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* ovl: use generic vfs_ioc_setflags_prepare() helperAmir Goldstein2020-10-061-32/+30
| | | | | | | | | | | | | 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>
* ovl: support [S|G]ETFLAGS and FS[S|G]ETXATTR ioctls for directoriesAmir Goldstein2020-10-063-12/+51
| | | | | | | | | | | | | | | | | [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>
* ovl: rearrange ovl_can_list()Miklos Szeredi2020-09-021-3/+6
| | | | | | | | | | | | | | 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>
* ovl: enumerate private xattrsMiklos Szeredi2020-09-023-26/+59
| | | | | | | | 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>
* ovl: pass ovl_fs down to functions accessing private xattrsMiklos Szeredi2020-09-029-86/+107
| | | | | | | This paves the way for optionally using the "user.overlay." xattr namespace. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: drop flags argument from ovl_do_setxattr()Miklos Szeredi2020-09-026-9/+9
| | | | | | All callers pass zero flags to ovl_do_setxattr(). So drop this argument. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* ovl: adhere to the vfs_ vs. ovl_do_ conventions for xattrsMiklos Szeredi2020-09-022-4/+4
| | | | | | | | | | 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>
* ovl: use ovl_do_getxattr() for private xattrMiklos Szeredi2020-09-024-8/+15
| | | | | | | | | | 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>
* ovl: fold ovl_getxattr() into ovl_get_redirect_xattr()Miklos Szeredi2020-09-021-36/+17
| | | | | | | | This is a partial revert (with some cleanups) of commit 993a0b2aec52 ("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>
* ovl: clean up ovl_getxattr() in copy_up.cMiklos Szeredi2020-09-021-21/+11
| | | | | | | 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>
* duplicate ovl_getxattr()Miklos Szeredi2020-09-023-4/+35
| | | | | | | | | | | | | 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>
* ovl: provide a mount option "volatile"Vivek Goyal2020-09-025-8/+97
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* ovl: check for incompatible features in work dirAmir Goldstein2020-09-022-11/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Merge tag 'uninit-macro-v5.9-rc1' of ↵Linus Torvalds2020-08-041-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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()
| * treewide: Remove uninitialized_var() usageKees Cook2020-07-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | ovl: fix lookup of indexed hardlinks with metacopyAmir Goldstein2020-07-161-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: 28166ab3c875 ("ovl: initialize OVL_UPPERDATA in ovl_lookup()") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | ovl: fix unneeded call to ovl_change_flags()Amir Goldstein2020-07-161-4/+6
| | | | | | | | | | | | | | | | | | | | 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>
* | ovl: fix mount option checks for nfs_export with no upperdirAmir Goldstein2020-07-161-13/+18
| | | | | | | | | | | | | | | | | | | | | | | | 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>
* | ovl: force read-only sb on failure to create index dirAmir Goldstein2020-07-161-5/+6
| | | | | | | | | | | | | | | | | | | | 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>
* | ovl: fix regression with re-formatted lower squashfsAmir Goldstein2020-07-161-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | ovl: fix oops in ovl_indexdir_cleanup() with nfs_export=onAmir Goldstein2020-07-161-9/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 c21c839b8448 ("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: c21c839b8448 ("ovl: whiteout inode sharing") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | ovl: relax WARN_ON() when decoding lower directory file handleAmir Goldstein2020-07-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | ovl: remove not used argument in ovl_check_originyoungjun2020-07-161-9/+2
| | | | | | | | | | | | | | | | | | 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>
* | ovl: change ovl_copy_up_flags staticyoungjun2020-07-162-2/+1
| | | | | | | | | | | | | | | | "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>
* | ovl: inode reference leak in ovl_is_inuse true case.youngjun2020-07-161-1/+10
|/ | | | | | | | | | | 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>
* Merge tag 'ovl-update-5.8' of ↵Linus Torvalds2020-06-1011-219/+405
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 ...
| * ovl: remove unnecessary lock checkyoungjun2020-06-081-6/+1
| | | | | | | | | | | | | | | | 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>
| * ovl: make oip->index boolMiklos Szeredi2020-06-042-2/+2
| | | | | | | | | | | | ovl_get_inode() uses oip->index as a bool value, not as a pointer. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: only pass ->ki_flags to ovl_iocb_to_rwf()Miklos Szeredi2020-06-041-4/+3
| | | | | | | | | | | | Next patch will want to pass a modified set of flags, so... Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: make private mounts longtermMiklos Szeredi2020-06-041-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: get rid of redundant members in struct ovl_fsMiklos Szeredi2020-06-042-55/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: add accessor for ofs->upper_mntMiklos Szeredi2020-06-047-30/+35
| | | | | | | | | | | | | | Next patch will remove ofs->upper_mnt, so add an accessor function for this field. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: initialize error in ovl_copy_xattrYuxuan Shui2020-06-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: drop negative dentry in upper layerChengguang Xu2020-06-031-7/+28
| | | | | | | | | | | | | | | | | | | | 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>
| * ovl: check permission to open real fileMiklos Szeredi2020-06-031-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: call secutiry hook in ovl_real_ioctl()Miklos Szeredi2020-06-031-1/+4
| | | | | | | | | | | | | | | | | | 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>
| * ovl: verify permissions in ovl_path_open()Miklos Szeredi2020-06-021-1/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: switch to mounter creds in readdirMiklos Szeredi2020-06-021-6/+21
| | | | | | | | | | | | | | In preparation for more permission checking, override credentials for directory operations on the underlying filesystems. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: pass correct flags for opening real directoryMiklos Szeredi2020-06-021-3/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: fix redirect traversal on metacopy dentriesVivek Goyal2020-06-021-12/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: initialize OVL_UPPERDATA in ovl_lookup()Vivek Goyal2020-06-023-10/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: use only uppermetacopy state in ovl_lookup()Vivek Goyal2020-06-021-29/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: simplify setting of origin for index lookupVivek Goyal2020-06-021-12/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: fix out of bounds access warning in ovl_check_fb_len()Amir Goldstein2020-06-021-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: return required buffer size for file handlesLubos Dolezel2020-05-131-10/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * ovl: sync dirty data when remounting to ro modeChengguang Xu2020-05-131-1/+10
| | | | | | | | | | | | | | | | | | 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>
| * ovl: whiteout inode sharingChengguang Xu2020-05-136-15/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Share inode with different whiteout files for saving inode and speeding up delete operation. If EMLINK is encountered when linking a shared whiteout, create a new one. In case of any other error, disable sharing for this super block. Note: ofs->whiteout is protected by inode lock on workdir. Signed-off-by: Chengguang Xu <cgxu519@mykernel.net> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: inherit SB_NOSEC flag from upperdirJeffle Xu2020-05-131-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the stacking of regular file operations [1], the overlayfs edition of write_iter() is called when writing regular files. Since then, xattr lookup is needed on every write since file_remove_privs() is called from ovl_write_iter(), which would become the performance bottleneck when writing small chunks of data. In my test case, file_remove_privs() would consume ~15% CPU when running fstime of unixbench (the workload is repeadly writing 1 KB to the same file) [2]. Inherit the SB_NOSEC flag from upperdir. Since then xattr lookup would be done only once on the first write. Unixbench fstime gets a ~20% performance gain with this patch. [1] https://lore.kernel.org/lkml/20180606150905.GC9426@magnolia/T/ [2] https://www.spinics.net/lists/linux-unionfs/msg07153.html Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: skip overlayfs superblocks at global syncKonstantin Khlebnikov2020-05-131-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stacked filesystems like overlayfs has no own writeback, but they have to forward syncfs() requests to backend for keeping data integrity. During global sync() each overlayfs instance calls method ->sync_fs() for backend although it itself is in global list of superblocks too. As a result one syscall sync() could write one superblock several times and send multiple disk barriers. This patch adds flag SB_I_SKIP_SYNC into sb->sb_iflags to avoid that. Reported-by: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| * ovl: index dir act as work dirAmir Goldstein2020-05-131-5/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With index=on, let index dir act as the work dir for copy up and cleanups. This will help implementing whiteout inode sharing. We still create the "work" dir on mount regardless of index=on and it is used to test the features supported by upper fs. One reason is that before the feature tests, we do not know if index could be enabled or not. The reason we do not use "index" directory also as workdir with index=off is because the existence of the "index" directory acts as a simple persistent signal that index was enabled on this filesystem and tools may want to use that signal. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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