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2021-07-20ceph: don't WARN if we're still opening a session to an MDSLuis Henriques
If MDSs aren't available while mounting a filesystem, the session state will transition from SESSION_OPENING to SESSION_CLOSING. And in that scenario check_session_state() will be called from delayed_work() and trigger this WARN. Avoid this by only WARNing after a session has already been established (i.e., the s_ttl will be different from 0). Fixes: 62575e270f66 ("ceph: check session state after bumping session->s_seq") Signed-off-by: Luis Henriques <lhenriques@suse.de> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: take reference to req->r_parent at point of assignmentJeff Layton
Currently, we set the r_parent pointer but then don't take a reference to it until we submit the request. If we end up freeing the req before that point, then we'll do a iput when we shouldn't. Instead, take the inode reference in the callers, so that it's always safe to call ceph_mdsc_put_request on the req, even before submission. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Luis Henriques <lhenriques@suse.de> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: eliminate ceph_async_iput()Jeff Layton
Now that we don't need to hold session->s_mutex or the snap_rwsem when calling ceph_check_caps, we can eliminate ceph_async_iput and just use normal iput calls. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: don't take s_mutex in ceph_flush_snapsJeff Layton
Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Luis Henriques <lhenriques@suse.de> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: don't take s_mutex in try_flush_capsJeff Layton
The s_mutex doesn't protect anything in this codepath. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Luis Henriques <lhenriques@suse.de> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: don't take s_mutex or snap_rwsem in ceph_check_capsJeff Layton
These locks appear to be completely unnecessary. Almost all of this function is done under the inode->i_ceph_lock, aside from the actual sending of the message. Don't take either lock in this function. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Luis Henriques <lhenriques@suse.de> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: eliminate session->s_gen_ttl_lockJeff Layton
Turn s_cap_gen field into an atomic_t, and just rely on the fact that we hold the s_mutex when changing the s_cap_ttl field. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Luis Henriques <lhenriques@suse.de> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: allow ceph_put_mds_session to take NULL or ERR_PTRJeff Layton
...to simplify some error paths. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Luis Henriques <lhenriques@suse.de> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: clean up locking annotation for ceph_get_snap_realm and ↵Jeff Layton
__lookup_snap_realm They both say that the snap_rwsem must be held for write, but I don't see any real reason for it, and it's not currently always called that way. The lookup is just walking the rbtree, so holding it for read should be fine there. The "get" is bumping the refcount and (possibly) removing it from the empty list. I see no need to hold the snap_rwsem for write for that. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: add some lockdep assertions around snaprealm handlingJeff Layton
Turn some comments into lockdep asserts. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: decoding error in ceph_update_snap_realm should return -EIOJeff Layton
Currently ceph_update_snap_realm returns -EINVAL when it hits a decoding error, which is the wrong error code. -EINVAL implies that the user gave us a bogus argument to a syscall or something similar. -EIO is more descriptive when we hit a decoding error. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: add IO size metrics supportXiubo Li
This will collect IO's total size and then calculate the average size, and also will collect the min/max IO sizes. The debugfs will show the size metrics in bytes and will let the userspace applications to switch to what they need. URL: https://tracker.ceph.com/issues/49913 Signed-off-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: update and rename __update_latency helper to __update_stdevXiubo Li
The new __update_stdev() helper will only compute the standard deviation. Signed-off-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-29ceph: simplify the metrics structXiubo Li
Signed-off-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-28ceph: make ceph_queue_cap_snap staticJeff Layton
Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-28ceph: make ceph_netfs_read_ops staticWei Yongjun
The sparse tool complains as follows: fs/ceph/addr.c:316:37: warning: symbol 'ceph_netfs_read_ops' was not declared. Should it be static? This symbol is not used outside of addr.c, so mark it static. Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-28ceph: remove bogus checks and WARN_ONs from ceph_set_page_dirtyJeff Layton
The checks for page->mapping are odd, as set_page_dirty is an address_space operation, and I don't see where it would be called on a non-pagecache page. The warning about the page lock also seems bogus. The comment over set_page_dirty() says that it can be called without the page lock in some rare cases. I don't think we want to warn if that's the case. Reported-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-22ceph: fix error handling in ceph_atomic_open and ceph_lookupJeff Layton
Commit aa60cfc3f7ee broke the error handling in these functions such that they don't handle non-ENOENT errors from ceph_mdsc_do_request properly. Move the checking of -ENOENT out of ceph_handle_snapdir and into the callers, and if we get a different error, return it immediately. Fixes: aa60cfc3f7ee ("ceph: don't use d_add in ceph_handle_snapdir") Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-06-22ceph: must hold snap_rwsem when filling inode for async createJeff Layton
...and add a lockdep assertion for it to ceph_fill_inode(). Cc: stable@vger.kernel.org # v5.7+ Fixes: 9a8d03ca2e2c3 ("ceph: attempt to do async create when possible") Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-05-06Merge tag 'ceph-for-5.13-rc1' of git://github.com/ceph/ceph-clientLinus Torvalds
Pull ceph updates from Ilya Dryomov: "Notable items here are - a series to take advantage of David Howells' netfs helper library from Jeff - three new filesystem client metrics from Xiubo - ceph.dir.rsnaps vxattr from Yanhu - two auth-related fixes from myself, marked for stable. Interspersed is a smattering of assorted fixes and cleanups across the filesystem" * tag 'ceph-for-5.13-rc1' of git://github.com/ceph/ceph-client: (24 commits) libceph: allow addrvecs with a single NONE/blank address libceph: don't set global_id until we get an auth ticket libceph: bump CephXAuthenticate encoding version ceph: don't allow access to MDS-private inodes ceph: fix up some bare fetches of i_size ceph: convert some PAGE_SIZE invocations to thp_size() ceph: support getting ceph.dir.rsnaps vxattr ceph: drop pinned_page parameter from ceph_get_caps ceph: fix inode leak on getattr error in __fh_to_dentry ceph: only check pool permissions for regular files ceph: send opened files/pinned caps/opened inodes metrics to MDS daemon ceph: avoid counting the same request twice or more ceph: rename the metric helpers ceph: fix kerneldoc copypasta over ceph_start_io_direct ceph: use attach/detach_page_private for tracking snap context ceph: don't use d_add in ceph_handle_snapdir ceph: don't clobber i_snap_caps on non-I_NEW inode ceph: fix fall-through warnings for Clang ceph: convert ceph_readpages to ceph_readahead ceph: convert ceph_write_begin to netfs_write_begin ...
2021-04-27ceph: don't allow access to MDS-private inodesJeff Layton
The MDS reserves a set of inodes for its own usage, and these should never be accessible to clients. Add a new helper to vet a proposed inode number against that range, and complain loudly and refuse to create or look it up if it's in it. Also, ensure that the MDS doesn't try to delegate inodes that are in that range or lower. Print a warning if it does, and don't save the range in the xarray. URL: https://tracker.ceph.com/issues/49922 Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: fix up some bare fetches of i_sizeJeff Layton
We need to use i_size_read(), which properly handles the torn read case on 32-bit arches. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: convert some PAGE_SIZE invocations to thp_size()Jeff Layton
Start preparing to allow the use of THPs in the pagecache with ceph by making it use thp_size() in lieu of PAGE_SIZE in the appropriate places. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: support getting ceph.dir.rsnaps vxattrYanhu Cao
Add support for grabbing the rsnaps value out of the inode info in traces, and exposing that via ceph.dir.rsnaps xattr. Signed-off-by: Yanhu Cao <gmayyyha@gmail.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: drop pinned_page parameter from ceph_get_capsJeff Layton
All of the existing callers that don't set this to NULL just drop the page reference at some arbitrary point later in processing. There's no point in keeping a page reference that we don't use, so just drop the reference immediately after checking the Uptodate flag. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: fix inode leak on getattr error in __fh_to_dentryJeff Layton
Fixes: 878dabb64117 ("ceph: don't return -ESTALE if there's still an open file") Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: only check pool permissions for regular filesJeff Layton
There is no need to do a ceph_pool_perm_check() on anything that isn't a regular file, as the MDS is what handles talking to the OSD in those cases. Just return 0 if it's not a regular file. Reported-by: Luis Henriques <lhenriques@suse.de> Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Xiubo Li <xiubli@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: send opened files/pinned caps/opened inodes metrics to MDS daemonXiubo Li
For the old ceph version, if it received this metric info, it will just ignore them. URL: https://tracker.ceph.com/issues/46866 Signed-off-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: avoid counting the same request twice or moreXiubo Li
If the request will retry, skip updating the latency metric. Signed-off-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: rename the metric helpersXiubo Li
Signed-off-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: fix kerneldoc copypasta over ceph_start_io_directJeff Layton
Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: use attach/detach_page_private for tracking snap contextJeff Layton
There is some ambiguity around the use of PagePrivate. It's generally expected in core code that if PagePrivate is set then you have a reference to it. It's not clear that ceph always does (and I believe it may not). Change ceph to use attach/detach_page_private so that we keep a reference to the page until the snap context is detached. Link: https://lore.kernel.org/ceph-devel/2503810.1616508988@warthog.procyon.org.uk/T/#mf29e5abbb0ec8035cde0de30778690de7d956f84 Reported-by: David Howells <dhowells@redhat.com> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: don't use d_add in ceph_handle_snapdirJeff Layton
It's possible ceph_get_snapdir could end up finding a (disconnected) inode that already exists in the cache. Change the prototype for ceph_handle_snapdir to return a dentry pointer and have it use d_splice_alias so we don't end up with an aliased dentry in the cache. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: don't clobber i_snap_caps on non-I_NEW inodeJeff Layton
We want the snapdir to mirror the non-snapped directory's attributes for most things, but i_snap_caps represents the caps granted on the snapshot directory by the MDS itself. A misbehaving MDS could issue different caps for the snapdir and we lose them here. Only reset i_snap_caps when the inode is I_NEW. Also, move the setting of i_op and i_fop inside the if block since they should never change anyway. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: fix fall-through warnings for ClangGustavo A. R. Silva
In preparation to enable -Wimplicit-fallthrough for Clang, fix a couple of warnings by explicitly adding a break and a goto statements instead of just letting the code fall through to the next case. URL: https://github.com/KSPP/linux/issues/115 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: convert ceph_readpages to ceph_readaheadJeff Layton
Convert ceph_readpages to ceph_readahead and make it use netfs_readahead. With this we can rip out a lot of the old readpage/readpages infrastructure. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: convert ceph_write_begin to netfs_write_beginJeff Layton
Convert ceph_write_begin to use the netfs_write_begin helper. Most of the ops we need for it are already in place from the readpage conversion but we do add a new check_write_begin op since ceph needs to be able to vet whether there is an incompatible writeback already in flight before reading in the page. With this, we can also remove the old ceph_do_readpage helper. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: convert ceph_readpage to netfs_readpageJeff Layton
Have the ceph KConfig select NETFS_SUPPORT. Add a new netfs ops structure and the operations for it. Convert ceph_readpage to use the new netfs_readpage helper. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: fix fscache invalidationJeff Layton
Ensure that we invalidate the fscache whenever we invalidate the pagecache. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: rework PageFsCache handlingJeff Layton
With the new fscache API, the PageFsCache bit now indicates that the page is being written to the cache and shouldn't be modified or released until it's finished. Change releasepage and invalidatepage to wait on that bit before returning. Also define FSCACHE_USE_NEW_IO_API so that we opt into the new fscache API. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-04-27ceph: rip out old fscache readpage handlingJeff Layton
With the new netfs read helper functions, we won't need a lot of this infrastructure as it handles the pagecache pages itself. Rip out the read handling for now, and much of the old infrastructure that deals in individual pages. The cookie handling is mostly unchanged, however. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-03-08ceph: don't allow type or device number to change on non-I_NEW inodesJeff Layton
Al pointed out that a malicious or broken MDS could change the type or device number of a given inode number. It may also be possible for the MDS to reuse an old inode number. Ensure that we never allow fill_inode to change the type part of the i_mode or the i_rdev unless I_NEW is set. Throw warnings if the MDS ever changes these on us mid-stream, and return an error. Don't set i_rdev directly, and rely on init_special_inode to do it. Also, fix up error handling in the callers of ceph_get_inode. In handle_cap_grant, check for and warn if the inode type changes, and only overwrite the mode if it didn't. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-03-08ceph: fix up error handling with snapdirsJeff Layton
There are several warts in the snapdir error handling. The -EOPNOTSUPP return in __snapfh_to_dentry is currently lost, and the call to ceph_handle_snapdir is not currently checked at all. Fix all of this up and eliminate a BUG_ON in ceph_get_snapdir. We can handle that case with a warning and return an error. Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-02-23Merge tag 'idmapped-mounts-v5.12' of ↵Linus Torvalds
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 namespaces. The idmapping of the user namespace will be used to map the ids of vfs objects when they are accessed through that mount. By default all vfsmounts are marked with the initial user namespace. The initial user namespace is used to indicate that a mount is not idmapped. All operations behave as before and this is verified in the testsuite. Based on prior discussions we want to attach the whole user namespace and not just a dedicated idmapping struct. This allows us to reuse all the helpers that already exist for dealing with idmappings instead of introducing a whole new range of helpers. In addition, if we decide in the future that we are confident enough to enable unprivileged users to setup idmapped mounts the permission checking can take into account whether the caller is privileged in the user namespace the mount is currently marked with. The user namespace the mount will be marked with can be specified by passing a file descriptor refering to the user namespace as an argument to the new mount_setattr() syscall together with the new MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern of extensibility. The following conditions must be met in order to create an idmapped mount: - The caller must currently have the CAP_SYS_ADMIN capability in the user namespace the underlying filesystem has been mounted in. - The underlying filesystem must support idmapped mounts. - The mount must not already be idmapped. This also implies that the idmapping of a mount cannot be altered once it has been idmapped. - The mount must be a detached/anonymous mount, i.e. it must have been created by calling open_tree() with the OPEN_TREE_CLONE flag and it must not already have been visible in the filesystem. The last two points guarantee easier semantics for userspace and the kernel and make the implementation significantly simpler. By default vfsmounts are marked with the initial user namespace and no behavioral or performance changes are observed. The manpage with a detailed description can be found here: https://git.kernel.org/brauner/man-pages/c/1d7b902e2875a1ff342e036a9f866a995640aea8 In order to support idmapped mounts, filesystems need to be changed and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The patches to convert individual filesystem are not very large or complicated overall as can be seen from the included fat, ext4, and xfs ports. Patches for other filesystems are actively worked on and will be sent out separately. The xfstestsuite can be used to verify that port has been done correctly. The mount_setattr() syscall is motivated independent of the idmapped mounts patches and it's been around since July 2019. One of the most valuable features of the new mount api is the ability to perform mounts based on file descriptors only. Together with the lookup restrictions available in the openat2() RESOLVE_* flag namespace which we added in v5.6 this is the first time we are close to hardened and race-free (e.g. symlinks) mounting and path resolution. While userspace has started porting to the new mount api to mount proper filesystems and create new bind-mounts it is currently not possible to change mount options of an already existing bind mount in the new mount api since the mount_setattr() syscall is missing. With the addition of the mount_setattr() syscall we remove this last restriction and userspace can now fully port to the new mount api, covering every use-case the old mount api could. We also add the crucial ability to recursively change mount options for a whole mount tree, both removing and adding mount options at the same time. This syscall has been requested multiple times by various people and projects. There is a simple tool available at https://github.com/brauner/mount-idmapped that allows to create idmapped mounts so people can play with this patch series. I'll add support for the regular mount binary should you decide to pull this in the following weeks: Here's an example to a simple idmapped mount of another user's home directory: u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt u1001@f2-vm:/$ ls -al /home/ubuntu/ total 28 drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 . drwxr-xr-x 4 root root 4096 Oct 28 04:00 .. -rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history -rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout -rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc -rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile -rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful -rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo u1001@f2-vm:/$ ls -al /mnt/ total 28 drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 . drwxr-xr-x 29 root root 4096 Oct 28 22:01 .. -rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history -rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout -rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc -rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile -rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful -rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo u1001@f2-vm:/$ touch /mnt/my-file u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file u1001@f2-vm:/$ ls -al /mnt/my-file -rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file u1001@f2-vm:/$ ls -al /home/ubuntu/my-file -rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file u1001@f2-vm:/$ getfacl /mnt/my-file getfacl: Removing leading '/' from absolute path names # file: mnt/my-file # owner: u1001 # group: u1001 user::rw- user:u1001:rwx group::rw- mask::rwx other::r-- u1001@f2-vm:/$ getfacl /home/ubuntu/my-file getfacl: Removing leading '/' from absolute path names # file: home/ubuntu/my-file # owner: ubuntu # group: ubuntu user::rw- user:ubuntu:rwx group::rw- mask::rwx other::r--" * tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits) xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl xfs: support idmapped mounts ext4: support idmapped mounts fat: handle idmapped mounts tests: add mount_setattr() selftests fs: introduce MOUNT_ATTR_IDMAP fs: add mount_setattr() fs: add attr_flags_to_mnt_flags helper fs: split out functions to hold writers namespace: only take read lock in do_reconfigure_mnt() mount: make {lock,unlock}_mount_hash() static namespace: take lock_mount_hash() directly when changing flags nfs: do not export idmapped mounts overlayfs: do not mount on top of idmapped mounts ecryptfs: do not mount on top of idmapped mounts ima: handle idmapped mounts apparmor: handle idmapped mounts fs: make helpers idmap mount aware exec: handle idmapped mounts would_dump: handle idmapped mounts ...
2021-02-16ceph: defer flushing the capsnap if the Fb is usedXiubo Li
If the Fb cap is used it means the current inode is flushing the dirty data to OSD, just defer flushing the capsnap. URL: https://tracker.ceph.com/issues/48640 Signed-off-by: Xiubo Li <xiubli@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-02-16ceph: allow queueing cap/snap handling after putting cap referencesJeff Layton
Testing with the fscache overhaul has triggered some lockdep warnings about circular lock dependencies involving page_mkwrite and the mmap_lock. It'd be better to do the "real work" without the mmap lock being held. Change the skip_checking_caps parameter in __ceph_put_cap_refs to an enum, and use that to determine whether to queue check_caps, do it synchronously or not at all. Change ceph_page_mkwrite to do a ceph_put_cap_refs_async(). Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-02-16ceph: clean up inode work queueingJeff Layton
Add a generic function for taking an inode reference, setting the I_WORK bit and queueing i_work. Turn the ceph_queue_* functions into static inline wrappers that pass in the right bit. Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-02-16ceph: fix flush_snap logic after putting capsJeff Layton
A primary reason for skipping ceph_check_caps after putting the references was to avoid the locking in ceph_check_caps during a reconnect. __ceph_put_cap_refs can still call ceph_flush_snaps in that case though, and that takes many of the same inconvenient locks. Fix the logic in __ceph_put_cap_refs to skip flushing snaps when the skip_checking_caps flag is set. Fixes: e64f44a88465 ("ceph: skip checking caps when session reconnecting and releasing reqs") Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Ilya Dryomov <idryomov@gmail.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2021-01-24fs: make helpers idmap mount awareChristian Brauner
Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24stat: handle idmapped mountsChristian Brauner
The generic_fillattr() helper fills in the basic attributes associated with an inode. Enable it to handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace before we store the uid and gid. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-12-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>