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2023-03-05xfs: quotacheck failure can race with background inode inactivationDave Chinner1-14/+26
The background inode inactivation can attached dquots to inodes, but this can race with a foreground quotacheck failure that leads to disabling quotas and freeing the mp->m_quotainfo structure. The background inode inactivation then tries to allocate a quota, tries to dereference mp->m_quotainfo, and crashes like so: XFS (loop1): Quotacheck: Unsuccessful (Error -5): Disabling quotas. xfs filesystem being mounted at /root/syzkaller.qCVHXV/0/file0 supports timestamps until 2038 (0x7fffffff) BUG: kernel NULL pointer dereference, address: 00000000000002a8 .... CPU: 0 PID: 161 Comm: kworker/0:4 Not tainted 6.2.0-c9c3395d5e3d #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Workqueue: xfs-inodegc/loop1 xfs_inodegc_worker RIP: 0010:xfs_dquot_alloc+0x95/0x1e0 .... Call Trace: <TASK> xfs_qm_dqread+0x46/0x440 xfs_qm_dqget_inode+0x154/0x500 xfs_qm_dqattach_one+0x142/0x3c0 xfs_qm_dqattach_locked+0x14a/0x170 xfs_qm_dqattach+0x52/0x80 xfs_inactive+0x186/0x340 xfs_inodegc_worker+0xd3/0x430 process_one_work+0x3b1/0x960 worker_thread+0x52/0x660 kthread+0x161/0x1a0 ret_from_fork+0x29/0x50 </TASK> .... Prevent this race by flushing all the queued background inode inactivations pending before purging all the cached dquots when quotacheck fails. Reported-by: Pengfei Xu <pengfei.xu@intel.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2023-02-20Merge tag 'fs.idmapped.v6.3' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping Pull vfs idmapping updates from Christian Brauner: - Last cycle we introduced the dedicated struct mnt_idmap type for mount idmapping and the required infrastucture in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). As promised in last cycle's pull request message this converts everything to rely on struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevant on the mount level. Especially for non-vfs developers without detailed knowledge in this area this was a potential source for bugs. This finishes the conversion. Instead of passing the plain namespace around this updates all places that currently take a pointer to a mnt_userns with a pointer to struct mnt_idmap. Now that the conversion is done all helpers down to the really low-level helpers only accept a struct mnt_idmap argument instead of two namespace arguments. Conflating mount and other idmappings will now cause the compiler to complain loudly thus eliminating the possibility of any bugs. This makes it impossible for filesystem developers to mix up mount and filesystem idmappings as they are two distinct types and require distinct helpers that cannot be used interchangeably. Everything associated with struct mnt_idmap is moved into a single separate file. With that change no code can poke around in struct mnt_idmap. It can only be interacted with through dedicated helpers. That means all filesystems are and all of the vfs is completely oblivious to the actual implementation of idmappings. We are now also able to extend struct mnt_idmap as we see fit. For example, we can decouple it completely from namespaces for users that don't require or don't want to use them at all. We can also extend the concept of idmappings so we can cover filesystem specific requirements. In combination with the vfs{g,u}id_t work we finished in v6.2 this makes this feature substantially more robust and thus difficult to implement wrong by a given filesystem and also protects the vfs. - Enable idmapped mounts for tmpfs and fulfill a longstanding request. A long-standing request from users had been to make it possible to create idmapped mounts for tmpfs. For example, to share the host's tmpfs mount between multiple sandboxes. This is a prerequisite for some advanced Kubernetes cases. Systemd also has a range of use-cases to increase service isolation. And there are more users of this. However, with all of the other work going on this was way down on the priority list but luckily someone other than ourselves picked this up. As usual the patch is tiny as all the infrastructure work had been done multiple kernel releases ago. In addition to all the tests that we already have I requested that Rodrigo add a dedicated tmpfs testsuite for idmapped mounts to xfstests. It is to be included into xfstests during the v6.3 development cycle. This should add a slew of additional tests. * tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits) shmem: support idmapped mounts for tmpfs fs: move mnt_idmap fs: port vfs{g,u}id helpers to mnt_idmap fs: port fs{g,u}id helpers to mnt_idmap fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap fs: port i_{g,u}id_{needs_}update() to mnt_idmap quota: port to mnt_idmap fs: port privilege checking helpers to mnt_idmap fs: port inode_owner_or_capable() to mnt_idmap fs: port inode_init_owner() to mnt_idmap fs: port acl to mnt_idmap fs: port xattr to mnt_idmap fs: port ->permission() to pass mnt_idmap fs: port ->fileattr_set() to pass mnt_idmap fs: port ->set_acl() to pass mnt_idmap fs: port ->get_acl() to pass mnt_idmap fs: port ->tmpfile() to pass mnt_idmap fs: port ->rename() to pass mnt_idmap fs: port ->mknod() to pass mnt_idmap fs: port ->mkdir() to pass mnt_idmap ...
2023-01-19fs: port inode_init_owner() to mnt_idmapChristian Brauner1-1/+1
Convert to struct mnt_idmap. Last cycle we merged the necessary infrastructure in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). This is just the conversion to struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevent on the mount level. Especially for non-vfs developers without detailed knowledge in this area this can be a potential source for bugs. Once the conversion to struct mnt_idmap is done all helpers down to the really low-level helpers will take a struct mnt_idmap argument instead of two namespace arguments. This way it becomes impossible to conflate the two eliminating the possibility of any bugs. All of the vfs and all filesystems only operate on struct mnt_idmap. Acked-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-03xfs: xfs_qm: remove unnecessary ‘0’ values from errorLi zeming1-1/+1
error is assigned first, so it does not need to initialize the assignment. Signed-off-by: Li zeming <zeming@nfschina.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-12-08xfs: dquot shrinker doesn't check for XFS_DQFLAG_FREEINGDave Chinner1-4/+12
Resulting in a UAF if the shrinker races with some other dquot freeing mechanism that sets XFS_DQFLAG_FREEING before the dquot is removed from the LRU. This can occur if a dquot purge races with drop_caches. Reported-by: syzbot+912776840162c13db1a3@syzkaller.appspotmail.com Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-08-13Merge tag 'xfs-5.20-merge-8' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds1-0/+5
Pull more xfs updates from Darrick Wong: "There's not a lot this time around, just the usual bug fixes and corrections for missing error returns. - Return error codes from block device flushes to userspace - Fix a deadlock between reclaim and mount time quotacheck - Fix an unnecessary ENOSPC return when doing COW on a filesystem with severe free space fragmentation - Fix a miscalculation in the transaction reservation computations for file removal operations" * tag 'xfs-5.20-merge-8' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: xfs: fix inode reservation space for removing transaction xfs: Fix false ENOSPC when performing direct write on a delalloc extent in cow fork xfs: fix intermittent hang during quotacheck xfs: check return codes when flushing block devices
2022-08-05xfs: fix intermittent hang during quotacheckDarrick J. Wong1-0/+5
Every now and then, I see the following hang during mount time quotacheck when running fstests. Turning on KASAN seems to make it happen somewhat more frequently. I've edited the backtrace for brevity. XFS (sdd): Quotacheck needed: Please wait. XFS: Assertion failed: bp->b_flags & _XBF_DELWRI_Q, file: fs/xfs/xfs_buf.c, line: 2411 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1831409 at fs/xfs/xfs_message.c:104 assfail+0x46/0x4a [xfs] CPU: 0 PID: 1831409 Comm: mount Tainted: G W 5.19.0-rc6-xfsx #rc6 09911566947b9f737b036b4af85e399e4b9aef64 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 RIP: 0010:assfail+0x46/0x4a [xfs] Code: a0 8f 41 a0 e8 45 fe ff ff 8a 1d 2c 36 10 00 80 fb 01 76 0f 0f b6 f3 48 c7 c7 c0 f0 4f a0 e8 10 f0 02 e1 80 e3 01 74 02 0f 0b <0f> 0b 5b c3 48 8d 45 10 48 89 e2 4c 89 e6 48 89 1c 24 48 89 44 24 RSP: 0018:ffffc900078c7b30 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8880099ac000 RCX: 000000007fffffff RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffa0418fa0 RBP: ffff8880197bc1c0 R08: 0000000000000000 R09: 000000000000000a R10: 000000000000000a R11: f000000000000000 R12: ffffc900078c7d20 R13: 00000000fffffff5 R14: ffffc900078c7d20 R15: 0000000000000000 FS: 00007f0449903800(0000) GS:ffff88803ec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005610ada631f0 CR3: 0000000014dd8002 CR4: 00000000001706f0 Call Trace: <TASK> xfs_buf_delwri_pushbuf+0x150/0x160 [xfs 4561f5b32c9bfb874ec98d58d0719464e1f87368] xfs_qm_flush_one+0xd6/0x130 [xfs 4561f5b32c9bfb874ec98d58d0719464e1f87368] xfs_qm_dquot_walk.isra.0+0x109/0x1e0 [xfs 4561f5b32c9bfb874ec98d58d0719464e1f87368] xfs_qm_quotacheck+0x319/0x490 [xfs 4561f5b32c9bfb874ec98d58d0719464e1f87368] xfs_qm_mount_quotas+0x65/0x2c0 [xfs 4561f5b32c9bfb874ec98d58d0719464e1f87368] xfs_mountfs+0x6b5/0xab0 [xfs 4561f5b32c9bfb874ec98d58d0719464e1f87368] xfs_fs_fill_super+0x781/0x990 [xfs 4561f5b32c9bfb874ec98d58d0719464e1f87368] get_tree_bdev+0x175/0x280 vfs_get_tree+0x1a/0x80 path_mount+0x6f5/0xaa0 __x64_sys_mount+0x103/0x140 do_syscall_64+0x2b/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 I /think/ this can happen if xfs_qm_flush_one is racing with xfs_qm_dquot_isolate (i.e. dquot reclaim) when the second function has taken the dquot flush lock but xfs_qm_dqflush hasn't yet locked the dquot buffer, let alone queued it to the delwri list. In this case, flush_one will fail to get the dquot flush lock, but it can lock the incore buffer, but xfs_buf_delwri_pushbuf will then trip over this ASSERT, which checks that the buffer isn't on a delwri list. The hang results because the _delwri_submit_buffers ignores non DELWRI_Q buffers, which means that xfs_buf_iowait waits forever for an IO that has not yet been scheduled. AFAICT, a reasonable solution here is to detect a dquot buffer that is not on a DELWRI list, drop it, and return -EAGAIN to try the flush again. It's not /that/ big of a deal if quotacheck writes the dquot buffer repeatedly before we even set QUOTA_CHKD. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-08-05Merge tag 'mm-stable-2022-08-03' of ↵Linus Torvalds1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "Most of the MM queue. A few things are still pending. Liam's maple tree rework didn't make it. This has resulted in a few other minor patch series being held over for next time. Multi-gen LRU still isn't merged as we were waiting for mapletree to stabilize. The current plan is to merge MGLRU into -mm soon and to later reintroduce mapletree, with a view to hopefully getting both into 6.1-rc1. Summary: - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe Lin, Yang Shi, Anshuman Khandual and Mike Rapoport - Some kmemleak fixes from Patrick Wang and Waiman Long - DAMON updates from SeongJae Park - memcg debug/visibility work from Roman Gushchin - vmalloc speedup from Uladzislau Rezki - more folio conversion work from Matthew Wilcox - enhancements for coherent device memory mapping from Alex Sierra - addition of shared pages tracking and CoW support for fsdax, from Shiyang Ruan - hugetlb optimizations from Mike Kravetz - Mel Gorman has contributed some pagealloc changes to improve latency and realtime behaviour. - mprotect soft-dirty checking has been improved by Peter Xu - Many other singleton patches all over the place" [ XFS merge from hell as per Darrick Wong in https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ] * tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits) tools/testing/selftests/vm/hmm-tests.c: fix build mm: Kconfig: fix typo mm: memory-failure: convert to pr_fmt() mm: use is_zone_movable_page() helper hugetlbfs: fix inaccurate comment in hugetlbfs_statfs() hugetlbfs: cleanup some comments in inode.c hugetlbfs: remove unneeded header file hugetlbfs: remove unneeded hugetlbfs_ops forward declaration hugetlbfs: use helper macro SZ_1{K,M} mm: cleanup is_highmem() mm/hmm: add a test for cross device private faults selftests: add soft-dirty into run_vmtests.sh selftests: soft-dirty: add test for mprotect mm/mprotect: fix soft-dirty check in can_change_pte_writable() mm: memcontrol: fix potential oom_lock recursion deadlock mm/gup.c: fix formatting in check_and_migrate_movable_page() xfs: fail dax mount if reflink is enabled on a partition mm/memcontrol.c: remove the redundant updating of stats_flush_threshold userfaultfd: don't fail on unrecognized features hugetlb_cgroup: fix wrong hugetlb cgroup numa stat ...
2022-07-14Merge tag 'make-attr-fork-permanent-5.20_2022-07-14' of ↵Darrick J. Wong1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-5.20-mergeB xfs: make attr forks permanent This series fixes a use-after-free bug that syzbot uncovered. The UAF itself is a result of a race condition between getxattr and removexattr because callers to getxattr do not necessarily take any sort of locks before calling into the filesystem. Although the race condition itself can be fixed through clever use of a memory barrier, further consideration of the use cases of extended attributes shows that most files always have at least one attribute, so we might as well make them permanent. v2: Minor tweaks suggested by Dave, and convert some more macros to helper functions. Signed-off-by: Darrick J. Wong <djwong@kernel.org> * tag 'make-attr-fork-permanent-5.20_2022-07-14' of git://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux: xfs: replace inode fork size macros with functions xfs: replace XFS_IFORK_Q with a proper predicate function xfs: use XFS_IFORK_Q to determine the presence of an xattr fork xfs: make inode attribute forks a permanent part of struct xfs_inode xfs: convert XFS_IFORK_PTR to a static inline helper
2022-07-09xfs: convert XFS_IFORK_PTR to a static inline helperDarrick J. Wong1-1/+1
We're about to make this logic do a bit more, so convert the macro to a static inline function for better typechecking and fewer shouty macros. No functional changes here. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-07-07xfs: rework xfs_buf_incore() APIDave Chinner1-5/+4
Make it consistent with the other buffer APIs to return a error and the buffer is placed in a parameter. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2022-07-03mm: shrinkers: provide shrinkers with namesRoman Gushchin1-1/+2
Currently shrinkers are anonymous objects. For debugging purposes they can be identified by count/scan function names, but it's not always useful: e.g. for superblock's shrinkers it's nice to have at least an idea of to which superblock the shrinker belongs. This commit adds names to shrinkers. register_shrinker() and prealloc_shrinker() functions are extended to take a format and arguments to master a name. In some cases it's not possible to determine a good name at the time when a shrinker is allocated. For such cases shrinker_debugfs_rename() is provided. The expected format is: <subsystem>-<shrinker_type>[:<instance>]-<id> For some shrinkers an instance can be encoded as (MAJOR:MINOR) pair. After this change the shrinker debugfs directory looks like: $ cd /sys/kernel/debug/shrinker/ $ ls dquota-cache-16 sb-devpts-28 sb-proc-47 sb-tmpfs-42 mm-shadow-18 sb-devtmpfs-5 sb-proc-48 sb-tmpfs-43 mm-zspool:zram0-34 sb-hugetlbfs-17 sb-pstore-31 sb-tmpfs-44 rcu-kfree-0 sb-hugetlbfs-33 sb-rootfs-2 sb-tmpfs-49 sb-aio-20 sb-iomem-12 sb-securityfs-6 sb-tracefs-13 sb-anon_inodefs-15 sb-mqueue-21 sb-selinuxfs-22 sb-xfs:vda1-36 sb-bdev-3 sb-nsfs-4 sb-sockfs-8 sb-zsmalloc-19 sb-bpf-32 sb-pipefs-14 sb-sysfs-26 thp-deferred_split-10 sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-1 thp-zero-9 sb-cgroup2-30 sb-proc-39 sb-tmpfs-27 xfs-buf:vda1-37 sb-configfs-23 sb-proc-41 sb-tmpfs-29 xfs-inodegc:vda1-38 sb-dax-11 sb-proc-45 sb-tmpfs-35 sb-debugfs-7 sb-proc-46 sb-tmpfs-40 [roman.gushchin@linux.dev: fix build warnings] Link: https://lkml.kernel.org/r/Yr+ZTnLb9lJk6fJO@castle Reported-by: kernel test robot <lkp@intel.com> Link: https://lkml.kernel.org/r/20220601032227.4076670-4-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: Dave Chinner <dchinner@redhat.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-27xfs: purge dquots after inode walk fails during quotacheckDarrick J. Wong1-1/+8
xfs/434 and xfs/436 have been reporting occasional memory leaks of xfs_dquot objects. These tests themselves were the messenger, not the culprit, since they unload the xfs module, which trips the slub debugging code while tearing down all the xfs slab caches: ============================================================================= BUG xfs_dquot (Tainted: G W ): Objects remaining in xfs_dquot on __kmem_cache_shutdown() ----------------------------------------------------------------------------- Slab 0xffffea000606de00 objects=30 used=5 fp=0xffff888181b78a78 flags=0x17ff80000010200(slab|head|node=0|zone=2|lastcpupid=0xfff) CPU: 0 PID: 3953166 Comm: modprobe Tainted: G W 5.18.0-rc6-djwx #rc6 d5824be9e46a2393677bda868f9b154d917ca6a7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20171121_152543-x86-ol7-builder-01.us.oracle.com-4.el7.1 04/01/2014 Since we don't generally rmmod the xfs module between fstests, this means that xfs/434 is really just the canary in the coal mine -- something leaked a dquot, but we don't know who. After days of pounding on fstests with kmemleak enabled, I finally got it to spit this out: unreferenced object 0xffff8880465654c0 (size 536): comm "u10:4", pid 88, jiffies 4294935810 (age 29.512s) hex dump (first 32 bytes): 60 4a 56 46 80 88 ff ff 58 ea e4 5c 80 88 ff ff `JVF....X..\.... 00 e0 52 49 80 88 ff ff 01 00 01 00 00 00 00 00 ..RI............ backtrace: [<ffffffffa0740f6c>] xfs_dquot_alloc+0x2c/0x530 [xfs] [<ffffffffa07443df>] xfs_qm_dqread+0x6f/0x330 [xfs] [<ffffffffa07462a2>] xfs_qm_dqget+0x132/0x4e0 [xfs] [<ffffffffa0756bb0>] xfs_qm_quotacheck_dqadjust+0xa0/0x3e0 [xfs] [<ffffffffa075724d>] xfs_qm_dqusage_adjust+0x35d/0x4f0 [xfs] [<ffffffffa06c9068>] xfs_iwalk_ag_recs+0x348/0x5d0 [xfs] [<ffffffffa06c95d3>] xfs_iwalk_run_callbacks+0x273/0x540 [xfs] [<ffffffffa06c9e8d>] xfs_iwalk_ag+0x5ed/0x890 [xfs] [<ffffffffa06ca22f>] xfs_iwalk_ag_work+0xff/0x170 [xfs] [<ffffffffa06d22c9>] xfs_pwork_work+0x79/0x130 [xfs] [<ffffffff81170bb2>] process_one_work+0x672/0x1040 [<ffffffff81171b1b>] worker_thread+0x59b/0xec0 [<ffffffff8118711e>] kthread+0x29e/0x340 [<ffffffff810032bf>] ret_from_fork+0x1f/0x30 Now we know that quotacheck is at fault, but even this report was canaryish -- it was triggered by xfs/494, which doesn't actually mount any filesystems. (kmemleak can be a little slow to notice leaks, even with fstests repeatedly whacking it to look for them.) Looking at the *previous* fstest, however, showed that the test run before xfs/494 was xfs/117. The tipoff to the problem is in this excerpt from dmesg: XFS (sda4): Quotacheck needed: Please wait. XFS (sda4): Metadata corruption detected at xfs_dinode_verify.part.0+0xdb/0x7b0 [xfs], inode 0x119 dinode XFS (sda4): Unmount and run xfs_repair XFS (sda4): First 128 bytes of corrupted metadata buffer: 00000000: 49 4e 81 a4 03 02 00 00 00 00 00 00 00 00 00 00 IN.............. 00000010: 00 00 00 01 00 00 00 00 00 90 57 54 54 1a 4c 68 ..........WTT.Lh 00000020: 81 f9 7d e1 6d ee 16 00 34 bd 7d e1 6d ee 16 00 ..}.m...4.}.m... 00000030: 34 bd 7d e1 6d ee 16 00 00 00 00 00 00 00 00 00 4.}.m........... 00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000050: 00 00 00 02 00 00 00 00 00 00 00 00 96 80 f3 ab ................ 00000060: ff ff ff ff da 57 7b 11 00 00 00 00 00 00 00 03 .....W{......... 00000070: 00 00 00 01 00 00 00 10 00 00 00 00 00 00 00 08 ................ XFS (sda4): Quotacheck: Unsuccessful (Error -117): Disabling quotas. The dinode verifier decided that the inode was corrupt, which causes iget to return with EFSCORRUPTED. Since this happened during quotacheck, it is obvious that the kernel aborted the inode walk on account of the corruption error and disabled quotas. Unfortunately, we neglect to purge the dquot cache before doing that, which is how the dquots leaked. The problems started 10 years ago in commit b84a3a, when the dquot lists were converted to a radix tree, but the error handling behavior was not correctly preserved -- in that commit, if the bulkstat failed and usrquota was enabled, the bulkstat failure code would be overwritten by the result of flushing all the dquots to disk. As long as that succeeds, we'd continue the quota mount as if everything were ok, but instead we're now operating with a corrupt inode and incorrect quota usage counts. I didn't notice this bug in 2019 when I wrote commit ebd126a, which changed quotacheck to skip the dqflush when the scan doesn't complete due to inode walk failures. Introduced-by: b84a3a96751f ("xfs: remove the per-filesystem list of dquots") Fixes: ebd126a651f8 ("xfs: convert quotacheck to use the new iwalk functions") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2022-05-11xfs: remove quota warning limit from struct xfs_quota_limitsCatherine Hoang1-9/+0
Warning limits in xfs quota is an unused feature that is currently documented as unimplemented, and it is unclear what the intended behavior of these limits are. Remove the ‘warn’ field from struct xfs_quota_limits and any other related code. Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Dave Chinner <david@fromorbit.com>
2022-03-20xfs: xfs_is_shutdown vs xlog_is_shutdown cage fightDave Chinner1-4/+4
I've been chasing a recent resurgence in generic/388 recovery failure and/or corruption events. The events have largely been uninitialised inode chunks being tripped over in log recovery such as: XFS (pmem1): User initiated shutdown received. pmem1: writeback error on inode 12621949, offset 1019904, sector 12968096 XFS (pmem1): Log I/O Error (0x6) detected at xfs_fs_goingdown+0xa3/0xf0 (fs/xfs/xfs_fsops.c:500). Shutting down filesystem. XFS (pmem1): Please unmount the filesystem and rectify the problem(s) XFS (pmem1): Unmounting Filesystem XFS (pmem1): Mounting V5 Filesystem XFS (pmem1): Starting recovery (logdev: internal) XFS (pmem1): bad inode magic/vsn daddr 8723584 #0 (magic=1818) XFS (pmem1): Metadata corruption detected at xfs_inode_buf_verify+0x180/0x190, xfs_inode block 0x851c80 xfs_inode_buf_verify XFS (pmem1): Unmount and run xfs_repair XFS (pmem1): First 128 bytes of corrupted metadata buffer: 00000000: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................ 00000010: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................ 00000020: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................ 00000030: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................ 00000040: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................ 00000050: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................ 00000060: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................ 00000070: 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 ................ XFS (pmem1): metadata I/O error in "xlog_recover_items_pass2+0x52/0xc0" at daddr 0x851c80 len 32 error 117 XFS (pmem1): log mount/recovery failed: error -117 XFS (pmem1): log mount failed There have been isolated random other issues, too - xfs_repair fails because it finds some corruption in symlink blocks, rmap inconsistencies, etc - but they are nowhere near as common as the uninitialised inode chunk failure. The problem has clearly happened at runtime before recovery has run; I can see the ICREATE log item in the log shortly before the actively recovered range of the log. This means the ICREATE was definitely created and written to the log, but for some reason the tail of the log has been moved past the ordered buffer log item that tracks INODE_ALLOC buffers and, supposedly, prevents the tail of the log moving past the ICREATE log item before the inode chunk buffer is written to disk. Tracing the fsstress processes that are running when the filesystem shut down immediately pin-pointed the problem: user shutdown marks xfs_mount as shutdown godown-213341 [008] 6398.022871: console: [ 6397.915392] XFS (pmem1): User initiated shutdown received. ..... aild tries to push ordered inode cluster buffer xfsaild/pmem1-213314 [001] 6398.022974: xfs_buf_trylock: dev 259:1 daddr 0x851c80 bbcount 0x20 hold 16 pincount 0 lock 0 flags DONE|INODES|PAGES caller xfs_inode_item_push+0x8e xfsaild/pmem1-213314 [001] 6398.022976: xfs_ilock_nowait: dev 259:1 ino 0x851c80 flags ILOCK_SHARED caller xfs_iflush_cluster+0xae xfs_iflush_cluster() checks xfs_is_shutdown(), returns true, calls xfs_iflush_abort() to kill writeback of the inode. Inode is removed from AIL, drops cluster buffer reference. xfsaild/pmem1-213314 [001] 6398.022977: xfs_ail_delete: dev 259:1 lip 0xffff88880247ed80 old lsn 7/20344 new lsn 7/21000 type XFS_LI_INODE flags IN_AIL xfsaild/pmem1-213314 [001] 6398.022978: xfs_buf_rele: dev 259:1 daddr 0x851c80 bbcount 0x20 hold 17 pincount 0 lock 0 flags DONE|INODES|PAGES caller xfs_iflush_abort+0xd7 ..... All inodes on cluster buffer are aborted, then the cluster buffer itself is aborted and removed from the AIL *without writeback*: xfsaild/pmem1-213314 [001] 6398.023011: xfs_buf_error_relse: dev 259:1 daddr 0x851c80 bbcount 0x20 hold 2 pincount 0 lock 0 flags ASYNC|DONE|STALE|INODES|PAGES caller xfs_buf_ioend_fail+0x33 xfsaild/pmem1-213314 [001] 6398.023012: xfs_ail_delete: dev 259:1 lip 0xffff8888053efde8 old lsn 7/20344 new lsn 7/20344 type XFS_LI_BUF flags IN_AIL The inode buffer was at 7/20344 when it was removed from the AIL. xfsaild/pmem1-213314 [001] 6398.023012: xfs_buf_item_relse: dev 259:1 daddr 0x851c80 bbcount 0x20 hold 2 pincount 0 lock 0 flags ASYNC|DONE|STALE|INODES|PAGES caller xfs_buf_item_done+0x31 xfsaild/pmem1-213314 [001] 6398.023012: xfs_buf_rele: dev 259:1 daddr 0x851c80 bbcount 0x20 hold 2 pincount 0 lock 0 flags ASYNC|DONE|STALE|INODES|PAGES caller xfs_buf_item_relse+0x39 ..... Userspace is still running, doing stuff. an fsstress process runs syncfs() or sync() and we end up in sync_fs_one_sb() which issues a log force. This pushes on the CIL: fsstress-213322 [001] 6398.024430: xfs_fs_sync_fs: dev 259:1 m_features 0x20000000019ff6e9 opstate (clean|shutdown|inodegc|blockgc) s_flags 0x70810000 caller sync_fs_one_sb+0x26 fsstress-213322 [001] 6398.024430: xfs_log_force: dev 259:1 lsn 0x0 caller xfs_fs_sync_fs+0x82 fsstress-213322 [001] 6398.024430: xfs_log_force: dev 259:1 lsn 0x5f caller xfs_log_force+0x7c <...>-194402 [001] 6398.024467: kmem_alloc: size 176 flags 0x14 caller xlog_cil_push_work+0x9f And the CIL fills up iclogs with pending changes. This picks up the current tail from the AIL: <...>-194402 [001] 6398.024497: xlog_iclog_get_space: dev 259:1 state XLOG_STATE_ACTIVE refcnt 1 offset 0 lsn 0x0 flags caller xlog_write+0x149 <...>-194402 [001] 6398.024498: xlog_iclog_switch: dev 259:1 state XLOG_STATE_ACTIVE refcnt 1 offset 0 lsn 0x700005408 flags caller xlog_state_get_iclog_space+0x37e <...>-194402 [001] 6398.024521: xlog_iclog_release: dev 259:1 state XLOG_STATE_WANT_SYNC refcnt 1 offset 32256 lsn 0x700005408 flags caller xlog_write+0x5f9 <...>-194402 [001] 6398.024522: xfs_log_assign_tail_lsn: dev 259:1 new tail lsn 7/21000, old lsn 7/20344, last sync 7/21448 And it moves the tail of the log to 7/21000 from 7/20344. This *moves the tail of the log beyond the ICREATE transaction* that was at 7/20344 and pinned by the inode cluster buffer that was cancelled above. .... godown-213341 [008] 6398.027005: xfs_force_shutdown: dev 259:1 tag logerror flags log_io|force_umount file fs/xfs/xfs_fsops.c line_num 500 godown-213341 [008] 6398.027022: console: [ 6397.915406] pmem1: writeback error on inode 12621949, offset 1019904, sector 12968096 godown-213341 [008] 6398.030551: console: [ 6397.919546] XFS (pmem1): Log I/O Error (0x6) detected at xfs_fs_goingdown+0xa3/0xf0 (fs/ And finally the log itself is now shutdown, stopping all further writes to the log. But this is too late to prevent the corruption that moving the tail of the log forwards after we start cancelling writeback causes. The fundamental problem here is that we are using the wrong shutdown checks for log items. We've long conflated mount shutdown with log shutdown state, and I started separating that recently with the atomic shutdown state changes in commit b36d4651e165 ("xfs: make forced shutdown processing atomic"). The changes in that commit series are directly responsible for being able to diagnose this issue because it clearly separated mount shutdown from log shutdown. Essentially, once we start cancelling writeback of log items and removing them from the AIL because the filesystem is shut down, we *cannot* update the journal because we may have cancelled the items that pin the tail of the log. That moves the tail of the log forwards without having written the metadata back, hence we have corrupt in memory state and writing to the journal propagates that to the on-disk state. What commit b36d4651e165 makes clear is that log item state needs to change relative to log shutdown, not mount shutdown. IOWs, anything that aborts metadata writeback needs to check log shutdown state because log items directly affect log consistency. Having them check mount shutdown state introduces the above race condition where we cancel metadata writeback before the log shuts down. To fix this, this patch works through all log items and converts shutdown checks to use xlog_is_shutdown() rather than xfs_is_shutdown(), so that we don't start aborting metadata writeback before we shut off journal writes. AFAICT, this race condition is a zero day IO error handling bug in XFS that dates back to the introduction of XLOG_IO_ERROR, XLOG_STATE_IOERROR and XFS_FORCED_SHUTDOWN back in January 1997. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-10-14xfs: remove the xfs_dqblk_t typedefChristoph Hellwig1-1/+1
Remove the few leftover instances of the xfs_dinode_t typedef. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-19xfs: replace XFS_FORCED_SHUTDOWN with xfs_is_shutdownDave Chinner1-2/+2
Remove the shouty macro and instead use the inline function that matches other state/feature check wrapper naming. This conversion was done with sed. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-19xfs: replace xfs_sb_version checks with feature flag checksDave Chinner1-7/+7
Convert the xfs_sb_version_hasfoo() to checks against mp->m_features. Checks of the superblock itself during disk operations (e.g. in the read/write verifiers and the to/from disk formatters) are not converted - they operate purely on the superblock state. Everything else should use the mount features. Large parts of this conversion were done with sed with commands like this: for f in `git grep -l xfs_sb_version_has fs/xfs/*.c`; do sed -i -e 's/xfs_sb_version_has\(.*\)(&\(.*\)->m_sb)/xfs_has_\1(\2)/' $f done With manual cleanups for things like "xfs_has_extflgbit" and other little inconsistencies in naming. The result is ia lot less typing to check features and an XFS binary size reduced by a bit over 3kB: $ size -t fs/xfs/built-in.a text data bss dec hex filenam before 1130866 311352 484 1442702 16038e (TOTALS) after 1127727 311352 484 1439563 15f74b (TOTALS) Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-09xfs: queue inactivation immediately when quota is nearing enforcementDarrick J. Wong1-0/+34
Now that we have made the inactivation of unlinked inodes a background task to increase the throughput of file deletions, we need to be a little more careful about how long of a delay we can tolerate. Specifically, if the dquots attached to the inode being inactivated are nearing any kind of enforcement boundary, we want to queue that inactivation work immediately so that users don't get EDQUOT/ENOSPC errors even after they deleted a bunch of files to stay within quota. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2021-08-06xfs: remove the active vs running quota differentiationChristoph Hellwig1-14/+12
These only made a difference when quotaoff supported disabling quota accounting on a mounted file system, so we can switch everyone to use a single set of flags and helpers now. Note that the *QUOTA_ON naming for the helpers is kept as it was the much more commonly used one. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-06xfs: remove the flags argument to xfs_qm_dquot_walkChristoph Hellwig1-10/+6
We always purge all dquots now, so drop the argument. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-06xfs: remove support for disabling quota accounting on a mounted file systemChristoph Hellwig1-1/+1
Disabling quota accounting is hairy, racy code with all kinds of pitfalls. And it has a very strange mind set, as quota accounting (unlike enforcement) really is a propery of the on-disk format. There is no good use case for supporting this. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-06-02xfs: get rid of xfs_dir_ialloc()Dave Chinner1-2/+7
This is just a simple wrapper around the per-ag inode allocation that doesn't need to exist. The internal mechanism to select and allocate within an AG does not need to be exposed outside xfs_ialloc.c, and it being exposed simply makes it harder to follow the code and simplify it. This is simplified by internalising xf_dialloc_select_ag() and xfs_dialloc_ag() into a single xfs_dialloc() function and then xfs_dir_ialloc() can go away. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-06-02xfs: move xfs_perag_get/put to xfs_ag.[ch]Dave Chinner1-0/+1
They are AG functions, not superblock functions, so move them to the appropriate location. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-04-15xfs: move the XFS_IFEXTENTS check into xfs_iread_extentsChristoph Hellwig1-5/+3
Move the XFS_IFEXTENTS check from the callers into xfs_iread_extents to simplify the code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07xfs: move the di_nblocks field to struct xfs_inodeChristoph Hellwig1-4/+4
In preparation of removing the historic icinode struct, move the nblocks field into the containing xfs_inode structure. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07xfs: move the di_projid field to struct xfs_inodeChristoph Hellwig1-2/+2
In preparation of removing the historic icinode struct, move the projid field into the containing xfs_inode structure. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-03-25xfs: initialise attr fork on inode createDave Chinner1-1/+1
When we allocate a new inode, we often need to add an attribute to the inode as part of the create. This can happen as a result of needing to add default ACLs or security labels before the inode is made visible to userspace. This is highly inefficient right now. We do the create transaction to allocate the inode, then we do an "add attr fork" transaction to modify the just created empty inode to set the inode fork offset to allow attributes to be stored, then we go and do the attribute creation. This means 3 transactions instead of 1 to allocate an inode, and this greatly increases the load on the CIL commit code, resulting in excessive contention on the CIL spin locks and performance degradation: 18.99% [kernel] [k] __pv_queued_spin_lock_slowpath 3.57% [kernel] [k] do_raw_spin_lock 2.51% [kernel] [k] __raw_callee_save___pv_queued_spin_unlock 2.48% [kernel] [k] memcpy 2.34% [kernel] [k] xfs_log_commit_cil The typical profile resulting from running fsmark on a selinux enabled filesytem is adds this overhead to the create path: - 15.30% xfs_init_security - 15.23% security_inode_init_security - 13.05% xfs_initxattrs - 12.94% xfs_attr_set - 6.75% xfs_bmap_add_attrfork - 5.51% xfs_trans_commit - 5.48% __xfs_trans_commit - 5.35% xfs_log_commit_cil - 3.86% _raw_spin_lock - do_raw_spin_lock __pv_queued_spin_lock_slowpath - 0.70% xfs_trans_alloc 0.52% xfs_trans_reserve - 5.41% xfs_attr_set_args - 5.39% xfs_attr_set_shortform.constprop.0 - 4.46% xfs_trans_commit - 4.46% __xfs_trans_commit - 4.33% xfs_log_commit_cil - 2.74% _raw_spin_lock - do_raw_spin_lock __pv_queued_spin_lock_slowpath 0.60% xfs_inode_item_format 0.90% xfs_attr_try_sf_addname - 1.99% selinux_inode_init_security - 1.02% security_sid_to_context_force - 1.00% security_sid_to_context_core - 0.92% sidtab_entry_to_string - 0.90% sidtab_sid2str_get 0.59% sidtab_sid2str_put.part.0 - 0.82% selinux_determine_inode_label - 0.77% security_transition_sid 0.70% security_compute_sid.part.0 And fsmark creation rate performance drops by ~25%. The key point to note here is that half the additional overhead comes from adding the attribute fork to the newly created inode. That's crazy, considering we can do this same thing at inode create time with a couple of lines of code and no extra overhead. So, if we know we are going to add an attribute immediately after creating the inode, let's just initialise the attribute fork inside the create transaction and chop that whole chunk of code out of the create fast path. This completely removes the performance drop caused by enabling SELinux, and the profile looks like: - 8.99% xfs_init_security - 9.00% security_inode_init_security - 6.43% xfs_initxattrs - 6.37% xfs_attr_set - 5.45% xfs_attr_set_args - 5.42% xfs_attr_set_shortform.constprop.0 - 4.51% xfs_trans_commit - 4.54% __xfs_trans_commit - 4.59% xfs_log_commit_cil - 2.67% _raw_spin_lock - 3.28% do_raw_spin_lock 3.08% __pv_queued_spin_lock_slowpath 0.66% xfs_inode_item_format - 0.90% xfs_attr_try_sf_addname - 0.60% xfs_trans_alloc - 2.35% selinux_inode_init_security - 1.25% security_sid_to_context_force - 1.21% security_sid_to_context_core - 1.19% sidtab_entry_to_string - 1.20% sidtab_sid2str_get - 0.86% sidtab_sid2str_put.part.0 - 0.62% _raw_spin_lock_irqsave - 0.77% do_raw_spin_lock __pv_queued_spin_lock_slowpath - 0.84% selinux_determine_inode_label - 0.83% security_transition_sid 0.86% security_compute_sid.part.0 Which indicates the XFS overhead of creating the selinux xattr has been halved. This doesn't fix the CIL lock contention problem, just means it's not a limiting factor for this workload. Lock contention in the security subsystems is going to be an issue soon, though... Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> [djwong: fix compilation error when CONFIG_SECURITY=n] Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
2021-02-23Merge tag 'idmapped-mounts-v5.12' of ↵Linus Torvalds1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull idmapped mounts from Christian Brauner: "This introduces idmapped mounts which has been in the making for some time. Simply put, different mounts can expose the same file or directory with different ownership. This initial implementation comes with ports for fat, ext4 and with Christoph's port for xfs with more filesystems being actively worked on by independent people and maintainers. Idmapping mounts handle a wide range of long standing use-cases. Here are just a few: - Idmapped mounts make it possible to easily share files between multiple users or multiple machines especially in complex scenarios. For example, idmapped mounts will be used in the implementation of portable home directories in systemd-homed.service(8) where they allow users to move their home directory to an external storage device and use it on multiple computers where they are assigned different uids and gids. This effectively makes it possible to assign random uids and gids at login time. - It is possible to share files from the host with unprivileged containers without having to change ownership permanently through chown(2). - It is possible to idmap a container's rootfs and without having to mangle every file. For example, Chromebooks use it to share the user's Download folder with their unprivileged containers in their Linux subsystem. - It is possible to share files between containers with non-overlapping idmappings. - Filesystem that lack a proper concept of ownership such as fat can use idmapped mounts to implement discretionary access (DAC) permission checking. - They allow users to efficiently changing ownership on a per-mount basis without having to (recursively) chown(2) all files. In contrast to chown (2) changing ownership of large sets of files is instantenous with idmapped mounts. This is especially useful when ownership of a whole root filesystem of a virtual machine or container is changed. With idmapped mounts a single syscall mount_setattr syscall will be sufficient to change the ownership of all files. - Idmapped mounts always take the current ownership into account as idmappings specify what a given uid or gid is supposed to be mapped to. This contrasts with the chown(2) syscall which cannot by itself take the current ownership of the files it changes into account. It simply changes the ownership to the specified uid and gid. This is especially problematic when recursively chown(2)ing a large set of files which is commong with the aforementioned portable home directory and container and vm scenario. - Idmapped mounts allow to change ownership locally, restricting it to specific mounts, and temporarily as the ownership changes only apply as long as the mount exists. Several userspace projects have either already put up patches and pull-requests for this feature or will do so should you decide to pull this: - systemd: In a wide variety of scenarios but especially right away in their implementation of portable home directories. https://systemd.io/HOME_DIRECTORY/ - container runtimes: containerd, runC, LXD:To share data between host and unprivileged containers, unprivileged and privileged containers, etc. The pull request for idmapped mounts support in containerd, the default Kubernetes runtime is already up for quite a while now: https://github.com/containerd/containerd/pull/4734 - The virtio-fs developers and several users have expressed interest in using this feature with virtual machines once virtio-fs is ported. - ChromeOS: Sharing host-directories with unprivileged containers. I've tightly synced with all those projects and all of those listed here have also expressed their need/desire for this feature on the mailing list. For more info on how people use this there's a bunch of talks about this too. Here's just two recent ones: https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf https://fosdem.org/2021/schedule/event/containers_idmap/ This comes with an extensive xfstests suite covering both ext4 and xfs: https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts It covers truncation, creation, opening, xattrs, vfscaps, setid execution, setgid inheritance and more both with idmapped and non-idmapped mounts. It already helped to discover an unrelated xfs setgid inheritance bug which has since been fixed in mainline. It will be sent for inclusion with the xfstests project should you decide to merge this. In order to support per-mount idmappings vfsmounts are marked with user n