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commit 81a33c1ee941c3bb9ffc6bac8f676be13351344e upstream.
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: d989903058a8 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 124c2de2c0aee96271e4ddab190083d8aa7aa71a upstream.
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: 4b91c30a5a19 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 24f14009b8f1754ec2ae4c168940c01259b0f88a upstream.
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: 0be0bfd2de9d ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a888db310195400f050b89c47673f0f8babfbb41 upstream.
Commit 9df085f3c9a2 ("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: 9df085f3c9a2 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 520da69d265a91c6536c63851cbb8a53946974f0 upstream.
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: 0956254a2d5b ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 522f6e6cba6880a038e2bd88e10390b84cd3febd upstream.
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: cbe7fba8edfc ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The "buflen" value comes from the user and there is a potential that it
could be zero. In do_handle_to_path() we know that "handle->handle_bytes"
is non-zero and we do:
handle_dwords = handle->handle_bytes >> 2;
So values 1-3 become zero. Then in ovl_fh_to_dentry() we do:
int len = fh_len << 2;
So now len is in the "0,4-128" range and a multiple of 4. But if
"buflen" is zero it will try to copy negative bytes when we do the
memcpy in ovl_fid_to_fh().
memcpy(&fh->fb, fid, buflen - OVL_FH_WIRE_OFFSET);
And that will lead to a crash. Thanks to Amir Goldstein for his help
with this patch.
Fixes: cbe7fba8edfc ("ovl: make sure that real fid is 32bit aligned in memory")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Cc: <stable@vger.kernel.org> # v5.5
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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Changes to underlying layers should not cause WARN_ON(), but this repro
does:
mkdir w l u mnt
sudo mount -t overlay -o workdir=w,lowerdir=l,upperdir=u overlay mnt
touch mnt/h
ln u/h u/k
rm -rf mnt/k
rm -rf mnt/h
dmesg
------------[ cut here ]------------
WARNING: CPU: 1 PID: 116244 at fs/inode.c:302 drop_nlink+0x28/0x40
After upper hardlinks were added while overlay is mounted, unlinking all
overlay hardlinks drops overlay nlink to zero before all upper inodes
are unlinked.
After unlink/rename prevent i_nlink from going to zero if there are still
hashed aliases (i.e. cached hard links to the victim) remaining.
Reported-by: Phasip <phasip@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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The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare variable-length
types such as these ones is a flexible array member[1][2], introduced in
C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this
change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Fixes: cbe7fba8edfc ("ovl: make sure that real fid is 32bit aligned in memory")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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The situation is the same as for __d_obtain_alias() (which is what that
thing is parallel to) - if we find a preexisting alias, we want to grab it,
drop the inode and return the alias we'd found.
The only thing d_instantiate_anon() does compared to that is spurious
security_d_instiate() that has already been done to that dentry with exact
same arguments.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Overlayfs works sub-optimally with upper fs that has no xattr/d_type/
RENAME_WHITEOUT support. We should basically deprecate support for those
filesystems, but so far, we only issue a warning and don't fail the mount
for the sake of backward compat. Some features are already being disabled
with no xattr support.
For newly supported remote upper fs, we do not need to worry about backward
compatibility, so we can fail the mount if upper fs is a sub-optimal
filesystem.
This reduces the in-tree remote filesystems supported as upper to just
FUSE, for which the remote upper fs support was added.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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As with other required upper fs features, we only warn if support is
missing to avoid breaking existing sub-optimal setups.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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No reason to prevent upper layer being a remote filesystem. Do the
revalidation in that case, just as we already do for lower layers.
This lets virtiofs be used as upper layer, which appears to be a real use
case.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Allow completely skipping ->revalidate() on a per-dentry basis, in case the
underlying layers used for a dentry do not themselves have ->revalidate().
E.g. negative overlay dentry has no underlying layers, hence revalidate is
unnecessary. Or if lower layer is remote but overlay dentry is pure-upper,
then can skip revalidate.
The following places need to update whether the dentry needs revalidate or
not:
- fill-super (root dentry)
- lookup
- create
- fh_to_dentry
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Following patch will allow remote as upper layer, but not overlay stacked
on upper layer. Separate the two concepts.
This patch is doesn't change behavior.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Use a common loop for plain and weak revalidation. This will aid doing
revalidation on upper layer.
This patch doesn't change behavior.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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This issue came up with NFSv4 as the lower layer, which generates
"system.nfs4_acl" xattrs (even for plain old unix permissions). Prior to
this patch this prevented copy-up from succeeding.
The overlayfs permission model mandates that permissions are checked
locally for the task and remotely for the mounter(*). NFS4 ACLs are not
supported by the Linux kernel currently, hence they cannot be enforced
locally. Which means it is indifferent whether this attribute is copied or
not.
Generalize this to any xattr that is not used in access checking (i.e. it's
not a POSIX ACL and not in the "security." namespace).
Incidentally, best effort copying of xattrs seems to also be the behavior
of "cp -a", which is what overlayfs tries to mimic.
(*) Documentation/filesystems/overlayfs.txt#Permission model
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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Allocates and initializes the root dentry and inode.
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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Lockdep reports "WARNING: lock held when returning to user space!" due to
async write holding freeze lock over the write. Apparently aio.c already
deals with this by lying to lockdep about the state of the lock.
Do the same here. No need to check for S_IFREG() here since these file ops
are regular-only.
Reported-by: syzbot+9331a354f4f624a52a55@syzkaller.appspotmail.com
Fixes: 2406a307ac7d ("ovl: implement async IO routines")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Fix up two bugs in the coversion to xino_mode:
1. xino=off does not always end up in disabled mode
2. xino=auto on 32bit arch should end up in disabled mode
Take a proactive approach to disabling xino on 32bit kernel:
1. Disable XINO_AUTO config during build time
2. Disable xino with a warning on mount time
As a by product, xino=on on 32bit arch also ends up in disabled mode.
We never intended to enable xino on 32bit arch and this will make the
rest of the logic simpler.
Fixes: 0f831ec85eda ("ovl: simplify ovl_same_sb() helper")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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ovl_inode_lock() is interruptible. When inode_lock() in ovl_llseek()
was replaced with ovl_inode_lock(), we did not add a check for error.
Fix this by making ovl_inode_lock() uninterruptible and change the
existing call sites to use an _interruptible variant.
Reported-by: syzbot+66a9752fa927f745385e@syzkaller.appspotmail.com
Fixes: b1f9d3858f72 ("ovl: use ovl_inode_lock in ovl_llseek()")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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ovl_lseek() is using ssize_t to return the value from vfs_llseek(). On a
32-bit kernel ssize_t is a 32-bit signed int, which overflows above 2 GB.
Assign the return value of vfs_llseek() to loff_t to fix this.
Reported-by: Boris Gjenero <boris.gjenero@gmail.com>
Fixes: 9e46b840c705 ("ovl: support stacked SEEK_HOLE/SEEK_DATA")
Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Now overlayfs falls back to use default file splice read
and write, which is not compatiple with overlayfs, returning
EFAULT. xfstests generic/591 can reproduce part of this.
Tested this patch with xfstests auto group tests.
Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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A performance regression was observed since linux v4.19 with aio test using
fio with iodepth 128 on overlayfs. The queue depth of the device was
always 1 which is unexpected.
After investigation, it was found that commit 16914e6fc7e1 ("ovl: add
ovl_read_iter()") and commit 2a92e07edc5e ("ovl: add ovl_write_iter()")
resulted in vfs_iter_{read,write} being called on underlying filesystem,
which always results in syncronous IO.
Implement async IO for stacked reading and writing. This resolves the
performance regresion.
This is implemented by allocating a new kiocb for submitting the AIO
request on the underlying filesystem. When the request is completed, the
new kiocb is freed and the completion callback is called on the original
iocb.
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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The ovl_layer struct is never modified except at initialization.
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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This fixes ovl_lower_uuid_ok() to correctly detect the corner case:
- two filesystems, A and B, both have null uuid
- upper layer is on A
- lower layer 1 is also on A
- lower layer 2 is on B
In this case, bad_uuid would not have been set for B, because the check
only involved the list of lower fs. Hence we'll try to decode a layer 2
origin on layer 1 and fail.
We check for conflicting (and null) uuid among all lower layers, including
those layers that are on the same fs as the upper layer.
Reported-by: Miklos Szeredi <mszeredi@redhat.com>
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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Rename lower_layers[] array to layers[], extend its size by one and
initialize layers[0] with upper layer values. Lower layers are now
addressed with index 1..numlower. layers[0] is reserved even with lower
only overlay.
[SzM: replace ofs->numlower with ofs->numlayer, the latter's value is
incremented by one]
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Current copy-up is not efficient for big sparse file,
It's not only slow but also wasting more disk space
when the target lower file has huge hole inside.
This patch tries to recognize file hole and skip it
during copy-up.
Detail logic of hole detection as below:
When we detect next data position is larger than current
position we will skip that hole, otherwise we copy
data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually,
it may not recognize all kind of holes and sometimes
only skips partial of hole area. However, it will be
enough for most of the use cases.
Additionally, this optimization relies on lseek(2)
SEEK_DATA implementation, so for some specific
filesystems which do not support this feature
will behave as before on copy-up.
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
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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The WARN_ON() that child entry is always on overlay st_dev became wrong
when we allowed this function to update d_ino in non-samefs setup with xino
enabled.
It is not true in case of xino bits overflow on a non-dir inode. Leave the
WARN_ON() only for directories, where assertion is still true.
Fixes: adbf4f7ea834 ("ovl: consistent d_ino for non-samefs with xino")
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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git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs fixes from Miklos Szeredi:
"Fix some bugs and documentation"
* tag 'ovl-fixes-5.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
docs: filesystems: overlayfs: Fix restview warnings
docs: filesystems: overlayfs: Rename overlayfs.txt to .rst
ovl: relax WARN_ON() on rename to self
ovl: fix corner case of non-unique st_dev;st_ino
ovl: don't use a temp buf for encoding real fh
ovl: make sure that real fid is 32bit aligned in memory
ovl: fix lookup failure on multi lower squashfs
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In ovl_rename(), if new upper is hardlinked to old upper underneath
overlayfs before upper dirs are locked, user will get an ESTALE error
and a WARN_ON will be printed.
Changes to underlying layers while overlayfs is mounted may result in
unexpected behavior, but it shouldn't crash the kernel and it shouldn't
trigger WARN_ON() either, so relax this WARN_ON().
Reported-by: syzbot+bb1836a212e69f8e201a@syzkaller.appspotmail.com
Fixes: 804032fabb3b ("ovl: don't check rename to self")
Cc: <stable@vger.kernel.org> # v4.9+
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 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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We can allocate maximum fh size and encode into it directly.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Seprate on-disk encoding from in-memory and on-wire resresentation
of overlay file handle.
In-memory and on-wire we only ever pass around pointers to struct
ovl_fh, which encapsulates at offset 3 the on-disk format struct
ovl_fb. struct ovl_fb encapsulates at offset 21 the real file handle.
That makes sure that the real file handle is always 32bit aligned
in-memory when passed down to the underlying filesystem.
On-disk format remains the same and store/load are done into
correctly aligned buffer.
New nfs exported file handles are exported with aligned real fid.
Old nfs file handles are copied to an aligned buffer before being
decoded.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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In the past, overlayfs required that lower fs have non null uuid in
order to support nfs export and decode copy up origin file handles.
Commit 9df085f3c9a2 ("ovl: relax requirement for non null uuid of
lower fs") relaxed this requirement for nfs export support, as long
as uuid (even if null) is unique among all lower fs.
However, said commit unintentionally also relaxed the non null uuid
requirement for decoding copy up origin file handles, regardless of
the unique uuid requirement.
Amend this mistake by disabling decoding of copy up origin file handle
from lower fs with a conflicting uuid.
We still encode copy up origin file handles from those fs, because
file handles like those already exist in the wild and because they
might provide useful information in the future.
There is an unhandled corner case described by Miklos this way:
- two filesystems, A and B, both have null uuid
- upper layer is on A
- lower layer 1 is also on A
- lower layer 2 is on B
In this case bad_uuid won't be set for B, because the check only
involves the list of lower fs. Hence we'll try to decode a layer 2
origin on layer 1 and fail.
We will deal with this corner case later.
Reported-by: Colin Ian King <colin.king@canonical.com>
Tested-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/lkml/20191106234301.283006-1-colin.king@canonical.com/
Fixes: 9df085f3c9a2 ("ovl: relax requirement for non null uuid ...")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Most of the callers of lookup_one_len_unlocked() treat negatives are
ERR_PTR(-ENOENT). Provide a helper that would do just that. Note
that a pinned positive dentry remains positive - it's ->d_inode is
stable, etc.; a pinned _negative_ dentry can become positive at any
point as long as you are not holding its parent at least shared.
So using lookup_one_len_unlocked() needs to be careful;
lookup_positive_unlocked() is safer and that's what the callers
end up open-coding anyway.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Amir Goldstein
youngjun
Yuxuan Shui
Dan Carpenter
Vivek Goyal
Miklos Szeredi
Chengguang Xu
Gustavo A. R. Silva
Al Viro
Murphy Zhou
Jiufei Xue
lijiazi
Linus Torvalds