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2021-04-23fscache, cachefiles: Add alternate API to use kiocb for read/write to cacheDavid Howells
Add an alternate API by which the cache can be accessed through a kiocb, doing async DIO, rather than using the current API that tells the cache where all the pages are. The new API is intended to be used in conjunction with the netfs helper library. A filesystem must pick one or the other and not mix them. Filesystems wanting to use the new API must #define FSCACHE_USE_NEW_IO_API before #including the header. This prevents them from continuing to use the old API at the same time as there are incompatibilities in how the PG_fscache page bit is used. Changes: v6: - Provide a routine to shape a write so that the start and length can be aligned for DIO[3]. v4: - Use the vfs_iocb_iter_read/write() helpers[1] - Move initial definition of fscache_begin_read_operation() here. - Remove a commented-out line[2] - Combine ki->term_func calls in cachefiles_read_complete()[2]. - Remove explicit NULL initialiser[2]. - Remove extern on func decl[2]. - Put in param names on func decl[2]. - Remove redundant else[2]. - Fill out the kdoc comment for fscache_begin_read_operation(). - Rename fs/fscache/page2.c to io.c to match later patches. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org> Tested-by: Dave Wysochanski <dwysocha@redhat.com> Tested-By: Marc Dionne <marc.dionne@auristor.com> cc: Christoph Hellwig <hch@lst.de> cc: linux-cachefs@redhat.com cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-cifs@vger.kernel.org cc: ceph-devel@vger.kernel.org cc: v9fs-developer@lists.sourceforge.net cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20210216102614.GA27555@lst.de/ [1] Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [2] Link: https://lore.kernel.org/r/161781047695.463527.7463536103593997492.stgit@warthog.procyon.org.uk/ [3] Link: https://lore.kernel.org/r/161118142558.1232039.17993829899588971439.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/161161037850.2537118.8819808229350326503.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/161340402057.1303470.8038373593844486698.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/161539545919.286939.14573472672781434757.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/161653801477.2770958.10543270629064934227.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/161789084517.6155.12799689829859169640.stgit@warthog.procyon.org.uk/ # v6
2021-03-24Merge tag 'afs-cachefiles-fixes-20210323' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull cachefiles and afs fixes from David Howells: "Fixes from Matthew Wilcox for page waiting-related issues in cachefiles and afs as extracted from his folio series[1]: - In cachefiles, remove the use of the wait_bit_key struct to access something that's actually in wait_page_key format. The proper struct is now available in the header, so that should be used instead. - Add a proper wait function for waiting killably on the page writeback flag. This includes a recent bugfix[2] that's not in the afs code. - In afs, use the function added in (2) rather than using wait_on_page_bit_killable() which doesn't provide the aforementioned bugfix" Link: https://lore.kernel.org/r/20210320054104.1300774-1-willy@infradead.org[1] Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c2407cf7d22d0c0d94cf20342b3b8f06f1d904e7 [2] Link: https://lore.kernel.org/r/20210323120829.GC1719932@casper.infradead.org/ # v1 * tag 'afs-cachefiles-fixes-20210323' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: afs: Use wait_on_page_writeback_killable mm/writeback: Add wait_on_page_writeback_killable fs/cachefiles: Remove wait_bit_key layout dependency
2021-03-24cachefiles: do not yet allow on idmapped mountsChristian Brauner
Based on discussions (e.g. in [1]) my understanding of cachefiles and the cachefiles userspace daemon is that it creates a cache on a local filesystem (e.g. ext4, xfs etc.) for a network filesystem. The way this is done is by writing "bind" to /dev/cachefiles and pointing it to the directory to use as the cache. Currently this directory can technically also be an idmapped mount but cachefiles aren't yet fully aware of such mounts and thus don't take the idmapping into account when creating cache entries. This could leave users confused as the ownership of the files wouldn't match to what they expressed in the idmapping. Block cache files on idmapped mounts until the fscache rework is done and we have ported it to support idmapped mounts. Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: David Howells <dhowells@redhat.com> Cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/lkml/20210303161528.n3jzg66ou2wa43qb@wittgenstein [1] Link: https://lore.kernel.org/r/20210316112257.2974212-1-christian.brauner@ubuntu.com/ # v1 Link: https://listman.redhat.com/archives/linux-cachefs/2021-March/msg00044.html # v2 Link: https://lore.kernel.org/r/20210319114146.410329-1-christian.brauner@ubuntu.com/ # v3 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-03-23fs/cachefiles: Remove wait_bit_key layout dependencyMatthew Wilcox (Oracle)
Cachefiles was relying on wait_page_key and wait_bit_key being the same layout, which is fragile. Now that wait_page_key is exposed in the pagemap.h header, we can remove that fragility A comment on the need to maintain structure layout equivalence was added by Linus[1] and that is no longer applicable. Fixes: 62906027091f ("mm: add PageWaiters indicating tasks are waiting for a page bit") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: kafs-testing@auristor.com cc: linux-cachefs@redhat.com cc: linux-mm@kvack.org Link: https://lore.kernel.org/r/20210320054104.1300774-2-willy@infradead.org/ Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3510ca20ece0150af6b10c77a74ff1b5c198e3e2 [1]
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 ...
2021-01-24namei: prepare for idmapped mountsChristian Brauner
The various vfs_*() helpers are called by filesystems or by the vfs itself to perform core operations such as create, link, mkdir, mknod, rename, rmdir, tmpfile and unlink. Enable them to handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace and pass it down. Afterwards the checks and operations are identical to non-idmapped mounts. 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/20210121131959.646623-15-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>
2021-01-24namei: introduce struct renamedataChristian Brauner
In order to handle idmapped mounts we will extend the vfs rename helper to take two new arguments in follow up patches. Since this operations already takes a bunch of arguments add a simple struct renamedata and make the current helper use it before we extend it. Link: https://lore.kernel.org/r/20210121131959.646623-14-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>
2021-01-24xattr: handle idmapped mountsTycho Andersen
When interacting with extended attributes the vfs verifies that the caller is privileged over the inode with which the extended attribute is associated. For posix access and posix default extended attributes a uid or gid can be stored on-disk. Let the functions handle posix extended attributes on idmapped mounts. If the inode is accessed through an idmapped mount we need to map it according to the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. This has no effect for e.g. security xattrs since they don't store uids or gids and don't perform permission checks on them like posix acls do. Link: https://lore.kernel.org/r/20210121131959.646623-10-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: Tycho Andersen <tycho@tycho.pizza> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24attr: handle idmapped mountsChristian Brauner
When file attributes are changed most filesystems rely on the setattr_prepare(), setattr_copy(), and notify_change() helpers for initialization and permission checking. Let them handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Helpers that perform checks on the ia_uid and ia_gid fields in struct iattr assume that ia_uid and ia_gid are intended values and have already been mapped correctly at the userspace-kernelspace boundary as we already do today. 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/20210121131959.646623-8-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>
2021-01-20cachefiles: Drop superfluous readpages aops NULL checkTakashi Iwai
After the recent actions to convert readpages aops to readahead, the NULL checks of readpages aops in cachefiles_read_or_alloc_page() may hit falsely. More badly, it's an ASSERT() call, and this panics. Drop the superfluous NULL checks for fixing this regression. [DH: Note that cachefiles never actually used readpages, so this check was never actually necessary] BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=208883 BugLink: https://bugzilla.opensuse.org/show_bug.cgi?id=1175245 Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem") Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-26cachefiles: Handle readpage error correctlyMatthew Wilcox (Oracle)
If ->readpage returns an error, it has already unlocked the page. Fixes: 5e929b33c393 ("CacheFiles: Handle truncate unlocking the page we're reading") Cc: stable@vger.kernel.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-08cachefiles: switch to kernel_writeChristoph Hellwig
__kernel_write doesn't take a sb_writers references, which we need here. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: David Howells <dhowells@redhat.com>
2020-06-01Merge tag 'docs-5.8' of git://git.lwn.net/linuxLinus Torvalds
Pull documentation updates from Jonathan Corbet: "A fair amount of stuff this time around, dominated by yet another massive set from Mauro toward the completion of the RST conversion. I *really* hope we are getting close to the end of this. Meanwhile, those patches reach pretty far afield to update document references around the tree; there should be no actual code changes there. There will be, alas, more of the usual trivial merge conflicts. Beyond that we have more translations, improvements to the sphinx scripting, a number of additions to the sysctl documentation, and lots of fixes" * tag 'docs-5.8' of git://git.lwn.net/linux: (130 commits) Documentation: fixes to the maintainer-entry-profile template zswap: docs/vm: Fix typo accept_threshold_percent in zswap.rst tracing: Fix events.rst section numbering docs: acpi: fix old http link and improve document format docs: filesystems: add info about efivars content Documentation: LSM: Correct the basic LSM description mailmap: change email for Ricardo Ribalda docs: sysctl/kernel: document unaligned controls Documentation: admin-guide: update bug-hunting.rst docs: sysctl/kernel: document ngroups_max nvdimm: fixes to maintainter-entry-profile Documentation/features: Correct RISC-V kprobes support entry Documentation/features: Refresh the arch support status files Revert "docs: sysctl/kernel: document ngroups_max" docs: move locking-specific documents to locking/ docs: move digsig docs to the security book docs: move the kref doc into the core-api book docs: add IRQ documentation at the core-api book docs: debugging-via-ohci1394.txt: add it to the core-api book docs: fix references for ipmi.rst file ...
2020-05-08cachefiles: Fix race between read_waiter and read_copier involving op->to_doLei Xue
There is a potential race in fscache operation enqueuing for reading and copying multiple pages from cachefiles to netfs. The problem can be seen easily on a heavy loaded system (for example many processes reading files continually on an NFS share covered by fscache triggered this problem within a few minutes). The race is due to cachefiles_read_waiter() adding the op to the monitor to_do list and then then drop the object->work_lock spinlock before completing fscache_enqueue_operation(). Once the lock is dropped, cachefiles_read_copier() grabs the op, completes processing it, and makes it through fscache_retrieval_complete() which sets the op->state to the final state of FSCACHE_OP_ST_COMPLETE(4). When cachefiles_read_waiter() finally gets through the remainder of fscache_enqueue_operation() it sees the invalid state, and hits the ASSERTCMP and the following oops is seen: [ 2259.612361] FS-Cache: [ 2259.614785] FS-Cache: Assertion failed [ 2259.618639] FS-Cache: 4 == 5 is false [ 2259.622456] ------------[ cut here ]------------ [ 2259.627190] kernel BUG at fs/fscache/operation.c:70! ... [ 2259.791675] RIP: 0010:[<ffffffffc061b4cf>] [<ffffffffc061b4cf>] fscache_enqueue_operation+0xff/0x170 [fscache] [ 2259.802059] RSP: 0000:ffffa0263d543be0 EFLAGS: 00010046 [ 2259.807521] RAX: 0000000000000019 RBX: ffffa01a4d390480 RCX: 0000000000000006 [ 2259.814847] RDX: 0000000000000000 RSI: 0000000000000046 RDI: ffffa0263d553890 [ 2259.822176] RBP: ffffa0263d543be8 R08: 0000000000000000 R09: ffffa0263c2d8708 [ 2259.829502] R10: 0000000000001e7f R11: 0000000000000000 R12: ffffa01a4d390480 [ 2259.844483] R13: ffff9fa9546c5920 R14: ffffa0263d543c80 R15: ffffa0293ff9bf10 [ 2259.859554] FS: 00007f4b6efbd700(0000) GS:ffffa0263d540000(0000) knlGS:0000000000000000 [ 2259.875571] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2259.889117] CR2: 00007f49e1624ff0 CR3: 0000012b38b38000 CR4: 00000000007607e0 [ 2259.904015] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2259.918764] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 2259.933449] PKRU: 55555554 [ 2259.943654] Call Trace: [ 2259.953592] <IRQ> [ 2259.955577] [<ffffffffc03a7c12>] cachefiles_read_waiter+0x92/0xf0 [cachefiles] [ 2259.978039] [<ffffffffa34d3942>] __wake_up_common+0x82/0x120 [ 2259.991392] [<ffffffffa34d3a63>] __wake_up_common_lock+0x83/0xc0 [ 2260.004930] [<ffffffffa34d3510>] ? task_rq_unlock+0x20/0x20 [ 2260.017863] [<ffffffffa34d3ab3>] __wake_up+0x13/0x20 [ 2260.030230] [<ffffffffa34c72a0>] __wake_up_bit+0x50/0x70 [ 2260.042535] [<ffffffffa35bdcdb>] unlock_page+0x2b/0x30 [ 2260.054495] [<ffffffffa35bdd09>] page_endio+0x29/0x90 [ 2260.066184] [<ffffffffa368fc81>] mpage_end_io+0x51/0x80 CPU1 cachefiles_read_waiter() 20 static int cachefiles_read_waiter(wait_queue_entry_t *wait, unsigned mode, 21 int sync, void *_key) 22 { ... 61 spin_lock(&object->work_lock); 62 list_add_tail(&monitor->op_link, &op->to_do); 63 spin_unlock(&object->work_lock); <begin race window> 64 65 fscache_enqueue_retrieval(op); 182 static inline void fscache_enqueue_retrieval(struct fscache_retrieval *op) 183 { 184 fscache_enqueue_operation(&op->op); 185 } 58 void fscache_enqueue_operation(struct fscache_operation *op) 59 { 60 struct fscache_cookie *cookie = op->object->cookie; 61 62 _enter("{OBJ%x OP%x,%u}", 63 op->object->debug_id, op->debug_id, atomic_read(&op->usage)); 64 65 ASSERT(list_empty(&op->pend_link)); 66 ASSERT(op->processor != NULL); 67 ASSERT(fscache_object_is_available(op->object)); 68 ASSERTCMP(atomic_read(&op->usage), >, 0); <end race window> CPU2 cachefiles_read_copier() 168 while (!list_empty(&op->to_do)) { ... 202 fscache_end_io(op, monitor->netfs_page, error); 203 put_page(monitor->netfs_page); 204 fscache_retrieval_complete(op, 1); CPU1 58 void fscache_enqueue_operation(struct fscache_operation *op) 59 { ... 69 ASSERTIFCMP(op->state != FSCACHE_OP_ST_IN_PROGRESS, 70 op->state, ==, FSCACHE_OP_ST_CANCELLED); Signed-off-by: Lei Xue <carmark.dlut@gmail.com> Signed-off-by: Dave Wysochanski <dwysocha@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com>
2020-05-05docs: filesystems: caching/cachefiles.txt: convert to ReSTMauro Carvalho Chehab
- Add a SPDX header; - Adjust document title; - Mark literal blocks as such; - Add table markups; - Comment out text ToC for html/pdf output; - Add lists markups; - Add it to filesystems/caching/index.rst. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/eec0cfc268e8dca348f760224685100c9c2caba6.1588021877.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-05-04cachefiles: Fix corruption of the return value in ↵David Howells
cachefiles_read_or_alloc_pages() The patch which changed cachefiles from calling ->bmap() to using the bmap() wrapper overwrote the running return value with the result of calling bmap(). This causes an assertion failure elsewhere in the code. Fix this by using ret2 rather than ret to hold the return value. The oops looks like: kernel BUG at fs/nfs/fscache.c:468! ... RIP: 0010:__nfs_readpages_from_fscache+0x18b/0x190 [nfs] ... Call Trace: nfs_readpages+0xbf/0x1c0 [nfs] ? __alloc_pages_nodemask+0x16c/0x320 read_pages+0x67/0x1a0 __do_page_cache_readahead+0x1cf/0x1f0 ondemand_readahead+0x172/0x2b0 page_cache_async_readahead+0xaa/0xe0 generic_file_buffered_read+0x852/0xd50 ? mem_cgroup_commit_charge+0x6e/0x140 ? nfs4_have_delegation+0x19/0x30 [nfsv4] generic_file_read_iter+0x100/0x140 ? nfs_revalidate_mapping+0x176/0x2b0 [nfs] nfs_file_read+0x6d/0xc0 [nfs] new_sync_read+0x11a/0x1c0 __vfs_read+0x29/0x40 vfs_read+0x8e/0x140 ksys_read+0x61/0xd0 __x64_sys_read+0x1a/0x20 do_syscall_64+0x60/0x1e0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f5d148267e0 Fixes: 10d83e11a582 ("cachefiles: drop direct usage of ->bmap method.") Reported-by: David Wysochanski <dwysocha@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: David Wysochanski <dwysocha@redhat.com> cc: Carlos Maiolino <cmaiolino@redhat.com>
2020-02-03cachefiles: drop direct usage of ->bmap method.Carlos Maiolino
Replace the direct usage of ->bmap method by a bmap() call. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-24treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public licence as published by the free software foundation either version 2 of the licence or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 114 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner
Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14fs/cachefiles/namei.c: remove duplicate headerSabyasachi Gupta
linux/xattr.h is included more than once. Link: http://lkml.kernel.org/r/5c86803d.1c69fb81.1a7c6.2b78@mx.google.com Signed-off-by: Sabyasachi Gupta <sabyasachi.linux@gmail.com> Acked-by: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-30fscache, cachefiles: remove redundant variable 'cache'Colin Ian King
Variable 'cache' is being assigned but is never used hence it is redundant and can be removed. Cleans up clang warning: warning: variable 'cache' set but not used [-Wunused-but-set-variable] Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: David Howells <dhowells@redhat.com>
2018-11-30cachefiles: avoid deprecated get_seconds()Arnd Bergmann
get_seconds() returns an unsigned long can overflow on some architectures and is deprecated because of that. In cachefs, we cast that number to a a 32-bit integer, which will overflow in year 2106 on all architectures. As confirmed by David Howells, the overflow probably isn't harmful in the end, since the timestamps are only used to make the file names unique, but they don't strictly have to be in monotonically increasing order since the files only exist in order to be deleted as quickly as possible. Moving to ktime_get_real_seconds() avoids the deprecated interface. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David Howells <dhowells@redhat.com>
2018-11-30cachefiles: Explicitly cast enumerated type in put_objectNathan Chancellor
Clang warns when one enumerated type is implicitly converted to another. fs/cachefiles/namei.c:247:50: warning: implicit conversion from enumeration type 'enum cachefiles_obj_ref_trace' to different enumeration type 'enum fscache_obj_ref_trace' [-Wenum-conversion] cache->cache.ops->put_object(&xobject->fscache, cachefiles_obj_put_wait_retry); Silence this warning by explicitly casting to fscache_obj_ref_trace, which is also done in put_object. Reported-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com>
2018-11-28cachefiles: Fix page leak in cachefiles_read_backing_file while vmscan is activeKiran Kumar Modukuri
[Description] In a heavily loaded system where the system pagecache is nearing memory limits and fscache is enabled, pages can be leaked by fscache while trying read pages from cachefiles backend. This can happen because two applications can be reading same page from a single mount, two threads can be trying to read the backing page at same time. This results in one of the threads finding that a page for the backing file or netfs file is already in the radix tree. During the error handling cachefiles does not clean up the reference on backing page, leading to page leak. [Fix] The fix is straightforward, to decrement the reference when error is encountered. [dhowells: Note that I've removed the clearance and put of newpage as they aren't attested in the commit message and don't appear to actually achieve anything since a new page is only allocated is newpage!=NULL and any residual new page is cleared before returning.] [Testing] I have tested the fix using following method for 12+ hrs. 1) mkdir -p /mnt/nfs ; mount -o vers=3,fsc <server_ip>:/export /mnt/nfs 2) create 10000 files of 2.8MB in a NFS mount. 3) start a thread to simulate heavy VM presssure (while true ; do echo 3 > /proc/sys/vm/drop_caches ; sleep 1 ; done)& 4) start multiple parallel reader for data set at same time find /mnt/nfs -type f | xargs -P 80 cat > /dev/null & find /mnt/nfs -type f | xargs -P 80 cat > /dev/null & find /mnt/nfs -type f | xargs -P 80 cat > /dev/null & .. .. find /mnt/nfs -type f | xargs -P 80 cat > /dev/null & find /mnt/nfs -type f | xargs -P 80 cat > /dev/null & 5) finally check using cat /proc/fs/fscache/stats | grep -i pages ; free -h , cat /proc/meminfo and page-types -r -b lru to ensure all pages are freed. Reviewed-by: Daniel Axtens <dja@axtens.net> Signed-off-by: Shantanu Goel <sgoel01@yahoo.com> Signed-off-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com> [dja: forward ported to current upstream] Signed-off-by: Daniel Axtens <dja@axtens.net> Signed-off-by: David Howells <dhowells@redhat.com>
2018-11-28cachefiles: Fix an assertion failure when trying to update a failed objectDavid Howells
If cachefiles gets an error other then ENOENT when trying to look up an object in the cache (in this case, EACCES), the object state machine will eventually transition to the DROP_OBJECT state. This state invokes fscache_drop_object() which tries to sync the auxiliary data with the cache (this is done lazily since commit 402cb8dda949d) on an incomplete cache object struct. The problem comes when cachefiles_update_object_xattr() is called to rewrite the xattr holding the data. There's an assertion there that the cache object points to a dentry as we're going to update its xattr. The assertion trips, however, as dentry didn't get set. Fix the problem by skipping the update in cachefiles if the object doesn't refer to a dentry. A better way to do it could be to skip the update from the DROP_OBJECT state handler in fscache, but that might deny the cache the opportunity to update intermediate state. If this error occurs, the kernel log includes lines that look like the following: CacheFiles: Lookup failed error -13 CacheFiles: CacheFiles: Assertion failed ------------[ cut here ]------------ kernel BUG at fs/cachefiles/xattr.c:138! ... Workqueue: fscache_object fscache_object_work_func [fscache] RIP: 0010:cachefiles_update_object_xattr.cold.4+0x18/0x1a [cachefiles] ... Call Trace: cachefiles_update_object+0xdd/0x1c0 [cachefiles] fscache_update_aux_data+0x23/0x30 [fscache] fscache_drop_object+0x18e/0x1c0 [fscache] fscache_object_work_func+0x74/0x2b0 [fscache] process_one_work+0x18d/0x340 worker_thread+0x2e/0x390 ? pwq_unbound_release_workfn+0xd0/0xd0 kthread+0x112/0x130 ? kthread_bind+0x30/0x30 ret_from_fork+0x35/0x40 Note that there are actually two issues here: (1) EACCES happened on a cache object and (2) an oops occurred. I think that the second is a consequence of the first (it certainly looks like it ought to be). This patch only deals with the second. Fixes: 402cb8dda949 ("fscache: Attach the index key and aux data to the cookie") Reported-by: Zhibin Li <zhibli@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com>
2018-10-18cachefiles: fix the race between cachefiles_bury_object() and rmdir(2)Al Viro
the victim might've been rmdir'ed just before the lock_rename(); unlike the normal callers, we do not look the source up after the parents are locked - we know it beforehand and just recheck that it's still the child of what used to be its parent. Unfortunately, the check is too weak - we don't spot a dead directory since its ->d_parent is unchanged, dentry is positive, etc. So we sail all the way to ->rename(), with hosting filesystems _not_ expecting to be asked renaming an rmdir'ed subdirectory. The fix is easy, fortunately - the lock on parent is sufficient for making IS_DEADDIR() on child safe. Cc: stable@vger.kernel.org Fixes: 9ae326a69004 (CacheFiles: A cache that backs onto a mounted filesystem) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-25cachefiles: Wait rather than BUG'ing on "Unexpected object collision"Kiran Kumar Modukuri
If we meet a conflicting object that is marked FSCACHE_OBJECT_IS_LIVE in the active object tree, we have been emitting a BUG after logging information about it and the new object. Instead, we should wait for the CACHEFILES_OBJECT_ACTIVE flag to be cleared on the old object (or return an error). The ACTIVE flag should be cleared after it has been removed from the active object tree. A timeout of 60s is used in the wait, so we shouldn't be able to get stuck there. Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem") Signed-off-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com>
2018-07-25cachefiles: Fix missing clear of the CACHEFILES_OBJECT_ACTIVE flagKiran Kumar Modukuri
In cachefiles_mark_object_active(), the new object is marked active and then we try to add it to the active object tree. If a conflicting object is already present, we want to wait for that to go away. After the wait, we go round again and try to re-mark the object as being active - but it's already marked active from the first time we went through and a BUG is issued. Fix this by clearing the CACHEFILES_OBJECT_ACTIVE flag before we try again. Analysis from Kiran Kumar Modukuri: [Impact] Oops during heavy NFS + FSCache + Cachefiles CacheFiles: Error: Overlong wait for old active object to go away. BUG: unable to handle kernel NULL pointer dereference at 0000000000000002 CacheFiles: Error: Object already active kernel BUG at fs/cachefiles/namei.c:163! [Cause] In a heavily loaded system with big files being read and truncated, an fscache object for a cookie is being dropped and a new object being looked. The new object being looked for has to wait for the old object to go away before the new object is moved to active state. [Fix] Clear the flag 'CACHEFILES_OBJECT_ACTIVE' for the new object when retrying the object lookup. [Testcase] Have run ~100 hours of NFS stress tests and have not seen this bug recur. [Regression Potential] - Limited to fscache/cachefiles. Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem") Signed-off-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com>
2018-07-25fscache: Fix reference overput in fscache_attach_object() error handlingKiran Kumar Modukuri
When a cookie is allocated that causes fscache_object structs to be allocated, those objects are initialised with the cookie pointer, but aren't blessed with a ref on that cookie unless the attachment is successfully completed in fscache_attach_object(). If attachment fails because the parent object was dying or there was a collision, fscache_attach_object() returns without incrementing the cookie counter - but upon failure of this function, the object is released which then puts the cookie, whether or not a ref was taken on the cookie. Fix this by taking a ref on the cookie when it is assigned in fscache_object_init(), even when we're creating a root object. Analysis from Kiran Kumar: This bug has been seen in 4.4.0-124-generic #148-Ubuntu kernel BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1776277 fscache cookie ref count updated incorrectly during fscache object allocation resulting in following Oops. kernel BUG at /build/linux-Y09MKI/linux-4.4.0/fs/fscache/internal.h:321! kernel BUG at /build/linux-Y09MKI/linux-4.4.0/fs/fscache/cookie.c:639! [Cause] Two threads are trying to do operate on a cookie and two objects. (1) One thread tries to unmount the filesystem and in process goes over a huge list of objects marking them dead and deleting the objects. cookie->usage is also decremented in following path: nfs_fscache_release_super_cookie -> __fscache_relinquish_cookie ->__fscache_cookie_put ->BUG_ON(atomic_read(&cookie->usage) <= 0); (2) A second thread tries to lookup an object for reading data in following path: fscache_alloc_object 1) cachefiles_alloc_object -> fscache_object_init -> assign cookie, but usage not bumped. 2) fscache_attach_object -> fails in cant_attach_object because the cookie's backing object or cookie's->parent object are going away 3) fscache_put_object -> cachefiles_put_object ->fscache_object_destroy ->fscache_cookie_put ->BUG_ON(atomic_read(&cookie->usage) <= 0); [NOTE from dhowells] It's unclear as to the circumstances in which (2) can take place, given that thread (1) is in nfs_kill_super(), however a conflicting NFS mount with slightly different parameters that creates a different superblock would do it. A backtrace from Kiran seems to show that this is a possibility: kernel BUG at/build/linux-Y09MKI/linux-4.4.0/fs/fscache/cookie.c:639! ... RIP: __fscache_cookie_put+0x3a/0x40 [fscache] Call Trace: __fscache_relinquish_cookie+0x87/0x120 [fscache] nfs_fscache_release_super_cookie+0x2d/0xb0 [nfs] nfs_kill_super+0x29/0x40 [nfs] deactivate_locked_super+0x48/0x80 deactivate_super+0x5c/0x60 cleanup_mnt+0x3f/0x90 __cleanup_mnt+0x12/0x20 task_work_run+0x86/0xb0 exit_to_usermode_loop+0xc2/0xd0 syscall_return_slowpath+0x4e/0x60 int_ret_from_sys_call+0x25/0x9f [Fix] Bump up the cookie usage in fscache_object_init, when it is first being assigned a cookie atomically such that the cookie is added and bumped up if its refcount is not zero. Remove the assignment in fscache_attach_object(). [Testcase] I have run ~100 hours of NFS stress tests and not seen this bug recur. [Regression Potential] - Limited to fscache/cachefiles. Fixes: ccc4fc3d11e9 ("FS-Cache: Implement the cookie management part of the netfs API") Signed-off-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com>
2018-07-25cachefiles: Fix refcounting bug in backing-file read monitoringKiran Kumar Modukuri
cachefiles_read_waiter() has the right to access a 'monitor' object by virtue of being called under the waitqueue lock for one of the pages in its purview. However, it has no ref on that monitor object or on the associated operation. What it is allowed to do is to move the monitor object to the operation's to_do list, but once it drops the work_lock, it's actually no longer permitted to access that object. However, it is trying to enqueue the retrieval operation for processing - but it can only do this via a pointer in the monitor object, something it shouldn't be doing. If it doesn't enqueue the operation, the operation may not get processed. If the order is flipped so that the enqueue is first, then it's possible for the work processor to look at the to_do list before the monitor is enqueued upon it. Fix this by getting a ref on the operation so that we can trust that it will still be there once we've added the monitor to the to_do list and dropped the work_lock. The op can then be enqueued after the lock is dropped. The bug can manifest in one of a couple of ways. The first manifestation looks like: FS-Cache: FS-Cache: Assertion failed FS-Cache: 6 == 5 is false ------------[ cut here ]------------ kernel BUG at fs/fscache/operation.c:494! RIP: 0010:fscache_put_operation+0x1e3/0x1f0 ... fscache_op_work_func+0x26/0x50 process_one_work+0x131/0x290 worker_thread+0x45/0x360 kthread+0xf8/0x130 ? create_worker+0x190/0x190 ? kthread_cancel_work_sync+0x10/0x10 ret_from_fork+0x1f/0x30 This is due to the operation being in the DEAD state (6) rather than INITIALISED, COMPLETE or CANCELLED (5) because it's already passed through fscache_put_operation(). The bug can also manifest like the following: kernel BUG at fs/fscache/operation.c:69! ... [exception RIP: fscache_enqueue_operation+246] ... #7 [ffff883fff083c10] fscache_enqueue_operation at ffffffffa0b793c6 #8 [ffff883fff083c28] cachefiles_read_waiter at ffffffffa0b15a48 #9 [ffff883fff083c48] __wake_up_common at ffffffff810af028 I'm not entirely certain as to which is line 69 in Lei's kernel, so I'm not entirely clear which assertion failed. Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem") Reported-by: Lei Xue <carmark.dlut@gmail.com> Reported-by: Vegard Nossum <vegard.nossum@gmail.com> Reported-by: Anthony DeRobertis <aderobertis@metrics.net> Reported-by: NeilBrown <neilb@suse.com> Reported-by: Daniel Axtens <dja@axtens.net> Reported-by: Kiran Kumar Modukuri <kiran.modukuri@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Daniel Axtens <dja@axtens.net>
2018-06-04Merge branch 'hch.procfs' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull procfs updates from Al Viro: "Christoph's proc_create_... cleanups series" * 'hch.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (44 commits) xfs, proc: hide unused xfs procfs helpers isdn/gigaset: add back gigaset_procinfo assignment proc: update SIZEOF_PDE_INLINE_NAME for the new pde fields tty: replace ->proc_fops with ->proc_show ide: replace ->proc_fops with ->proc_show ide: remove ide_driver_proc_write isdn: replace ->proc_fops with ->proc_show atm: switch to proc_create_seq_private atm: simplify procfs code bluetooth: switch to proc_create_seq_data netfilter/x_tables: switch to proc_create_seq_private netfilter/xt_hashlimit: switch to proc_create_{seq,single}_data neigh: switch to proc_create_seq_data hostap: switch to proc_create_{seq,single}_data bonding: switch to proc_create_seq_data rtc/proc: switch to proc_create_single_data drbd: switch to proc_create_single resource: switch to proc_create_seq_data staging/rtl8192u: simplify procfs code jfs: simplify procfs code ...
2018-05-21cachefiles: vfs_mkdir() might succeed leaving dentry negative unhashedAl Viro
That can (and does, on some filesystems) happen - ->mkdir() (and thus vfs_mkdir()) can legitimately leave its argument negative and just unhash it, counting upon the lookup to pick the object we'd created next time we try to look at that name. Some vfs_mkdir() callers forget about that possibility... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-05-16proc: introduce proc_create_seq{,_data}Christoph Hellwig
Variants of proc_create{,_data} that directly take a struct seq_operations argument and drastically reduces the boilerplate code in the callers. All trivial callers converted over. Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-04-06fscache: Pass object size in rather than calling back for itDavid Howells
Pass the object size in to fscache_acquire_cookie() and fscache_write_page() rather than the netfs providing a callback by which it can be received. This makes it easier to update the size of the object when a new page is written that extends the object. The current object size is also passed by fscache to the check_aux function, obviating the need to store it in the aux data. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Anna Schumaker <anna.schumaker@netapp.com> Tested-by: Steve Dickson <steved@redhat.com>
2018-04-04fscache: Attach the index key and aux data to the cookieDavid Howells
Attach copies of the index key and auxiliary data to the fscache cookie so that: (1) The callbacks to the netfs for this stuff can be eliminated. This can simplify things in the cache as the information is still available, even after the cache has relinquished the cookie. (2) Simplifies the locking requirements of accessing the information as we don't have to worry about the netfs object going away on us. (3) The cache can do lazy updating of the coherency information on disk. As long as the cache is flushed before reboot/poweroff, there's no need to update the coherency info on disk every time it changes. (4) Cookies can be hashed or put in a tree as the index key is easily available. This allows: (a) Checks for duplicate cookies can be made at the top fscache layer rather than down in the bowels of the cache backend. (b) Caching can be added to a netfs object that has a cookie if the cache is brought online after the netfs object is allocated. A certain amount of space is made in the cookie for inline copies of the data, but if it won't fit there, extra memory will be allocated for it. The downside of this is that live cache operation requires more memory. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Anna Schumaker <anna.schumaker@netapp.com> Tested-by: Steve Dickson <steved@redhat.com>
2018-04-04fscache: Add tracepointsDavid Howells
Add some tracepoints to fscache: (*) fscache_cookie - Tracks a cookie's usage count. (*) fscache_netfs - Logs registration of a network filesystem, including the pointer to the cookie allocated. (*) fscache_acquire - Logs cookie acquisition. (*) fscache_relinquish - Logs cookie relinquishment. (*) fscache_enable - Logs enablement of a cookie. (*) fscache_disable - Logs disablement of a cookie. (*) fscache_osm - Tracks execution of states in the object state machine. and cachefiles: (*) cachefiles_ref - Tracks a cachefiles object's usage count. (*) cachefiles_lookup - Logs result of lookup_one_len(). (*) cachefiles_mkdir - Logs result of vfs_mkdir(). (*) cachefiles_create - Logs result of vfs_create(). (*) cachefiles_unlink - Logs calls to vfs_unlink(). (*) cachefiles_rename - Logs calls to vfs_rename(). (*) cachefiles_mark_active - Logs an object becoming active. (*) cachefiles_wait_active - Logs a wait for an old object to be destroyed. (*) cachefiles_mark_inactive - Logs an object becoming inactive. (*) cachefiles_mark_buried - Logs the burial of an object. Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-04fscache, cachefiles: Fix checker warningsDavid Howells
Fix a couple of checker warnings in fscache and cachefiles: (1) fscache_n_op_requeue is never used, so get rid of it. (2) cachefiles_uncache_page() is passed in a lock that it releases, so this needs annotating. Signed-off-by: David Howells <dhowells@redhat.com>
2018-02-11vfs: do bulk POLL* -> EPOLL* replacementLinus Torvalds
This is the mindless scripted replacement of kernel use of POLL* variables as described by Al, done by this script: for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'` for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done done with de-mangling cleanups yet to come. NOTE! On almost all architectures, the EPOLL* constants have the same values as the POLL* constants do. But they keyword here is "almost". For various bad reasons they aren't the same, and epoll() doesn't actually work quite correctly in some cases due to this on Sparc et al. The next patch from Al will sort out the final differences, and we should be all done. Scripted-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-27fs: annotate ->poll() instancesAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-11-15mm: remove __GFP_COLDMel Gorman
As the page free path makes no distinction between cache hot and cold pages, there is no real useful ordering of pages in the free list that allocation requests can take advantage of. Juding from the users of __GFP_COLD, it is likely that a number of them are the result of copying other sites instead of actually measuring the impact. Remove the __GFP_COLD parameter which simplifies a number of paths in the page allocator. This is potentially controversial but bear in mind that the size of the per-cpu pagelists versus modern cache sizes means that the whole per-cpu list can often fit in the L3 cache. Hence, there is only a potential benefit for microbenchmarks that alloc/free pages in a tight loop. It's even worse when THP is taken into account which has little or no chance of getting a cache-hot page as the per-cpu list is bypassed and the zeroing of multiple pages will thrash the cache anyway. The truncate microbenchmarks are not shown as this patch affects the allocation path and not the free path. A page fault microbenchmark was tested but it showed no sigificant difference which is not surprising given that the __GFP_COLD branches are a miniscule percentage of the fault path. Link: http://lkml.kernel.org/r/20171018075952.10627-9-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15mm, pagevec: remove cold parameter for pagevecsMel Gorman
Every pagevec_init user claims the pages being released are hot even in cases where it is unlikely the pages are hot. As no one cares about the hotness of pages being released to the allocator, just ditch the parameter. No performance impact is expected as the overhead is marginal. The parameter is removed simply because it is a bit stupid to have a useless parameter copied everywhere. Link: http://lkml.kernel.org/r/20171018075952.10627-6-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-17VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)David Howells
Firstly by applying the following with coccinelle's spatch: @@ expression SB; @@ -SB->s_flags & MS_RDONLY +sb_rdonly(SB) to effect the conversion to sb_rdonly(sb), then by applying: @@ expression A, SB; @@ ( -(!sb_rdonly(SB)) && A +!sb_rdonly(SB) && A | -A != (sb_rdonly(SB)) +A != sb_rdonly(SB) | -A == (sb_rdonly(SB)) +A == sb_rdonly(SB) | -!(sb_rdonly(SB)) +!sb_rdonly(SB) | -A && (sb_rdonly(SB)) +A && sb_rdonly(SB) | -A || (sb_rdonly(SB)) +A || sb_rdonly(SB) | -(sb_rdonly(SB)) != A +sb_rdonly(SB) != A | -(sb_rdonly(SB)) == A +sb_rdonly(SB) == A | -(sb_rdonly(SB)) && A +sb_rdonly(SB) && A | -(sb_rdonly(SB)) || A +sb_rdonly(SB) || A ) @@ expression A, B, SB; @@ ( -(sb_rdonly(SB)) ? 1 : 0 +sb_rdonly(SB) | -(sb_rdonly(SB)) ? A : B +sb_rdonly(SB) ? A : B ) to remove left over excess bracketage and finally by applying: @@ expression A, SB; @@ ( -(A & MS_RDONLY) != sb_rdonly(SB) +(bool)(A & MS_RDONLY) != sb_rdonly(SB) | -(A & MS_RDONLY) == sb_rdonly(SB) +(bool)(A & MS_RDONLY) == sb_rdonly(SB) ) to make comparisons against the result of sb_rdonly() (which is a bool) work correctly. Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-20sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list namingIngo Molnar
So I've noticed a number of instances where it was not obvious from the code whether ->task_list was for a wait-queue head or a wait-queue entry. Furthermore, there's a number of wait-queue users where the lists are not for 'tasks' but other entities (poll tables, etc.), in which case the 'task_list' name is actively confusing. To clear this all up, name the wait-queue head and entry list structure fields unambiguously: struct wait_queue_head::task_list => ::head struct wait_queue_entry::task_list => ::entry For example, this code: rqw->wait.task_list.next != &wait->task_list ... is was pretty unclear (to me) what it's doing, while now it's written this way: rqw->wait.head.next != &wait->entry ... which makes it pretty clear that we are iterating a list until we see the head. Other examples are: list_for_each_entry_safe(pos, next, &x->task_list, task_list) { list_for_each_entry(wq, &fence->wait.task_list, task_list) { ... where it's unclear (to me) what we are iterating, and during review it's hard to tell whether it's trying to walk a wait-queue entry (which would be a bug), while now it's written as: list_for_each_entry_safe(pos, next, &x->head, entry) { list_for_each_entry(wq, &fence->wait.head, entry) { Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-20sched/wait: Split out the wait_bit*() APIs from <linux/wait.h> into ↵Ingo Molnar
<linux/wait_bit.h> The wait_bit*() types and APIs are mixed into wait.h, but they are a pretty orthogonal extension of wait-queues. Furthermore, only about 50 kernel files use these APIs, while over 1000 use the regular wait-queue functionality. So clean up the main wait.h by moving the wait-bit functionality out of it, into a separate .h and .c file: include/linux/wait_bit.h for types and APIs kernel/sched/wait_bit.c for the implementation Update all header dependencies. This reduces the size of wait.h rather significantly, by about 30%. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-20sched/wait: Rename wait_queue_t => wait_queue_entry_tIngo Molnar
Rename: wait_queue_t => wait_queue_entry_t 'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue", but in reality it's a queue *entry*. The 'real' queue is the wait queue head, which had to carry the name. Start sorting this out by renaming it to 'wait_queue_entry_t'. This also allows the real structure name 'struct __wait_queue' to lose its double underscore and become 'struct wait_queue_entry', which is the more canonical nomenclature for such data types. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>Ingo Molnar
Add #include <linux/cred.h> dependencies to all .c files rely on sched.h doing that for them. Note that even if the count where we need to add extra headers seems high, it's still a net win, because <linux/sched.h> is included in over 2,200 files ... Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-10Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: ">rename2() work from Miklos + current_time() from Deepa" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: Replace current_fs_time() with current_time() fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps fs: Replace CURRENT_TIME with current_time() for inode timestamps fs: proc: Delete inode time initializations in proc_alloc_inode() vfs: Add current_time() api vfs: add note about i_op->rename changes to porting fs: rename "rename2" i_op to "rename" vfs: remove unused i_op->rename fs: make remaining filesystems use .rename2 libfs: support RENAME_NOREPLACE in simple_rename() fs: support RENAME_NOREPLACE for local filesystems ncpfs: fix unused variable warning
2016-10-10Merge branch 'work.xattr' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs xattr updates from Al Viro: "xattr stuff from Andreas This completes the switch to xattr_handler ->get()/->set() from ->getxattr/->setxattr/->removexattr" * 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: vfs: Remove {get,set,remove}xattr inode operations xattr: Stop calling {get,set,remove}xattr inode operations vfs: Check for the IOP_XATTR flag in listxattr xattr: Add __vfs_{get,set,remove}xattr helpers libfs: Use IOP_XATTR flag for empty directory handling vfs: Use IOP_XATTR flag for bad-inode handling vfs: Add IOP_XATTR inode operations flag vfs: Move xattr_resolve_name to the front of fs/xattr.c ecryptfs: Switch to generic xattr handlers sockfs: Get rid of getxattr iop sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names kernfs: Switch to generic xattr handlers hfs: Switch to generic xattr handlers jffs2: Remove jffs2_{get,set,remove}xattr macros xattr: Remove unnecessary NULL attribute name check
2016-10-07xattr: Add __vfs_{get,set,remove}xattr helpersAndreas Gruenbacher
Right now, various places in the kernel check for the existence of getxattr, setxattr, and removexattr inode operations and directly call those operations. Switch to helper functions and test for the IOP_XATTR flag instead. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Acked-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>