From d3e3b7eac886fb1383db2f22b81550fa6d87f62f Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 6 Jul 2017 15:50:27 +0100 Subject: 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 Signed-off-by: Linus Torvalds --- fs/afs/Makefile | 3 +- fs/afs/dir.c | 1 + fs/afs/file.c | 1 + fs/afs/inode.c | 7 +++- fs/afs/internal.h | 5 +++ fs/afs/mntpt.c | 1 + fs/afs/super.c | 1 + fs/afs/xattr.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 8 files changed, 138 insertions(+), 2 deletions(-) create mode 100644 fs/afs/xattr.c diff --git a/fs/afs/Makefile b/fs/afs/Makefile index 4f64b95d57bd..095c54165dfd 100644 --- a/fs/afs/Makefile +++ b/fs/afs/Makefile @@ -27,6 +27,7 @@ kafs-objs := \ vlocation.o \ vnode.o \ volume.o \ - write.o + write.o \ + xattr.o obj-$(CONFIG_AFS_FS) := kafs.o diff --git a/fs/afs/dir.c b/fs/afs/dir.c index 949f960337f5..613a77058263 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -61,6 +61,7 @@ const struct inode_operations afs_dir_inode_operations = { .permission = afs_permission, .getattr = afs_getattr, .setattr = afs_setattr, + .listxattr = afs_listxattr, }; const struct dentry_operations afs_fs_dentry_operations = { diff --git a/fs/afs/file.c b/fs/afs/file.c index 0d5b8508869b..510cba15fa56 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -46,6 +46,7 @@ const struct inode_operations afs_file_inode_operations = { .getattr = afs_getattr, .setattr = afs_setattr, .permission = afs_permission, + .listxattr = afs_listxattr, }; const struct address_space_operations afs_fs_aops = { diff --git a/fs/afs/inode.c b/fs/afs/inode.c index aae55dd15108..342316a9e3e0 100644 --- a/fs/afs/inode.c +++ b/fs/afs/inode.c @@ -28,6 +28,11 @@ struct afs_iget_data { struct afs_volume *volume; /* volume on which resides */ }; +static const struct inode_operations afs_symlink_inode_operations = { + .get_link = page_get_link, + .listxattr = afs_listxattr, +}; + /* * map the AFS file status to the inode member variables */ @@ -67,7 +72,7 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key) inode->i_fop = &afs_mntpt_file_operations; } else { inode->i_mode = S_IFLNK | vnode->status.mode; - inode->i_op = &page_symlink_inode_operations; + inode->i_op = &afs_symlink_inode_operations; } inode_nohighmem(inode); break; diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 4e2556606623..82e16556afea 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -731,6 +731,11 @@ extern int afs_writeback_all(struct afs_vnode *); extern int afs_flush(struct file *, fl_owner_t); extern int afs_fsync(struct file *, loff_t, loff_t, int); +/* + * xattr.c + */ +extern const struct xattr_handler *afs_xattr_handlers[]; +extern ssize_t afs_listxattr(struct dentry *, char *, size_t); /*****************************************************************************/ /* diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c index bd3b65cde282..690fea9d84c3 100644 --- a/fs/afs/mntpt.c +++ b/fs/afs/mntpt.c @@ -35,6 +35,7 @@ const struct inode_operations afs_mntpt_inode_operations = { .lookup = afs_mntpt_lookup, .readlink = page_readlink, .getattr = afs_getattr, + .listxattr = afs_listxattr, }; const struct inode_operations afs_autocell_inode_operations = { diff --git a/fs/afs/super.c b/fs/afs/super.c index c79633e5cfd8..67680c2d96cf 100644 --- a/fs/afs/super.c +++ b/fs/afs/super.c @@ -319,6 +319,7 @@ static int afs_fill_super(struct super_block *sb, sb->s_blocksize_bits = PAGE_SHIFT; sb->s_magic = AFS_FS_MAGIC; sb->s_op = &afs_super_ops; + sb->s_xattr = afs_xattr_handlers; ret = super_setup_bdi(sb); if (ret) return ret; diff --git a/fs/afs/xattr.c b/fs/afs/xattr.c new file mode 100644 index 000000000000..2830e4f48d85 --- /dev/null +++ b/fs/afs/xattr.c @@ -0,0 +1,121 @@ +/* Extended attribute handling for AFS. We use xattrs to get and set metadata + * instead of providing pioctl(). + * + * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include "internal.h" + +static const char afs_xattr_list[] = + "afs.cell\0" + "afs.fid\0" + "afs.volume"; + +/* + * Retrieve a list of the supported xattrs. + */ +ssize_t afs_listxattr(struct dentry *dentry, char *buffer, size_t size) +{ + if (size == 0) + return sizeof(afs_xattr_list); + if (size < sizeof(afs_xattr_list)) + return -ERANGE; + memcpy(buffer, afs_xattr_list, sizeof(afs_xattr_list)); + return sizeof(afs_xattr_list); +} + +/* + * Get the name of the cell on which a file resides. + */ +static int afs_xattr_get_cell(const struct xattr_handler *handler, + struct dentry *dentry, + struct inode *inode, const char *name, + void *buffer, size_t size) +{ + struct afs_vnode *vnode = AFS_FS_I(inode); + struct afs_cell *cell = vnode->volume->cell; + size_t namelen; + + namelen = strlen(cell->name); + if (size == 0) + return namelen; + if (namelen > size) + return -ERANGE; + memcpy(buffer, cell->name, size); + return namelen; +} + +static const struct xattr_handler afs_xattr_afs_cell_handler = { + .name = "afs.cell", + .get = afs_xattr_get_cell, +}; + +/* + * Get the volume ID, vnode ID and vnode uniquifier of a file as a sequence of + * hex numbers separated by colons. + */ +static int afs_xattr_get_fid(const struct xattr_handler *handler, + struct dentry *dentry, + struct inode *inode, const char *name, + void *buffer, size_t size) +{ + struct afs_vnode *vnode = AFS_FS_I(inode); + char text[8 + 1 + 8 + 1 + 8 + 1]; + size_t len; + + len = sprintf(text, "%x:%x:%x", + vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique); + if (size == 0) + return len; + if (len > size) + return -ERANGE; + memcpy(buffer, text, len); + return len; +} + +static const struct xattr_handler afs_xattr_afs_fid_handler = { + .name = "afs.fid", + .get = afs_xattr_get_fid, +}; + +/* + * Get the name of the volume on which a file resides. + */ +static int afs_xattr_get_volume(const struct xattr_handler *handler, + struct dentry *dentry, + struct inode *inode, const char *name, + void *buffer, size_t size) +{ + struct afs_vnode *vnode = AFS_FS_I(inode); + const char *volname = vnode->volume->vlocation->vldb.name; + size_t namelen; + + namelen = strlen(volname); + if (size == 0) + return namelen; + if (namelen > size) + return -ERANGE; + memcpy(buffer, volname, size); + return namelen; +} + +static const struct xattr_handler afs_xattr_afs_volume_handler = { + .name = "afs.volume", + .get = afs_xattr_get_volume, +}; + +const struct xattr_handler *afs_xattr_handlers[] = { + &afs_xattr_afs_cell_handler, + &afs_xattr_afs_fid_handler, + &afs_xattr_afs_volume_handler, + NULL +}; -- cgit v1.2.3