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d9c740d225
* Layouts describe the way a file is spread on multiple devices.
The layout information is stored in the objects attribute introduced
in this patch.
* There can be multiple generating function for the layout.
Currently defined:
- No attribute present - use below moving-window on global
device table, all devices.
(This is the only one currently used in exofs)
- an obj_id generated moving window - the obj_id is a randomizing
factor in the otherwise global map layout.
- An explicit layout stored, including a data_map and a device
index list.
- More might be defined in future ...
* There are two attributes defined of the same structure:
A-data-files-layout - This layout is used by data-files. If present
at a directory, all files of that directory will
be created with this layout.
A-meta-data-layout - This layout is used by a directory and other
meta-data information. Also inherited at creation
of subdirectories.
* At creation time inodes are created with the layout specified above.
A usermode utility may change the creation layout on a give directory
or file. Which in the case of directories, will also apply to newly
created files/subdirectories, children of that directory.
In the simple unaltered case of a newly created exofs, no layout
attributes are present, and all layouts adhere to the layout specified
at the device-table.
* In case of a future file system loaded in an old exofs-driver.
At iget(), the generating_function is inspected and if not supported
will return an IO error to the application and the inode will not
be loaded. So not to damage any data.
Note: After this patch we do not yet support any type of layout
only the RAID0 patch that enables striping at the super-block
level will add support for RAID0 layouts above. This way we
are past and future compatible and fully bisectable.
* Access to the device table is done by an accessor since
it will change according to above information.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
249 lines
8.2 KiB
C
249 lines
8.2 KiB
C
/*
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* common.h - Common definitions for both Kernel and user-mode utilities
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*
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* Copyright (C) 2005, 2006
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* Avishay Traeger (avishay@gmail.com)
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* Copyright (C) 2008, 2009
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* Boaz Harrosh <bharrosh@panasas.com>
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*
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* Copyrights for code taken from ext2:
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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* from
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* linux/fs/minix/inode.c
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* This file is part of exofs.
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*
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* exofs is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation. Since it is based on ext2, and the only
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* valid version of GPL for the Linux kernel is version 2, the only valid
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* version of GPL for exofs is version 2.
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*
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* exofs is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with exofs; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef __EXOFS_COM_H__
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#define __EXOFS_COM_H__
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#include <linux/types.h>
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#include <scsi/osd_attributes.h>
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#include <scsi/osd_initiator.h>
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#include <scsi/osd_sec.h>
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/****************************************************************************
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* Object ID related defines
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* NOTE: inode# = object ID - EXOFS_OBJ_OFF
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****************************************************************************/
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#define EXOFS_MIN_PID 0x10000 /* Smallest partition ID */
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#define EXOFS_OBJ_OFF 0x10000 /* offset for objects */
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#define EXOFS_SUPER_ID 0x10000 /* object ID for on-disk superblock */
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#define EXOFS_DEVTABLE_ID 0x10001 /* object ID for on-disk device table */
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#define EXOFS_ROOT_ID 0x10002 /* object ID for root directory */
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/* exofs Application specific page/attribute */
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# define EXOFS_APAGE_FS_DATA (OSD_APAGE_APP_DEFINED_FIRST + 3)
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# define EXOFS_ATTR_INODE_DATA 1
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# define EXOFS_ATTR_INODE_FILE_LAYOUT 2
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# define EXOFS_ATTR_INODE_DIR_LAYOUT 3
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/*
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* The maximum number of files we can have is limited by the size of the
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* inode number. This is the largest object ID that the file system supports.
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* Object IDs 0, 1, and 2 are always in use (see above defines).
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*/
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enum {
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EXOFS_MAX_INO_ID = (sizeof(ino_t) * 8 == 64) ? ULLONG_MAX :
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(1ULL << (sizeof(ino_t) * 8ULL - 1ULL)),
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EXOFS_MAX_ID = (EXOFS_MAX_INO_ID - 1 - EXOFS_OBJ_OFF),
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};
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/****************************************************************************
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* Misc.
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****************************************************************************/
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#define EXOFS_BLKSHIFT 12
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#define EXOFS_BLKSIZE (1UL << EXOFS_BLKSHIFT)
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/****************************************************************************
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* superblock-related things
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****************************************************************************/
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#define EXOFS_SUPER_MAGIC 0x5DF5
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/*
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* The file system control block - stored in object EXOFS_SUPER_ID's data.
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* This is where the in-memory superblock is stored on disk.
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*/
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enum {EXOFS_FSCB_VER = 1, EXOFS_DT_VER = 1};
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struct exofs_fscb {
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__le64 s_nextid; /* Highest object ID used */
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__le64 s_numfiles; /* Number of files on fs */
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__le32 s_version; /* == EXOFS_FSCB_VER */
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__le16 s_magic; /* Magic signature */
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__le16 s_newfs; /* Non-zero if this is a new fs */
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/* From here on it's a static part, only written by mkexofs */
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__le64 s_dev_table_oid; /* Resurved, not used */
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__le64 s_dev_table_count; /* == 0 means no dev_table */
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} __packed;
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/*
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* Describes the raid used in the FS. It is part of the device table.
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* This here is taken from the pNFS-objects definition. In exofs we
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* use one raid policy through-out the filesystem. (NOTE: the funny
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* alignment at begining. We take care of it at exofs_device_table.
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*/
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struct exofs_dt_data_map {
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__le32 cb_num_comps;
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__le64 cb_stripe_unit;
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__le32 cb_group_width;
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__le32 cb_group_depth;
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__le32 cb_mirror_cnt;
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__le32 cb_raid_algorithm;
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} __packed;
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/*
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* This is an osd device information descriptor. It is a single entry in
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* the exofs device table. It describes an osd target lun which
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* contains data belonging to this FS. (Same partition_id on all devices)
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*/
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struct exofs_dt_device_info {
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__le32 systemid_len;
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u8 systemid[OSD_SYSTEMID_LEN];
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__le64 long_name_offset; /* If !0 then offset-in-file */
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__le32 osdname_len; /* */
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u8 osdname[44]; /* Embbeded, Ususally an asci uuid */
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} __packed;
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/*
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* The EXOFS device table - stored in object EXOFS_DEVTABLE_ID's data.
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* It contains the raid used for this multy-device FS and an array of
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* participating devices.
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*/
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struct exofs_device_table {
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__le32 dt_version; /* == EXOFS_DT_VER */
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struct exofs_dt_data_map dt_data_map; /* Raid policy to use */
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/* Resurved space For future use. Total includeing this:
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* (8 * sizeof(le64))
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*/
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__le64 __Resurved[4];
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__le64 dt_num_devices; /* Array size */
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struct exofs_dt_device_info dt_dev_table[]; /* Array of devices */
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} __packed;
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/****************************************************************************
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* inode-related things
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****************************************************************************/
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#define EXOFS_IDATA 5
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/*
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* The file control block - stored in an object's attributes. This is where
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* the in-memory inode is stored on disk.
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*/
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struct exofs_fcb {
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__le64 i_size; /* Size of the file */
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__le16 i_mode; /* File mode */
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__le16 i_links_count; /* Links count */
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__le32 i_uid; /* Owner Uid */
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__le32 i_gid; /* Group Id */
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__le32 i_atime; /* Access time */
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__le32 i_ctime; /* Creation time */
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__le32 i_mtime; /* Modification time */
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__le32 i_flags; /* File flags (unused for now)*/
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__le32 i_generation; /* File version (for NFS) */
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__le32 i_data[EXOFS_IDATA]; /* Short symlink names and device #s */
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};
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#define EXOFS_INO_ATTR_SIZE sizeof(struct exofs_fcb)
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/* This is the Attribute the fcb is stored in */
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static const struct __weak osd_attr g_attr_inode_data = ATTR_DEF(
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EXOFS_APAGE_FS_DATA,
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EXOFS_ATTR_INODE_DATA,
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EXOFS_INO_ATTR_SIZE);
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/****************************************************************************
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* dentry-related things
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****************************************************************************/
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#define EXOFS_NAME_LEN 255
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/*
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* The on-disk directory entry
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*/
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struct exofs_dir_entry {
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__le64 inode_no; /* inode number */
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__le16 rec_len; /* directory entry length */
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u8 name_len; /* name length */
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u8 file_type; /* umm...file type */
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char name[EXOFS_NAME_LEN]; /* file name */
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};
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enum {
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EXOFS_FT_UNKNOWN,
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EXOFS_FT_REG_FILE,
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EXOFS_FT_DIR,
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EXOFS_FT_CHRDEV,
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EXOFS_FT_BLKDEV,
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EXOFS_FT_FIFO,
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EXOFS_FT_SOCK,
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EXOFS_FT_SYMLINK,
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EXOFS_FT_MAX
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};
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#define EXOFS_DIR_PAD 4
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#define EXOFS_DIR_ROUND (EXOFS_DIR_PAD - 1)
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#define EXOFS_DIR_REC_LEN(name_len) \
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(((name_len) + offsetof(struct exofs_dir_entry, name) + \
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EXOFS_DIR_ROUND) & ~EXOFS_DIR_ROUND)
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/*
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* The on-disk (optional) layout structure.
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* sits in an EXOFS_ATTR_INODE_FILE_LAYOUT or EXOFS_ATTR_INODE_DIR_LAYOUT
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* attribute, attached to any inode, usually to a directory.
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*/
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enum exofs_inode_layout_gen_functions {
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LAYOUT_MOVING_WINDOW = 0,
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LAYOUT_IMPLICT = 1,
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};
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struct exofs_on_disk_inode_layout {
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__le16 gen_func; /* One of enum exofs_inode_layout_gen_functions */
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__le16 pad;
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union {
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/* gen_func == LAYOUT_MOVING_WINDOW (default) */
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struct exofs_layout_sliding_window {
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__le32 num_devices; /* first n devices in global-table*/
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} sliding_window __packed;
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/* gen_func == LAYOUT_IMPLICT */
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struct exofs_layout_implict_list {
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struct exofs_dt_data_map data_map;
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/* Variable array of size data_map.cb_num_comps. These
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* are device indexes of the devices in the global table
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*/
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__le32 dev_indexes[];
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} implict __packed;
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};
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} __packed;
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static inline size_t exofs_on_disk_inode_layout_size(unsigned max_devs)
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{
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return sizeof(struct exofs_on_disk_inode_layout) +
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max_devs * sizeof(__le32);
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}
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#endif /*ifndef __EXOFS_COM_H__*/
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