This work is in preperation for being able to set a different root as the
default mounting root.
There is currently a problem with how we mount subvolumes. We cannot currently
mount a subvolume of a subvolume, you can only mount subvolumes/snapshots of the
default subvolume. So say you take a snapshot of the default subvolume and call
it snap1, and then take a snapshot of snap1 and call it snap2, so now you have
/
/snap1
/snap1/snap2
as your available volumes. Currently you can only mount / and /snap1, you
cannot mount /snap1/snap2. To fix this problem instead of passing
subvol=<name>
you must pass in subvol=<treeid>, where <treeid> is the tree id that
gets spit
out via the subvolume listing you get from the subvolume listing patches
(btrfsctl -l). This allows us to mount /, /snap1 and /snap1/snap2 as the root
volume.
In addition to the above, we also now read the default dir item in the tree root
to get the root key that it points to. For now this just points at what has
always been the default subvolme, but later on I plan to change it to point at
whatever root you want to be the new default root, so you can just set the
default mount and not have to mount with -o subvol=<treeid>. I tested
this out
with the above scenario and it worked perfectly. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
---
fs/btrfs/ctree.h | 2 +-
fs/btrfs/export.c | 4 +-
fs/btrfs/inode.c | 10 ++-
fs/btrfs/relocation.c | 2 +-
fs/btrfs/super.c | 167 +++++++++++++++++++++++++++++++++++-------------
fs/btrfs/tree-log.c | 2 +-
6 files changed, 133 insertions(+), 54 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 444b3e9..464f688 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2318,7 +2318,7 @@ int btrfs_init_cachep(void);
void btrfs_destroy_cachep(void);
long btrfs_ioctl_trans_end(struct file *file);
struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
- struct btrfs_root *root);
+ struct btrfs_root *root, int *was_new);
int btrfs_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to);
struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index ba5c3fd..951ef09 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -95,7 +95,7 @@ static struct dentry *btrfs_get_dentry(struct super_block *sb,
u64 objectid,
btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
key.offset = 0;
- inode = btrfs_iget(sb, &key, root);
+ inode = btrfs_iget(sb, &key, root, NULL);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
goto fail;
@@ -223,7 +223,7 @@ static struct dentry *btrfs_get_parent(struct dentry *child)
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
- dentry = d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root));
+ dentry = d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root,
NULL));
if (!IS_ERR(dentry))
dentry->d_op = &btrfs_dentry_operations;
return dentry;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index b3ad168..b383e53 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2131,7 +2131,7 @@ void btrfs_orphan_cleanup(struct btrfs_root *root)
found_key.objectid = found_key.offset;
found_key.type = BTRFS_INODE_ITEM_KEY;
found_key.offset = 0;
- inode = btrfs_iget(root->fs_info->sb, &found_key, root);
+ inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
if (IS_ERR(inode))
break;
@@ -3609,7 +3609,7 @@ static struct inode *btrfs_iget_locked(struct super_block
*s,
* Returns in *is_new if the inode was read from disk
*/
struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
- struct btrfs_root *root)
+ struct btrfs_root *root, int *new)
{
struct inode *inode;
@@ -3624,6 +3624,8 @@ struct inode *btrfs_iget(struct super_block *s, struct
btrfs_key *location,
inode_tree_add(inode);
unlock_new_inode(inode);
+ if (new)
+ *new = 1;
}
return inode;
@@ -3676,7 +3678,7 @@ struct inode *btrfs_lookup_dentry(struct inode *dir,
struct dentry *dentry)
return NULL;
if (location.type == BTRFS_INODE_ITEM_KEY) {
- inode = btrfs_iget(dir->i_sb, &location, root);
+ inode = btrfs_iget(dir->i_sb, &location, root, NULL);
return inode;
}
@@ -3691,7 +3693,7 @@ struct inode *btrfs_lookup_dentry(struct inode *dir,
struct dentry *dentry)
else
inode = new_simple_dir(dir->i_sb, &location, sub_root);
} else {
- inode = btrfs_iget(dir->i_sb, &location, sub_root);
+ inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
}
srcu_read_unlock(&root->fs_info->subvol_srcu, index);
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index cfcc93c..69fc10b 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -3478,7 +3478,7 @@ static struct inode *create_reloc_inode(struct
btrfs_fs_info *fs_info,
key.objectid = objectid;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
- inode = btrfs_iget(root->fs_info->sb, &key, root);
+ inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
BTRFS_I(inode)->index_cnt = group->key.objectid;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 752a546..bcbdc1b 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -72,7 +72,7 @@ enum {
static match_table_t tokens = {
{Opt_degraded, "degraded"},
- {Opt_subvol, "subvol=%s"},
+ {Opt_subvol, "subvol=%d"},
{Opt_device, "device=%s"},
{Opt_nodatasum, "nodatasum"},
{Opt_nodatacow, "nodatacow"},
@@ -277,12 +277,13 @@ int btrfs_parse_options(struct btrfs_root *root, char
*options)
* only when we need to allocate a new super block.
*/
static int btrfs_parse_early_options(const char *options, fmode_t flags,
- void *holder, char **subvol_name,
+ void *holder, u64 *subvol_objectid,
struct btrfs_fs_devices **fs_devices)
{
substring_t args[MAX_OPT_ARGS];
char *opts, *p;
int error = 0;
+ int intarg;
if (!options)
goto out;
@@ -303,7 +304,10 @@ static int btrfs_parse_early_options(const char *options,
fmode_t flags,
token = match_token(p, tokens, args);
switch (token) {
case Opt_subvol:
- *subvol_name = match_strdup(&args[0]);
+ intarg = 0;
+ match_int(&args[0], &intarg);
+ if (intarg)
+ *subvol_objectid = intarg;
break;
case Opt_device:
error = btrfs_scan_one_device(match_strdup(&args[0]),
@@ -319,17 +323,110 @@ static int btrfs_parse_early_options(const char *options,
fmode_t flags,
out_free_opts:
kfree(opts);
out:
+ return error;
+}
+
+static struct dentry *get_default_root(struct super_block *sb, u64
subvol_objectid)
+{
+ struct btrfs_root *root = sb->s_fs_info;
+ struct btrfs_root *new_root;
+ struct btrfs_dir_item *di;
+ struct btrfs_path *path;
+ struct btrfs_key location;
+ struct inode *inode;
+ struct dentry *dentry;
+ u64 dir_id;
+ int new = 0;
+
/*
- * If no subvolume name is specified we use the default one. Allocate
- * a copy of the string "." here so that code later in the
- * mount path doesn''t care if it''s the default volume or
another one.
+ * We have a specific subvol we want to mount, just setup location and
+ * go look up the root.
*/
- if (!*subvol_name) {
- *subvol_name = kstrdup(".", GFP_KERNEL);
- if (!*subvol_name)
- return -ENOMEM;
+ if (subvol_objectid) {
+ location.objectid = subvol_objectid;
+ location.type = BTRFS_ROOT_ITEM_KEY;
+ location.offset = (u64)-1;
+ goto find_root;
}
- return error;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return ERR_PTR(-ENOMEM);
+ path->leave_spinning = 1;
+
+ /*
+ * Find the "default" dir item which points to the root item that we
+ * will mount by default if we haven''t been given a specific
subvolume
+ * to mount.
+ */
+ dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
+ di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7,
0);
+ if (!di) {
+ /*
+ * Ok the default dir item isn''t there. This is weird since
+ * it''s always been there, but don''t freak out, just try
and
+ * mount to root most subvolume.
+ */
+ btrfs_free_path(path);
+ dir_id = BTRFS_FIRST_FREE_OBJECTID;
+ new_root = root->fs_info->fs_root;
+ goto setup_root;
+ }
+
+ btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
+ btrfs_free_path(path);
+
+find_root:
+ new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
+ if (IS_ERR(new_root))
+ return ERR_PTR(PTR_ERR(new_root));
+
+ if (btrfs_root_refs(&new_root->root_item) == 0)
+ return ERR_PTR(-ENOENT);
+
+ dir_id = btrfs_root_dirid(&new_root->root_item);
+setup_root:
+ location.objectid = dir_id;
+ location.type = BTRFS_INODE_ITEM_KEY;
+ location.offset = 0;
+
+ inode = btrfs_iget(sb, &location, new_root, &new);
+ if (!inode)
+ return ERR_PTR(-ENOMEM);
+
+ /*
+ * If we''re just mounting the root most subvol put the inode and
return
+ * a reference to the dentry. We will have already gotten a reference
+ * to the inode in btrfs_fill_super so we''re good to go.
+ */
+ if (!new && sb->s_root->d_inode == inode) {
+ iput(inode);
+ return dget(sb->s_root);
+ }
+
+ if (new) {
+ const struct qstr name = { .name = "/", .len = 1 };
+
+ /*
+ * New inode, we need to make the dentry a sibling of s_root so
+ * everything gets cleaned up properly on unmount.
+ */
+ dentry = d_alloc(sb->s_root, &name);
+ if (!dentry) {
+ iput(inode);
+ return ERR_PTR(-ENOMEM);
+ }
+ d_splice_alias(inode, dentry);
+ } else {
+ /*
+ * We found the inode in cache, just find a dentry for it and
+ * put the reference to the inode we just got.
+ */
+ dentry = d_find_alias(inode);
+ iput(inode);
+ }
+
+ return dentry;
}
static int btrfs_fill_super(struct super_block *sb,
@@ -365,7 +462,7 @@ static int btrfs_fill_super(struct super_block *sb,
key.objectid = BTRFS_FIRST_FREE_OBJECTID;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
- inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root);
+ inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
goto fail_close;
@@ -377,12 +474,6 @@ static int btrfs_fill_super(struct super_block *sb,
err = -ENOMEM;
goto fail_close;
}
-#if 0
- /* this does the super kobj at the same time */
- err = btrfs_sysfs_add_super(tree_root->fs_info);
- if (err)
- goto fail_close;
-#endif
sb->s_root = root_dentry;
@@ -472,29 +563,30 @@ static int btrfs_test_super(struct super_block *s, void
*data)
static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data, struct vfsmount *mnt)
{
- char *subvol_name = NULL;
struct block_device *bdev = NULL;
struct super_block *s;
struct dentry *root;
struct btrfs_fs_devices *fs_devices = NULL;
fmode_t mode = FMODE_READ;
+ u64 subvol_objectid = 0;
int error = 0;
+ int found = 0;
if (!(flags & MS_RDONLY))
mode |= FMODE_WRITE;
error = btrfs_parse_early_options(data, mode, fs_type,
- &subvol_name, &fs_devices);
+ &subvol_objectid, &fs_devices);
if (error)
return error;
error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
if (error)
- goto error_free_subvol_name;
+ goto error;
error = btrfs_open_devices(fs_devices, mode, fs_type);
if (error)
- goto error_free_subvol_name;
+ goto error;
if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
error = -EACCES;
@@ -513,6 +605,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
int flags,
goto error_close_devices;
}
+ found = 1;
btrfs_close_devices(fs_devices);
} else {
char b[BDEVNAME_SIZE];
@@ -523,46 +616,30 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
int flags,
flags & MS_SILENT ? 1 : 0);
if (error) {
deactivate_locked_super(s);
- goto error_free_subvol_name;
+ goto error;
}
btrfs_sb(s)->fs_info->bdev_holder = fs_type;
s->s_flags |= MS_ACTIVE;
}
- if (!strcmp(subvol_name, "."))
- root = dget(s->s_root);
- else {
- mutex_lock(&s->s_root->d_inode->i_mutex);
- root = lookup_one_len(subvol_name, s->s_root,
- strlen(subvol_name));
- mutex_unlock(&s->s_root->d_inode->i_mutex);
-
- if (IS_ERR(root)) {
- deactivate_locked_super(s);
- error = PTR_ERR(root);
- goto error_free_subvol_name;
- }
- if (!root->d_inode) {
- dput(root);
- deactivate_locked_super(s);
- error = -ENXIO;
- goto error_free_subvol_name;
- }
+ root = get_default_root(s, subvol_objectid);
+ if (IS_ERR(root)) {
+ error = PTR_ERR(root);
+ deactivate_locked_super(s);
+ goto error;
}
mnt->mnt_sb = s;
mnt->mnt_root = root;
- kfree(subvol_name);
return 0;
error_s:
error = PTR_ERR(s);
error_close_devices:
btrfs_close_devices(fs_devices);
-error_free_subvol_name:
- kfree(subvol_name);
+error:
return error;
}
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 741666a..c0c2c1c 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -445,7 +445,7 @@ static noinline struct inode *read_one_inode(struct
btrfs_root *root,
key.objectid = objectid;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
- inode = btrfs_iget(root->fs_info->sb, &key, root);
+ inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
if (IS_ERR(inode)) {
inode = NULL;
} else if (is_bad_inode(inode)) {
--
1.5.4.3
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Goffredo Baroncelli
2009-Dec-04 18:49 UTC
Re: [PATCH] Btrfs: change how we mount subvolumes
Hi Josef On Friday 04 December 2009, Josef Bacik wrote:> This work is in preperation for being able to set a different root as the > default mounting root. > > There is currently a problem with how we mount subvolumes. We cannotcurrently> mount a subvolume of a subvolume, you can only mount subvolumes/snapshots ofthe> default subvolume. So say you take a snapshot of the default subvolume andcall> it snap1, and then take a snapshot of snap1 and call it snap2, so now youhave> > / > /snap1 > /snap1/snap2 > > as your available volumes. Currently you can only mount / and /snap1, you > cannot mount /snap1/snap2. To fix this problem instead of passingsubvol=<name>> you must pass in subvol=<treeid>, where <treeid> is the tree id that getsspit> out via the subvolume listing you get from the subvolume listing patches > (btrfsctl -l). This allows us to mount /, /snap1 and /snap1/snap2 as theroot> volume. >Nice feature. But only for clarification purpose I have to correct you: the only limit of the "subvol=" mount option is that the "volume name" or "snapshot name" have to be under the root of the "btrfs" filesystem (or if you prefer under the root of the "." volume). So: - a subvolume created under / may be mounted using the subvol= mount option - a subvolume created under a directory *can''t* be mounted using the subvol= mount option - a subvolume created under a directory and moved under "/" *may* be mounted using the subvol= mount option - a snapshot of a subvolume created under / may be mounted using the subvol= option And so... (As side note: a subvol may be renamed/moved with a simple "mv" command.) In fact the "subvol=" mount option related code, search in the root of the btrfs a subvolume/snapshot named as required, then mount it. Doesn''t matter if it is a snapshot of a subvolume or where it is originally created. In any case I like your idea. BR G.Baroncelli -- gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo) <kreijackATinwind.it> Key fingerprint = 4769 7E51 5293 D36C 814E C054 BF04 F161 3DC5 0512 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, When I made snapshot listing, I thought ''subvol'' parameter is not enough as G.Baroncelli wrote. I think nice feature too. (I tried to expand subvol parameter feature, by iterating dentry search(lookup_one_len) but I cannot treat dentries correctly yet. :) But, is ''subvol=name'' not prohibited yet? When I specified ''subvol=name'', mount command simply mounts filesystem root without error. Josef Bacik wrote:> This work is in preperation for being able to set a different root as the > default mounting root. > > There is currently a problem with how we mount subvolumes. We cannot currently > mount a subvolume of a subvolume, you can only mount subvolumes/snapshots of the > default subvolume. So say you take a snapshot of the default subvolume and call > it snap1, and then take a snapshot of snap1 and call it snap2, so now you have > > / > /snap1 > /snap1/snap2 > > as your available volumes. Currently you can only mount / and /snap1, you > cannot mount /snap1/snap2. To fix this problem instead of passing subvol=<name> > you must pass in subvol=<treeid>, where <treeid> is the tree id that gets spit > out via the subvolume listing you get from the subvolume listing patches > (btrfsctl -l). This allows us to mount /, /snap1 and /snap1/snap2 as the root > volume. > > In addition to the above, we also now read the default dir item in the tree root > to get the root key that it points to. For now this just points at what has > always been the default subvolme, but later on I plan to change it to point at > whatever root you want to be the new default root, so you can just set the > default mount and not have to mount with -o subvol=<treeid>. I tested this out > with the above scenario and it worked perfectly. Thanks, > > Signed-off-by: Josef Bacik <josef@redhat.com> > --- > fs/btrfs/ctree.h | 2 +- > fs/btrfs/export.c | 4 +- > fs/btrfs/inode.c | 10 ++- > fs/btrfs/relocation.c | 2 +- > fs/btrfs/super.c | 167 +++++++++++++++++++++++++++++++++++------------- > fs/btrfs/tree-log.c | 2 +- > 6 files changed, 133 insertions(+), 54 deletions(-) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 444b3e9..464f688 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -2318,7 +2318,7 @@ int btrfs_init_cachep(void); > void btrfs_destroy_cachep(void); > long btrfs_ioctl_trans_end(struct file *file); > struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location, > - struct btrfs_root *root); > + struct btrfs_root *root, int *was_new); > int btrfs_commit_write(struct file *file, struct page *page, > unsigned from, unsigned to); > struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page, > diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c > index ba5c3fd..951ef09 100644 > --- a/fs/btrfs/export.c > +++ b/fs/btrfs/export.c > @@ -95,7 +95,7 @@ static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid, > btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY); > key.offset = 0; > > - inode = btrfs_iget(sb, &key, root); > + inode = btrfs_iget(sb, &key, root, NULL); > if (IS_ERR(inode)) { > err = PTR_ERR(inode); > goto fail; > @@ -223,7 +223,7 @@ static struct dentry *btrfs_get_parent(struct dentry *child) > > key.type = BTRFS_INODE_ITEM_KEY; > key.offset = 0; > - dentry = d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root)); > + dentry = d_obtain_alias(btrfs_iget(root->fs_info->sb, &key, root, NULL)); > if (!IS_ERR(dentry)) > dentry->d_op = &btrfs_dentry_operations; > return dentry; > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index b3ad168..b383e53 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -2131,7 +2131,7 @@ void btrfs_orphan_cleanup(struct btrfs_root *root) > found_key.objectid = found_key.offset; > found_key.type = BTRFS_INODE_ITEM_KEY; > found_key.offset = 0; > - inode = btrfs_iget(root->fs_info->sb, &found_key, root); > + inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL); > if (IS_ERR(inode)) > break; > > @@ -3609,7 +3609,7 @@ static struct inode *btrfs_iget_locked(struct super_block *s, > * Returns in *is_new if the inode was read from disk > */ > struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location, > - struct btrfs_root *root) > + struct btrfs_root *root, int *new) > { > struct inode *inode; > > @@ -3624,6 +3624,8 @@ struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location, > > inode_tree_add(inode); > unlock_new_inode(inode); > + if (new) > + *new = 1; > } > > return inode; > @@ -3676,7 +3678,7 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry) > return NULL; > > if (location.type == BTRFS_INODE_ITEM_KEY) { > - inode = btrfs_iget(dir->i_sb, &location, root); > + inode = btrfs_iget(dir->i_sb, &location, root, NULL); > return inode; > } > > @@ -3691,7 +3693,7 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry) > else > inode = new_simple_dir(dir->i_sb, &location, sub_root); > } else { > - inode = btrfs_iget(dir->i_sb, &location, sub_root); > + inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL); > } > srcu_read_unlock(&root->fs_info->subvol_srcu, index); > > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c > index cfcc93c..69fc10b 100644 > --- a/fs/btrfs/relocation.c > +++ b/fs/btrfs/relocation.c > @@ -3478,7 +3478,7 @@ static struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info, > key.objectid = objectid; > key.type = BTRFS_INODE_ITEM_KEY; > key.offset = 0; > - inode = btrfs_iget(root->fs_info->sb, &key, root); > + inode = btrfs_iget(root->fs_info->sb, &key, root, NULL); > BUG_ON(IS_ERR(inode) || is_bad_inode(inode)); > BTRFS_I(inode)->index_cnt = group->key.objectid; > > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index 752a546..bcbdc1b 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -72,7 +72,7 @@ enum { > > static match_table_t tokens = { > {Opt_degraded, "degraded"}, > - {Opt_subvol, "subvol=%s"}, > + {Opt_subvol, "subvol=%d"}, > {Opt_device, "device=%s"}, > {Opt_nodatasum, "nodatasum"}, > {Opt_nodatacow, "nodatacow"}, > @@ -277,12 +277,13 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) > * only when we need to allocate a new super block. > */ > static int btrfs_parse_early_options(const char *options, fmode_t flags, > - void *holder, char **subvol_name, > + void *holder, u64 *subvol_objectid, > struct btrfs_fs_devices **fs_devices) > { > substring_t args[MAX_OPT_ARGS]; > char *opts, *p; > int error = 0; > + int intarg; > > if (!options) > goto out; > @@ -303,7 +304,10 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags, > token = match_token(p, tokens, args); > switch (token) { > case Opt_subvol: > - *subvol_name = match_strdup(&args[0]); > + intarg = 0; > + match_int(&args[0], &intarg); > + if (intarg) > + *subvol_objectid = intarg; > break; > case Opt_device: > error = btrfs_scan_one_device(match_strdup(&args[0]), > @@ -319,17 +323,110 @@ static int btrfs_parse_early_options(const char *options, fmode_t flags, > out_free_opts: > kfree(opts); > out: > + return error; > +} > + > +static struct dentry *get_default_root(struct super_block *sb, u64 subvol_objectid) > +{ > + struct btrfs_root *root = sb->s_fs_info; > + struct btrfs_root *new_root; > + struct btrfs_dir_item *di; > + struct btrfs_path *path; > + struct btrfs_key location; > + struct inode *inode; > + struct dentry *dentry; > + u64 dir_id; > + int new = 0; > + > /* > - * If no subvolume name is specified we use the default one. Allocate > - * a copy of the string "." here so that code later in the > - * mount path doesn''t care if it''s the default volume or another one. > + * We have a specific subvol we want to mount, just setup location and > + * go look up the root. > */ > - if (!*subvol_name) { > - *subvol_name = kstrdup(".", GFP_KERNEL); > - if (!*subvol_name) > - return -ENOMEM; > + if (subvol_objectid) { > + location.objectid = subvol_objectid; > + location.type = BTRFS_ROOT_ITEM_KEY; > + location.offset = (u64)-1; > + goto find_root; > } > - return error; > + > + path = btrfs_alloc_path(); > + if (!path) > + return ERR_PTR(-ENOMEM); > + path->leave_spinning = 1; > + > + /* > + * Find the "default" dir item which points to the root item that we > + * will mount by default if we haven''t been given a specific subvolume > + * to mount. > + */ > + dir_id = btrfs_super_root_dir(&root->fs_info->super_copy); > + di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0); > + if (!di) { > + /* > + * Ok the default dir item isn''t there. This is weird since > + * it''s always been there, but don''t freak out, just try and > + * mount to root most subvolume. > + */ > + btrfs_free_path(path); > + dir_id = BTRFS_FIRST_FREE_OBJECTID; > + new_root = root->fs_info->fs_root; > + goto setup_root; > + } > + > + btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location); > + btrfs_free_path(path); > + > +find_root: > + new_root = btrfs_read_fs_root_no_name(root->fs_info, &location); > + if (IS_ERR(new_root)) > + return ERR_PTR(PTR_ERR(new_root)); > + > + if (btrfs_root_refs(&new_root->root_item) == 0) > + return ERR_PTR(-ENOENT); > + > + dir_id = btrfs_root_dirid(&new_root->root_item); > +setup_root: > + location.objectid = dir_id; > + location.type = BTRFS_INODE_ITEM_KEY; > + location.offset = 0; > + > + inode = btrfs_iget(sb, &location, new_root, &new); > + if (!inode) > + return ERR_PTR(-ENOMEM); > + > + /* > + * If we''re just mounting the root most subvol put the inode and return > + * a reference to the dentry. We will have already gotten a reference > + * to the inode in btrfs_fill_super so we''re good to go. > + */ > + if (!new && sb->s_root->d_inode == inode) { > + iput(inode); > + return dget(sb->s_root); > + } > + > + if (new) { > + const struct qstr name = { .name = "/", .len = 1 }; > + > + /* > + * New inode, we need to make the dentry a sibling of s_root so > + * everything gets cleaned up properly on unmount. > + */ > + dentry = d_alloc(sb->s_root, &name); > + if (!dentry) { > + iput(inode); > + return ERR_PTR(-ENOMEM); > + } > + d_splice_alias(inode, dentry); > + } else { > + /* > + * We found the inode in cache, just find a dentry for it and > + * put the reference to the inode we just got. > + */ > + dentry = d_find_alias(inode); > + iput(inode); > + } > + > + return dentry; > } > > static int btrfs_fill_super(struct super_block *sb, > @@ -365,7 +462,7 @@ static int btrfs_fill_super(struct super_block *sb, > key.objectid = BTRFS_FIRST_FREE_OBJECTID; > key.type = BTRFS_INODE_ITEM_KEY; > key.offset = 0; > - inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root); > + inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL); > if (IS_ERR(inode)) { > err = PTR_ERR(inode); > goto fail_close; > @@ -377,12 +474,6 @@ static int btrfs_fill_super(struct super_block *sb, > err = -ENOMEM; > goto fail_close; > } > -#if 0 > - /* this does the super kobj at the same time */ > - err = btrfs_sysfs_add_super(tree_root->fs_info); > - if (err) > - goto fail_close; > -#endif > > sb->s_root = root_dentry; > > @@ -472,29 +563,30 @@ static int btrfs_test_super(struct super_block *s, void *data) > static int btrfs_get_sb(struct file_system_type *fs_type, int flags, > const char *dev_name, void *data, struct vfsmount *mnt) > { > - char *subvol_name = NULL; > struct block_device *bdev = NULL; > struct super_block *s; > struct dentry *root; > struct btrfs_fs_devices *fs_devices = NULL; > fmode_t mode = FMODE_READ; > + u64 subvol_objectid = 0; > int error = 0; > + int found = 0; > > if (!(flags & MS_RDONLY)) > mode |= FMODE_WRITE; > > error = btrfs_parse_early_options(data, mode, fs_type, > - &subvol_name, &fs_devices); > + &subvol_objectid, &fs_devices); > if (error) > return error; > > error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices); > if (error) > - goto error_free_subvol_name; > + goto error; > > error = btrfs_open_devices(fs_devices, mode, fs_type); > if (error) > - goto error_free_subvol_name; > + goto error; > > if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) { > error = -EACCES; > @@ -513,6 +605,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, > goto error_close_devices; > } > > + found = 1; > btrfs_close_devices(fs_devices); > } else { > char b[BDEVNAME_SIZE]; > @@ -523,46 +616,30 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, > flags & MS_SILENT ? 1 : 0); > if (error) { > deactivate_locked_super(s); > - goto error_free_subvol_name; > + goto error; > } > > btrfs_sb(s)->fs_info->bdev_holder = fs_type; > s->s_flags |= MS_ACTIVE; > } > > - if (!strcmp(subvol_name, ".")) > - root = dget(s->s_root); > - else { > - mutex_lock(&s->s_root->d_inode->i_mutex); > - root = lookup_one_len(subvol_name, s->s_root, > - strlen(subvol_name)); > - mutex_unlock(&s->s_root->d_inode->i_mutex); > - > - if (IS_ERR(root)) { > - deactivate_locked_super(s); > - error = PTR_ERR(root); > - goto error_free_subvol_name; > - } > - if (!root->d_inode) { > - dput(root); > - deactivate_locked_super(s); > - error = -ENXIO; > - goto error_free_subvol_name; > - } > + root = get_default_root(s, subvol_objectid); > + if (IS_ERR(root)) { > + error = PTR_ERR(root); > + deactivate_locked_super(s); > + goto error; > } > > mnt->mnt_sb = s; > mnt->mnt_root = root; > > - kfree(subvol_name); > return 0; > > error_s: > error = PTR_ERR(s); > error_close_devices: > btrfs_close_devices(fs_devices); > -error_free_subvol_name: > - kfree(subvol_name); > +error: > return error; > } > > diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c > index 741666a..c0c2c1c 100644 > --- a/fs/btrfs/tree-log.c > +++ b/fs/btrfs/tree-log.c > @@ -445,7 +445,7 @@ static noinline struct inode *read_one_inode(struct btrfs_root *root, > key.objectid = objectid; > key.type = BTRFS_INODE_ITEM_KEY; > key.offset = 0; > - inode = btrfs_iget(root->fs_info->sb, &key, root); > + inode = btrfs_iget(root->fs_info->sb, &key, root, NULL); > if (IS_ERR(inode)) { > inode = NULL; > } else if (is_bad_inode(inode)) {-- taruisi -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html