1. 30 Sep, 2018 3 commits
  2. 05 Jun, 2018 1 commit
    • Deepa Dinamani's avatar
      vfs: change inode times to use struct timespec64 · 95582b00
      Deepa Dinamani authored
      struct timespec is not y2038 safe. Transition vfs to use
      y2038 safe struct timespec64 instead.
      
      The change was made with the help of the following cocinelle
      script. This catches about 80% of the changes.
      All the header file and logic changes are included in the
      first 5 rules. The rest are trivial substitutions.
      I avoid changing any of the function signatures or any other
      filesystem specific data structures to keep the patch simple
      for review.
      
      The script can be a little shorter by combining different cases.
      But, this version was sufficient for my usecase.
      
      virtual patch
      
      @ depends on patch @
      identifier now;
      @@
      - struct timespec
      + struct timespec64
        current_time ( ... )
        {
      - struct timespec now = current_kernel_time();
      + struct timespec64 now = current_kernel_time64();
        ...
      - return timespec_trunc(
      + return timespec64_trunc(
        ... );
        }
      
      @ depends on patch @
      identifier xtime;
      @@
       struct \( iattr \| inode \| kstat \) {
       ...
      -       struct timespec xtime;
      +       struct timespec64 xtime;
       ...
       }
      
      @ depends on patch @
      identifier t;
      @@
       struct inode_operations {
       ...
      int (*update_time) (...,
      -       struct timespec t,
      +       struct timespec64 t,
      ...);
       ...
       }
      
      @ depends on patch @
      identifier t;
      identifier fn_update_time =~ "update_time$";
      @@
       fn_update_time (...,
      - struct timespec *t,
      + struct timespec64 *t,
       ...) { ... }
      
      @ depends on patch @
      identifier t;
      @@
      lease_get_mtime( ... ,
      - struct timespec *t
      + struct timespec64 *t
        ) { ... }
      
      @te depends on patch forall@
      identifier ts;
      local idexpression struct inode *inode_node;
      identifier i_xtime =~ "^i_[acm]time$";
      identifier ia_xtime =~ "^ia_[acm]time$";
      identifier fn_update_time =~ "update_time$";
      identifier fn;
      expression e, E3;
      local idexpression struct inode *node1;
      local idexpression struct inode *node2;
      local idexpression struct iattr *attr1;
      local idexpression struct iattr *attr2;
      local idexpression struct iattr attr;
      identifier i_xtime1 =~ "^i_[acm]time$";
      identifier i_xtime2 =~ "^i_[acm]time$";
      identifier ia_xtime1 =~ "^ia_[acm]time$";
      identifier ia_xtime2 =~ "^ia_[acm]time$";
      @@
      (
      (
      - struct timespec ts;
      + struct timespec64 ts;
      |
      - struct timespec ts = current_time(inode_node);
      + struct timespec64 ts = current_time(inode_node);
      )
      
      <+... when != ts
      (
      - timespec_equal(&inode_node->i_xtime, &ts)
      + timespec64_equal(&inode_node->i_xtime, &ts)
      |
      - timespec_equal(&ts, &inode_node->i_xtime)
      + timespec64_equal(&ts, &inode_node->i_xtime)
      |
      - timespec_compare(&inode_node->i_xtime, &ts)
      + timespec64_compare(&inode_node->i_xtime, &ts)
      |
      - timespec_compare(&ts, &inode_node->i_xtime)
      + timespec64_compare(&ts, &inode_node->i_xtime)
      |
      ts = current_time(e)
      |
      fn_update_time(..., &ts,...)
      |
      inode_node->i_xtime = ts
      |
      node1->i_xtime = ts
      |
      ts = inode_node->i_xtime
      |
      <+... attr1->ia_xtime ...+> = ts
      |
      ts = attr1->ia_xtime
      |
      ts.tv_sec
      |
      ts.tv_nsec
      |
      btrfs_set_stack_timespec_sec(..., ts.tv_sec)
      |
      btrfs_set_stack_timespec_nsec(..., ts.tv_nsec)
      |
      - ts = timespec64_to_timespec(
      + ts =
      ...
      -)
      |
      - ts = ktime_to_timespec(
      + ts = ktime_to_timespec64(
      ...)
      |
      - ts = E3
      + ts = timespec_to_timespec64(E3)
      |
      - ktime_get_real_ts(&ts)
      + ktime_get_real_ts64(&ts)
      |
      fn(...,
      - ts
      + timespec64_to_timespec(ts)
      ,...)
      )
      ...+>
      (
      <... when != ts
      - return ts;
      + return timespec64_to_timespec(ts);
      ...>
      )
      |
      - timespec_equal(&node1->i_xtime1, &node2->i_xtime2)
      + timespec64_equal(&node1->i_xtime2, &node2->i_xtime2)
      |
      - timespec_equal(&node1->i_xtime1, &attr2->ia_xtime2)
      + timespec64_equal(&node1->i_xtime2, &attr2->ia_xtime2)
      |
      - timespec_compare(&node1->i_xtime1, &node2->i_xtime2)
      + timespec64_compare(&node1->i_xtime1, &node2->i_xtime2)
      |
      node1->i_xtime1 =
      - timespec_trunc(attr1->ia_xtime1,
      + timespec64_trunc(attr1->ia_xtime1,
      ...)
      |
      - attr1->ia_xtime1 = timespec_trunc(attr2->ia_xtime2,
      + attr1->ia_xtime1 =  timespec64_trunc(attr2->ia_xtime2,
      ...)
      |
      - ktime_get_real_ts(&attr1->ia_xtime1)
      + ktime_get_real_ts64(&attr1->ia_xtime1)
      |
      - ktime_get_real_ts(&attr.ia_xtime1)
      + ktime_get_real_ts64(&attr.ia_xtime1)
      )
      
      @ depends on patch @
      struct inode *node;
      struct iattr *attr;
      identifier fn;
      identifier i_xtime =~ "^i_[acm]time$";
      identifier ia_xtime =~ "^ia_[acm]time$";
      expression e;
      @@
      (
      - fn(node->i_xtime);
      + fn(timespec64_to_timespec(node->i_xtime));
      |
       fn(...,
      - node->i_xtime);
      + timespec64_to_timespec(node->i_xtime));
      |
      - e = fn(attr->ia_xtime);
      + e = fn(timespec64_to_timespec(attr->ia_xtime));
      )
      
      @ depends on patch forall @
      struct inode *node;
      struct iattr *attr;
      identifier i_xtime =~ "^i_[acm]time$";
      identifier ia_xtime =~ "^ia_[acm]time$";
      identifier fn;
      @@
      {
      + struct timespec ts;
      <+...
      (
      + ts = timespec64_to_timespec(node->i_xtime);
      fn (...,
      - &node->i_xtime,
      + &ts,
      ...);
      |
      + ts = timespec64_to_timespec(attr->ia_xtime);
      fn (...,
      - &attr->ia_xtime,
      + &ts,
      ...);
      )
      ...+>
      }
      
      @ depends on patch forall @
      struct inode *node;
      struct iattr *attr;
      struct kstat *stat;
      identifier ia_xtime =~ "^ia_[acm]time$";
      identifier i_xtime =~ "^i_[acm]time$";
      identifier xtime =~ "^[acm]time$";
      identifier fn, ret;
      @@
      {
      + struct timespec ts;
      <+...
      (
      + ts = timespec64_to_timespec(node->i_xtime);
      ret = fn (...,
      - &node->i_xtime,
      + &ts,
      ...);
      |
      + ts = timespec64_to_timespec(node->i_xtime);
      ret = fn (...,
      - &node->i_xtime);
      + &ts);
      |
      + ts = timespec64_to_timespec(attr->ia_xtime);
      ret = fn (...,
      - &attr->ia_xtime,
      + &ts,
      ...);
      |
      + ts = timespec64_to_timespec(attr->ia_xtime);
      ret = fn (...,
      - &attr->ia_xtime);
      + &ts);
      |
      + ts = timespec64_to_timespec(stat->xtime);
      ret = fn (...,
      - &stat->xtime);
      + &ts);
      )
      ...+>
      }
      
      @ depends on patch @
      struct inode *node;
      struct inode *node2;
      identifier i_xtime1 =~ "^i_[acm]time$";
      identifier i_xtime2 =~ "^i_[acm]time$";
      identifier i_xtime3 =~ "^i_[acm]time$";
      struct iattr *attrp;
      struct iattr *attrp2;
      struct iattr attr ;
      identifier ia_xtime1 =~ "^ia_[acm]time$";
      identifier ia_xtime2 =~ "^ia_[acm]time$";
      struct kstat *stat;
      struct kstat stat1;
      struct timespec64 ts;
      identifier xtime =~ "^[acmb]time$";
      expression e;
      @@
      (
      ( node->i_xtime2 \| attrp->ia_xtime2 \| attr.ia_xtime2 \) = node->i_xtime1  ;
      |
       node->i_xtime2 = \( node2->i_xtime1 \| timespec64_trunc(...) \);
      |
       node->i_xtime2 = node->i_xtime1 = node->i_xtime3 = \(ts \| current_time(...) \);
      |
       node->i_xtime1 = node->i_xtime3 = \(ts \| current_time(...) \);
      |
       stat->xtime = node2->i_xtime1;
      |
       stat1.xtime = node2->i_xtime1;
      |
      ( node->i_xtime2 \| attrp->ia_xtime2 \) = attrp->ia_xtime1  ;
      |
      ( attrp->ia_xtime1 \| attr.ia_xtime1 \) = attrp2->ia_xtime2;
      |
      - e = node->i_xtime1;
      + e = timespec64_to_timespec( node->i_xtime1 );
      |
      - e = attrp->ia_xtime1;
      + e = timespec64_to_timespec( attrp->ia_xtime1 );
      |
      node->i_xtime1 = current_time(...);
      |
       node->i_xtime2 = node->i_xtime1 = node->i_xtime3 =
      - e;
      + timespec_to_timespec64(e);
      |
       node->i_xtime1 = node->i_xtime3 =
      - e;
      + timespec_to_timespec64(e);
      |
      - node->i_xtime1 = e;
      + node->i_xtime1 = timespec_to_timespec64(e);
      )
      Signed-off-by: default avatarDeepa Dinamani <deepa.kernel@gmail.com>
      Cc: <anton@tuxera.com>
      Cc: <balbi@kernel.org>
      Cc: <bfields@fieldses.org>
      Cc: <darrick.wong@oracle.com>
      Cc: <dhowells@redhat.com>
      Cc: <dsterba@suse.com>
      Cc: <dwmw2@infradead.org>
      Cc: <hch@lst.de>
      Cc: <hirofumi@mail.parknet.co.jp>
      Cc: <hubcap@omnibond.com>
      Cc: <jack@suse.com>
      Cc: <jaegeuk@kernel.org>
      Cc: <jaharkes@cs.cmu.edu>
      Cc: <jslaby@suse.com>
      Cc: <keescook@chromium.org>
      Cc: <mark@fasheh.com>
      Cc: <miklos@szeredi.hu>
      Cc: <nico@linaro.org>
      Cc: <reiserfs-devel@vger.kernel.org>
      Cc: <richard@nod.at>
      Cc: <sage@redhat.com>
      Cc: <sfrench@samba.org>
      Cc: <swhiteho@redhat.com>
      Cc: <tj@kernel.org>
      Cc: <trond.myklebust@primarydata.com>
      Cc: <tytso@mit.edu>
      Cc: <viro@zeniv.linux.org.uk>
      95582b00
  3. 04 Jun, 2018 6 commits
  4. 31 May, 2018 2 commits
  5. 25 May, 2018 1 commit
  6. 10 Apr, 2018 7 commits
  7. 27 Mar, 2018 1 commit
  8. 20 Mar, 2018 1 commit
  9. 27 Feb, 2018 1 commit
  10. 01 Feb, 2018 1 commit
  11. 29 Jan, 2018 1 commit
  12. 28 Jan, 2018 1 commit
  13. 15 Jan, 2018 1 commit
  14. 27 Nov, 2017 1 commit
    • Linus Torvalds's avatar
      Rename superblock flags (MS_xyz -> SB_xyz) · 1751e8a6
      Linus Torvalds authored
      This is a pure automated search-and-replace of the internal kernel
      superblock flags.
      
      The s_flags are now called SB_*, with the names and the values for the
      moment mirroring the MS_* flags that they're equivalent to.
      
      Note how the MS_xyz flags are the ones passed to the mount system call,
      while the SB_xyz flags are what we then use in sb->s_flags.
      
      The script to do this was:
      
          # places to look in; re security/*: it generally should *not* be
          # touched (that stuff parses mount(2) arguments directly), but
          # there are two places where we really deal with superblock flags.
          FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
                  include/linux/fs.h include/uapi/linux/bfs_fs.h \
                  security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
          # the list of MS_... constants
          SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
                DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
                POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
                I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
                ACTIVE NOUSER"
      
          SED_PROG=
          for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done
      
          # we want files that contain at least one of MS_...,
          # with fs/namespace.c and fs/pnode.c excluded.
          L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')
      
          for f in $L; do sed -i $f $SED_PROG; done
      Requested-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1751e8a6
  15. 17 Nov, 2017 2 commits
  16. 13 Nov, 2017 1 commit
    • David Howells's avatar
      Pass mode to wait_on_atomic_t() action funcs and provide default actions · 5e4def20
      David Howells authored
      Make wait_on_atomic_t() pass the TASK_* mode onto its action function as an
      extra argument and make it 'unsigned int throughout.
      
      Also, consolidate a bunch of identical action functions into a default
      function that can do the appropriate thing for the mode.
      
      Also, change the argument name in the bit_wait*() function declarations to
      reflect the fact that it's the mode and not the bit number.
      
      [Peter Z gives this a grudging ACK, but thinks that the whole atomic_t wait
      should be done differently, though he's not immediately sure as to how]
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
      cc: Ingo Molnar <mingo@kernel.org>
      5e4def20
  17. 15 Aug, 2017 3 commits
  18. 13 Jul, 2017 3 commits
    • Peng Tao's avatar
      nfs: add a nfs_ilookup helper · f174ff7a
      Peng Tao authored
      This helper will allow to find an existing NFS inode by the file handle
      and fattr.
      Signed-off-by: default avatarPeng Tao <tao.peng@primarydata.com>
      [hch: split from a larger patch]
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      f174ff7a
    • NeilBrown's avatar
      NFS: check for nfs_refresh_inode() errors in nfs_fhget() · 26fde4df
      NeilBrown authored
      If an NFS server returns a filehandle that we have previously
      seen, and reports a different type, then nfs_refresh_inode()
      will log a warning and return an error.
      
      nfs_fhget() does not check for this error and may return an
      inode with a different type than the one that the server
      reported.
      
      This is likely to cause confusion, and is one way that
      ->open_context() could return a directory inode as discussed
      in the previous patch.
      
      So if nfs_refresh_inode() returns and error, return that error
      from nfs_fhget() to avoid the confusion propagating.
      Signed-off-by: default avatarNeilBrown <neilb@suse.com>
      Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      26fde4df
    • NeilBrown's avatar
      NFS: only invalidate dentrys that are clearly invalid. · cc89684c
      NeilBrown authored
      Since commit bafc9b75 ("vfs: More precise tests in d_invalidate")
      in v3.18, a return of '0' from ->d_revalidate() will cause the dentry
      to be invalidated even if it has filesystems mounted on or it or on a
      descendant.  The mounted filesystem is unmounted.
      
      This means we need to be careful not to return 0 unless the directory
      referred to truly is invalid.  So -ESTALE or -ENOENT should invalidate
      the directory.  Other errors such a -EPERM or -ERESTARTSYS should be
      returned from ->d_revalidate() so they are propagated to the caller.
      
      A particular problem can be demonstrated by:
      
      1/ mount an NFS filesystem using NFSv3 on /mnt
      2/ mount any other filesystem on /mnt/foo
      3/ ls /mnt/foo
      4/ turn off network, or otherwise make the server unable to respond
      5/ ls /mnt/foo &
      6/ cat /proc/$!/stack # note that nfs_lookup_revalidate is in the call stack
      7/ kill -9 $! # this results in -ERESTARTSYS being returned
      8/ observe that /mnt/foo has been unmounted.
      
      This patch changes nfs_lookup_revalidate() to only treat
        -ESTALE from nfs_lookup_verify_inode() and
        -ESTALE or -ENOENT from ->lookup()
      as indicating an invalid inode.  Other errors are returned.
      
      Also nfs_check_inode_attributes() is changed to return -ESTALE rather
      than -EIO.  This is consistent with the error returned in similar
      circumstances from nfs_update_inode().
      
      As this bug allows any user to unmount a filesystem mounted on an NFS
      filesystem, this fix is suitable for stable kernels.
      
      Fixes: bafc9b75 ("vfs: More precise tests in d_invalidate")
      Cc: stable@vger.kernel.org (v3.18+)
      Signed-off-by: default avatarNeilBrown <neilb@suse.com>
      Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
      cc89684c
  19. 05 May, 2017 1 commit
  20. 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
  21. 02 Mar, 2017 1 commit