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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>
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This paves the way for optionally using the "user.overlay." xattr
namespace.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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All callers pass zero flags to ovl_do_setxattr(). So drop this argument.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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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>
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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
...
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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()
...
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ovl_get_inode() uses oip->index as a bool value, not as a pointer.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Next patch will remove ofs->upper_mnt, so add an accessor function for this
field.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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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>
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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>
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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>
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As of now during open(), we don't pass bunch of flags to underlying
filesystem. O_TRUNC is one of these. Normally this is not a problem as VFS
calls ->setattr() with zero size and underlying filesystem sets file size
to 0.
But when overlayfs is running on top of virtiofs, it has an optimization
where it does not send setattr request to server if dectects that
truncation is part of open(O_TRUNC). It assumes that server already zeroed
file size as part of open(O_TRUNC).
fuse_do_setattr() {
if (attr->ia_valid & ATTR_OPEN) {
/*
* No need to send request to userspace, since actual
* truncation has already been done by OPEN. But still
* need to truncate page cache.
*/
}
}
IOW, fuse expects O_TRUNC to be passed to it as part of open flags.
But currently overlayfs does not pass O_TRUNC to underlying filesystem
hence fuse/virtiofs breaks. Setup overlayfs on top of virtiofs and
following does not zero the file size of a file is either upper only or has
already been copied up.
fd = open(foo.txt, O_TRUNC | O_WRONLY);
There are two ways to fix this. Either pass O_TRUNC to underlying
filesystem or clear ATTR_OPEN from attr->ia_valid so that fuse ends up
sending a SETATTR request to server. Miklos is concerned that O_TRUNC might
have side affects so it is better to clear ATTR_OPEN for now. Hence this
patch clears ATTR_OPEN from attr->ia_valid.
I found this problem while running unionmount-testsuite. With this patch,
unionmount-testsuite passes with overlayfs on top of virtiofs.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Fixes: bccece1ead36 ("ovl: allow remote upper")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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ovl_setattr() can be passed an attr which has ATTR_FILE set and
attr->ia_file is a file pointer to overlay file. This is done in
open(O_TRUNC) path.
We should either replace with attr->ia_file with underlying file object or
clear ATTR_FILE so that underlying filesystem does not end up using
overlayfs file object pointer.
There are no good use cases yet so for now clear ATTR_FILE. fuse seems to
be one user which can use this. But it can work even without this. So it
is not mandatory to pass ATTR_FILE to fuse.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Fixes: bccece1ead36 ("ovl: allow remote upper")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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So far, with xino=auto, we only enable xino if we know that all
underlying filesystem use 32bit inode numbers.
When users configure overlay with xino=auto, they already declare that
they are ready to handle 64bit inode number from overlay.
It is a very common case, that underlying filesystem uses 64bit ino,
but rarely or never uses the high inode number bits (e.g. tmpfs, xfs).
Leaving it for the users to declare high ino bits are unused with
xino=on is not a recipe for many users to enjoy the benefits of xino.
There appears to be very little reason not to enable xino when users
declare xino=auto even if we do not know how many bits underlying
filesystem uses for inode numbers.
In the worst case of xino bits overflow by real inode number, we
already fall back to the non-xino behavior - real inode number with
unique pseudo dev or to non persistent inode number and overlay st_dev
(for directories).
The only annoyance from auto enabling xino is that xino bits overflow
emits a warning to kmsg. Suppress those warnings unless users explicitly
asked for xino=on, suggesting that they expected high ino bits to be
unused by underlying filesystem.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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When xino feature is enabled and a real directory inode number overflows
the lower xino bits, we cannot map this directory inode number to a unique
and persistent inode number and we fall back to the real inode st_ino and
overlay st_dev.
The real inode st_ino with high bits may collide with a lower inode number
on overlay st_dev that was mapped using xino.
To avoid possible collision with legitimate xino values, map a non
persistent inode number to a dedicated range in the xino address space.
The dedicated range is created by adding one more bit to the number of
reserved high xino bits. We could have added just one more fsid, but that
would have had the undesired effect of changing persistent overlay inode
numbers on kernel or require more complex xino mapping code.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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There is no reason to deplete the system's global get_next_ino() pool for
overlay non-persistent inode numbers and there is no reason at all to
allocate non-persistent inode numbers for non-directories.
For non-directories, it is much better to leave i_ino the same as real
i_ino, to be consistent with st_ino/d_ino.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Fix a typo in comment. (annonate -> annotate)
Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Move i_ino initialization to ovl_inode_init() to avoid the dance of setting
i_ino in ovl_fill_inode() sometimes on the first call and sometimes on the
seconds call.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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ovl_inode_update() is no longer called from create object code path.
Fixes: 01b39dcc9568 ("ovl: use inode_insert5() to hash a newly...")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Commit 6dde1e42f497 ("ovl: make i_ino consistent with st_ino in more
cases"), relaxed the condition nfs_export=on in order to set the value of
i_ino to xino map of real ino.
Specifically, it also relaxed the pre-condition that index=on for
consistent i_ino. This opened the corner case of lower hardlink in
ovl_get_inode(), which calls ovl_fill_inode() with ino=0 and then
ovl_init_inode() is called to set i_ino to lower real ino without the xino
mapping.
Pass the correct values of ino;fsid in this case to ovl_fill_inode(), so it
can initialize i_ino correctly.
Fixes: 6dde1e42f497 ("ovl: make i_ino consistent with st_ino in more ...")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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On non-samefs overlay without xino, non pure upper inodes should use a
pseudo_dev assigned to each unique lower fs, but if lower layer is on the
same fs and upper layer, it has no pseudo_dev assigned.
In this overlay layers setup:
- two filesystems, A and B
- upper layer is on A
- lower layer 1 is also on A
- lower layer 2 is on B
Non pure upper overlay inode, whose origin is in layer 1 will have the
st_dev;st_ino values of the real lower inode before copy up and the
st_dev;st_ino values of the real upper inode after copy up.
Fix this inconsitency by assigning a unique pseudo_dev also for upper fs,
that will be used as st_dev value along with the lower inode st_dev for
overlay inodes in the case above.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Rename lower_fs[] array to fs[], extend its size by one and use index fsid
(instead of fsid-1) to access the fs[] array.
Initialize fs[0] with upper fs values. fsid 0 is reserved even with lower
only overlay, so fs[0] remains null in this case.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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No code uses the sb returned from this helper, so make it retrun a boolean
and rename it to ovl_same_fs().
The xino mode is irrelevant when all layers are on same fs, so instead of
describing samefs with mode OVL_XINO_OFF, use a new xino_mode state, which
is 0 in the case of samefs, -1 in the case of xino=off and > 0 with xino
enabled.
Create a new helper ovl_same_dev(), to use instead of the common check for
(ovl_same_fs() || xinobits).
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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In ovl_llseek() we use the overlay inode rwsem to protect against
concurrent modifications to real file f_pos, because we copy the overlay
file f_pos to/from the real file f_pos.
This caused a lockdep warning of locking order violation when the
ovl_llseek() operation was called on a lower nested overlay layer while the
upper layer fs sb_writers is held (with patch improving copy-up efficiency
for big sparse file).
Use the internal ovl_inode_lock() instead of the overlay inode rwsem in
those cases. It is meant to be used for protecting against concurrent
changes to overlay inode internal state changes.
The locking order rules are documented to explain this case.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Use pr_fmt auto generate "overlayfs: " prefix.
Signed-off-by: lijiazi <lijiazi@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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On non-samefs overlay without xino, non pure upper inodes should use a
pseudo_dev assigned to each unique lower fs and pure upper inodes use the
real upper st_dev.
It is fine for an overlay pure upper inode to use the same st_dev;st_ino
values as the real upper inode, because the content of those two different
filesystem objects is always the same.
In this case, however:
- two filesystems, A and B
- upper layer is on A
- lower layer 1 is also on A
- lower layer 2 is on B
Non pure upper overlay inode, whose origin is in layer 1 will have the same
st_dev;st_ino values as the real lower inode. This may result with a false
positive results of 'diff' between the real lower and copied up overlay
inode.
Fix this by using the upper st_dev;st_ino values in this case. This breaks
the property of constant st_dev;st_ino across copy up of this case. This
breakage will be fixed by a later patch.
Fixes: 5148626b806a ("ovl: allocate anon bdev per unique lower fs")
Cc: stable@vger.kernel.org # v4.17+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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When filtering xattr list for reading, presence of trusted xattr
results in a security audit log. However, if there is other content
no errno will be set, and if there isn't, the errno will be -ENODATA
and not -EPERM as is usually associated with a lack of capability.
The check does not block the request to list the xattrs present.
Switch to ns_capable_noaudit to reflect a more appropriate check.
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: linux-security-module@vger.kernel.org
Cc: kernel-team@android.com
Cc: stable@vger.kernel.org # v3.18+
Fixes: a082c6f680da ("ovl: filter trusted xattr for non-admin")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx
Pull still more SPDX updates from Greg KH:
"Another round of SPDX updates for 5.2-rc6
Here is what I am guessing is going to be the last "big" SPDX update
for 5.2. It contains all of the remaining GPLv2 and GPLv2+ updates
that were "easy" to determine by pattern matching. The ones after this
are going to be a bit more difficult and the people on the spdx list
will be discussing them on a case-by-case basis now.
Another 5000+ files are fixed up, so our overall totals are:
Files checked: 64545
Files with SPDX: 45529
Compared to the 5.1 kernel which was:
Files checked: 63848
Files with SPDX: 22576
This is a huge improvement.
Also, we deleted another 20000 lines of boilerplate license crud,
always nice to see in a diffstat"
* tag 'spdx-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: (65 commits)
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 507
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 506
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 503
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 502
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 501
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 498
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 496
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 495
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 491
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 490
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 489
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 488
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 487
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 486
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 485
...
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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 <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Relax the condition that overlayfs supports nfs export, to require
that i_ino is consistent with st_ino/d_ino.
It is enough to require that st_ino and d_ino are consistent.
This fixes the failure of xfstest generic/504, due to mismatch of
st_ino to inode number in the output of /proc/locks.
Fixes: 12574a9f4c9c ("ovl: consistent i_ino for non-samefs with xino")
Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Overlapping overlay layers are not supported and can cause unexpected
behavior, but overlayfs does not currently check or warn about these
configurations.
User is not supposed to specify the same directory for upper and
lower dirs or for different lower layers and user is not supposed to
specify directories that are descendants of each other for overlay
layers, but that is exactly what this zysbot repro did:
https://syzkaller.appspot.com/x/repro.syz?x=12c7a94f400000
Moving layer root directories into other layers while overlayfs
is mounted could also result in unexpected behavior.
This commit places "traps" in the overlay inode hash table.
Those traps are dummy overlay inodes that are hashed by the layers
root inodes.
On mount, the hash table trap entries are used to verify that overlay
layers are not overlapping. While at it, we also verify that overlay
layers are not overlapping with directories "in-use" by other overlay
instances as upperdir/workdir.
On lookup, the trap entries are used to verify that overlay layers
root inodes have not been moved into other layers after mount.
Some examples:
$ ./run --ov --samefs -s
...
( mkdir -p base/upper/0/u base/upper/0/w base/lower lower upper mnt
mount -o bind base/lower lower
mount -o bind base/upper upper
mount -t overlay none mnt ...
-o lowerdir=lower,upperdir=upper/0/u,workdir=upper/0/w)
$ umount mnt
$ mount -t overlay none mnt ...
-o lowerdir=base,upperdir=upper/0/u,workdir=upper/0/w
[ 94.434900] overlayfs: overlapping upperdir path
mount: mount overlay on mnt failed: Too many levels of symbolic links
$ mount -t overlay none mnt ...
-o lowerdir=upper/0/u,upperdir=upper/0/u,workdir=upper/0/w
[ 151.350132] overlayfs: conflicting lowerdir path
mount: none is already mounted or mnt busy
$ mount -t overlay none mnt ...
-o lowerdir=lower:lower/a,upperdir=upper/0/u,workdir=upper/0/w
[ 201.205045] overlayfs: overlapping lowerdir path
mount: mount overlay on mnt failed: Too many levels of symbolic links
$ mount -t overlay none mnt ...
-o lowerdir=lower,upperdir=upper/0/u,workdir=upper/0/w
$ mv base/upper/0/ base/lower/
$ find mnt/0
mnt/0
mnt/0/w
find: 'mnt/0/w/work': Too many levels of symbolic links
find: 'mnt/0/u': Too many levels of symbolic links
Reported-by: syzbot+9c69c282adc4edd2b540@syzkaller.appspotmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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This nasty little syzbot repro:
https://syzkaller.appspot.com/x/repro.syz?x=12c7a94f400000
Creates overlay mounts where the same directory is both in upper and lower
layers. Simplified example:
mkdir foo work
mount -t overlay none foo -o"lowerdir=.,upperdir=foo,workdir=work"
The repro runs several threads in parallel that attempt to chdir into foo
and attempt to symlink/rename/exec/mkdir the file bar.
The repro hits a WARN_ON() I placed in ovl_instantiate(), which suggests
that an overlay inode already exists in cache and is hashed by the pointer
of the real upper dentry that ovl_create_real() has just created. At the
point of the WARN_ON(), for overlay dir inode lock is held and upper dir
inode lock, so at first, I did not see how this was possible.
On a closer look, I see that after ovl_create_real(), because of the
overlapping upper and lower layers, a lookup by another thread can find the
file foo/bar that was just created in upper layer, at overlay path
foo/foo/bar and hash the an overlay inode with the new real dentry as lower
dentry. This is possible because the overlay directory foo/foo is not
locked and the upper dentry foo/bar is in dcache, so ovl_lookup() can find
it without taking upper dir inode shared lock.
Overlapping layers is considered a wrong setup which would result in
unexpected behavior, but it shouldn't crash the kernel and it shouldn't
trigger WARN_ON() either, so relax this WARN_ON() and leave a pr_warn()
instead to cover all cases of failure to get an overlay inode.
The error returned from failure to insert new inode to cache with
inode_insert5() was changed to -EEXIST, to distinguish from the error
-ENOMEM returned on failure to get/allocate inode with iget5_locked().
Reported-by: syzbot+9c69c282adc4edd2b540@syzkaller.appspotmail.com
Fixes: 01b39dcc9568 ("ovl: use inode_insert5() to hash a newly...")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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This reverts commit 007ea44892e6fa963a0876a979e34890325c64eb.
The commit broke some selinux-testsuite cases, and it looks like there's no
straightforward fix keeping the direction of this patch, so revert for now.
The original patch was trying to fix the consistency of permission checks, and
not an observed bug. So reverting should be safe.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Make permission checking more consistent:
- special files don't need any access check on underling fs
- exec permission check doesn't need to be performed on underlying fs
Reported-by: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Fixes the following sparse warning:
fs/overlayfs/inode.c:507:39: warning:
symbol 'ovl_aops' was not declared. Should it be static?
Fixes: 5b910bd615ba ("ovl: fix GPF in swapfile_activate of file from overlayfs over xfs")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Since overlayfs implements stacked file operations, the underlying
filesystems are not supposed to be exposed to the overlayfs file,
whose f_inode is an overlayfs inode.
Assigning an overlayfs file to swap_file results in an attempt of xfs
code to dereference an xfs_inode struct from an ovl_inode pointer:
CPU: 0 PID: 2462 Comm: swapon Not tainted
4.18.0-xfstests-12721-g33e17876ea4e #3402
RIP: 0010:xfs_find_bdev_for_inode+0x23/0x2f
Call Trace:
xfs_iomap_swapfile_activate+0x1f/0x43
__se_sys_swapon+0xb1a/0xee9
Fix this by not assigning the real inode mapping to f_mapping, which
will cause swapon() to return an error (-EINVAL). Although it makes
sense not to allow setting swpafile on an overlayfs file, some users
may depend on it, so we may need to fix this up in the future.
Keeping f_mapping pointing to overlay inode mapping will cause O_DIRECT
open to fail. Fix this by installing ovl_aops with noop_direct_IO in
overlay inode mapping.
Keeping f_mapping pointing to overlay inode mapping will cause other
a_ops related operations to fail (e.g. readahead()). Those will be
fixed by follow up patches.
Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: f7c72396d0de ("ovl: add O_DIRECT support")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Stacked overlayfs fiemap operation broke xfstests that test delayed
allocation (with "_test_generic_punch -d"), because ovl_fiemap()
failed to write dirty pages when requested.
Fixes: 9e142c4102db ("ovl: add ovl_fiemap()")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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truncate should copy up full file (and not do metacopy only), otherwise it
will be broken. For example, use truncate to increase size of a file so
that any read beyong existing size will return null bytes. If we don't
copy up full file, then we end up opening lower file and read from it only
reads upto the old size (and not new size after truncate). Hence to avoid
such situations, copy up data as well when file size changes.
So far it was being done by d_real(O_WRONLY) call in truncate() path. Now
that patch has been reverted. So force full copy up in ovl_setattr() if
size of file is changing.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Add an ovl_inode flag OVL_CONST_INO. This flag signifies if inode number
will remain constant over copy up or not. This flag does not get updated
over copy up and remains unmodifed after setting once.
Next patch in the series will make use of this flag. It will basically
figure out if dentry is of type ORIGIN or not. And this can be derived by
this flag.
ORIGIN = (upperdentry && ovl_test_flag(OVL_CONST_INO, inode)).
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>
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Right now ovl_inode stores inode pointer for lower inode. This helps with
quickly getting lower inode given overlay inode (ovl_inode_lower()).
Now with metadata only copy-up, we can have metacopy inode in middle layer
as well and inode containing data can be different from ->lower. I need to
be able to open the real file in ovl_open_realfile() and for that I need to
quickly find the lower data inode.
Hence store lower data inode also in ovl_inode. Also provide an helper
ovl_inode_lowerdata() to access this field.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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If an inode has been copied up metadata only, then we need to query the
number of blocks from lower and fill up the stat->st_blocks.
We need to be careful about races where we are doing stat on one cpu and
data copy up is taking place on other cpu. We want to return
stat->st_blocks either from lower or stable upper and not something in
between. Hence, ovl_has_upperdata() is called first to figure out whether
block reporting will take place from lower or upper.
We now support metacopy dentries in middle layer. That means number of
blocks reporting needs to come from lowest data dentry and this could be
different from lower dentry. Hence we end up making a separate
vfs_getxattr() call for metacopy dentries to get number of blocks.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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This patch modifies ovl_lookup() and friends to lookup metacopy dentries.
It also allows for presence of metacopy dentries in lower layer.
During lookup, check for presence of OVL_XATTR_METACOPY and if not present,
set OVL_UPPERDATA bit in flags.
We don't support metacopy feature with nfs_export. So in nfs_export code,
we set OVL_UPPERDATA flag set unconditionally if upper inode exists.
Do not follow metacopy origin if we find a metacopy only inode and metacopy
feature is not enabled for that mount. Like redirect, this can have
security implications where an attacker could hand craft upper and try to
gain access to file on lower which it should not have to begin with.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Right now we use goto out_nomem which assumes error code is -ENOMEM. But
there are other errors returned like -ESTALE as well. So instead of
out_nomem, use out_err which will do ERR_PTR(err). That way one can put
error code in err and jump to out_err.
This just code reorganization and no change of functionality.
I am about to add more code and this organization helps laying more code
and error paths on top of it.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Right now two copy up helpers are in inode.c. Amir suggested it might be
better to move these to copy_up.c.
There will one more related function which will come in later patch.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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ovl_inode->redirect is an inode property and should be initialized in
ovl_get_inode() only when we are adding a new inode to cache. If inode is
already in cache, it is already initialized and we should not be touching
ovl_inode->redirect field.
As of now this is not a problem as redirects are used only for directories
which don't share inode. But soon I want to use redirects for regular
files also and there it can become an issue.
Hence, move ->redirect initialization in ovl_get_inode().
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Implement stacked fiemap().
Need to split inode operations for regular file (which has fiemap) and
special file (which doesn't have fiemap).
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Implement file operations on a regular overlay file. The underlying file
is opened separately and cached in ->private_data.
It might be worth making an exception for such files when accounting in
nr_file to confirm to userspace expectations. We are only adding a small
overhead (248bytes for the struct file) since the real inode and dentry are
pinned by overlayfs anyway.
This patch doesn't have any effect, since the vfs will use d_real() to find
the real underlying file to open. The patch at the end of the series will
actually enable this functionality.
AV: make it use open_with_fake_path(), don't mess with override_creds
SzM: still need to mess with override_creds() until no fs uses
current_cred() in their open method.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Copy i_size of the underlying inode to the overlay inode in ovl_copyattr().
This is in preparation for stacking I/O operations on overlay files.
This patch shouldn't have any observable effect.
Remove stale comment from ovl_setattr() [spotted by Vivek Goyal].
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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This reverts commit 31c3a7069593b072bd57192b63b62f9a7e994e9a.
Re-add functionality dealing with i_writecount on truncate to overlayfs.
This patch shouldn't have any observable effects, since we just re-assert
the writecout that vfs_truncate() already got for us.
This is in preparation for moving overlay functionality out of the VFS.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Copy up mtime and ctime to overlay inode after times in real object are
modified. Be careful not to dirty cachelines when not necessary.
This is in preparation for moving overlay functionality out of the VFS.
This patch shouldn't have any observable effect.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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