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* kernfs: Check KERNFS_HAS_RELEASE before calling kernfs_release_file()Vaibhav Jain2017-03-171-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recently started seeing a kernel oops when a module tries removing a memory mapped sysfs bin_attribute. On closer investigation the root cause seems to be kernfs_release_file() trying to call kernfs_op.release() callback that's NULL for such sysfs bin_attributes. The oops occurs when kernfs_release_file() is called from kernfs_drain_open_files() to cleanup any open handles with active memory mappings. The patch fixes this by checking for flag KERNFS_HAS_RELEASE before calling kernfs_release_file() in function kernfs_drain_open_files(). On ppc64-le arch with cxl module the oops back-trace is of the form below: [ 861.381126] Unable to handle kernel paging request for instruction fetch [ 861.381360] Faulting instruction address: 0x00000000 [ 861.381428] Oops: Kernel access of bad area, sig: 11 [#1] .... [ 861.382481] NIP: 0000000000000000 LR: c000000000362c60 CTR: 0000000000000000 .... Call Trace: [c000000f1680b750] [c000000000362c34] kernfs_drain_open_files+0x104/0x1d0 (unreliable) [c000000f1680b790] [c00000000035fa00] __kernfs_remove+0x260/0x2c0 [c000000f1680b820] [c000000000360da0] kernfs_remove_by_name_ns+0x60/0xe0 [c000000f1680b8b0] [c0000000003638f4] sysfs_remove_bin_file+0x24/0x40 [c000000f1680b8d0] [c00000000062a164] device_remove_bin_file+0x24/0x40 [c000000f1680b8f0] [d000000009b7b22c] cxl_sysfs_afu_remove+0x144/0x170 [cxl] [c000000f1680b940] [d000000009b7c7e4] cxl_remove+0x6c/0x1a0 [cxl] [c000000f1680b990] [c00000000052f694] pci_device_remove+0x64/0x110 [c000000f1680b9d0] [c0000000006321d4] device_release_driver_internal+0x1f4/0x2b0 [c000000f1680ba20] [c000000000525cb0] pci_stop_bus_device+0xa0/0xd0 [c000000f1680ba60] [c000000000525e80] pci_stop_and_remove_bus_device+0x20/0x40 [c000000f1680ba90] [c00000000004a6c4] pci_hp_remove_devices+0x84/0xc0 [c000000f1680bad0] [c00000000004a688] pci_hp_remove_devices+0x48/0xc0 [c000000f1680bb10] [c0000000009dfda4] eeh_reset_device+0xb0/0x290 [c000000f1680bbb0] [c000000000032b4c] eeh_handle_normal_event+0x47c/0x530 [c000000f1680bc60] [c000000000032e64] eeh_handle_event+0x174/0x350 [c000000f1680bd10] [c000000000033228] eeh_event_handler+0x1e8/0x1f0 [c000000f1680bdc0] [c0000000000d384c] kthread+0x14c/0x190 [c000000f1680be30] [c00000000000b5a0] ret_from_kernel_thread+0x5c/0xbc Fixes: f83f3c515654 ("kernfs: fix locking around kernfs_ops->release() callback") Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'rebased-statx' of ↵Linus Torvalds2017-03-032-6/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs 'statx()' update from Al Viro. This adds the new extended stat() interface that internally subsumes our previous stat interfaces, and allows user mode to specify in more detail what kind of information it wants. It also allows for some explicit synchronization information to be passed to the filesystem, which can be relevant for network filesystems: is the cached value ok, or do you need open/close consistency, or what? From David Howells. Andreas Dilger points out that the first version of the extended statx interface was posted June 29, 2010: https://www.spinics.net/lists/linux-fsdevel/msg33831.html * 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: statx: Add a system call to make enhanced file info available
| * statx: Add a system call to make enhanced file info availableDavid Howells2017-03-022-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | sched/headers: Prepare to remove the <linux/mm_types.h> dependency from ↵Ingo Molnar2017-03-021-1/+1
|/ | | | | | | | | | | | | | | <linux/sched.h> Update code that relied on sched.h including various MM types for them. This will allow us to remove the <linux/mm_types.h> include from <linux/sched.h>. 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>
* Merge branch 'for-4.11' of ↵Linus Torvalds2017-02-273-9/+57
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "Several noteworthy changes. - Parav's rdma controller is finally merged. It is very straight forward and can limit the abosolute numbers of common rdma constructs used by different cgroups. - kernel/cgroup.c got too chubby and disorganized. Created kernel/cgroup/ subdirectory and moved all cgroup related files under kernel/ there and reorganized the core code. This hurts for backporting patches but was long overdue. - cgroup v2 process listing reimplemented so that it no longer depends on allocating a buffer large enough to cache the entire result to sort and uniq the output. v2 has always mangled the sort order to ensure that users don't depend on the sorted output, so this shouldn't surprise anybody. This makes the pid listing functions use the same iterators that are used internally, which have to have the same iterating capabilities anyway. - perf cgroup filtering now works automatically on cgroup v2. This patch was posted a long time ago but somehow fell through the cracks. - misc fixes asnd documentation updates" * 'for-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (27 commits) kernfs: fix locking around kernfs_ops->release() callback cgroup: drop the matching uid requirement on migration for cgroup v2 cgroup, perf_event: make perf_event controller work on cgroup2 hierarchy cgroup: misc cleanups cgroup: call subsys->*attach() only for subsystems which are actually affected by migration cgroup: track migration context in cgroup_mgctx cgroup: cosmetic update to cgroup_taskset_add() rdmacg: Fixed uninitialized current resource usage cgroup: Add missing cgroup-v2 PID controller documentation. rdmacg: Added documentation for rdmacg IB/core: added support to use rdma cgroup controller rdmacg: Added rdma cgroup controller cgroup: fix a comment typo cgroup: fix RCU related sparse warnings cgroup: move namespace code to kernel/cgroup/namespace.c cgroup: rename functions for consistency cgroup: move v1 mount functions to kernel/cgroup/cgroup-v1.c cgroup: separate out cgroup1_kf_syscall_ops cgroup: refactor mount path and clearly distinguish v1 and v2 paths cgroup: move cgroup v1 specific code to kernel/cgroup/cgroup-v1.c ...
| * kernfs: fix locking around kernfs_ops->release() callbackTejun Heo2017-02-211-5/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The release callback may be called from two places - file release operation and kernfs open file draining. kernfs_open_file->mutex is used to synchronize the two callsites. This unfortunately leads to possible circular locking because of->mutex is used to protect the usual kernfs operations which may use locking constructs which are held while removing and thus draining kernfs files. @of->mutex is for synchronizing concurrent kernfs access operations and all we need here is synchronization between the releaes and drain paths. As the drain path has to grab kernfs_open_file_mutex anyway, let's use the mutex to synchronize the release operation instead. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-and-tested-by: Tony Lindgren <tony@atomide.com> Fixes: 0e67db2f9fe9 ("kernfs: add kernfs_ops->open/release() callbacks") Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * kernfs: add kernfs_ops->open/release() callbacksTejun Heo2016-12-273-8/+47
| | | | | | | | | | | | | | | | | | | | | | Add ->open/release() methods to kernfs_ops. ->open() is called when the file is opened and ->release() when the file is either released or severed. These callbacks can be used, for example, to manage persistent caching objects over multiple seq_file iterations. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Acked-by: Zefan Li <lizefan@huawei.com>
| * kernfs: make kernfs_open_file->mmapped a bitfieldTejun Heo2016-12-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | More kernfs_open_file->mutex synchronized flags are planned to be added. Convert ->mmapped to a bitfield in preparation. While at it, make kernfs_fop_mmap() use "true" instead of "1" on ->mmapped. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Acked-by: Zefan Li <lizefan@huawei.com>
* | mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmfDave Jiang2017-02-241-7/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ->fault(), ->page_mkwrite(), and ->pfn_mkwrite() calls do not need to take a vma and vmf parameter when the vma already resides in vmf. Remove the vma parameter to simplify things. [arnd@arndb.de: fix ARM build] Link: http://lkml.kernel.org/r/20170125223558.1451224-1-arnd@arndb.de Link: http://lkml.kernel.org/r/148521301778.19116.10840599906674778980.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@suse.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | kernfs: handle null pointers while printing node name and pathKonstantin Khlebnikov2017-02-101-0/+10
|/ | | | | | | | | | Null kernfs nodes could be found at cgroups during construction. It seems safer to handle these null pointers right in kernfs in the same way as printf prints "(null)" for null pointer string. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge uncontroversial parts of branch 'readlink' of ↵Linus Torvalds2016-12-171-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull partial readlink cleanups from Miklos Szeredi. This is the uncontroversial part of the readlink cleanup patch-set that simplifies the default readlink handling. Miklos and Al are still discussing the rest of the series. * git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: vfs: make generic_readlink() static vfs: remove ".readlink = generic_readlink" assignments vfs: default to generic_readlink() vfs: replace calling i_op->readlink with vfs_readlink() proc/self: use generic_readlink ecryptfs: use vfs_get_link() bad_inode: add missing i_op initializers
| * vfs: remove ".readlink = generic_readlink" assignmentsMiklos Szeredi2016-12-091-1/+0
| | | | | | | | | | | | | | | | | | | | | | If .readlink == NULL implies generic_readlink(). Generated by: to_del="\.readlink.*=.*generic_readlink" for i in `git grep -l $to_del`; do sed -i "/$to_del"/d $i; done Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | kernfs: Declare two local data structures staticBart Van Assche2016-11-291-2/+2
|/ | | | | | | | This was spotted by the 'sparse' static checker. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: Add noop_fsync to supported kernfs_file_fopsTony Luck2016-10-271-0/+1
| | | | | | | | | | | If you edit a kernfs backed file with vi(1), you see an ugly error message when you write the file because vi tries to fsync(2) the file after writing, which fails. We have noop_fsync() for this, use it. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'for-4.9' of ↵Linus Torvalds2016-10-141-67/+17
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: - tracepoints for basic cgroup management operations added - kernfs and cgroup path formatting functions updated to behave in the style of strlcpy() - non-critical bug fixes * 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: blkcg: Unlock blkcg_pol_mutex only once when cpd == NULL cgroup: fix error handling regressions in proc_cgroup_show() and cgroup_release_agent() cpuset: fix error handling regression in proc_cpuset_show() cgroup: add tracepoints for basic operations cgroup: make cgroup_path() and friends behave in the style of strlcpy() kernfs: remove kernfs_path_len() kernfs: make kernfs_path*() behave in the style of strlcpy() kernfs: add dummy implementation of kernfs_path_from_node()
| * kernfs: remove kernfs_path_len()Tejun Heo2016-08-101-23/+0
| | | | | | | | | | | | | | | | | | It doesn't have any in-kernel user and the same result can be obtained from kernfs_path(@kn, NULL, 0). Remove it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
| * kernfs: make kernfs_path*() behave in the style of strlcpy()Tejun Heo2016-08-101-44/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kernfs_path*() functions always return the length of the full path but the path content is undefined if the length is larger than the provided buffer. This makes its behavior different from strlcpy() and requires error handling in all its users even when they don't care about truncation. In addition, the implementation can actully be simplified by making it behave properly in strlcpy() style. * Update kernfs_path_from_node_locked() to always fill up the buffer with path. If the buffer is not large enough, the output is truncated and terminated. * kernfs_path() no longer needs error handling. Make it a simple inline wrapper around kernfs_path_from_node(). * sysfs_warn_dup()'s use of kernfs_path() doesn't need error handling. Updated accordingly. * cgroup_path()'s use of kernfs_path() updated to retain the old behavior. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
* | Merge branch 'for-linus' of ↵Linus Torvalds2016-10-102-2/+6
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| * \ Merge remote-tracking branch 'ovl/rename2' into for-linusAl Viro2016-10-101-1/+5
| |\ \
| | * | fs: rename "rename2" i_op to "rename"Miklos Szeredi2016-09-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Generated patch: sed -i "s/\.rename2\t/\.rename\t\t/" `git grep -wl rename2` sed -i "s/\brename2\b/rename/g" `git grep -wl rename2` Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| | * | fs: make remaining filesystems use .rename2Miklos Szeredi2016-09-271-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is trivial to do: - add flags argument to foo_rename() - check if flags is zero - assign foo_rename() to .rename2 instead of .rename This doesn't mean it's impossible to support RENAME_NOREPLACE for these filesystems, but it is not trivial, like for local filesystems. RENAME_NOREPLACE must guarantee atomicity (i.e. it shouldn't be possible for a file to be created on one host while it is overwritten by rename on another host). Filesystems converted: 9p, afs, ceph, coda, ecryptfs, kernfs, lustre, ncpfs, nfs, ocfs2, orangefs. After this, we can get rid of the duplicate interfaces for rename. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: David Howells <dhowells@redhat.com> [AFS] Acked-by: Mike Marshall <hubcap@omnibond.com> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jan Harkes <jaharkes@cs.cmu.edu> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: Trond Myklebust <trond.myklebust@primarydata.com> Cc: Mark Fasheh <mfasheh@suse.com>
| * | | fs: Replace current_fs_time() with current_time()Deepa Dinamani2016-09-271-1/+1
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | current_fs_time() uses struct super_block* as an argument. As per Linus's suggestion, this is changed to take struct inode* as a parameter instead. This is because the function is primarily meant for vfs inode timestamps. Also the function was renamed as per Arnd's suggestion. Change all calls to current_fs_time() to use the new current_time() function instead. current_fs_time() will be deleted. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | Merge branch 'work.xattr' of ↵Linus Torvalds2016-10-105-86/+83
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| * | | vfs: Remove {get,set,remove}xattr inode operationsAndreas Gruenbacher2016-10-073-9/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | These inode operations are no longer used; remove them. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | kernfs: Switch to generic xattr handlersAndreas Gruenbacher2016-10-065-86/+92
| |/ / | | | | | | | | | | | | | | | | | | Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | Merge remote-tracking branch 'jk/vfs' into work.miscAl Viro2016-10-081-1/+1
|\ \ \ | |/ / |/| |
| * | fs: Give dentry to inode_change_ok() instead of inodeJan Kara2016-09-221-1/+1
| |/ | | | | | | | | | | | | | | | | | | | | inode_change_ok() will be resposible for clearing capabilities and IMA extended attributes and as such will need dentry. Give it as an argument to inode_change_ok() instead of an inode. Also rename inode_change_ok() to setattr_prepare() to better relect that it does also some modifications in addition to checks. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
* / kernfs: don't depend on d_find_any_alias() when generating notificationsTejun Heo2016-08-311-7/+21
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kernfs_notify_workfn() sends out file modified events for the scheduled kernfs_nodes. Because the modifications aren't from userland, it doesn't have the matching file struct at hand and can't use fsnotify_modify(). Instead, it looked up the inode and then used d_find_any_alias() to find the dentry and used fsnotify_parent() and fsnotify() directly to generate notifications. The assumption was that the relevant dentries would have been pinned if there are listeners, which isn't true as inotify doesn't pin dentries at all and watching the parent doesn't pin the child dentries even for dnotify. This led to, for example, inotify watchers not getting notifications if the system is under memory pressure and the matching dentries got reclaimed. It can also be triggered through /proc/sys/vm/drop_caches or a remount attempt which involves shrinking dcache. fsnotify_parent() only uses the dentry to access the parent inode, which kernfs can do easily. Update kernfs_notify_workfn() so that it uses fsnotify() directly for both the parent and target inodes without going through d_find_any_alias(). While at it, supply the target file name to fsnotify() from kernfs_node->name. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Evgeny Vereshchagin <evvers@ya.ru> Fixes: d911d9874801 ("kernfs: make kernfs_notify() trigger inotify events too") Cc: John McCutchan <john@johnmccutchan.com> Cc: Robert Love <rlove@rlove.org> Cc: Eric Paris <eparis@parisplace.org> Cc: stable@vger.kernel.org # v3.16+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2016-07-291-1/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull userns vfs updates from Eric Biederman: "This tree contains some very long awaited work on generalizing the user namespace support for mounting filesystems to include filesystems with a backing store. The real world target is fuse but the goal is to update the vfs to allow any filesystem to be supported. This patchset is based on a lot of code review and testing to approach that goal. While looking at what is needed to support the fuse filesystem it became clear that there were things like xattrs for security modules that needed special treatment. That the resolution of those concerns would not be fuse specific. That sorting out these general issues made most sense at the generic level, where the right people could be drawn into the conversation, and the issues could be solved for everyone. At a high level what this patchset does a couple of simple things: - Add a user namespace owner (s_user_ns) to struct super_block. - Teach the vfs to handle filesystem uids and gids not mapping into to kuids and kgids and being reported as INVALID_UID and INVALID_GID in vfs data structures. By assigning a user namespace owner filesystems that are mounted with only user namespace privilege can be detected. This allows security modules and the like to know which mounts may not be trusted. This also allows the set of uids and gids that are communicated to the filesystem to be capped at the set of kuids and kgids that are in the owning user namespace of the filesystem. One of the crazier corner casees this handles is the case of inodes whose i_uid or i_gid are not mapped into the vfs. Most of the code simply doesn't care but it is easy to confuse the inode writeback path so no operation that could cause an inode write-back is permitted for such inodes (aka only reads are allowed). This set of changes starts out by cleaning up the code paths involved in user namespace permirted mounts. Then when things are clean enough adds code that cleanly sets s_user_ns. Then additional restrictions are added that are possible now that the filesystem superblock contains owner information. These changes should not affect anyone in practice, but there are some parts of these restrictions that are changes in behavior. - Andy's restriction on suid executables that does not honor the suid bit when the path is from another mount namespace (think /proc/[pid]/fd/) or when the filesystem was mounted by a less privileged user. - The replacement of the user namespace implicit setting of MNT_NODEV with implicitly setting SB_I_NODEV on the filesystem superblock instead. Using SB_I_NODEV is a stronger form that happens to make this state user invisible. The user visibility can be managed but it caused problems when it was introduced from applications reasonably expecting mount flags to be what they were set to. There is a little bit of work remaining before it is safe to support mounting filesystems with backing store in user namespaces, beyond what is in this set of changes. - Verifying the mounter has permission to read/write the block device during mount. - Teaching the integrity modules IMA and EVM to handle filesystems mounted with only user namespace root and to reduce trust in their security xattrs accordingly. - Capturing the mounters credentials and using that for permission checks in d_automount and the like. (Given that overlayfs already does this, and we need the work in d_automount it make sense to generalize this case). Furthermore there are a few changes that are on the wishlist: - Get all filesystems supporting posix acls using the generic posix acls so that posix_acl_fix_xattr_from_user and posix_acl_fix_xattr_to_user may be removed. [Maintainability] - Reducing the permission checks in places such as remount to allow the superblock owner to perform them. - Allowing the superblock owner to chown files with unmapped uids and gids to something that is mapped so the files may be treated normally. I am not considering even obvious relaxations of permission checks until it is clear there are no more corner cases that need to be locked down and handled generically. Many thanks to Seth Forshee who kept this code alive, and putting up with me rewriting substantial portions of what he did to handle more corner cases, and for his diligent testing and reviewing of my changes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (30 commits) fs: Call d_automount with the filesystems creds fs: Update i_[ug]id_(read|write) to translate relative to s_user_ns evm: Translate user/group ids relative to s_user_ns when computing HMAC dquot: For now explicitly don't support filesystems outside of init_user_ns quota: Handle quota data stored in s_user_ns in quota_setxquota quota: Ensure qids map to the filesystem vfs: Don't create inodes with a uid or gid unknown to the vfs vfs: Don't modify inodes with a uid or gid unknown to the vfs cred: Reject inodes with invalid ids in set_create_file_as() fs: Check for invalid i_uid in may_follow_link() vfs: Verify acls are valid within superblock's s_user_ns. userns: Handle -1 in k[ug]id_has_mapping when !CONFIG_USER_NS fs: Refuse uid/gid changes which don't map into s_user_ns selinux: Add support for unprivileged mounts from user namespaces Smack: Handle labels consistently in untrusted mounts Smack: Add support for unprivileged mounts from user namespaces fs: Treat foreign mounts as nosuid fs: Limit file caps to the user namespace of the super block userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flag userns: Remove implicit MNT_NODEV fragility. ...
| * vfs: Generalize filesystem nodev handling.Eric W. Biederman2016-06-231-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce a function may_open_dev that tests MNT_NODEV and a new superblock flab SB_I_NODEV. Use this new function in all of the places where MNT_NODEV was previously tested. Add the new SB_I_NODEV s_iflag to proc, sysfs, and mqueuefs as those filesystems should never support device nodes, and a simple superblock flags makes that very hard to get wrong. With SB_I_NODEV set if any device nodes somehow manage to show up on on a filesystem those device nodes will be unopenable. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * kernfs: The cgroup filesystem also benefits from SB_I_NOEXECEric W. Biederman2016-06-231-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The cgroup filesystem is in the same boat as sysfs. No one ever permits executables of any kind on the cgroup filesystem, and there is no reasonable future case to support executables in the future. Therefore move the setting of SB_I_NOEXEC which makes the code proof against future mistakes of accidentally creating executables from sysfs to kernfs itself. Making the code simpler and covering the sysfs, cgroup, and cgroup2 filesystems. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
| * fs: Add user namespace member to struct super_blockEric W. Biederman2016-06-231-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Start marking filesystems with a user namespace owner, s_user_ns. In this change this is only used for permission checks of who may mount a filesystem. Ultimately s_user_ns will be used for translating ids and checking capabilities for filesystems mounted from user namespaces. The default policy for setting s_user_ns is implemented in sget(), which arranges for s_user_ns to be set to current_user_ns() and to ensure that the mounter of the filesystem has CAP_SYS_ADMIN in that user_ns. The guts of sget are split out into another function sget_userns(). The function sget_userns calls alloc_super with the specified user namespace or it verifies the existing superblock that was found has the expected user namespace, and fails with EBUSY when it is not. This failing prevents users with the wrong privileges mounting a filesystem. The reason for the split of sget_userns from sget is that in some cases such as mount_ns and kernfs_mount_ns a different policy for permission checking of mounts and setting s_user_ns is necessary, and the existence of sget_userns() allows those policies to be implemented. The helper mount_ns is expected to be used for filesystems such as proc and mqueuefs which present per namespace information. The function mount_ns is modified to call sget_userns instead of sget to ensure the user namespace owner of the namespace whose information is presented by the filesystem is used on the superblock. For sysfs and cgroup the appropriate permission checks are already in place, and kernfs_mount_ns is modified to call sget_userns so that the init_user_ns is the only user namespace used. For the cgroup filesystem cgroup namespace mounts are bind mounts of a subset of the full cgroup filesystem and as such s_user_ns must be the same for all of them as there is only a single superblock. Mounts of sysfs that vary based on the network namespace could in principle change s_user_ns but it keeps the analysis and implementation of kernfs simpler if that is not supported, and at present there appear to be no benefits from supporting a different s_user_ns on any sysfs mount. Getting the details of setting s_user_ns correct has been a long process. Thanks to Pavel Tikhorirorv who spotted a leak in sget_userns. Thanks to Seth Forshee who has kept the work alive. Thanks-to: Seth Forshee <seth.forshee@canonical.com> Thanks-to: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* | vfs: make the string hashes salt the hashLinus Torvalds2016-06-101-2/+2
|/ | | | | | | | | | | | | | | | | | We always mixed in the parent pointer into the dentry name hash, but we did it late at lookup time. It turns out that we can simplify that lookup-time action by salting the hash with the parent pointer early instead of late. A few other users of our string hashes also wanted to mix in their own pointers into the hash, and those are updated to use the same mechanism. Hash users that don't have any particular initial salt can just use the NULL pointer as a no-salt. Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* switch ->setxattr() to passing dentry and inode separatelyAl Viro2016-05-272-6/+8
| | | | | | | | | | | | | | | | smack ->d_instantiate() uses ->setxattr(), so to be able to call it before we'd hashed the new dentry and attached it to inode, we need ->setxattr() instances getting the inode as an explicit argument rather than obtaining it from dentry. Similar change for ->getxattr() had been done in commit ce23e64. Unlike ->getxattr() (which is used by both selinux and smack instances of ->d_instantiate()) ->setxattr() is used only by smack one and unfortunately it got missed back then. Reported-by: Seung-Woo Kim <sw0312.kim@samsung.com> Tested-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge tag 'driver-core-4.7-rc1' of ↵Linus Torvalds2016-05-203-30/+44
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here's the "big" driver core update for 4.7-rc1. Mostly just debugfs changes, the long-known and messy races with removing debugfs files should be fixed thanks to the great work of Nicolai Stange. We also have some isa updates in here (the x86 maintainers told me to take it through this tree), a new warning when we run out of dynamic char major numbers, and a few other assorted changes, details in the shortlog. All have been in linux-next for some time with no reported issues" * tag 'driver-core-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits) Revert "base: dd: don't remove driver_data in -EPROBE_DEFER case" gpio: ws16c48: Utilize the ISA bus driver gpio: 104-idio-16: Utilize the ISA bus driver gpio: 104-idi-48: Utilize the ISA bus driver gpio: 104-dio-48e: Utilize the ISA bus driver watchdog: ebc-c384_wdt: Utilize the ISA bus driver iio: stx104: Utilize the module_isa_driver and max_num_isa_dev macros iio: stx104: Add X86 dependency to STX104 Kconfig option Documentation: Add ISA bus driver documentation isa: Implement the max_num_isa_dev macro isa: Implement the module_isa_driver macro pnp: pnpbios: Add explicit X86_32 dependency to PNPBIOS isa: Decouple X86_32 dependency from the ISA Kconfig option driver-core: use 'dev' argument in dev_dbg_ratelimited stub base: dd: don't remove driver_data in -EPROBE_DEFER case kernfs: Move faulting copy_user operations outside of the mutex devcoredump: add scatterlist support debugfs: unproxify files created through debugfs_create_u32_array() debugfs: unproxify files created through debugfs_create_blob() debugfs: unproxify files created through debugfs_create_bool() ...
| * kernfs: Move faulting copy_user operations outside of the mutexChris Wilson2016-04-301-22/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A fault in a user provided buffer may lead anywhere, and lockdep warns that we have a potential deadlock between the mm->mmap_sem and the kernfs file mutex: [ 82.811702] ====================================================== [ 82.811705] [ INFO: possible circular locking dependency detected ] [ 82.811709] 4.5.0-rc4-gfxbench+ #1 Not tainted [ 82.811711] ------------------------------------------------------- [ 82.811714] kms_setmode/5859 is trying to acquire lock: [ 82.811717] (&dev->struct_mutex){+.+.+.}, at: [<ffffffff8150d9c1>] drm_gem_mmap+0x1a1/0x270 [ 82.811731] but task is already holding lock: [ 82.811734] (&mm->mmap_sem){++++++}, at: [<ffffffff8117b364>] vm_mmap_pgoff+0x44/0xa0 [ 82.811745] which lock already depends on the new lock. [ 82.811749] the existing dependency chain (in reverse order) is: [ 82.811752] -> #3 (&mm->mmap_sem){++++++}: [ 82.811761] [<ffffffff810cc883>] lock_acquire+0xc3/0x1d0 [ 82.811766] [<ffffffff8118bc65>] __might_fault+0x75/0xa0 [ 82.811771] [<ffffffff8124da4a>] kernfs_fop_write+0x8a/0x180 [ 82.811787] [<ffffffff811d1023>] __vfs_write+0x23/0xe0 [ 82.811792] [<ffffffff811d1d74>] vfs_write+0xa4/0x190 [ 82.811797] [<ffffffff811d2c14>] SyS_write+0x44/0xb0 [ 82.811801] [<ffffffff817bb81b>] entry_SYSCALL_64_fastpath+0x16/0x73 [ 82.811807] -> #2 (s_active#6){++++.+}: [ 82.811814] [<ffffffff810cc883>] lock_acquire+0xc3/0x1d0 [ 82.811819] [<ffffffff8124c070>] __kernfs_remove+0x210/0x2f0 [ 82.811823] [<ffffffff8124d040>] kernfs_remove_by_name_ns+0x40/0xa0 [ 82.811828] [<ffffffff8124e9e0>] sysfs_remove_file_ns+0x10/0x20 [ 82.811832] [<ffffffff815318d4>] device_del+0x124/0x250 [ 82.811837] [<ffffffff81531a19>] device_unregister+0x19/0x60 [ 82.811841] [<ffffffff8153c051>] cpu_cache_sysfs_exit+0x51/0xb0 [ 82.811846] [<ffffffff8153c628>] cacheinfo_cpu_callback+0x38/0x70 [ 82.811851] [<ffffffff8109ae89>] notifier_call_chain+0x39/0xa0 [ 82.811856] [<ffffffff8109aef9>] __raw_notifier_call_chain+0x9/0x10 [ 82.811860] [<ffffffff810786de>] cpu_notify+0x1e/0x40 [ 82.811865] [<ffffffff81078779>] cpu_notify_nofail+0x9/0x20 [ 82.811869] [<ffffffff81078ac3>] _cpu_down+0x233/0x340 [ 82.811874] [<ffffffff81079019>] disable_nonboot_cpus+0xc9/0x350 [ 82.811878] [<ffffffff810d2e11>] suspend_devices_and_enter+0x5a1/0xb50 [ 82.811883] [<ffffffff810d3903>] pm_suspend+0x543/0x8d0 [ 82.811888] [<ffffffff810d1b77>] state_store+0x77/0xe0 [ 82.811892] [<ffffffff813fa68f>] kobj_attr_store+0xf/0x20 [ 82.811897] [<ffffffff8124e740>] sysfs_kf_write+0x40/0x50 [ 82.811902] [<ffffffff8124dafc>] kernfs_fop_write+0x13c/0x180 [ 82.811906] [<ffffffff811d1023>] __vfs_write+0x23/0xe0 [ 82.811910] [<ffffffff811d1d74>] vfs_write+0xa4/0x190 [ 82.811914] [<ffffffff811d2c14>] SyS_write+0x44/0xb0 [ 82.811918] [<ffffffff817bb81b>] entry_SYSCALL_64_fastpath+0x16/0x73 [ 82.811923] -> #1 (cpu_hotplug.lock){+.+.+.}: [ 82.811929] [<ffffffff810cc883>] lock_acquire+0xc3/0x1d0 [ 82.811933] [<ffffffff817b6f72>] mutex_lock_nested+0x62/0x3b0 [ 82.811940] [<ffffffff810784c1>] get_online_cpus+0x61/0x80 [ 82.811944] [<ffffffff811170eb>] stop_machine+0x1b/0xe0 [ 82.811949] [<ffffffffa0178edd>] gen8_ggtt_insert_entries__BKL+0x2d/0x30 [i915] [ 82.812009] [<ffffffffa017d3a6>] ggtt_bind_vma+0x46/0x70 [i915] [ 82.812045] [<ffffffffa017eb70>] i915_vma_bind+0x140/0x290 [i915] [ 82.812081] [<ffffffffa01862b9>] i915_gem_object_do_pin+0x899/0xb00 [i915] [ 82.812117] [<ffffffffa0186555>] i915_gem_object_pin+0x35/0x40 [i915] [ 82.812154] [<ffffffffa019a23e>] intel_init_pipe_control+0xbe/0x210 [i915] [ 82.812192] [<ffffffffa0197312>] intel_logical_rings_init+0xe2/0xde0 [i915] [ 82.812232] [<ffffffffa0186fe3>] i915_gem_init+0xf3/0x130 [i915] [ 82.812278] [<ffffffffa02097ed>] i915_driver_load+0xf2d/0x1770 [i915] [ 82.812318] [<ffffffff81512474>] drm_dev_register+0xa4/0xb0 [ 82.812323] [<ffffffff8151467e>] drm_get_pci_dev+0xce/0x1e0 [ 82.812328] [<ffffffffa01472cf>] i915_pci_probe+0x2f/0x50 [i915] [ 82.812360] [<ffffffff8143f907>] pci_device_probe+0x87/0xf0 [ 82.812366] [<ffffffff81535f89>] driver_probe_device+0x229/0x450 [ 82.812371] [<ffffffff81536233>] __driver_attach+0x83/0x90 [ 82.812375] [<ffffffff81533c61>] bus_for_each_dev+0x61/0xa0 [ 82.812380] [<ffffffff81535879>] driver_attach+0x19/0x20 [ 82.812384] [<ffffffff8153535f>] bus_add_driver+0x1ef/0x290 [ 82.812388] [<ffffffff81536e9b>] driver_register+0x5b/0xe0 [ 82.812393] [<ffffffff8143e83b>] __pci_register_driver+0x5b/0x60 [ 82.812398] [<ffffffff81514866>] drm_pci_init+0xd6/0x100 [ 82.812402] [<ffffffffa027c094>] 0xffffffffa027c094 [ 82.812406] [<ffffffff810003de>] do_one_initcall+0xae/0x1d0 [ 82.812412] [<ffffffff811595a0>] do_init_module+0x5b/0x1cb [ 82.812417] [<ffffffff81106160>] load_module+0x1c20/0x2480 [ 82.812422] [<ffffffff81106bae>] SyS_finit_module+0x7e/0xa0 [ 82.812428] [<ffffffff817bb81b>] entry_SYSCALL_64_fastpath+0x16/0x73 [ 82.812433] -> #0 (&dev->struct_mutex){+.+.+.}: [ 82.812439] [<ffffffff810cbe59>] __lock_acquire+0x1fc9/0x20f0 [ 82.812443] [<ffffffff810cc883>] lock_acquire+0xc3/0x1d0 [ 82.812456] [<ffffffff8150d9e7>] drm_gem_mmap+0x1c7/0x270 [ 82.812460] [<ffffffff81196a14>] mmap_region+0x334/0x580 [ 82.812466] [<ffffffff81196fc4>] do_mmap+0x364/0x410 [ 82.812470] [<ffffffff8117b38d>] vm_mmap_pgoff+0x6d/0xa0 [ 82.812474] [<ffffffff811950f4>] SyS_mmap_pgoff+0x184/0x220 [ 82.812479] [<ffffffff8100a0fd>] SyS_mmap+0x1d/0x20 [ 82.812484] [<ffffffff817bb81b>] entry_SYSCALL_64_fastpath+0x16/0x73 [ 82.812489] other info that might help us debug this: [ 82.812493] Chain exists of: &dev->struct_mutex --> s_active#6 --> &mm->mmap_sem [ 82.812502] Possible unsafe locking scenario: [ 82.812506] CPU0 CPU1 [ 82.812508] ---- ---- [ 82.812510] lock(&mm->mmap_sem); [ 82.812514] lock(s_active#6); [ 82.812519] lock(&mm->mmap_sem); [ 82.812522] lock(&dev->struct_mutex); [ 82.812526] *** DEADLOCK *** [ 82.812531] 1 lock held by kms_setmode/5859: [ 82.812533] #0: (&mm->mmap_sem){++++++}, at: [<ffffffff8117b364>] vm_mmap_pgoff+0x44/0xa0 [ 82.812541] stack backtrace: [ 82.812547] CPU: 0 PID: 5859 Comm: kms_setmode Not tainted 4.5.0-rc4-gfxbench+ #1 [ 82.812550] Hardware name: /NUC5CPYB, BIOS PYBSWCEL.86A.0040.2015.0814.1353 08/14/2015 [ 82.812553] 0000000000000000 ffff880079407bf0 ffffffff813f8505 ffffffff825fb270 [ 82.812560] ffffffff825c4190 ffff880079407c30 ffffffff810c84ac ffff880079407c90 [ 82.812566] ffff8800797ed328 ffff8800797ecb00 0000000000000001 ffff8800797ed350 [ 82.812573] Call Trace: [ 82.812578] [<ffffffff813f8505>] dump_stack+0x67/0x92 [ 82.812582] [<ffffffff810c84ac>] print_circular_bug+0x1fc/0x310 [ 82.812586] [<ffffffff810cbe59>] __lock_acquire+0x1fc9/0x20f0 [ 82.812590] [<ffffffff810cc883>] lock_acquire+0xc3/0x1d0 [ 82.812594] [<ffffffff8150d9c1>] ? drm_gem_mmap+0x1a1/0x270 [ 82.812599] [<ffffffff8150d9e7>] drm_gem_mmap+0x1c7/0x270 [ 82.812603] [<ffffffff8150d9c1>] ? drm_gem_mmap+0x1a1/0x270 [ 82.812608] [<ffffffff81196a14>] mmap_region+0x334/0x580 [ 82.812612] [<ffffffff81196fc4>] do_mmap+0x364/0x410 [ 82.812616] [<ffffffff8117b38d>] vm_mmap_pgoff+0x6d/0xa0 [ 82.812629] [<ffffffff811950f4>] SyS_mmap_pgoff+0x184/0x220 [ 82.812633] [<ffffffff8100a0fd>] SyS_mmap+0x1d/0x20 [ 82.812637] [<ffffffff817bb81b>] entry_SYSCALL_64_fastpath+0x16/0x73 Highly unlikely though this scenario is, we can avoid the issue entirely by moving the copy operation from out under the kernfs_get_active() tracking by assigning the preallocated buffer its own mutex. The temporary buffer allocation doesn't require mutex locking as it is entirely local. The locked section was extended by the addition of the preallocated buf to speed up md user operations in commit 2b75869bba676c248d8d25ae6d2bd9221dfffdb6 Author: NeilBrown <neilb@suse.de> Date: Mon Oct 13 16:41:28 2014 +1100 sysfs/kernfs: allow attributes to request write buffer be pre-allocated. Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94350 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: NeilBrown <neilb@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * Merge 4.6-rc4 into driver-core-nextGreg Kroah-Hartman2016-04-191-2/+2
| |\ | | | | | | | | | | | | | | | We want those fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | fs: kernfs: Replace CURRENT_TIME by current_fs_time()Deepa Dinamani2016-03-292-8/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is in preparation for the series that transitions filesystem timestamps to use 64 bit time and hence make them y2038 safe. CURRENT_TIME macro will be deleted before merging the aforementioned series. Use current_fs_time() instead of CURRENT_TIME for inode timestamps. struct kernfs_node is associated with a sysfs file/ directory. Truncate the values to appropriate time granularity when writing to inode timestamps of the files. ktime_get_real_ts() is used to obtain times for struct kernfs_iattrs. Since these times are later assigned to inode times using timespec_truncate() for all filesystem based operations, we can save the supers list traversal time here by using ktime_get_real_ts() directly. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | Merge branch 'for-linus' of ↵Linus Torvalds2016-05-174-23/+9
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull parallel filesystem directory handling update from Al Viro. This is the main parallel directory work by Al that makes the vfs layer able to do lookup and readdir in parallel within a single directory. That's a big change, since this used to be all protected by the directory inode mutex. The inode mutex is replaced by an rwsem, and serialization of lookups of a single name is done by a "in-progress" dentry marker. The series begins with xattr cleanups, and then ends with switching filesystems over to actually doing the readdir in parallel (switching to the "iterate_shared()" that only takes the read lock). A more detailed explanation of the process from Al Viro: "The xattr work starts with some acl fixes, then switches ->getxattr to passing inode and dentry separately. This is the point where the things start to get tricky - that got merged into the very beginning of the -rc3-based #work.lookups, to allow untangling the security_d_instantiate() mess. The xattr work itself proceeds to switch a lot of filesystems to generic_...xattr(); no complications there. After that initial xattr work, the series then does the following: - untangle security_d_instantiate() - convert a bunch of open-coded lookup_one_len_unlocked() to calls of that thing; one such place (in overlayfs) actually yields a trivial conflict with overlayfs fixes later in the cycle - overlayfs ended up switching to a variant of lookup_one_len_unlocked() sans the permission checks. I would've dropped that commit (it gets overridden on merge from #ovl-fixes in #for-next; proper resolution is to use the variant in mainline fs/overlayfs/super.c), but I didn't want to rebase the damn thing - it was fairly late in the cycle... - some filesystems had managed to depend on lookup/lookup exclusion for *fs-internal* data structures in a way that would break if we relaxed the VFS exclusion. Fixing hadn't been hard, fortunately. - core of that series - parallel lookup machinery, replacing ->i_mutex with rwsem, making lookup_slow() take it only shared. At that point lookups happen in parallel; lookups on the same name wait for the in-progress one to be done with that dentry. Surprisingly little code, at that - almost all of it is in fs/dcache.c, with fs/namei.c changes limited to lookup_slow() - making it use the new primitive and actually switching to locking shared. - parallel readdir stuff - first of all, we provide the exclusion on per-struct file basis, same as we do for read() vs lseek() for regular files. That takes care of most of the needed exclusion in readdir/readdir; however, these guys are trickier than lookups, so I went for switching them one-by-one. To do that, a new method '->iterate_shared()' is added and filesystems are switched to it as they are either confirmed to be OK with shared lock on directory or fixed to be OK with that. I hope to kill the original method come next cycle (almost all in-tree filesystems are switched already), but it's still not quite finished. - several filesystems get switched to parallel readdir. The interesting part here is dealing with dcache preseeding by readdir; that needs minor adjustment to be safe with directory locked only shared. Most of the filesystems doing that got switched to in those commits. Important exception: NFS. Turns out that NFS folks, with their, er, insistence on VFS getting the fuck out of the way of the Smart Filesystem Code That Knows How And What To Lock(tm) have grown the locking of their own. They had their own homegrown rwsem, with lookup/readdir/atomic_open being *writers* (sillyunlink is the reader there). Of course, with VFS getting the fuck out of the way, as requested, the actual smarts of the smart filesystem code etc. had become exposed... - do_last/lookup_open/atomic_open cleanups. As the result, open() without O_CREAT locks the directory only shared. Including the ->atomic_open() case. Backmerge from #for-linus in the middle of that - atomic_open() fix got brought in. - then comes NFS switch to saner (VFS-based ;-) locking, killing the homegrown "lookup and readdir are writers" kinda-sorta rwsem. All exclusion for sillyunlink/lookup is done by the parallel lookups mechanism. Exclusion between sillyunlink and rmdir is a real rwsem now - rmdir being the writer. Result: NFS lookups/readdirs/O_CREAT-less opens happen in parallel now. - the rest of the series consists of switching a lot of filesystems to parallel readdir; in a lot of cases ->llseek() gets simplified as well. One backmerge in there (again, #for-linus - rockridge fix)" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (74 commits) ext4: switch to ->iterate_shared() hfs: switch to ->iterate_shared() hfsplus: switch to ->iterate_shared() hostfs: switch to ->iterate_shared() hpfs: switch to ->iterate_shared() hpfs: handle allocation failures in hpfs_add_pos() gfs2: switch to ->iterate_shared() f2fs: switch to ->iterate_shared() afs: switch to ->iterate_shared() befs: switch to ->iterate_shared() befs: constify stuff a bit isofs: switch to ->iterate_shared() get_acorn_filename(): deobfuscate a bit btrfs: switch to ->iterate_shared() logfs: no need to lock directory in lseek switch ecryptfs to ->iterate_shared 9p: switch to ->iterate_shared() fat: switch to ->iterate_shared() romfs, squashfs: switch to ->iterate_shared() more trivial ->iterate_shared conversions ...
| * | | kernfs: no point locking directory around that generic_file_llseek()Al Viro2016-05-091-15/+2
| | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | kernfs: use lookup_one_len_unlocked()Al Viro2016-05-021-3/+2
| | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | Merge getxattr prototype change into work.lookupsAl Viro2016-05-022-5/+5
| |\ \ \ | | |_|/ | |/| | | | | | The rest of work.xattr stuff isn't needed for this branch
| | * | ->getxattr(): pass dentry and inode as separate argumentsAl Viro2016-04-112-5/+5
| | |/ | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | kernfs: kernfs_sop_show_path: don't return 0 after seq_dentry callSerge E. Hallyn2016-05-121-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Our caller expects 0 on success, not >0. This fixes a bug in the patch cgroup, kernfs: make mountinfo show properly scoped path for cgroup namespaces where /sys does not show up in mountinfo, breaking criu. Thanks for catching this, Andrei. Reported-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | | cgroup, kernfs: make mountinfo show properly scoped path for cgroup namespacesSerge E. Hallyn2016-05-091-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch summary: When showing a cgroupfs entry in mountinfo, show the path of the mount root dentry relative to the reader's cgroup namespace root. Short explanation (courtesy of mkerrisk): If we create a new cgroup namespace, then we want both /proc/self/cgroup and /proc/self/mountinfo to show cgroup paths that are correctly virtualized with respect to the cgroup mount point. Previous to this patch, /proc/self/cgroup shows the right info, but /proc/self/mountinfo does not. Long version: When a uid 0 task which is in freezer cgroup /a/b, unshares a new cgroup namespace, and then mounts a new instance of the freezer cgroup, the new mount will be rooted at /a/b. The root dentry field of the mountinfo entry will show '/a/b'. cat > /tmp/do1 << EOF mount -t cgroup -o freezer freezer /mnt grep freezer /proc/self/mountinfo EOF unshare -Gm bash /tmp/do1 > 330 160 0:34 / /sys/fs/cgroup/freezer rw,nosuid,nodev,noexec,relatime - cgroup cgroup rw,freezer > 355 133 0:34 /a/b /mnt rw,relatime - cgroup freezer rw,freezer The task's freezer cgroup entry in /proc/self/cgroup will simply show '/': grep freezer /proc/self/cgroup 9:freezer:/ If instead the same task simply bind mounts the /a/b cgroup directory, the resulting mountinfo entry will again show /a/b for the dentry root. However in this case the task will find its own cgroup at /mnt/a/b, not at /mnt: mount --bind /sys/fs/cgroup/freezer/a/b /mnt 130 25 0:34 /a/b /mnt rw,nosuid,nodev,noexec,relatime shared:21 - cgroup cgroup rw,freezer In other words, there is no way for the task to know, based on what is in mountinfo, which cgroup directory is its own. Example (by mkerrisk): First, a little script to save some typing and verbiage: echo -e "\t/proc/self/cgroup:\t$(cat /proc/self/cgroup | grep freezer)" cat /proc/self/mountinfo | grep freezer | awk '{print "\tmountinfo:\t\t" $4 "\t" $5}' Create cgroup, place this shell into the cgroup, and look at the state of the /proc files: 2653 2653 # Our shell 14254 # cat(1) /proc/self/cgroup: 10:freezer:/a/b mountinfo: / /sys/fs/cgroup/freezer Create a shell in new cgroup and mount namespaces. The act of creating a new cgroup namespace causes the process's current cgroups directories to become its cgroup root directories. (Here, I'm using my own version of the "unshare" utility, which takes the same options as the util-linux version): Look at the state of the /proc files: /proc/self/cgroup: 10:freezer:/ mountinfo: / /sys/fs/cgroup/freezer The third entry in /proc/self/cgroup (the pathname of the cgroup inside the hierarchy) is correctly virtualized w.r.t. the cgroup namespace, which is rooted at /a/b in the outer namespace. However, the info in /proc/self/mountinfo is not for this cgroup namespace, since we are seeing a duplicate of the mount from the old mount namespace, and the info there does not correspond to the new cgroup namespace. However, trying to create a new mount still doesn't show us the right information in mountinfo: # propagating to other mountns /proc/self/cgroup: 7:freezer:/ mountinfo: /a/b /mnt/freezer The act of creating a new cgroup namespace caused the process's current freezer directory, "/a/b", to become its cgroup freezer root directory. In other words, the pathname directory of the directory within the newly mounted cgroup filesystem should be "/", but mountinfo wrongly shows us "/a/b". The consequence of this is that the process in the cgroup namespace cannot correctly construct the pathname of its cgroup root directory from the information in /proc/PID/mountinfo. With this patch, the dentry root field in mountinfo is shown relative to the reader's cgroup namespace. So the same steps as above: /proc/self/cgroup: 10:freezer:/a/b mountinfo: / /sys/fs/cgroup/freezer /proc/self/cgroup: 10:freezer:/ mountinfo: /../.. /sys/fs/cgroup/freezer /proc/self/cgroup: 10:freezer:/ mountinfo: / /mnt/freezer cgroup.clone_children freezer.parent_freezing freezer.state tasks cgroup.procs freezer.self_freezing notify_on_release 3164 2653 # First shell that placed in this cgroup 3164 # Shell started by 'unshare' 14197 # cat(1) Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com> Tested-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | | kernfs_path_from_node_locked: don't overwrite nlenSerge Hallyn2016-05-021-3/+3
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We've calculated @len to be the bytes we need for '/..' entries from @kn_from to the common ancestor, and calculated @nlen to be the extra bytes we need to get from the common ancestor to @kn_to. We use them as such at the end. But in the loop copying the actual entries, we overwrite @nlen. Use a temporary variable for that instead. Without this, the return length, when the buffer is large enough, is wrong. (When the buffer is NULL or too small, the returned value is correct. The buffer contents are also correct.) Interestingly, no callers of this function are affected by this as of yet. However the upcoming cgroup_show_path() will be. Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
* / mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov2016-04-041-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-4.6-ns' of ↵Linus Torvalds2016-03-212-31/+229
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup namespace support from Tejun Heo: "These are changes to implement namespace support for cgroup which has been pending for quite some time now. It is very straight-forward and only affects what part of cgroup hierarchies are visible. After unsharing, mounting a cgroup fs will be scoped to the cgroups the task belonged to at the time of unsharing and the cgroup paths exposed to userland would be adjusted accordingly" * 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: fix and restructure error handling in copy_cgroup_ns() cgroup: fix alloc_cgroup_ns() error handling in copy_cgroup_ns() Add FS_USERNS_FLAG to cgroup fs cgroup: Add documentation for cgroup namespaces cgroup: mount cgroupns-root when inside non-init cgroupns kernfs: define kernfs_node_dentry cgroup: cgroup namespace setns support cgroup: introduce cgroup namespaces sched: new clone flag CLONE_NEWCGROUP for cgroup namespace kernfs: Add API to generate relative kernfs path
| * kernfs: define kernfs_node_dentryAditya Kali2016-02-161-0/+69
| | | | | | | | | | | | | | | | | | | | Add a new kernfs api is added to lookup the dentry for a particular kernfs path. Signed-off-by: Aditya Kali <adityakali@google.com> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Tejun Heo <tj@kernel.org>
| * kernfs: Add API to generate relative kernfs pathAditya Kali2016-02-161-31/+160
| | | | | | | | | | | | | | | | | | | | The new function kernfs_path_from_node() generates and returns kernfs path of a given kernfs_node relative to a given parent kernfs_node. Signed-off-by: Aditya Kali <adityakali@google.com> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Tejun Heo <tj@kernel.org>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-05 04:26:29 +0000