fs/ceph/ioctl.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef FS_CEPH_IOCTL_H
   3 #define FS_CEPH_IOCTL_H
   4
   5 #include <linux/ioctl.h>
   6 #include <linux/types.h>
   7
   8 #define CEPH_IOCTL_MAGIC 0x97
   9
  10 /*
  11  * CEPH_IOC_GET_LAYOUT - get file layout or dir layout policy
  12  * CEPH_IOC_SET_LAYOUT - set file layout
  13  * CEPH_IOC_SET_LAYOUT_POLICY - set dir layout policy
  14  *
  15  * The file layout specifies how file data is striped over objects in
  16  * the distributed object store, which object pool they belong to (if
  17  * it differs from the default), and an optional 'preferred osd' to
  18  * store them on.
  19  *
  20  * Files get a new layout based on the policy set on the containing
  21  * directory or one of its ancestors.  The GET_LAYOUT ioctl will let
  22  * you examine the layout for a file or the policy on a directory.
  23  *
  24  * SET_LAYOUT will let you set a layout on a newly created file.  This
  25  * only works immediately after the file is created and before any
  26  * data is written to it.
  27  *
  28  * SET_LAYOUT_POLICY will let you set a layout policy (default layout)
  29  * on a directory that will apply to any new files created in that
  30  * directory (or any child directory that doesn't specify a layout of
  31  * its own).
  32  */
  33
  34 /* use u64 to align sanely on all archs */
  35 struct ceph_ioctl_layout {
  36         __u64 stripe_unit, stripe_count, object_size;
  37         __u64 data_pool;
  38
  39         /* obsolete.  new values ignored, always return -1 */
  40         __s64 preferred_osd;
  41 };
  42
  43 #define CEPH_IOC_GET_LAYOUT _IOR(CEPH_IOCTL_MAGIC, 1,           \
  44                                    struct ceph_ioctl_layout)
  45 #define CEPH_IOC_SET_LAYOUT _IOW(CEPH_IOCTL_MAGIC, 2,           \
  46                                    struct ceph_ioctl_layout)
  47 #define CEPH_IOC_SET_LAYOUT_POLICY _IOW(CEPH_IOCTL_MAGIC, 5,    \
  48                                    struct ceph_ioctl_layout)
  49
  50 /*
  51  * CEPH_IOC_GET_DATALOC - get location of file data in the cluster
  52  *
  53  * Extract identity, address of the OSD and object storing a given
  54  * file offset.
  55  */
  56 struct ceph_ioctl_dataloc {
  57         __u64 file_offset;           /* in+out: file offset */
  58         __u64 object_offset;         /* out: offset in object */
  59         __u64 object_no;             /* out: object # */
  60         __u64 object_size;           /* out: object size */
  61         char object_name[64];        /* out: object name */
  62         __u64 block_offset;          /* out: offset in block */
  63         __u64 block_size;            /* out: block length */
  64         __s64 osd;                   /* out: osd # */
  65         struct sockaddr_storage osd_addr; /* out: osd address */
  66 };
  67
  68 #define CEPH_IOC_GET_DATALOC _IOWR(CEPH_IOCTL_MAGIC, 3, \
  69                                    struct ceph_ioctl_dataloc)
  70
  71 /*
  72  * CEPH_IOC_LAZYIO - relax consistency
  73  *
  74  * Normally Ceph switches to synchronous IO when multiple clients have
  75  * the file open (and or more for write).  Reads and writes bypass the
  76  * page cache and go directly to the OSD.  Setting this flag on a file
  77  * descriptor will allow buffered IO for this file in cases where the
  78  * application knows it won't interfere with other nodes (or doesn't
  79  * care).
  80  */
  81 #define CEPH_IOC_LAZYIO _IO(CEPH_IOCTL_MAGIC, 4)
  82
  83 /*
  84  * CEPH_IOC_SYNCIO - force synchronous IO
  85  *
  86  * This ioctl sets a file flag that forces the synchronous IO that
  87  * bypasses the page cache, even if it is not necessary.  This is
  88  * essentially the opposite behavior of IOC_LAZYIO.  This forces the
  89  * same read/write path as a file opened by multiple clients when one
  90  * or more of those clients is opened for write.
  91  *
  92  * Note that this type of sync IO takes a different path than a file
  93  * opened with O_SYNC/D_SYNC (writes hit the page cache and are
  94  * immediately flushed on page boundaries).  It is very similar to
  95  * O_DIRECT (writes bypass the page cache) excep that O_DIRECT writes
  96  * are not copied (user page must remain stable) and O_DIRECT writes
  97  * have alignment restrictions (on the buffer and file offset).
  98  */
  99 #define CEPH_IOC_SYNCIO _IO(CEPH_IOCTL_MAGIC, 5)
 100
 101 #endif