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afs: Add metadata xattrs
Add xattrs to allow the user to get/set metadata in lieu of having pioctl() available. The following xattrs are now available: - "afs.cell" The name of the cell in which the vnode's volume resides. - "afs.fid" The volume ID, vnode ID and vnode uniquifier of the file as three hex numbers separated by colons. - "afs.volume" The name of the volume in which the vnode resides. For example: # getfattr -d -m ".*" /mnt/scratch getfattr: Removing leading '/' from absolute path names # file: mnt/scratch afs.cell="mycell.myorg.org" afs.fid="10000b:1:1" afs.volume="scratch" Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
fd2498211a
commit
d3e3b7eac8
8 changed files with 138 additions and 2 deletions
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@ -27,6 +27,7 @@ kafs-objs := \
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vlocation.o \
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vnode.o \
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volume.o \
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write.o
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write.o \
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xattr.o
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obj-$(CONFIG_AFS_FS) := kafs.o
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@ -61,6 +61,7 @@ const struct inode_operations afs_dir_inode_operations = {
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.permission = afs_permission,
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.getattr = afs_getattr,
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.setattr = afs_setattr,
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.listxattr = afs_listxattr,
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};
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const struct dentry_operations afs_fs_dentry_operations = {
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@ -46,6 +46,7 @@ const struct inode_operations afs_file_inode_operations = {
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.getattr = afs_getattr,
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.setattr = afs_setattr,
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.permission = afs_permission,
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.listxattr = afs_listxattr,
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};
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const struct address_space_operations afs_fs_aops = {
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@ -28,6 +28,11 @@ struct afs_iget_data {
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struct afs_volume *volume; /* volume on which resides */
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};
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static const struct inode_operations afs_symlink_inode_operations = {
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.get_link = page_get_link,
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.listxattr = afs_listxattr,
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};
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/*
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* map the AFS file status to the inode member variables
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*/
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@ -67,7 +72,7 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
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inode->i_fop = &afs_mntpt_file_operations;
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} else {
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inode->i_mode = S_IFLNK | vnode->status.mode;
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inode->i_op = &page_symlink_inode_operations;
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inode->i_op = &afs_symlink_inode_operations;
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}
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inode_nohighmem(inode);
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break;
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@ -731,6 +731,11 @@ extern int afs_writeback_all(struct afs_vnode *);
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extern int afs_flush(struct file *, fl_owner_t);
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extern int afs_fsync(struct file *, loff_t, loff_t, int);
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/*
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* xattr.c
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*/
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extern const struct xattr_handler *afs_xattr_handlers[];
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extern ssize_t afs_listxattr(struct dentry *, char *, size_t);
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/*****************************************************************************/
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/*
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@ -35,6 +35,7 @@ const struct inode_operations afs_mntpt_inode_operations = {
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.lookup = afs_mntpt_lookup,
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.readlink = page_readlink,
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.getattr = afs_getattr,
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.listxattr = afs_listxattr,
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};
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const struct inode_operations afs_autocell_inode_operations = {
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@ -319,6 +319,7 @@ static int afs_fill_super(struct super_block *sb,
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sb->s_blocksize_bits = PAGE_SHIFT;
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sb->s_magic = AFS_FS_MAGIC;
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sb->s_op = &afs_super_ops;
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sb->s_xattr = afs_xattr_handlers;
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ret = super_setup_bdi(sb);
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if (ret)
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return ret;
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121
fs/afs/xattr.c
Normal file
121
fs/afs/xattr.c
Normal file
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@ -0,0 +1,121 @@
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/* Extended attribute handling for AFS. We use xattrs to get and set metadata
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* instead of providing pioctl().
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*
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* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/xattr.h>
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#include "internal.h"
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static const char afs_xattr_list[] =
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"afs.cell\0"
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"afs.fid\0"
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"afs.volume";
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/*
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* Retrieve a list of the supported xattrs.
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*/
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ssize_t afs_listxattr(struct dentry *dentry, char *buffer, size_t size)
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{
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if (size == 0)
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return sizeof(afs_xattr_list);
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if (size < sizeof(afs_xattr_list))
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return -ERANGE;
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memcpy(buffer, afs_xattr_list, sizeof(afs_xattr_list));
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return sizeof(afs_xattr_list);
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}
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/*
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* Get the name of the cell on which a file resides.
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*/
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static int afs_xattr_get_cell(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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struct afs_cell *cell = vnode->volume->cell;
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size_t namelen;
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namelen = strlen(cell->name);
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if (size == 0)
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return namelen;
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if (namelen > size)
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return -ERANGE;
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memcpy(buffer, cell->name, size);
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return namelen;
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}
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static const struct xattr_handler afs_xattr_afs_cell_handler = {
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.name = "afs.cell",
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.get = afs_xattr_get_cell,
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};
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/*
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* Get the volume ID, vnode ID and vnode uniquifier of a file as a sequence of
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* hex numbers separated by colons.
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*/
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static int afs_xattr_get_fid(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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char text[8 + 1 + 8 + 1 + 8 + 1];
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size_t len;
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len = sprintf(text, "%x:%x:%x",
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vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
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if (size == 0)
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return len;
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if (len > size)
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return -ERANGE;
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memcpy(buffer, text, len);
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return len;
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}
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static const struct xattr_handler afs_xattr_afs_fid_handler = {
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.name = "afs.fid",
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.get = afs_xattr_get_fid,
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};
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/*
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* Get the name of the volume on which a file resides.
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*/
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static int afs_xattr_get_volume(const struct xattr_handler *handler,
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struct dentry *dentry,
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struct inode *inode, const char *name,
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void *buffer, size_t size)
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{
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struct afs_vnode *vnode = AFS_FS_I(inode);
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const char *volname = vnode->volume->vlocation->vldb.name;
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size_t namelen;
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namelen = strlen(volname);
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if (size == 0)
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return namelen;
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if (namelen > size)
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return -ERANGE;
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memcpy(buffer, volname, size);
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return namelen;
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}
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static const struct xattr_handler afs_xattr_afs_volume_handler = {
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.name = "afs.volume",
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.get = afs_xattr_get_volume,
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};
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const struct xattr_handler *afs_xattr_handlers[] = {
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&afs_xattr_afs_cell_handler,
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&afs_xattr_afs_fid_handler,
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&afs_xattr_afs_volume_handler,
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NULL
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};
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