1. 03 Mar, 2017 1 commit
    • David Howells's avatar
      statx: Add a system call to make enhanced file info available · a528d35e
      David Howells authored
      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: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      a528d35e
  2. 29 Nov, 2016 1 commit
  3. 08 Oct, 2016 1 commit
  4. 07 Oct, 2016 1 commit
  5. 28 Sep, 2016 1 commit
  6. 22 Sep, 2016 1 commit
  7. 28 May, 2016 1 commit
  8. 11 Apr, 2016 1 commit
  9. 29 Mar, 2016 1 commit
    • Deepa Dinamani's avatar
      fs: kernfs: Replace CURRENT_TIME by current_fs_time() · 3a3a5fec
      Deepa Dinamani authored
      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: default avatarDeepa Dinamani <deepa.kernel@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3a3a5fec
  10. 07 Dec, 2015 2 commits
  11. 01 Jul, 2015 1 commit
  12. 15 Apr, 2015 1 commit
  13. 20 Jan, 2015 2 commits
  14. 16 Apr, 2014 1 commit
  15. 03 Apr, 2014 1 commit
    • Johannes Weiner's avatar
      mm + fs: store shadow entries in page cache · 91b0abe3
      Johannes Weiner authored
      Reclaim will be leaving shadow entries in the page cache radix tree upon
      evicting the real page.  As those pages are found from the LRU, an
      iput() can lead to the inode being freed concurrently.  At this point,
      reclaim must no longer install shadow pages because the inode freeing
      code needs to ensure the page tree is really empty.
      
      Add an address_space flag, AS_EXITING, that the inode freeing code sets
      under the tree lock before doing the final truncate.  Reclaim will check
      for this flag before installing shadow pages.
      Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Reviewed-by: default avatarRik van Riel <riel@redhat.com>
      Reviewed-by: default avatarMinchan Kim <minchan@kernel.org>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Bob Liu <bob.liu@oracle.com>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Greg Thelen <gthelen@google.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Jan Kara <jack@suse.cz>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Luigi Semenzato <semenzato@google.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Metin Doslu <metin@citusdata.com>
      Cc: Michel Lespinasse <walken@google.com>
      Cc: Ozgun Erdogan <ozgun@citusdata.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Roman Gushchin <klamm@yandex-team.ru>
      Cc: Ryan Mallon <rmallon@gmail.com>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      91b0abe3
  16. 12 Dec, 2013 4 commits
    • Tejun Heo's avatar
      kernfs: s/sysfs/kernfs/ in internal functions and whatever is left · c637b8ac
      Tejun Heo authored
      kernfs has just been separated out from sysfs and we're already in
      full conflict mode.  Nothing can make the situation any worse.  Let's
      take the chance to name things properly.
      
      This patch performs the following renames.
      
      * s/sysfs_*()/kernfs_*()/ in all internal functions
      * s/sysfs/kernfs/ in internal strings, comments and whatever is remaining
      * Uniformly rename various vfs operations so that they're consistently
        named and distinguishable.
      
      This patch is strictly rename only and doesn't introduce any
      functional difference.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c637b8ac
    • Tejun Heo's avatar
      kernfs: s/sysfs/kernfs/ in global variables · a797bfc3
      Tejun Heo authored
      kernfs has just been separated out from sysfs and we're already in
      full conflict mode.  Nothing can make the situation any worse.  Let's
      take the chance to name things properly.
      
      This patch performs the following renames.
      
      * s/sysfs_mutex/kernfs_mutex/
      * s/sysfs_dentry_ops/kernfs_dops/
      * s/sysfs_dir_operations/kernfs_dir_fops/
      * s/sysfs_dir_inode_operations/kernfs_dir_iops/
      * s/kernfs_file_operations/kernfs_file_fops/ - renamed for consistency
      * s/sysfs_symlink_inode_operations/kernfs_symlink_iops/
      * s/sysfs_aops/kernfs_aops/
      * s/sysfs_backing_dev_info/kernfs_bdi/
      * s/sysfs_inode_operations/kernfs_iops/
      * s/sysfs_dir_cachep/kernfs_node_cache/
      * s/sysfs_ops/kernfs_sops/
      
      This patch is strictly rename only and doesn't introduce any
      functional difference.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a797bfc3
    • Tejun Heo's avatar
      kernfs: s/sysfs/kernfs/ in constants · df23fc39
      Tejun Heo authored
      kernfs has just been separated out from sysfs and we're already in
      full conflict mode.  Nothing can make the situation any worse.  Let's
      take the chance to name things properly.
      
      This patch performs the following renames.
      
      * s/SYSFS_DIR/KERNFS_DIR/
      * s/SYSFS_KOBJ_ATTR/KERNFS_FILE/
      * s/SYSFS_KOBJ_LINK/KERNFS_LINK/
      * s/SYSFS_{TYPE_FLAGS}/KERNFS_{TYPE_FLAGS}/
      * s/SYSFS_FLAG_{FLAG}/KERNFS_{FLAG}/
      * s/sysfs_type()/kernfs_type()/
      * s/SD_DEACTIVATED_BIAS/KN_DEACTIVATED_BIAS/
      
      This patch is strictly rename only and doesn't introduce any
      functional difference.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      df23fc39
    • Tejun Heo's avatar
      kernfs: s/sysfs/kernfs/ in various data structures · c525aadd
      Tejun Heo authored
      kernfs has just been separated out from sysfs and we're already in
      full conflict mode.  Nothing can make the situation any worse.  Let's
      take the chance to name things properly.
      
      This patch performs the following renames.
      
      * s/sysfs_open_dirent/kernfs_open_node/
      * s/sysfs_open_file/kernfs_open_file/
      * s/sysfs_inode_attrs/kernfs_iattrs/
      * s/sysfs_addrm_cxt/kernfs_addrm_cxt/
      * s/sysfs_super_info/kernfs_super_info/
      * s/sysfs_info()/kernfs_info()/
      * s/sysfs_open_dirent_lock/kernfs_open_node_lock/
      * s/sysfs_open_file_mutex/kernfs_open_file_mutex/
      * s/sysfs_of()/kernfs_of()/
      
      This patch is strictly rename only and doesn't introduce any
      functional difference.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c525aadd
  17. 11 Dec, 2013 2 commits
    • Tejun Heo's avatar
      kernfs: drop s_ prefix from kernfs_node members · adc5e8b5
      Tejun Heo authored
      kernfs has just been separated out from sysfs and we're already in
      full conflict mode.  Nothing can make the situation any worse.  Let's
      take the chance to name things properly.
      
      s_ prefix for kernfs members is used inconsistently and a misnomer
      now.  It's not like kernfs_node is used widely across the kernel
      making the ability to grep for the members particularly useful.  Let's
      just drop the prefix.
      
      This patch is strictly rename only and doesn't introduce any
      functional difference.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      adc5e8b5
    • Tejun Heo's avatar
      kernfs: s/sysfs_dirent/kernfs_node/ and rename its friends accordingly · 324a56e1
      Tejun Heo authored
      kernfs has just been separated out from sysfs and we're already in
      full conflict mode.  Nothing can make the situation any worse.  Let's
      take the chance to name things properly.
      
      This patch performs the following renames.
      
      * s/sysfs_elem_dir/kernfs_elem_dir/
      * s/sysfs_elem_symlink/kernfs_elem_symlink/
      * s/sysfs_elem_attr/kernfs_elem_file/
      * s/sysfs_dirent/kernfs_node/
      * s/sd/kn/ in kernfs proper
      * s/parent_sd/parent/
      * s/target_sd/target/
      * s/dir_sd/parent/
      * s/to_sysfs_dirent()/rb_to_kn()/
      * misc renames of local vars when they conflict with the above
      
      Because md, mic and gpio dig into sysfs details, this patch ends up
      modifying them.  All are sysfs_dirent renames and trivial.  While we
      can avoid these by introducing a dummy wrapping struct sysfs_dirent
      around kernfs_node, given the limited usage outside kernfs and sysfs
      proper, I don't think such workaround is called for.
      
      This patch is strictly rename only and doesn't introduce any
      functional difference.
      
      - mic / gpio renames were missing.  Spotted by kbuild test robot.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: Neil Brown <neilb@suse.de>
      Cc: Linus Walleij <linus.walleij@linaro.org>
      Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
      Cc: kbuild test robot <fengguang.wu@intel.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      324a56e1
  18. 04 Dec, 2013 2 commits
    • Tejun Heo's avatar
      kernfs: implement "trusted.*" xattr support · 2322392b
      Tejun Heo authored
      kernfs inherited "security.*" xattr support from sysfs.  This patch
      extends xattr support to "trusted.*" using simple_xattr_*().  As
      trusted xattrs are restricted to CAP_SYS_ADMIN, simple_xattr_*() which
      uses kernel memory for storage shouldn't be problematic.
      
      Note that the existing "security.*" support doesn't implement
      get/remove/list and the this patch only implements those ops for
      "trusted.*".  We probably want to extend those ops to include support
      for "security.*".
      
      This patch will allow using kernfs from cgroup which requires
      "trusted.*" xattr support.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: David P. Quigley <dpquigl@tycho.nsa.gov>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      2322392b
    • Tejun Heo's avatar
      kernfs: update sysfs_init_inode_attrs() · 9a8049af
      Tejun Heo authored
      sysfs_init_inode_attrs() is a bit clumsy to use requiring the caller
      to check whether @sd->s_iattr is already set or not.  Rename it to
      sysfs_inode_attrs(), update it to check whether @sd->s_iattr is
      already initialized before trying to initialize it and return
      @sd->s_iattr.  This simplifies the callers.
      
      While at it,
      
      * Rename struct sysfs_inode_attrs pointer variables to "attrs".  As
        kernfs no longer deals with "struct attribute", this isn't confusing
        and makes it easier to distinguish from struct iattr pointers.
      
      * A new field will be added to sysfs_inode_attrs.  Reindent in
        preparation.
      
      This patch doesn't introduce any behavior changes.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9a8049af
  19. 30 Nov, 2013 2 commits
    • Tejun Heo's avatar
      sysfs, kernfs: prepare mount path for kernfs · 4b93dc9b
      Tejun Heo authored
      We're in the process of separating out core sysfs functionality into
      kernfs which will deal with sysfs_dirents directly.  This patch
      rearranges mount path so that the kernfs and sysfs parts are separate.
      
      * As sysfs_super_info won't be visible outside kernfs proper,
        kernfs_super_ns() is added to allow kernfs users to access a
        super_block's namespace tag.
      
      * Generic mount operation is separated out into kernfs_mount_ns().
        sysfs_mount() now just performs sysfs-specific permission check,
        acquires namespace tag, and invokes kernfs_mount_ns().
      
      * Generic superblock release is separated out into kernfs_kill_sb()
        which can be used directly as file_system_type->kill_sb().  As sysfs
        needs to put the namespace tag, sysfs_kill_sb() wraps
        kernfs_kill_sb() with ns tag put.
      
      * sysfs_dir_cachep init and sysfs_inode_init() are separated out into
        kernfs_init().  kernfs_init() uses only small amount of memory and
        trying to handle and propagate kernfs_init() failure doesn't make
        much sense.  Use SLAB_PANIC for sysfs_dir_cachep and make
        sysfs_inode_init() panic on failure.
      
        After this change, kernfs_init() should be called before
        sysfs_init(), fs/namespace.c::mnt_init() modified accordingly.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: linux-fsdevel@vger.kernel.org
      Cc: Christoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      4b93dc9b
    • Tejun Heo's avatar
      sysfs, kernfs: move inode code to fs/kernfs/inode.c · ffed24e2
      Tejun Heo authored
      There's nothing sysfs-specific in fs/sysfs/inode.c.  Move everything
      in it to fs/kernfs/inode.c.  The respective declarations in
      fs/sysfs/sysfs.h are moved to fs/kernfs/kernfs-internal.h.
      
      This is pure relocation.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ffed24e2
  20. 27 Nov, 2013 1 commit
    • Tejun Heo's avatar
      sysfs, kernfs: add skeletons for kernfs · b8441ed2
      Tejun Heo authored
      Core sysfs implementation will be separated into kernfs so that it can
      be used by other non-kobject users.
      
      This patch creates fs/kernfs/ directory and makes boilerplate changes.
      kernfs interface will be directly based on sysfs_dirent and its
      forward declaration is moved to include/linux/kernfs.h which is
      included from include/linux/sysfs.h.  sysfs core implementation will
      be gradually separated out and moved to kernfs.
      
      This patch doesn't introduce any functional changes.
      
      v2: mount.c added.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: linux-fsdevel@vger.kernel.org
      Cc: Christoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b8441ed2