Linux Kernel  3.7.1
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ioctl.h
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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 */
37 
38  /* obsolete. new values ignored, always return -1 */
40 };
41 
42 #define CEPH_IOC_GET_LAYOUT _IOR(CEPH_IOCTL_MAGIC, 1, \
43  struct ceph_ioctl_layout)
44 #define CEPH_IOC_SET_LAYOUT _IOW(CEPH_IOCTL_MAGIC, 2, \
45  struct ceph_ioctl_layout)
46 #define CEPH_IOC_SET_LAYOUT_POLICY _IOW(CEPH_IOCTL_MAGIC, 5, \
47  struct ceph_ioctl_layout)
48 
49 /*
50  * CEPH_IOC_GET_DATALOC - get location of file data in the cluster
51  *
52  * Extract identity, address of the OSD and object storing a given
53  * file offset.
54  */
56  __u64 file_offset; /* in+out: file offset */
57  __u64 object_offset; /* out: offset in object */
58  __u64 object_no; /* out: object # */
59  __u64 object_size; /* out: object size */
60  char object_name[64]; /* out: object name */
61  __u64 block_offset; /* out: offset in block */
62  __u64 block_size; /* out: block length */
63  __s64 osd; /* out: osd # */
64  struct sockaddr_storage osd_addr; /* out: osd address */
65 };
66 
67 #define CEPH_IOC_GET_DATALOC _IOWR(CEPH_IOCTL_MAGIC, 3, \
68  struct ceph_ioctl_dataloc)
69 
70 /*
71  * CEPH_IOC_LAZYIO - relax consistency
72  *
73  * Normally Ceph switches to synchronous IO when multiple clients have
74  * the file open (and or more for write). Reads and writes bypass the
75  * page cache and go directly to the OSD. Setting this flag on a file
76  * descriptor will allow buffered IO for this file in cases where the
77  * application knows it won't interfere with other nodes (or doesn't
78  * care).
79  */
80 #define CEPH_IOC_LAZYIO _IO(CEPH_IOCTL_MAGIC, 4)
81 
82 /*
83  * CEPH_IOC_SYNCIO - force synchronous IO
84  *
85  * This ioctl sets a file flag that forces the synchronous IO that
86  * bypasses the page cache, even if it is not necessary. This is
87  * essentially the opposite behavior of IOC_LAZYIO. This forces the
88  * same read/write path as a file opened by multiple clients when one
89  * or more of those clients is opened for write.
90  *
91  * Note that this type of sync IO takes a different path than a file
92  * opened with O_SYNC/D_SYNC (writes hit the page cache and are
93  * immediately flushed on page boundaries). It is very similar to
94  * O_DIRECT (writes bypass the page cache) excep that O_DIRECT writes
95  * are not copied (user page must remain stable) and O_DIRECT writes
96  * have alignment restrictions (on the buffer and file offset).
97  */
98 #define CEPH_IOC_SYNCIO _IO(CEPH_IOCTL_MAGIC, 5)
99 
100 #endif