeredi
43d193f844 ovl: enumerate private xattrs
Instead of passing the xattr name down to the ovl_do_*xattr() accessor
functions, pass an enumerated value.  The enum can use the same names as
the the previous #define for each xattr name.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:49 +02:00
Miklos Szeredi
610afc0bd4 ovl: pass ovl_fs down to functions accessing private xattrs
This paves the way for optionally using the "user.overlay." xattr
namespace.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:49 +02:00
Miklos Szeredi
26150ab5ea ovl: drop flags argument from ovl_do_setxattr()
All callers pass zero flags to ovl_do_setxattr().  So drop this argument.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:48 +02:00
Miklos Szeredi
7109704705 ovl: adhere to the vfs_ vs. ovl_do_ conventions for xattrs
Call ovl_do_*xattr() when accessing an overlay private xattr, vfs_*xattr()
otherwise.

This has an effect on debug output, which is made more consistent by this
patch.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:48 +02:00
Miklos Szeredi
d5dc7486e8 ovl: use ovl_do_getxattr() for private xattr
Use the convention of calling ovl_do_foo() for operations which are overlay
specific.

This patch is a no-op, and will have significance for supporting
"user.overlay." xattr namespace.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:48 +02:00
Miklos Szeredi
92f0d6c9cf ovl: fold ovl_getxattr() into ovl_get_redirect_xattr()
This is a partial revert (with some cleanups) of commit 993a0b2aec ("ovl:
Do not lose security.capability xattr over metadata file copy-up"), which
introduced ovl_getxattr() in the first place.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:48 +02:00
Miklos Szeredi
de7a52c9c6 ovl: clean up ovl_getxattr() in copy_up.c
Lose the padding and the failure message (in line with other parts of the
copy up process).  Return zero for both nonexistent or empty xattr.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:48 +02:00
Miklos Szeredi
fee0f2980a duplicate ovl_getxattr()
ovl_getattr() returns the value of an xattr in a kmalloced buffer.  There
are two callers:

 ovl_copy_up_meta_inode_data()	(copy_up.c)
 ovl_get_redirect_xattr()	(util.c)

This patch just copies ovl_getxattr() to copy_up.c, the following patches
will deal with the differences in idividual callers.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:48 +02:00
Vivek Goyal
c86243b090 ovl: provide a mount option "volatile"
Container folks are complaining that dnf/yum issues too many sync while
installing packages and this slows down the image build. Build requirement
is such that they don't care if a node goes down while build was still
going on. In that case, they will simply throw away unfinished layer and
start new build. So they don't care about syncing intermediate state to the
disk and hence don't want to pay the price associated with sync.

So they are asking for mount options where they can disable sync on overlay
mount point.

They primarily seem to have two use cases.

- For building images, they will mount overlay with nosync and then sync
  upper layer after unmounting overlay and reuse upper as lower for next
  layer.

- For running containers, they don't seem to care about syncing upper layer
  because if node goes down, they will simply throw away upper layer and
  create a fresh one.

So this patch provides a mount option "volatile" which disables all forms
of sync. Now it is caller's responsibility to throw away upper if system
crashes or shuts down and start fresh.

With "volatile", I am seeing roughly 20% speed up in my VM where I am just
installing emacs in an image. Installation time drops from 31 seconds to 25
seconds when nosync option is used. This is for the case of building on top
of an image where all packages are already cached. That way I take out the
network operations latency out of the measurement.

Giuseppe is also looking to cut down on number of iops done on the disk. He
is complaining that often in cloud their VMs are throttled if they cross
the limit. This option can help them where they reduce number of iops (by
cutting down on frequent sync and writebacks).

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:48 +02:00
Amir Goldstein
235ce9ed96 ovl: check for incompatible features in work dir
An incompatible feature is marked by a non-empty directory nested
2 levels deep under "work" dir, e.g.:
workdir/work/incompat/volatile.

This commit checks for marked incompat features, warns about them
and fails to mount the overlay, for example:
  overlayfs: overlay with incompat feature 'volatile' cannot be mounted

Very old kernels (i.e. v3.18) will fail to remove a non-empty "work"
dir and fail the mount.  Newer kernels will fail to remove a "work"
dir with entries nested 3 levels and fall back to read-only mount.

User mounting with old kernel will see a warning like these in dmesg:
  overlayfs: cleanup of 'incompat/...' failed (-39)
  overlayfs: cleanup of 'work/incompat' failed (-39)
  overlayfs: cleanup of 'ovl-work/work' failed (-39)
  overlayfs: failed to create directory /vdf/ovl-work/work (errno: 17);
             mounting read-only

These warnings should give the hint to the user that:
1. mount failure is caused by backward incompatible features
2. mount failure can be resolved by manually removing the "work" directory

There is nothing preventing users on old kernels from manually removing
workdir entirely or mounting overlay with a new workdir, so this is in
no way a full proof backward compatibility enforcement, but only a best
effort.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-02 10:58:48 +02:00
Linus Torvalds
99ea1521a0 Remove uninitialized_var() macro for v5.9-rc1
- Clean up non-trivial uses of uninitialized_var()
 - Update documentation and checkpatch for uninitialized_var() removal
 - Treewide removal of uninitialized_var()
 -----BEGIN PGP SIGNATURE-----
 
 iQJKBAABCgA0FiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAl8oYLQWHGtlZXNjb29r
 QGNocm9taXVtLm9yZwAKCRCJcvTf3G3AJsfjEACvf0D3WL3H7sLHtZ2HeMwOgAzq
 il08t6vUscINQwiIIK3Be43ok3uQ1Q+bj8sr2gSYTwunV2IYHFferzgzhyMMno3o
 XBIGd1E+v1E4DGBOiRXJvacBivKrfvrdZ7AWiGlVBKfg2E0fL1aQbe9AYJ6eJSbp
 UGqkBkE207dugS5SQcwrlk1tWKUL089lhDAPd7iy/5RK76OsLRCJFzIerLHF2ZK2
 BwvA+NWXVQI6pNZ0aRtEtbbxwEU4X+2J/uaXH5kJDszMwRrgBT2qoedVu5LXFPi8
 +B84IzM2lii1HAFbrFlRyL/EMueVFzieN40EOB6O8wt60Y4iCy5wOUzAdZwFuSTI
 h0xT3JI8BWtpB3W+ryas9cl9GoOHHtPA8dShuV+Y+Q2bWe1Fs6kTl2Z4m4zKq56z
 63wQCdveFOkqiCLZb8s6FhnS11wKtAX4czvXRXaUPgdVQS1Ibyba851CRHIEY+9I
 AbtogoPN8FXzLsJn7pIxHR4ADz+eZ0dQ18f2hhQpP6/co65bYizNP5H3h+t9hGHG
 k3r2k8T+jpFPaddpZMvRvIVD8O2HvJZQTyY6Vvneuv6pnQWtr2DqPFn2YooRnzoa
 dbBMtpon+vYz6OWokC5QNWLqHWqvY9TmMfcVFUXE4AFse8vh4wJ8jJCNOFVp8On+
 drhmmImUr1YylrtVOw==
 =xHmk
 -----END PGP SIGNATURE-----

Merge tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull uninitialized_var() macro removal from Kees Cook:
 "This is long overdue, and has hidden too many bugs over the years. The
  series has several "by hand" fixes, and then a trivial treewide
  replacement.

   - Clean up non-trivial uses of uninitialized_var()

   - Update documentation and checkpatch for uninitialized_var() removal

   - Treewide removal of uninitialized_var()"

* tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  compiler: Remove uninitialized_var() macro
  treewide: Remove uninitialized_var() usage
  checkpatch: Remove awareness of uninitialized_var() macro
  mm/debug_vm_pgtable: Remove uninitialized_var() usage
  f2fs: Eliminate usage of uninitialized_var() macro
  media: sur40: Remove uninitialized_var() usage
  KVM: PPC: Book3S PR: Remove uninitialized_var() usage
  clk: spear: Remove uninitialized_var() usage
  clk: st: Remove uninitialized_var() usage
  spi: davinci: Remove uninitialized_var() usage
  ide: Remove uninitialized_var() usage
  rtlwifi: rtl8192cu: Remove uninitialized_var() usage
  b43: Remove uninitialized_var() usage
  drbd: Remove uninitialized_var() usage
  x86/mm/numa: Remove uninitialized_var() usage
  docs: deprecated.rst: Add uninitialized_var()
2020-08-04 13:49:43 -07:00
Kees Cook
3f649ab728 treewide: Remove uninitialized_var() usage
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-16 12:35:15 -07:00
Amir Goldstein
4518dfcf76 ovl: fix lookup of indexed hardlinks with metacopy
We recently moved setting inode flag OVL_UPPERDATA to ovl_lookup().

When looking up an overlay dentry, upperdentry may be found by index
and not by name.  In that case, we fail to read the metacopy xattr
and falsly set the OVL_UPPERDATA on the overlay inode.

This caused a regression in xfstest overlay/033 when run with
OVERLAY_MOUNT_OPTIONS="-o metacopy=on".

Fixes: 28166ab3c8 ("ovl: initialize OVL_UPPERDATA in ovl_lookup()")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-07-16 07:24:47 +02:00
Amir Goldstein
81a33c1ee9 ovl: fix unneeded call to ovl_change_flags()
The check if user has changed the overlay file was wrong, causing unneeded
call to ovl_change_flags() including taking f_lock on every file access.

Fixes: d989903058 ("ovl: do not generate duplicate fsnotify events for "fake" path")
Cc: <stable@vger.kernel.org> # v4.19+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-07-16 07:24:47 +02:00
Amir Goldstein
f0e1266ed2 ovl: fix mount option checks for nfs_export with no upperdir
Without upperdir mount option, there is no index dir and the dependency
checks nfs_export => index for mount options parsing are incorrect.

Allow the combination nfs_export=on,index=off with no upperdir and move
the check for dependency redirect_dir=nofollow for non-upper mount case
to mount options parsing.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-07-16 00:11:15 +02:00
Amir Goldstein
470c156361 ovl: force read-only sb on failure to create index dir
With index feature enabled, on failure to create index dir, overlay is
being mounted read-only.  However, we do not forbid user to remount overlay
read-write.  Fix that by setting ofs->workdir to NULL, which prevents
remount read-write.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-07-16 00:11:15 +02:00
Amir Goldstein
a888db3101 ovl: fix regression with re-formatted lower squashfs
Commit 9df085f3c9 ("ovl: relax requirement for non null uuid of lower
fs") relaxed the requirement for non null uuid with single lower layer to
allow enabling index and nfs_export features with single lower squashfs.

Fabian reported a regression in a setup when overlay re-uses an existing
upper layer and re-formats the lower squashfs image.  Because squashfs
has no uuid, the origin xattr in upper layer are decoded from the new
lower layer where they may resolve to a wrong origin file and user may
get an ESTALE or EIO error on lookup.

To avoid the reported regression while still allowing the new features
with single lower squashfs, do not allow decoding origin with lower null
uuid unless user opted-in to one of the new features that require
following the lower inode of non-dir upper (index, xino, metacopy).

Reported-by: Fabian <godi.beat@gmx.net>
Link: https://lore.kernel.org/linux-unionfs/32532923.JtPX5UtSzP@fgdesktop/
Fixes: 9df085f3c9 ("ovl: relax requirement for non null uuid of lower fs")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-07-16 00:10:31 +02:00
Amir Goldstein
20396365a1 ovl: fix oops in ovl_indexdir_cleanup() with nfs_export=on
Mounting with nfs_export=on, xfstests overlay/031 triggers a kernel panic
since v5.8-rc1 overlayfs updates.

 overlayfs: orphan index entry (index/00fb1..., ftype=4000, nlink=2)
 BUG: kernel NULL pointer dereference, address: 0000000000000030
 RIP: 0010:ovl_cleanup_and_whiteout+0x28/0x220 [overlay]

Bisect point at commit c21c839b84 ("ovl: whiteout inode sharing")

Minimal reproducer:
--------------------------------------------------
rm -rf l u w m
mkdir -p l u w m
mkdir -p l/testdir
touch l/testdir/testfile
mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m
echo 1 > m/testdir/testfile
umount m
rm -rf u/testdir
mount -t overlay -o lowerdir=l,upperdir=u,workdir=w,nfs_export=on overlay m
umount m
--------------------------------------------------

When mount with nfs_export=on, and fail to verify an orphan index, we're
cleaning this index from indexdir by calling ovl_cleanup_and_whiteout().
This dereferences ofs->workdir, that was earlier set to NULL.

The design was that ovl->workdir will point at ovl->indexdir, but we are
assigning ofs->indexdir to ofs->workdir only after ovl_indexdir_cleanup().
There is no reason not to do it sooner, because once we get success from
ofs->indexdir = ovl_workdir_create(... there is no turning back.

Reported-and-tested-by: Murphy Zhou <jencce.kernel@gmail.com>
Fixes: c21c839b84 ("ovl: whiteout inode sharing")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-07-16 00:09:59 +02:00
Amir Goldstein
124c2de2c0 ovl: relax WARN_ON() when decoding lower directory file handle
Decoding a lower directory file handle to overlay path with cold
inode/dentry cache may go as follows:

1. Decode real lower file handle to lower dir path
2. Check if lower dir is indexed (was copied up)
3. If indexed, get the upper dir path from index
4. Lookup upper dir path in overlay
5. If overlay path found, verify that overlay lower is the lower dir
   from step 1

On failure to verify step 5 above, user will get an ESTALE error and a
WARN_ON will be printed.

A mismatch in step 5 could be a result of lower directory that was renamed
while overlay was offline, after that lower directory has been copied up
and indexed.

This is a scripted reproducer based on xfstest overlay/052:

  # Create lower subdir
  create_dirs
  create_test_files $lower/lowertestdir/subdir
  mount_dirs
  # Copy up lower dir and encode lower subdir file handle
  touch $SCRATCH_MNT/lowertestdir
  test_file_handles $SCRATCH_MNT/lowertestdir/subdir -p -o $tmp.fhandle
  # Rename lower dir offline
  unmount_dirs
  mv $lower/lowertestdir $lower/lowertestdir.new/
  mount_dirs
  # Attempt to decode lower subdir file handle
  test_file_handles $SCRATCH_MNT -p -i $tmp.fhandle

Since this WARN_ON() can be triggered by user we need to relax it.

Fixes: 4b91c30a5a ("ovl: lookup connected ancestor of dir in inode cache")
Cc: <stable@vger.kernel.org> # v4.16+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-07-16 00:09:17 +02:00
youngjun
d78a0dcf64 ovl: remove not used argument in ovl_check_origin
ovl_check_origin outparam 'ctrp' argument not used by caller.  So remove
this argument.

Signed-off-by: youngjun <her0gyugyu@gmail.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-07-16 00:06:16 +02:00
youngjun
5ac8e8025a ovl: change ovl_copy_up_flags static
"ovl_copy_up_flags" is used in copy_up.c.
so, change it static.

Signed-off-by: youngjun <her0gyugyu@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-07-16 00:06:16 +02:00
youngjun
24f14009b8 ovl: inode reference leak in ovl_is_inuse true case.
When "ovl_is_inuse" true case, trap inode reference not put.  plus adding
the comment explaining sequence of ovl_is_inuse after ovl_setup_trap.

Fixes: 0be0bfd2de ("ovl: fix regression caused by overlapping layers detection")
Cc: <stable@vger.kernel.org> # v4.19+
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: youngjun <her0gyugyu@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-07-16 00:05:40 +02:00
Linus Torvalds
52435c86bf overlayfs update for 5.8
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYIAB0WIQSQHSd0lITzzeNWNm3h3BK/laaZPAUCXt9klAAKCRDh3BK/laaZ
 PBeeAP9GRI0yajPzBzz2ZK9KkDc6A7wPiaAec+86Q+c02VncVwEAvq5Pi4um5RTZ
 7SVv56ggKO3Cqx779zVyZTRYDs3+YA4=
 =bpKI
 -----END PGP SIGNATURE-----

Merge tag 'ovl-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull overlayfs updates from Miklos Szeredi:
 "Fixes:

   - Resolve mount option conflicts consistently

   - Sync before remount R/O

   - Fix file handle encoding corner cases

   - Fix metacopy related issues

   - Fix an unintialized return value

   - Add missing permission checks for underlying layers

  Optimizations:

   - Allow multipe whiteouts to share an inode

   - Optimize small writes by inheriting SB_NOSEC from upper layer

   - Do not call ->syncfs() multiple times for sync(2)

   - Do not cache negative lookups on upper layer

   - Make private internal mounts longterm"

* tag 'ovl-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (27 commits)
  ovl: remove unnecessary lock check
  ovl: make oip->index bool
  ovl: only pass ->ki_flags to ovl_iocb_to_rwf()
  ovl: make private mounts longterm
  ovl: get rid of redundant members in struct ovl_fs
  ovl: add accessor for ofs->upper_mnt
  ovl: initialize error in ovl_copy_xattr
  ovl: drop negative dentry in upper layer
  ovl: check permission to open real file
  ovl: call secutiry hook in ovl_real_ioctl()
  ovl: verify permissions in ovl_path_open()
  ovl: switch to mounter creds in readdir
  ovl: pass correct flags for opening real directory
  ovl: fix redirect traversal on metacopy dentries
  ovl: initialize OVL_UPPERDATA in ovl_lookup()
  ovl: use only uppermetacopy state in ovl_lookup()
  ovl: simplify setting of origin for index lookup
  ovl: fix out of bounds access warning in ovl_check_fb_len()
  ovl: return required buffer size for file handles
  ovl: sync dirty data when remounting to ro mode
  ...
2020-06-09 15:40:50 -07:00
youngjun
2068cf7dfb ovl: remove unnecessary lock check
Directory is always locked until "out_unlock" label.  So lock check is not
needed.

Signed-off-by: youngjun <her0gyugyu@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-08 09:57:19 +02:00
Linus Torvalds
0b166a57e6 A lot of bug fixes and cleanups for ext4, including:
* Fix performance problems found in dioread_nolock now that it is the
   default, caused by transaction leaks.
 * Clean up fiemap handling in ext4
 * Clean up and refactor multiple block allocator (mballoc) code
 * Fix a problem with mballoc with a smaller file systems running out
   of blocks because they couldn't properly use blocks that had been
   reserved by inode preallocation.
 * Fixed a race in ext4_sync_parent() versus rename()
 * Simplify the error handling in the extent manipulation code
 * Make sure all metadata I/O errors are felected to ext4_ext_dirty()'s and
   ext4_make_inode_dirty()'s callers.
 * Avoid passing an error pointer to brelse in ext4_xattr_set()
 * Fix race which could result to freeing an inode on the dirty last
   in data=journal mode.
 * Fix refcount handling if ext4_iget() fails
 * Fix a crash in generic/019 caused by a corrupted extent node
 -----BEGIN PGP SIGNATURE-----
 
 iQEyBAABCAAdFiEEK2m5VNv+CHkogTfJ8vlZVpUNgaMFAl7Ze8kACgkQ8vlZVpUN
 gaNChAf4xn0ytFSrweI/S2Sp05G/2L/ocZ2TZZk2ZdGeN1E+ABdSIv/zIF9zuFgZ
 /pY/C+fyEZWt4E3FlNO8gJzoEedkzMCMnUhSIfI+wZbcclyTOSNMJtnrnJKAEtVH
 HOvGZJmg357jy407RCGhZpJ773nwU2xhBTr5OFxvSf9mt/vzebxIOnw5D7HPlC1V
 Fgm6Du8q+tRrPsyjv1Yu4pUEVXMJ7qUcvt326AXVM3kCZO1Aa5GrURX0w3J4mzW1
 tc1tKmtbLcVVYTo9CwHXhk/edbxrhAydSP2iACand3tK6IJuI6j9x+bBJnxXitnr
 vsxsfTYMG18+2SxrJ9LwmagqmrRq
 =HMTs
 -----END PGP SIGNATURE-----

Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "A lot of bug fixes and cleanups for ext4, including:

   - Fix performance problems found in dioread_nolock now that it is the
     default, caused by transaction leaks.

   - Clean up fiemap handling in ext4

   - Clean up and refactor multiple block allocator (mballoc) code

   - Fix a problem with mballoc with a smaller file systems running out
     of blocks because they couldn't properly use blocks that had been
     reserved by inode preallocation.

   - Fixed a race in ext4_sync_parent() versus rename()

   - Simplify the error handling in the extent manipulation code

   - Make sure all metadata I/O errors are felected to
     ext4_ext_dirty()'s and ext4_make_inode_dirty()'s callers.

   - Avoid passing an error pointer to brelse in ext4_xattr_set()

   - Fix race which could result to freeing an inode on the dirty last
     in data=journal mode.

   - Fix refcount handling if ext4_iget() fails

   - Fix a crash in generic/019 caused by a corrupted extent node"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (58 commits)
  ext4: avoid unnecessary transaction starts during writeback
  ext4: don't block for O_DIRECT if IOCB_NOWAIT is set
  ext4: remove the access_ok() check in ext4_ioctl_get_es_cache
  fs: remove the access_ok() check in ioctl_fiemap
  fs: handle FIEMAP_FLAG_SYNC in fiemap_prep
  fs: move fiemap range validation into the file systems instances
  iomap: fix the iomap_fiemap prototype
  fs: move the fiemap definitions out of fs.h
  fs: mark __generic_block_fiemap static
  ext4: remove the call to fiemap_check_flags in ext4_fiemap
  ext4: split _ext4_fiemap
  ext4: fix fiemap size checks for bitmap files
  ext4: fix EXT4_MAX_LOGICAL_BLOCK macro
  add comment for ext4_dir_entry_2 file_type member
  jbd2: avoid leaking transaction credits when unreserving handle
  ext4: drop ext4_journal_free_reserved()
  ext4: mballoc: use lock for checking free blocks while retrying
  ext4: mballoc: refactor ext4_mb_good_group()
  ext4: mballoc: introduce pcpu seqcnt for freeing PA to improve ENOSPC handling
  ext4: mballoc: refactor ext4_mb_discard_preallocations()
  ...
2020-06-05 16:19:28 -07:00
Miklos Szeredi
74c6e384e9 ovl: make oip->index bool
ovl_get_inode() uses oip->index as a bool value, not as a pointer.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-04 10:48:19 +02:00
Miklos Szeredi
b778e1ee1a ovl: only pass ->ki_flags to ovl_iocb_to_rwf()
Next patch will want to pass a modified set of flags, so...

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-04 10:48:19 +02:00
Miklos Szeredi
df820f8de4 ovl: make private mounts longterm
Overlayfs is using clone_private_mount() to create internal mounts for
underlying layers.  These are used for operations requiring a path, such as
dentry_open().

Since these private mounts are not in any namespace they are treated as
short term, "detached" mounts and mntput() involves taking the global
mount_lock, which can result in serious cacheline pingpong.

Make these private mounts longterm instead, which trade the penalty on
mntput() for a slightly longer shutdown time due to an added RCU grace
period when putting these mounts.

Introduce a new helper kern_unmount_many() that can take care of multiple
longterm mounts with a single RCU grace period.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-04 10:48:19 +02:00
Miklos Szeredi
b8e42a651b ovl: get rid of redundant members in struct ovl_fs
ofs->upper_mnt is copied to ->layers[0].mnt and ->layers[0].trap could be
used instead of a separate ->upperdir_trap.

Split the lowerdir option early to get the number of layers, then allocate
the ->layers array, and finally fill the upper and lower layers, as before.

Get rid of path_put_init() in ovl_lower_dir(), since the only caller will
take care of that.

[Colin Ian King] Fix null pointer dereference on null stack pointer on
error return found by Coverity.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-04 10:48:19 +02:00
Miklos Szeredi
08f4c7c86d ovl: add accessor for ofs->upper_mnt
Next patch will remove ofs->upper_mnt, so add an accessor function for this
field.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-04 10:48:19 +02:00
Yuxuan Shui
520da69d26 ovl: initialize error in ovl_copy_xattr
In ovl_copy_xattr, if all the xattrs to be copied are overlayfs private
xattrs, the copy loop will terminate without assigning anything to the
error variable, thus returning an uninitialized value.

If ovl_copy_xattr is called from ovl_clear_empty, this uninitialized error
value is put into a pointer by ERR_PTR(), causing potential invalid memory
accesses down the line.

This commit initialize error with 0. This is the correct value because when
there's no xattr to copy, because all xattrs are private, ovl_copy_xattr
should succeed.

This bug is discovered with the help of INIT_STACK_ALL and clang.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
Link: https://bugs.chromium.org/p/chromium/issues/detail?id=1050405
Fixes: 0956254a2d ("ovl: don't copy up opaqueness")
Cc: stable@vger.kernel.org # v4.8
Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-04 10:48:19 +02:00
Christoph Hellwig
45dd052e67 fs: handle FIEMAP_FLAG_SYNC in fiemap_prep
By moving FIEMAP_FLAG_SYNC handling to fiemap_prep we ensure it is
handled once instead of duplicated, but can still be done under fs locks,
like xfs/iomap intended with its duplicate handling.  Also make sure the
error value of filemap_write_and_wait is propagated to user space.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20200523073016.2944131-8-hch@lst.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-06-03 23:16:55 -04:00
Christoph Hellwig
10c5db2864 fs: move the fiemap definitions out of fs.h
No need to pull the fiemap definitions into almost every file in the
kernel build.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20200523073016.2944131-5-hch@lst.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2020-06-03 23:16:55 -04:00
Chengguang Xu
1434a65ea6 ovl: drop negative dentry in upper layer
Negative dentries of upper layer are useless after construction of
overlayfs' own dentry and may keep in the memory long time even after
unmount of overlayfs instance. This patch tries to drop unnecessary
negative dentry of upper layer to effectively reclaim memory.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-03 09:45:22 +02:00
Miklos Szeredi
05acefb487 ovl: check permission to open real file
Call inode_permission() on real inode before opening regular file on one of
the underlying layers.

In some cases ovl_permission() already checks access to an underlying file,
but it misses the metacopy case, and possibly other ones as well.

Removing the redundant permission check from ovl_permission() should be
considered later.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-03 09:45:22 +02:00
Miklos Szeredi
292f902a40 ovl: call secutiry hook in ovl_real_ioctl()
Verify LSM permissions for underlying file, since vfs_ioctl() doesn't do
it.

[Stephen Rothwell] export security_file_ioctl

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-03 09:45:18 +02:00
Miklos Szeredi
56230d9567 ovl: verify permissions in ovl_path_open()
Check permission before opening a real file.

ovl_path_open() is used by readdir and copy-up routines.

ovl_permission() theoretically already checked copy up permissions, but it
doesn't hurt to re-do these checks during the actual copy-up.

For directory reading ovl_permission() only checks access to topmost
underlying layer.  Readdir on a merged directory accesses layers below the
topmost one as well.  Permission wasn't checked for these layers.

Note: modifying ovl_permission() to perform this check would be far more
complex and hence more bug prone.  The result is less precise permissions
returned in access(2).  If this turns out to be an issue, we can revisit
this bug.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-02 22:20:26 +02:00
Miklos Szeredi
48bd024b8a ovl: switch to mounter creds in readdir
In preparation for more permission checking, override credentials for
directory operations on the underlying filesystems.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-02 22:20:25 +02:00
Miklos Szeredi
130fdbc3d1 ovl: pass correct flags for opening real directory
The three instances of ovl_path_open() in overlayfs/readdir.c do three
different things:

 - pass f_flags from overlay file
 - pass O_RDONLY | O_DIRECTORY
 - pass just O_RDONLY

The value of f_flags can be (other than O_RDONLY):

O_WRONLY	- not possible for a directory
O_RDWR		- not possible for a directory
O_CREAT		- masked out by dentry_open()
O_EXCL		- masked out by dentry_open()
O_NOCTTY	- masked out by dentry_open()
O_TRUNC		- masked out by dentry_open()
O_APPEND	- no effect on directory ops
O_NDELAY	- no effect on directory ops
O_NONBLOCK	- no effect on directory ops
__O_SYNC	- no effect on directory ops
O_DSYNC		- no effect on directory ops
FASYNC		- no effect on directory ops
O_DIRECT	- no effect on directory ops
O_LARGEFILE	- ?
O_DIRECTORY	- only affects lookup
O_NOFOLLOW	- only affects lookup
O_NOATIME	- overlay sets this unconditionally in ovl_path_open()
O_CLOEXEC	- only affects fd allocation
O_PATH		- no effect on directory ops
__O_TMPFILE	- not possible for a directory


Fon non-merge directories we use the underlying filesystem's iterate; in
this case honor O_LARGEFILE from the original file to make sure that open
doesn't get rejected.

For merge directories it's safe to pass O_LARGEFILE unconditionally since
userspace will only see the artificial offsets created by overlayfs.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-02 22:20:25 +02:00
Vivek Goyal
21d8d66abf ovl: fix redirect traversal on metacopy dentries
Amir pointed me to metacopy test cases in unionmount-testsuite and I
decided to run "./run --ov=10 --meta" and it failed while running test
"rename-mass-5.py".

Problem is w.r.t absolute redirect traversal on intermediate metacopy
dentry.  We do not store intermediate metacopy dentries and also skip
current loop/layer and move onto lookup in next layer.  But at the end of
loop, we have logic to reset "poe" and layer index if currnently looked up
dentry has absolute redirect.  We skip all that and that means lookup in
next layer will fail.

Following is simple test case to reproduce this.

- mkdir -p lower upper work merged lower/a lower/b
- touch lower/a/foo.txt
- mount -t overlay -o lowerdir=lower,upperdir=upper,workdir=work,metacopy=on none merged

# Following will create absolute redirect "/a/foo.txt" on upper/b/bar.txt.
- mv merged/a/foo.txt merged/b/bar.txt

# unmount overlay and use upper as lower layer (lower2) for next mount.
- umount merged
- mv upper lower2
- rm -rf work; mkdir -p upper work
- mount -t overlay -o lowerdir=lower2:lower,upperdir=upper,workdir=work,metacopy=on none merged

# Force a metacopy copy-up
- chown bin:bin merged/b/bar.txt

# unmount overlay and use upper as lower layer (lower3) for next mount.
- umount merged
- mv upper lower3
- rm -rf work; mkdir -p upper work
- mount -t overlay -o lowerdir=lower3:lower2:lower,upperdir=upper,workdir=work,metacopy=on none merged

# ls merged/b/bar.txt
ls: cannot access 'bar.txt': Input/output error

Intermediate lower layer (lower2) has metacopy dentry b/bar.txt with
absolute redirect "/a/foo.txt".  We skipped redirect processing at the end
of loop which sets poe to roe and sets the appropriate next lower layer
index.  And that means lookup failed in next layer.

Fix this by continuing the loop for any intermediate dentries.  We still do
not save these at lower stack.  With this fix applied unionmount-testsuite,
"./run --ov-10 --meta" now passes.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-02 22:20:25 +02:00
Vivek Goyal
28166ab3c8 ovl: initialize OVL_UPPERDATA in ovl_lookup()
Currently ovl_get_inode() initializes OVL_UPPERDATA flag and for that it
has to call ovl_check_metacopy_xattr() and check if metacopy xattr is
present or not.

yangerkun reported sometimes underlying filesystem might return -EIO and in
that case error handling path does not cleanup properly leading to various
warnings.

Run generic/461 with ext4 upper/lower layer sometimes may trigger the bug
as below(linux 4.19):

[  551.001349] overlayfs: failed to get metacopy (-5)
[  551.003464] overlayfs: failed to get inode (-5)
[  551.004243] overlayfs: cleanup of 'd44/fd51' failed (-5)
[  551.004941] overlayfs: failed to get origin (-5)
[  551.005199] ------------[ cut here ]------------
[  551.006697] WARNING: CPU: 3 PID: 24674 at fs/inode.c:1528 iput+0x33b/0x400
...
[  551.027219] Call Trace:
[  551.027623]  ovl_create_object+0x13f/0x170
[  551.028268]  ovl_create+0x27/0x30
[  551.028799]  path_openat+0x1a35/0x1ea0
[  551.029377]  do_filp_open+0xad/0x160
[  551.029944]  ? vfs_writev+0xe9/0x170
[  551.030499]  ? page_counter_try_charge+0x77/0x120
[  551.031245]  ? __alloc_fd+0x160/0x2a0
[  551.031832]  ? do_sys_open+0x189/0x340
[  551.032417]  ? get_unused_fd_flags+0x34/0x40
[  551.033081]  do_sys_open+0x189/0x340
[  551.033632]  __x64_sys_creat+0x24/0x30
[  551.034219]  do_syscall_64+0xd5/0x430
[  551.034800]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

One solution is to improve error handling and call iget_failed() if error
is encountered.  Amir thinks that this path is little intricate and there
is not real need to check and initialize OVL_UPPERDATA in ovl_get_inode().
Instead caller of ovl_get_inode() can initialize this state.  And this will
avoid double checking of metacopy xattr lookup in ovl_lookup() and
ovl_get_inode().

OVL_UPPERDATA is inode flag.  So I was little concerned that initializing
it outside ovl_get_inode() might have some races.  But this is one way
transition.  That is once a file has been fully copied up, it can't go back
to metacopy file again.  And that seems to help avoid races.  So as of now
I can't see any races w.r.t OVL_UPPERDATA being set wrongly.  So move
settingof OVL_UPPERDATA inside the callers of ovl_get_inode().
ovl_obtain_alias() already does it.  So only two callers now left are
ovl_lookup() and ovl_instantiate().

Reported-by: yangerkun <yangerkun@huawei.com>
Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-02 22:20:25 +02:00
Vivek Goyal
6815f479ca ovl: use only uppermetacopy state in ovl_lookup()
Currently we use a variable "metacopy" which signifies that dentry could be
either uppermetacopy or lowermetacopy.  Amir suggested that we can move
code around and use d.metacopy in such a way that we don't need
lowermetacopy and just can do away with uppermetacopy.

So this patch replaces "metacopy" with "uppermetacopy".

It also moves some code little higher to keep reading little simpler.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-02 22:20:25 +02:00
Vivek Goyal
59fb20138a ovl: simplify setting of origin for index lookup
overlayfs can keep index of copied up files and directories and it seems to
serve two primary puroposes.  For regular files, it avoids breaking lower
hardlinks over copy up.  For directories it seems to be used for various
error checks.

During ovl_lookup(), we lookup for index using lower dentry in many a
cases.  That lower dentry is called "origin" and following is a summary of
current logic.

If there is no upperdentry, always lookup for index using lower dentry.
For regular files it helps avoiding breaking hard links over copyup and for
directories it seems to be just error checks.

If there is an upperdentry, then there are 3 possible cases.

 - For directories, lower dentry is found using two ways.  One is regular
  path based lookup in lower layers and second is using ORIGIN xattr on
  upper dentry.  First verify that path based lookup lower dentry matches
  the one pointed by upper ORIGIN xattr.  If yes, use this verified origin
  for index lookup.

 - For regular files (non-metacopy), there is no path based lookup in lower
  layers as lookup stops once we find upper dentry.  So there is no origin
  verification.  If there is ORIGIN xattr present on upper, use that to
  lookup index otherwise don't.

 - For regular metacopy files, again lower dentry is found using path based
  lookup as well as ORIGIN xattr on upper.  Path based lookup is continued
  in this case to find lower data dentry for metacopy upper.  So like
  directories we only use verified origin.  If ORIGIN xattr is not present
  (Either because lower did not support file handles or because this is
  hardlink copied up with index=off), then don't use path lookup based
  lower dentry as origin.  This is same as regular non-metacopy file case.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-02 22:20:25 +02:00
Amir Goldstein
522f6e6cba ovl: fix out of bounds access warning in ovl_check_fb_len()
syzbot reported out of bounds memory access from open_by_handle_at()
with a crafted file handle that looks like this:

  { .handle_bytes = 2, .handle_type = OVL_FILEID_V1 }

handle_bytes gets rounded down to 0 and we end up calling:
  ovl_check_fh_len(fh, 0) => ovl_check_fb_len(fh + 3, -3)

But fh buffer is only 2 bytes long, so accessing struct ovl_fb at
fh + 3 is illegal.

Fixes: cbe7fba8ed ("ovl: make sure that real fid is 32bit aligned in memory")
Reported-and-tested-by: syzbot+61958888b1c60361a791@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org> # v5.5
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-06-02 22:20:25 +02:00
Linus Torvalds
b23c4771ff A fair amount of stuff this time around, dominated by yet another massive
set from Mauro toward the completion of the RST conversion.  I *really*
 hope we are getting close to the end of this.  Meanwhile, those patches
 reach pretty far afield to update document references around the tree;
 there should be no actual code changes there.  There will be, alas, more of
 the usual trivial merge conflicts.
 
 Beyond that we have more translations, improvements to the sphinx
 scripting, a number of additions to the sysctl documentation, and lots of
 fixes.
 -----BEGIN PGP SIGNATURE-----
 
 iQFDBAABCAAtFiEEIw+MvkEiF49krdp9F0NaE2wMflgFAl7VId8PHGNvcmJldEBs
 d24ubmV0AAoJEBdDWhNsDH5Yq/gH/iaDgirQZV6UZ2v9sfwQNYolNpf2sKAuOZjd
 bPFB7WJoMQbKwQEvYrAUL2+5zPOcLYuIfzyOfo1BV1py+EyKbACcKjI4AedxfJF7
 +NchmOBhlEqmEhzx2U08HRc4/8J223WG17fJRVsV3p+opJySexSFeQucfOciX5NR
 RUCxweWWyg/FgyqjkyMMTtsePqZPmcT5dWTlVXISlbWzcv5NFhuJXnSrw8Sfzcmm
 SJMzqItv3O+CabnKQ8kMLV2PozXTMfjeWH47ZUK0Y8/8PP9+cvqwFzZ0UDQJ1Xaz
 oyW/TqmunaXhfMsMFeFGSwtfgwRHvXdxkQdtwNHvo1dV4dzTvDw=
 =fDC/
 -----END PGP SIGNATURE-----

Merge tag 'docs-5.8' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "A fair amount of stuff this time around, dominated by yet another
  massive set from Mauro toward the completion of the RST conversion. I
  *really* hope we are getting close to the end of this. Meanwhile,
  those patches reach pretty far afield to update document references
  around the tree; there should be no actual code changes there. There
  will be, alas, more of the usual trivial merge conflicts.

  Beyond that we have more translations, improvements to the sphinx
  scripting, a number of additions to the sysctl documentation, and lots
  of fixes"

* tag 'docs-5.8' of git://git.lwn.net/linux: (130 commits)
  Documentation: fixes to the maintainer-entry-profile template
  zswap: docs/vm: Fix typo accept_threshold_percent in zswap.rst
  tracing: Fix events.rst section numbering
  docs: acpi: fix old http link and improve document format
  docs: filesystems: add info about efivars content
  Documentation: LSM: Correct the basic LSM description
  mailmap: change email for Ricardo Ribalda
  docs: sysctl/kernel: document unaligned controls
  Documentation: admin-guide: update bug-hunting.rst
  docs: sysctl/kernel: document ngroups_max
  nvdimm: fixes to maintainter-entry-profile
  Documentation/features: Correct RISC-V kprobes support entry
  Documentation/features: Refresh the arch support status files
  Revert "docs: sysctl/kernel: document ngroups_max"
  docs: move locking-specific documents to locking/
  docs: move digsig docs to the security book
  docs: move the kref doc into the core-api book
  docs: add IRQ documentation at the core-api book
  docs: debugging-via-ohci1394.txt: add it to the core-api book
  docs: fix references for ipmi.rst file
  ...
2020-06-01 15:45:27 -07:00
Lubos Dolezel
144da23bea ovl: return required buffer size for file handles
Overlayfs doesn't work well with the fanotify mechanism.

Fanotify first probes for the required buffer size for the file handle,
but overlayfs currently bails out without passing the size back.

That results in errors in the kernel log, such as:

[527944.485384] overlayfs: failed to encode file handle (/, err=-75, buflen=0, len=29, type=1)
[527944.485386] fanotify: failed to encode fid (fsid=ae521e68.a434d95f, type=255, bytes=0, err=-2)

Signed-off-by: Lubos Dolezel <lubos@dolezel.info>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-13 11:11:24 +02:00
Chengguang Xu
399c109d35 ovl: sync dirty data when remounting to ro mode
sync_filesystem() does not sync dirty data for readonly filesystem during
umount, so before changing to readonly filesystem we should sync dirty data
for data integrity.

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-13 11:11:24 +02:00