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. 21 Jan, 2016 3 commits
  3. 17 Apr, 2015 2 commits
  4. 13 Dec, 2014 1 commit
    • Namjae Jeon's avatar
      fat: fix data past EOF resulting from fsx testsuite · c0ef0cc9
      Namjae Jeon authored
      When running FSX with direct I/O mode, fsx resulted in DATA past EOF issues.
      
        fsx ./file2 -Z -r 4096 -w 4096
        ...
        ..
        truncating to largest ever: 0x907c
        fallocating to largest ever: 0x11137
        truncating to largest ever: 0x2c6fe
        truncating to largest ever: 0x2cfdf
        fallocating to largest ever: 0x40000
        Mapped Read: non-zero data past EOF (0x18628) page offset 0x629 is 0x2a4e
        ...
        ..
      
      The reason being, it is doing a truncate down, but the zeroing does not
      happen on the last block boundary when offset is not aligned.  Even though
      it calls truncate_setsize()->truncate_inode_pages()->
      truncate_inode_pages_range() and considers the partial zeroout but it
      retrieves the page using find_lock_page() - which only looks the page in
      the cache.  So, zeroing out does not happen in case of direct IO.
      
      Make a truncate page based around block_truncate_page for FAT filesystem
      and invoke that helper to zerout in case the offset is not aligned with
      the blocksize.
      Signed-off-by: default avatarNamjae Jeon <namjae.jeon@samsung.com>
      Signed-off-by: default avatarAmit Sahrawat <a.sahrawat@samsung.com>
      Acked-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c0ef0cc9
  5. 06 Jun, 2014 1 commit
  6. 25 Oct, 2013 1 commit
  7. 09 Jul, 2013 1 commit
    • Mike Lockwood's avatar
      fatfs: add FAT_IOCTL_GET_VOLUME_ID · 6e5b93ee
      Mike Lockwood authored
      This patch, originally from Android kernel, adds vfat ioctl command
      FAT_IOCTL_GET_VOLUME_ID, with this command we can get the vfat volume ID
      using following code:
      
      	ioctl(fd, FAT_IOCTL_GET_VOLUME_ID, &volume_ID)
      
      This patch is a modified version of the patch by Mike Lockwood, with
      changes from Dmitry Pervushin, who noticed the original patch makes some
      volume IDs abiguous with error returns: for example, if volume id is
      0xFFFFFDAD, that matches -ENOIOCTLCMD, we get "FFFFFFFF" from the user
      space.
      
      So add a parameter to ioctl to get the correct volume ID.
      
      Android uses vfat volume ID to identify different sd card, when a new sd
      card is inserted to device, android can scan the media on it and pop up
      new contents.
      Signed-off-by: default avatarBintian Wang <bintian.wang@linaro.org>
      Cc: dmitry pervushin <dpervushin@gmail.com>
      Cc: Mike Lockwood <lockwood@android.com>
      Cc: Colin Cross <ccross@android.com>
      Acked-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
      Cc: John Stultz <john.stultz@linaro.org>
      Cc: Sean McNeil <sean@mcneil.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6e5b93ee
  8. 30 Apr, 2013 6 commits
  9. 28 Feb, 2013 1 commit
  10. 18 Dec, 2012 1 commit
    • Jan Kara's avatar
      fat: provide option for setting timezone offset · 58156c8f
      Jan Kara authored
      So far FAT either offsets time stamps by sys_tz.minuteswest or leaves them
      as they are (when tz=UTC mount option is used).  However in some cases it
      is useful if one can specify time stamp offset on his own (e.g.  when time
      zone of the camera connected is different from time zone of the computer,
      or when HW clock is in UTC and thus sys_tz.minuteswest == 0).
      
      So provide a mount option time_offset= which allows user to specify offset
      in minutes that should be applied to time stamps on the filesystem.
      
      akpm: this code would work incorrectly when used via `mount -o remount',
      because cached inodes would not be updated.  But fatfs's fat_remount() is
      basically a no-op anyway.
      Signed-off-by: default avatarJan Kara <jack@suse.cz>
      Acked-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      58156c8f
  11. 10 Oct, 2012 1 commit
  12. 05 Oct, 2012 4 commits
  13. 20 Sep, 2012 1 commit
  14. 31 Jul, 2012 1 commit
  15. 01 Jun, 2012 2 commits
    • Namjae Jeon's avatar
      fat: add fat_msg_ratelimit() · b742c341
      Namjae Jeon authored
      Add a fat_msg_ratelimit() to limit the message generation rate.
      Signed-off-by: default avatarNamjae Jeon <linkinjeon@gmail.com>
      Signed-off-by: default avatarAmit Sahrawat <amit.sahrawat83@gmail.com>
      Acked-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b742c341
    • Artem Bityutskiy's avatar
      fat: introduce special inode for managing the FSINFO block · 020ac5b6
      Artem Bityutskiy authored
      This is patchset makes fatfs stop using the VFS '->write_super()' method
      for writing out the FSINFO block.
      
      The final goal is to get rid of the 'sync_supers()' kernel thread.  This
      kernel thread wakes up every 5 seconds (by default) and calls
      '->write_super()' for all mounted file-systems.  And the bad thing is that
      this is done even if all the superblocks are clean.  Moreover, some
      file-systems do not even need this end they do not register the
      '->write_super()' method at all (e.g., btrfs).
      
      So 'sync_supers()' most often just generates useless wake-ups and wastes
      power.  I am trying to make all file-systems independent of
      '->write_super()' and plan to remove 'sync_supers()' and '->write_super'
      completely once there are no more users.
      
      The '->write_supers()' method is mostly used by baroque file-systems like
      hfs, udf, etc.  Modern file-systems like btrfs and xfs do not use it.
      This justifies removing this stuff from VFS completely and make every FS
      self-manage own superblock.
      
      Tested with xfstests.
      
      This patch:
      
      Preparation for further changes.  It introduces a special inode
      ('fsinfo_inode') in FAT file-system which we'll later use for managing the
      FSINFO block.  Note, this there is already one special inode ('fat_inode')
      which is used for managing the FAT tables.
      
      Introduce new 'MSDOS_FSINFO_INO' constant for this special inode.  It is
      safe to do because FAT file-system does not store inode numbers on the
      media but generates them run-time.
      
      I've also cleaned up the comment to existing 'MSDOS_ROOT_INO' constant,
      while on it.
      Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
      Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
      Cc: Al Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      020ac5b6
  16. 04 Jan, 2012 1 commit
  17. 01 Nov, 2011 1 commit
  18. 21 Jul, 2011 2 commits
  19. 12 Apr, 2011 3 commits
  20. 13 Jan, 2011 1 commit
  21. 09 Aug, 2010 1 commit
    • Christoph Hellwig's avatar
      check ATTR_SIZE contraints in inode_change_ok · 2c27c65e
      Christoph Hellwig authored
      Make sure we check the truncate constraints early on in ->setattr by adding
      those checks to inode_change_ok.  Also clean up and document inode_change_ok
      to make this obvious.
      
      As a fallout we don't have to call inode_newsize_ok from simple_setsize and
      simplify it down to a truncate_setsize which doesn't return an error.  This
      simplifies a lot of setattr implementations and means we use truncate_setsize
      almost everywhere.  Get rid of fat_setsize now that it's trivial and mark
      ext2_setsize static to make the calling convention obvious.
      
      Keep the inode_newsize_ok in vmtruncate for now as all callers need an
      audit for its removal anyway.
      
      Note: setattr code in ecryptfs doesn't call inode_change_ok at all and
      needs a deeper audit, but that is left for later.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      2c27c65e
  22. 28 May, 2010 2 commits
  23. 25 May, 2010 1 commit
  24. 16 May, 2010 1 commit