summaryrefslogtreecommitdiff
path: root/fs/afs/super.c
diff options
context:
space:
mode:
authorDavid Howells <dhowells@redhat.com>2018-02-06 09:26:30 +0300
committerDavid Howells <dhowells@redhat.com>2018-02-06 17:43:37 +0300
commit4d673da14533b32fe8d3125b5b7be4fea14e39a8 (patch)
treed0780b5603a48614696e7e9afebe5b61552c6cd1 /fs/afs/super.c
parent16280a15be751b9994e94c5dc944e93fa4293199 (diff)
downloadlinux-4d673da14533b32fe8d3125b5b7be4fea14e39a8.tar.xz
afs: Support the AFS dynamic root
Support the AFS dynamic root which is a pseudo-volume that doesn't connect to any server resource, but rather is just a root directory that dynamically creates mountpoint directories where the name of such a directory is the name of the cell. Such a mount can be created thus: mount -t afs none /afs -o dyn Dynamic root superblocks aren't shared except by bind mounts and propagation. Cell root volumes can then be mounted by referring to them by name, e.g.: ls /afs/grand.central.org/ ls /afs/.grand.central.org/ The kernel will upcall to consult the DNS if the address wasn't supplied directly. Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/afs/super.c')
-rw-r--r--fs/afs/super.c132
1 files changed, 90 insertions, 42 deletions
diff --git a/fs/afs/super.c b/fs/afs/super.c
index 1037dd41a622..3623c952b6ff 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -64,6 +64,7 @@ static atomic_t afs_count_active_inodes;
enum {
afs_no_opt,
afs_opt_cell,
+ afs_opt_dyn,
afs_opt_rwpath,
afs_opt_vol,
afs_opt_autocell,
@@ -71,6 +72,7 @@ enum {
static const match_table_t afs_options_list = {
{ afs_opt_cell, "cell=%s" },
+ { afs_opt_dyn, "dyn" },
{ afs_opt_rwpath, "rwpath" },
{ afs_opt_vol, "vol=%s" },
{ afs_opt_autocell, "autocell" },
@@ -148,6 +150,11 @@ static int afs_show_devname(struct seq_file *m, struct dentry *root)
const char *suf = "";
char pref = '%';
+ if (as->dyn_root) {
+ seq_puts(m, "none");
+ return 0;
+ }
+
switch (volume->type) {
case AFSVL_RWVOL:
break;
@@ -171,8 +178,12 @@ static int afs_show_devname(struct seq_file *m, struct dentry *root)
*/
static int afs_show_options(struct seq_file *m, struct dentry *root)
{
+ struct afs_super_info *as = AFS_FS_S(root->d_sb);
+
+ if (as->dyn_root)
+ seq_puts(m, ",dyn");
if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
- seq_puts(m, "autocell");
+ seq_puts(m, ",autocell");
return 0;
}
@@ -212,7 +223,7 @@ static int afs_parse_options(struct afs_mount_params *params,
break;
case afs_opt_rwpath:
- params->rwpath = 1;
+ params->rwpath = true;
break;
case afs_opt_vol:
@@ -220,7 +231,11 @@ static int afs_parse_options(struct afs_mount_params *params,
break;
case afs_opt_autocell:
- params->autocell = 1;
+ params->autocell = true;
+ break;
+
+ case afs_opt_dyn:
+ params->dyn_root = true;
break;
default:
@@ -254,7 +269,7 @@ static int afs_parse_device_name(struct afs_mount_params *params,
int cellnamesz;
_enter(",%s", name);
-
+
if (!name) {
printk(KERN_ERR "kAFS: no volume name specified\n");
return -EINVAL;
@@ -336,7 +351,14 @@ static int afs_test_super(struct super_block *sb, void *data)
struct afs_super_info *as1 = data;
struct afs_super_info *as = AFS_FS_S(sb);
- return as->net == as1->net && as->volume->vid == as1->volume->vid;
+ return (as->net == as1->net &&
+ as->volume &&
+ as->volume->vid == as1->volume->vid);
+}
+
+static int afs_dynroot_test_super(struct super_block *sb, void *data)
+{
+ return false;
}
static int afs_set_super(struct super_block *sb, void *data)
@@ -365,24 +387,30 @@ 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;
+ if (!as->dyn_root)
+ sb->s_xattr = afs_xattr_handlers;
ret = super_setup_bdi(sb);
if (ret)
return ret;
sb->s_bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
- sprintf(sb->s_id, "%u", as->volume->vid);
-
- afs_activate_volume(as->volume);
/* allocate the root inode and dentry */
- fid.vid = as->volume->vid;
- fid.vnode = 1;
- fid.unique = 1;
- inode = afs_iget(sb, params->key, &fid, NULL, NULL, NULL);
+ if (as->dyn_root) {
+ inode = afs_iget_pseudo_dir(sb, true);
+ sb->s_flags |= SB_RDONLY;
+ } else {
+ sprintf(sb->s_id, "%u", as->volume->vid);
+ afs_activate_volume(as->volume);
+ fid.vid = as->volume->vid;
+ fid.vnode = 1;
+ fid.unique = 1;
+ inode = afs_iget(sb, params->key, &fid, NULL, NULL, NULL);
+ }
+
if (IS_ERR(inode))
return PTR_ERR(inode);
- if (params->autocell)
+ if (params->autocell || params->dyn_root)
set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
ret = -ENOMEM;
@@ -407,7 +435,10 @@ static struct afs_super_info *afs_alloc_sbi(struct afs_mount_params *params)
as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
if (as) {
as->net = afs_get_net(params->net);
- as->cell = afs_get_cell(params->cell);
+ if (params->dyn_root)
+ as->dyn_root = true;
+ else
+ as->cell = afs_get_cell(params->cell);
}
return as;
}
@@ -451,18 +482,20 @@ static struct dentry *afs_mount(struct file_system_type *fs_type,
goto error;
}
- ret = afs_parse_device_name(&params, dev_name);
- if (ret < 0)
- goto error;
+ if (!params.dyn_root) {
+ ret = afs_parse_device_name(&params, dev_name);
+ if (ret < 0)
+ goto error;
- /* try and do the mount securely */
- key = afs_request_key(params.cell);
- if (IS_ERR(key)) {
- _leave(" = %ld [key]", PTR_ERR(key));
- ret = PTR_ERR(key);
- goto error;
+ /* try and do the mount securely */
+ key = afs_request_key(params.cell);
+ if (IS_ERR(key)) {
+ _leave(" = %ld [key]", PTR_ERR(key));
+ ret = PTR_ERR(key);
+ goto error;
+ }
+ params.key = key;
}
- params.key = key;
/* allocate a superblock info record */
ret = -ENOMEM;
@@ -470,20 +503,25 @@ static struct dentry *afs_mount(struct file_system_type *fs_type,
if (!as)
goto error_key;
- /* Assume we're going to need a volume record; at the very least we can
- * use it to update the volume record if we have one already. This
- * checks that the volume exists within the cell.
- */
- candidate = afs_create_volume(&params);
- if (IS_ERR(candidate)) {
- ret = PTR_ERR(candidate);
- goto error_as;
- }
+ if (!params.dyn_root) {
+ /* Assume we're going to need a volume record; at the very
+ * least we can use it to update the volume record if we have
+ * one already. This checks that the volume exists within the
+ * cell.
+ */
+ candidate = afs_create_volume(&params);
+ if (IS_ERR(candidate)) {
+ ret = PTR_ERR(candidate);
+ goto error_as;
+ }
- as->volume = candidate;
+ as->volume = candidate;
+ }
/* allocate a deviceless superblock */
- sb = sget(fs_type, afs_test_super, afs_set_super, flags, as);
+ sb = sget(fs_type,
+ as->dyn_root ? afs_dynroot_test_super : afs_test_super,
+ afs_set_super, flags, as);
if (IS_ERR(sb)) {
ret = PTR_ERR(sb);
goto error_as;
@@ -529,9 +567,11 @@ static void afs_kill_super(struct super_block *sb)
/* Clear the callback interests (which will do ilookup5) before
* deactivating the superblock.
*/
- afs_clear_callback_interests(as->net, as->volume->servers);
+ if (as->volume)
+ afs_clear_callback_interests(as->net, as->volume->servers);
kill_anon_super(sb);
- afs_deactivate_volume(as->volume);
+ if (as->volume)
+ afs_deactivate_volume(as->volume);
afs_destroy_sbi(as);
}
@@ -619,12 +659,24 @@ static void afs_destroy_inode(struct inode *inode)
*/
static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
+ struct afs_super_info *as = AFS_FS_S(dentry->d_sb);
struct afs_fs_cursor fc;
struct afs_volume_status vs;
struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
struct key *key;
int ret;
+ buf->f_type = dentry->d_sb->s_magic;
+ buf->f_bsize = AFS_BLOCK_SIZE;
+ buf->f_namelen = AFSNAMEMAX - 1;
+
+ if (as->dyn_root) {
+ buf->f_blocks = 1;
+ buf->f_bavail = 0;
+ buf->f_bfree = 0;
+ return 0;
+ }
+
key = afs_request_key(vnode->volume->cell);
if (IS_ERR(key))
return PTR_ERR(key);
@@ -645,10 +697,6 @@ static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
key_put(key);
if (ret == 0) {
- buf->f_type = dentry->d_sb->s_magic;
- buf->f_bsize = AFS_BLOCK_SIZE;
- buf->f_namelen = AFSNAMEMAX - 1;
-
if (vs.max_quota == 0)
buf->f_blocks = vs.part_max_blocks;
else