![David Howells](/assets/img/avatar_default.png)
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: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
868 lines
25 KiB
C
868 lines
25 KiB
C
/*
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* Copyright (c) International Business Machines Corp., 2006
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*
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* This program 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; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program 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
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* the 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 this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Author: Artem Bityutskiy (Битюцкий Артём)
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*/
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/* This file mostly implements UBI kernel API functions */
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/namei.h>
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#include <linux/fs.h>
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#include <asm/div64.h>
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#include "ubi.h"
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/**
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* ubi_do_get_device_info - get information about UBI device.
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* @ubi: UBI device description object
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* @di: the information is stored here
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*
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* This function is the same as 'ubi_get_device_info()', but it assumes the UBI
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* device is locked and cannot disappear.
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*/
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void ubi_do_get_device_info(struct ubi_device *ubi, struct ubi_device_info *di)
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{
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di->ubi_num = ubi->ubi_num;
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di->leb_size = ubi->leb_size;
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di->leb_start = ubi->leb_start;
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di->min_io_size = ubi->min_io_size;
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di->max_write_size = ubi->max_write_size;
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di->ro_mode = ubi->ro_mode;
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di->cdev = ubi->cdev.dev;
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}
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EXPORT_SYMBOL_GPL(ubi_do_get_device_info);
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/**
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* ubi_get_device_info - get information about UBI device.
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* @ubi_num: UBI device number
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* @di: the information is stored here
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*
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* This function returns %0 in case of success, %-EINVAL if the UBI device
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* number is invalid, and %-ENODEV if there is no such UBI device.
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*/
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int ubi_get_device_info(int ubi_num, struct ubi_device_info *di)
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{
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struct ubi_device *ubi;
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if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
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return -EINVAL;
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ubi = ubi_get_device(ubi_num);
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if (!ubi)
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return -ENODEV;
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ubi_do_get_device_info(ubi, di);
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ubi_put_device(ubi);
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return 0;
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}
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EXPORT_SYMBOL_GPL(ubi_get_device_info);
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/**
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* ubi_do_get_volume_info - get information about UBI volume.
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* @ubi: UBI device description object
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* @vol: volume description object
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* @vi: the information is stored here
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*/
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void ubi_do_get_volume_info(struct ubi_device *ubi, struct ubi_volume *vol,
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struct ubi_volume_info *vi)
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{
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vi->vol_id = vol->vol_id;
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vi->ubi_num = ubi->ubi_num;
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vi->size = vol->reserved_pebs;
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vi->used_bytes = vol->used_bytes;
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vi->vol_type = vol->vol_type;
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vi->corrupted = vol->corrupted;
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vi->upd_marker = vol->upd_marker;
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vi->alignment = vol->alignment;
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vi->usable_leb_size = vol->usable_leb_size;
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vi->name_len = vol->name_len;
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vi->name = vol->name;
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vi->cdev = vol->cdev.dev;
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}
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/**
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* ubi_get_volume_info - get information about UBI volume.
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* @desc: volume descriptor
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* @vi: the information is stored here
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*/
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void ubi_get_volume_info(struct ubi_volume_desc *desc,
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struct ubi_volume_info *vi)
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{
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ubi_do_get_volume_info(desc->vol->ubi, desc->vol, vi);
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}
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EXPORT_SYMBOL_GPL(ubi_get_volume_info);
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/**
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* ubi_open_volume - open UBI volume.
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* @ubi_num: UBI device number
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* @vol_id: volume ID
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* @mode: open mode
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*
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* The @mode parameter specifies if the volume should be opened in read-only
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* mode, read-write mode, or exclusive mode. The exclusive mode guarantees that
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* nobody else will be able to open this volume. UBI allows to have many volume
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* readers and one writer at a time.
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*
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* If a static volume is being opened for the first time since boot, it will be
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* checked by this function, which means it will be fully read and the CRC
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* checksum of each logical eraseblock will be checked.
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*
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* This function returns volume descriptor in case of success and a negative
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* error code in case of failure.
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*/
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struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode)
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{
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int err;
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struct ubi_volume_desc *desc;
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struct ubi_device *ubi;
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struct ubi_volume *vol;
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dbg_gen("open device %d, volume %d, mode %d", ubi_num, vol_id, mode);
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if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
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return ERR_PTR(-EINVAL);
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if (mode != UBI_READONLY && mode != UBI_READWRITE &&
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mode != UBI_EXCLUSIVE && mode != UBI_METAONLY)
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return ERR_PTR(-EINVAL);
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/*
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* First of all, we have to get the UBI device to prevent its removal.
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*/
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ubi = ubi_get_device(ubi_num);
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if (!ubi)
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return ERR_PTR(-ENODEV);
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if (vol_id < 0 || vol_id >= ubi->vtbl_slots) {
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err = -EINVAL;
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goto out_put_ubi;
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}
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desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL);
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if (!desc) {
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err = -ENOMEM;
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goto out_put_ubi;
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}
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err = -ENODEV;
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if (!try_module_get(THIS_MODULE))
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goto out_free;
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spin_lock(&ubi->volumes_lock);
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vol = ubi->volumes[vol_id];
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if (!vol)
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goto out_unlock;
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err = -EBUSY;
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switch (mode) {
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case UBI_READONLY:
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if (vol->exclusive)
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goto out_unlock;
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vol->readers += 1;
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break;
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case UBI_READWRITE:
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if (vol->exclusive || vol->writers > 0)
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goto out_unlock;
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vol->writers += 1;
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break;
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case UBI_EXCLUSIVE:
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if (vol->exclusive || vol->writers || vol->readers ||
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vol->metaonly)
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goto out_unlock;
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vol->exclusive = 1;
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break;
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case UBI_METAONLY:
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if (vol->metaonly || vol->exclusive)
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goto out_unlock;
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vol->metaonly = 1;
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break;
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}
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get_device(&vol->dev);
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vol->ref_count += 1;
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spin_unlock(&ubi->volumes_lock);
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desc->vol = vol;
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desc->mode = mode;
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mutex_lock(&ubi->ckvol_mutex);
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if (!vol->checked) {
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/* This is the first open - check the volume */
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err = ubi_check_volume(ubi, vol_id);
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if (err < 0) {
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mutex_unlock(&ubi->ckvol_mutex);
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ubi_close_volume(desc);
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return ERR_PTR(err);
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}
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if (err == 1) {
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ubi_warn(ubi, "volume %d on UBI device %d is corrupted",
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vol_id, ubi->ubi_num);
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vol->corrupted = 1;
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}
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vol->checked = 1;
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}
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mutex_unlock(&ubi->ckvol_mutex);
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return desc;
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out_unlock:
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spin_unlock(&ubi->volumes_lock);
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module_put(THIS_MODULE);
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out_free:
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kfree(desc);
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out_put_ubi:
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ubi_put_device(ubi);
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ubi_err(ubi, "cannot open device %d, volume %d, error %d",
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ubi_num, vol_id, err);
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return ERR_PTR(err);
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}
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EXPORT_SYMBOL_GPL(ubi_open_volume);
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/**
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* ubi_open_volume_nm - open UBI volume by name.
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* @ubi_num: UBI device number
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* @name: volume name
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* @mode: open mode
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*
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* This function is similar to 'ubi_open_volume()', but opens a volume by name.
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*/
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struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
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int mode)
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{
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int i, vol_id = -1, len;
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struct ubi_device *ubi;
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struct ubi_volume_desc *ret;
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dbg_gen("open device %d, volume %s, mode %d", ubi_num, name, mode);
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if (!name)
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return ERR_PTR(-EINVAL);
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len = strnlen(name, UBI_VOL_NAME_MAX + 1);
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if (len > UBI_VOL_NAME_MAX)
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return ERR_PTR(-EINVAL);
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if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
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return ERR_PTR(-EINVAL);
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ubi = ubi_get_device(ubi_num);
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if (!ubi)
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return ERR_PTR(-ENODEV);
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spin_lock(&ubi->volumes_lock);
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/* Walk all volumes of this UBI device */
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for (i = 0; i < ubi->vtbl_slots; i++) {
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struct ubi_volume *vol = ubi->volumes[i];
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if (vol && len == vol->name_len && !strcmp(name, vol->name)) {
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vol_id = i;
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break;
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}
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}
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spin_unlock(&ubi->volumes_lock);
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if (vol_id >= 0)
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ret = ubi_open_volume(ubi_num, vol_id, mode);
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else
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ret = ERR_PTR(-ENODEV);
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/*
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* We should put the UBI device even in case of success, because
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* 'ubi_open_volume()' took a reference as well.
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*/
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ubi_put_device(ubi);
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return ret;
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}
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EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
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/**
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* ubi_open_volume_path - open UBI volume by its character device node path.
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* @pathname: volume character device node path
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* @mode: open mode
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*
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* This function is similar to 'ubi_open_volume()', but opens a volume the path
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* to its character device node.
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*/
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struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
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{
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int error, ubi_num, vol_id;
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struct path path;
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struct kstat stat;
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dbg_gen("open volume %s, mode %d", pathname, mode);
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if (!pathname || !*pathname)
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return ERR_PTR(-EINVAL);
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error = kern_path(pathname, LOOKUP_FOLLOW, &path);
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if (error)
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return ERR_PTR(error);
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error = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
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path_put(&path);
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if (error)
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return ERR_PTR(error);
|
|
|
|
if (!S_ISCHR(stat.mode))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
ubi_num = ubi_major2num(MAJOR(stat.rdev));
|
|
vol_id = MINOR(stat.rdev) - 1;
|
|
|
|
if (vol_id >= 0 && ubi_num >= 0)
|
|
return ubi_open_volume(ubi_num, vol_id, mode);
|
|
return ERR_PTR(-ENODEV);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_open_volume_path);
|
|
|
|
/**
|
|
* ubi_close_volume - close UBI volume.
|
|
* @desc: volume descriptor
|
|
*/
|
|
void ubi_close_volume(struct ubi_volume_desc *desc)
|
|
{
|
|
struct ubi_volume *vol = desc->vol;
|
|
struct ubi_device *ubi = vol->ubi;
|
|
|
|
dbg_gen("close device %d, volume %d, mode %d",
|
|
ubi->ubi_num, vol->vol_id, desc->mode);
|
|
|
|
spin_lock(&ubi->volumes_lock);
|
|
switch (desc->mode) {
|
|
case UBI_READONLY:
|
|
vol->readers -= 1;
|
|
break;
|
|
case UBI_READWRITE:
|
|
vol->writers -= 1;
|
|
break;
|
|
case UBI_EXCLUSIVE:
|
|
vol->exclusive = 0;
|
|
break;
|
|
case UBI_METAONLY:
|
|
vol->metaonly = 0;
|
|
break;
|
|
}
|
|
vol->ref_count -= 1;
|
|
spin_unlock(&ubi->volumes_lock);
|
|
|
|
kfree(desc);
|
|
put_device(&vol->dev);
|
|
ubi_put_device(ubi);
|
|
module_put(THIS_MODULE);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_close_volume);
|
|
|
|
/**
|
|
* leb_read_sanity_check - does sanity checks on read requests.
|
|
* @desc: volume descriptor
|
|
* @lnum: logical eraseblock number to read from
|
|
* @offset: offset within the logical eraseblock to read from
|
|
* @len: how many bytes to read
|
|
*
|
|
* This function is used by ubi_leb_read() and ubi_leb_read_sg()
|
|
* to perform sanity checks.
|
|
*/
|
|
static int leb_read_sanity_check(struct ubi_volume_desc *desc, int lnum,
|
|
int offset, int len)
|
|
{
|
|
struct ubi_volume *vol = desc->vol;
|
|
struct ubi_device *ubi = vol->ubi;
|
|
int vol_id = vol->vol_id;
|
|
|
|
if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 ||
|
|
lnum >= vol->used_ebs || offset < 0 || len < 0 ||
|
|
offset + len > vol->usable_leb_size)
|
|
return -EINVAL;
|
|
|
|
if (vol->vol_type == UBI_STATIC_VOLUME) {
|
|
if (vol->used_ebs == 0)
|
|
/* Empty static UBI volume */
|
|
return 0;
|
|
if (lnum == vol->used_ebs - 1 &&
|
|
offset + len > vol->last_eb_bytes)
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (vol->upd_marker)
|
|
return -EBADF;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* ubi_leb_read - read data.
|
|
* @desc: volume descriptor
|
|
* @lnum: logical eraseblock number to read from
|
|
* @buf: buffer where to store the read data
|
|
* @offset: offset within the logical eraseblock to read from
|
|
* @len: how many bytes to read
|
|
* @check: whether UBI has to check the read data's CRC or not.
|
|
*
|
|
* This function reads data from offset @offset of logical eraseblock @lnum and
|
|
* stores the data at @buf. When reading from static volumes, @check specifies
|
|
* whether the data has to be checked or not. If yes, the whole logical
|
|
* eraseblock will be read and its CRC checksum will be checked (i.e., the CRC
|
|
* checksum is per-eraseblock). So checking may substantially slow down the
|
|
* read speed. The @check argument is ignored for dynamic volumes.
|
|
*
|
|
* In case of success, this function returns zero. In case of failure, this
|
|
* function returns a negative error code.
|
|
*
|
|
* %-EBADMSG error code is returned:
|
|
* o for both static and dynamic volumes if MTD driver has detected a data
|
|
* integrity problem (unrecoverable ECC checksum mismatch in case of NAND);
|
|
* o for static volumes in case of data CRC mismatch.
|
|
*
|
|
* If the volume is damaged because of an interrupted update this function just
|
|
* returns immediately with %-EBADF error code.
|
|
*/
|
|
int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
|
|
int len, int check)
|
|
{
|
|
struct ubi_volume *vol = desc->vol;
|
|
struct ubi_device *ubi = vol->ubi;
|
|
int err, vol_id = vol->vol_id;
|
|
|
|
dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
|
|
|
|
err = leb_read_sanity_check(desc, lnum, offset, len);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (len == 0)
|
|
return 0;
|
|
|
|
err = ubi_eba_read_leb(ubi, vol, lnum, buf, offset, len, check);
|
|
if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
|
|
ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
|
|
vol->corrupted = 1;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_leb_read);
|
|
|
|
|
|
/**
|
|
* ubi_leb_read_sg - read data into a scatter gather list.
|
|
* @desc: volume descriptor
|
|
* @lnum: logical eraseblock number to read from
|
|
* @buf: buffer where to store the read data
|
|
* @offset: offset within the logical eraseblock to read from
|
|
* @len: how many bytes to read
|
|
* @check: whether UBI has to check the read data's CRC or not.
|
|
*
|
|
* This function works exactly like ubi_leb_read_sg(). But instead of
|
|
* storing the read data into a buffer it writes to an UBI scatter gather
|
|
* list.
|
|
*/
|
|
int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
|
|
int offset, int len, int check)
|
|
{
|
|
struct ubi_volume *vol = desc->vol;
|
|
struct ubi_device *ubi = vol->ubi;
|
|
int err, vol_id = vol->vol_id;
|
|
|
|
dbg_gen("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset);
|
|
|
|
err = leb_read_sanity_check(desc, lnum, offset, len);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (len == 0)
|
|
return 0;
|
|
|
|
err = ubi_eba_read_leb_sg(ubi, vol, sgl, lnum, offset, len, check);
|
|
if (err && mtd_is_eccerr(err) && vol->vol_type == UBI_STATIC_VOLUME) {
|
|
ubi_warn(ubi, "mark volume %d as corrupted", vol_id);
|
|
vol->corrupted = 1;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_leb_read_sg);
|
|
|
|
/**
|
|
* ubi_leb_write - write data.
|
|
* @desc: volume descriptor
|
|
* @lnum: logical eraseblock number to write to
|
|
* @buf: data to write
|
|
* @offset: offset within the logical eraseblock where to write
|
|
* @len: how many bytes to write
|
|
*
|
|
* This function writes @len bytes of data from @buf to offset @offset of
|
|
* logical eraseblock @lnum.
|
|
*
|
|
* This function takes care of physical eraseblock write failures. If write to
|
|
* the physical eraseblock write operation fails, the logical eraseblock is
|
|
* re-mapped to another physical eraseblock, the data is recovered, and the
|
|
* write finishes. UBI has a pool of reserved physical eraseblocks for this.
|
|
*
|
|
* If all the data were successfully written, zero is returned. If an error
|
|
* occurred and UBI has not been able to recover from it, this function returns
|
|
* a negative error code. Note, in case of an error, it is possible that
|
|
* something was still written to the flash media, but that may be some
|
|
* garbage.
|
|
*
|
|
* If the volume is damaged because of an interrupted update this function just
|
|
* returns immediately with %-EBADF code.
|
|
*/
|
|
int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
|
|
int offset, int len)
|
|
{
|
|
struct ubi_volume *vol = desc->vol;
|
|
struct ubi_device *ubi = vol->ubi;
|
|
int vol_id = vol->vol_id;
|
|
|
|
dbg_gen("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset);
|
|
|
|
if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
|
|
return -EINVAL;
|
|
|
|
if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
|
|
return -EROFS;
|
|
|
|
if (!ubi_leb_valid(vol, lnum) || offset < 0 || len < 0 ||
|
|
offset + len > vol->usable_leb_size ||
|
|
offset & (ubi->min_io_size - 1) || len & (ubi->min_io_size - 1))
|
|
return -EINVAL;
|
|
|
|
if (vol->upd_marker)
|
|
return -EBADF;
|
|
|
|
if (len == 0)
|
|
return 0;
|
|
|
|
return ubi_eba_write_leb(ubi, vol, lnum, buf, offset, len);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_leb_write);
|
|
|
|
/*
|
|
* ubi_leb_change - change logical eraseblock atomically.
|
|
* @desc: volume descriptor
|
|
* @lnum: logical eraseblock number to change
|
|
* @buf: data to write
|
|
* @len: how many bytes to write
|
|
*
|
|
* This function changes the contents of a logical eraseblock atomically. @buf
|
|
* has to contain new logical eraseblock data, and @len - the length of the
|
|
* data, which has to be aligned. The length may be shorter than the logical
|
|
* eraseblock size, ant the logical eraseblock may be appended to more times
|
|
* later on. This function guarantees that in case of an unclean reboot the old
|
|
* contents is preserved. Returns zero in case of success and a negative error
|
|
* code in case of failure.
|
|
*/
|
|
int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
|
|
int len)
|
|
{
|
|
struct ubi_volume *vol = desc->vol;
|
|
struct ubi_device *ubi = vol->ubi;
|
|
int vol_id = vol->vol_id;
|
|
|
|
dbg_gen("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum);
|
|
|
|
if (vol_id < 0 || vol_id >= ubi->vtbl_slots)
|
|
return -EINVAL;
|
|
|
|
if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
|
|
return -EROFS;
|
|
|
|
if (!ubi_leb_valid(vol, lnum) || len < 0 ||
|
|
len > vol->usable_leb_size || len & (ubi->min_io_size - 1))
|
|
return -EINVAL;
|
|
|
|
if (vol->upd_marker)
|
|
return -EBADF;
|
|
|
|
if (len == 0)
|
|
return 0;
|
|
|
|
return ubi_eba_atomic_leb_change(ubi, vol, lnum, buf, len);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_leb_change);
|
|
|
|
/**
|
|
* ubi_leb_erase - erase logical eraseblock.
|
|
* @desc: volume descriptor
|
|
* @lnum: logical eraseblock number
|
|
*
|
|
* This function un-maps logical eraseblock @lnum and synchronously erases the
|
|
* correspondent physical eraseblock. Returns zero in case of success and a
|
|
* negative error code in case of failure.
|
|
*
|
|
* If the volume is damaged because of an interrupted update this function just
|
|
* returns immediately with %-EBADF code.
|
|
*/
|
|
int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum)
|
|
{
|
|
struct ubi_volume *vol = desc->vol;
|
|
struct ubi_device *ubi = vol->ubi;
|
|
int err;
|
|
|
|
dbg_gen("erase LEB %d:%d", vol->vol_id, lnum);
|
|
|
|
if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
|
|
return -EROFS;
|
|
|
|
if (!ubi_leb_valid(vol, lnum))
|
|
return -EINVAL;
|
|
|
|
if (vol->upd_marker)
|
|
return -EBADF;
|
|
|
|
err = ubi_eba_unmap_leb(ubi, vol, lnum);
|
|
if (err)
|
|
return err;
|
|
|
|
return ubi_wl_flush(ubi, vol->vol_id, lnum);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_leb_erase);
|
|
|
|
/**
|
|
* ubi_leb_unmap - un-map logical eraseblock.
|
|
* @desc: volume descriptor
|
|
* @lnum: logical eraseblock number
|
|
*
|
|
* This function un-maps logical eraseblock @lnum and schedules the
|
|
* corresponding physical eraseblock for erasure, so that it will eventually be
|
|
* physically erased in background. This operation is much faster than the
|
|
* erase operation.
|
|
*
|
|
* Unlike erase, the un-map operation does not guarantee that the logical
|
|
* eraseblock will contain all 0xFF bytes when UBI is initialized again. For
|
|
* example, if several logical eraseblocks are un-mapped, and an unclean reboot
|
|
* happens after this, the logical eraseblocks will not necessarily be
|
|
* un-mapped again when this MTD device is attached. They may actually be
|
|
* mapped to the same physical eraseblocks again. So, this function has to be
|
|
* used with care.
|
|
*
|
|
* In other words, when un-mapping a logical eraseblock, UBI does not store
|
|
* any information about this on the flash media, it just marks the logical
|
|
* eraseblock as "un-mapped" in RAM. If UBI is detached before the physical
|
|
* eraseblock is physically erased, it will be mapped again to the same logical
|
|
* eraseblock when the MTD device is attached again.
|
|
*
|
|
* The main and obvious use-case of this function is when the contents of a
|
|
* logical eraseblock has to be re-written. Then it is much more efficient to
|
|
* first un-map it, then write new data, rather than first erase it, then write
|
|
* new data. Note, once new data has been written to the logical eraseblock,
|
|
* UBI guarantees that the old contents has gone forever. In other words, if an
|
|
* unclean reboot happens after the logical eraseblock has been un-mapped and
|
|
* then written to, it will contain the last written data.
|
|
*
|
|
* This function returns zero in case of success and a negative error code in
|
|
* case of failure. If the volume is damaged because of an interrupted update
|
|
* this function just returns immediately with %-EBADF code.
|
|
*/
|
|
int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum)
|
|
{
|
|
struct ubi_volume *vol = desc->vol;
|
|
struct ubi_device *ubi = vol->ubi;
|
|
|
|
dbg_gen("unmap LEB %d:%d", vol->vol_id, lnum);
|
|
|
|
if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
|
|
return -EROFS;
|
|
|
|
if (!ubi_leb_valid(vol, lnum))
|
|
return -EINVAL;
|
|
|
|
if (vol->upd_marker)
|
|
return -EBADF;
|
|
|
|
return ubi_eba_unmap_leb(ubi, vol, lnum);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_leb_unmap);
|
|
|
|
/**
|
|
* ubi_leb_map - map logical eraseblock to a physical eraseblock.
|
|
* @desc: volume descriptor
|
|
* @lnum: logical eraseblock number
|
|
*
|
|
* This function maps an un-mapped logical eraseblock @lnum to a physical
|
|
* eraseblock. This means, that after a successful invocation of this
|
|
* function the logical eraseblock @lnum will be empty (contain only %0xFF
|
|
* bytes) and be mapped to a physical eraseblock, even if an unclean reboot
|
|
* happens.
|
|
*
|
|
* This function returns zero in case of success, %-EBADF if the volume is
|
|
* damaged because of an interrupted update, %-EBADMSG if the logical
|
|
* eraseblock is already mapped, and other negative error codes in case of
|
|
* other failures.
|
|
*/
|
|
int ubi_leb_map(struct ubi_volume_desc *desc, int lnum)
|
|
{
|
|
struct ubi_volume *vol = desc->vol;
|
|
struct ubi_device *ubi = vol->ubi;
|
|
|
|
dbg_gen("map LEB %d:%d", vol->vol_id, lnum);
|
|
|
|
if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME)
|
|
return -EROFS;
|
|
|
|
if (!ubi_leb_valid(vol, lnum))
|
|
return -EINVAL;
|
|
|
|
if (vol->upd_marker)
|
|
return -EBADF;
|
|
|
|
if (ubi_eba_is_mapped(vol, lnum))
|
|
return -EBADMSG;
|
|
|
|
return ubi_eba_write_leb(ubi, vol, lnum, NULL, 0, 0);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_leb_map);
|
|
|
|
/**
|
|
* ubi_is_mapped - check if logical eraseblock is mapped.
|
|
* @desc: volume descriptor
|
|
* @lnum: logical eraseblock number
|
|
*
|
|
* This function checks if logical eraseblock @lnum is mapped to a physical
|
|
* eraseblock. If a logical eraseblock is un-mapped, this does not necessarily
|
|
* mean it will still be un-mapped after the UBI device is re-attached. The
|
|
* logical eraseblock may become mapped to the physical eraseblock it was last
|
|
* mapped to.
|
|
*
|
|
* This function returns %1 if the LEB is mapped, %0 if not, and a negative
|
|
* error code in case of failure. If the volume is damaged because of an
|
|
* interrupted update this function just returns immediately with %-EBADF error
|
|
* code.
|
|
*/
|
|
int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum)
|
|
{
|
|
struct ubi_volume *vol = desc->vol;
|
|
|
|
dbg_gen("test LEB %d:%d", vol->vol_id, lnum);
|
|
|
|
if (!ubi_leb_valid(vol, lnum))
|
|
return -EINVAL;
|
|
|
|
if (vol->upd_marker)
|
|
return -EBADF;
|
|
|
|
return ubi_eba_is_mapped(vol, lnum);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_is_mapped);
|
|
|
|
/**
|
|
* ubi_sync - synchronize UBI device buffers.
|
|
* @ubi_num: UBI device to synchronize
|
|
*
|
|
* The underlying MTD device may cache data in hardware or in software. This
|
|
* function ensures the caches are flushed. Returns zero in case of success and
|
|
* a negative error code in case of failure.
|
|
*/
|
|
int ubi_sync(int ubi_num)
|
|
{
|
|
struct ubi_device *ubi;
|
|
|
|
ubi = ubi_get_device(ubi_num);
|
|
if (!ubi)
|
|
return -ENODEV;
|
|
|
|
mtd_sync(ubi->mtd);
|
|
ubi_put_device(ubi);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_sync);
|
|
|
|
/**
|
|
* ubi_flush - flush UBI work queue.
|
|
* @ubi_num: UBI device to flush work queue
|
|
* @vol_id: volume id to flush for
|
|
* @lnum: logical eraseblock number to flush for
|
|
*
|
|
* This function executes all pending works for a particular volume id / logical
|
|
* eraseblock number pair. If either value is set to %UBI_ALL, then it acts as
|
|
* a wildcard for all of the corresponding volume numbers or logical
|
|
* eraseblock numbers. It returns zero in case of success and a negative error
|
|
* code in case of failure.
|
|
*/
|
|
int ubi_flush(int ubi_num, int vol_id, int lnum)
|
|
{
|
|
struct ubi_device *ubi;
|
|
int err = 0;
|
|
|
|
ubi = ubi_get_device(ubi_num);
|
|
if (!ubi)
|
|
return -ENODEV;
|
|
|
|
err = ubi_wl_flush(ubi, vol_id, lnum);
|
|
ubi_put_device(ubi);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_flush);
|
|
|
|
BLOCKING_NOTIFIER_HEAD(ubi_notifiers);
|
|
|
|
/**
|
|
* ubi_register_volume_notifier - register a volume notifier.
|
|
* @nb: the notifier description object
|
|
* @ignore_existing: if non-zero, do not send "added" notification for all
|
|
* already existing volumes
|
|
*
|
|
* This function registers a volume notifier, which means that
|
|
* 'nb->notifier_call()' will be invoked when an UBI volume is created,
|
|
* removed, re-sized, re-named, or updated. The first argument of the function
|
|
* is the notification type. The second argument is pointer to a
|
|
* &struct ubi_notification object which describes the notification event.
|
|
* Using UBI API from the volume notifier is prohibited.
|
|
*
|
|
* This function returns zero in case of success and a negative error code
|
|
* in case of failure.
|
|
*/
|
|
int ubi_register_volume_notifier(struct notifier_block *nb,
|
|
int ignore_existing)
|
|
{
|
|
int err;
|
|
|
|
err = blocking_notifier_chain_register(&ubi_notifiers, nb);
|
|
if (err != 0)
|
|
return err;
|
|
if (ignore_existing)
|
|
return 0;
|
|
|
|
/*
|
|
* We are going to walk all UBI devices and all volumes, and
|
|
* notify the user about existing volumes by the %UBI_VOLUME_ADDED
|
|
* event. We have to lock the @ubi_devices_mutex to make sure UBI
|
|
* devices do not disappear.
|
|
*/
|
|
mutex_lock(&ubi_devices_mutex);
|
|
ubi_enumerate_volumes(nb);
|
|
mutex_unlock(&ubi_devices_mutex);
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_register_volume_notifier);
|
|
|
|
/**
|
|
* ubi_unregister_volume_notifier - unregister the volume notifier.
|
|
* @nb: the notifier description object
|
|
*
|
|
* This function unregisters volume notifier @nm and returns zero in case of
|
|
* success and a negative error code in case of failure.
|
|
*/
|
|
int ubi_unregister_volume_notifier(struct notifier_block *nb)
|
|
{
|
|
return blocking_notifier_chain_unregister(&ubi_notifiers, nb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(ubi_unregister_volume_notifier);
|