fs/ceph/ioctl.h

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