Hi Anand,
Some comments on your kernel patch from a quick jump through:
On 01.11.2012 11:46, Anand jain wrote:
From: Anand Jain <anand.jain@xxxxxxxxxx>
This modifies the struct btrfs_root_item to hold the label,
and make it v3 of this structure.
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
fs/btrfs/ctree.h | 14 ++++++++++++++
fs/btrfs/ioctl.c | 32 ++++++++++++++++++++++++++++++++
fs/btrfs/ioctl.h | 2 ++
fs/btrfs/root-tree.c | 44 +++++++++++++++++++++++---------------------
fs/btrfs/transaction.c | 1 +
5 files changed, 72 insertions(+), 21 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 994d255..b280256 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -759,6 +759,10 @@ struct btrfs_root_item {
struct btrfs_timespec otime;
struct btrfs_timespec stime;
struct btrfs_timespec rtime;
+
+ __le64 generation_v3;
What is that supposed to be?
+ char label[BTRFS_LABEL_SIZE]; /* Add label to subvol */
+
__le64 reserved[8]; /* for future */
} __attribute__ ((__packed__));
You can't do that. There's a reason why we've got reserved bytes for
future use. Never change the struct's size.
@@ -2428,6 +2432,8 @@ BTRFS_SETGET_STACK_FUNCS(root_last_snapshot, struct btrfs_root_item,
last_snapshot, 64);
BTRFS_SETGET_STACK_FUNCS(root_generation_v2, struct btrfs_root_item,
generation_v2, 64);
+BTRFS_SETGET_STACK_FUNCS(root_generation_v3, struct btrfs_root_item,
+ generation_v3, 64);
BTRFS_SETGET_STACK_FUNCS(root_ctransid, struct btrfs_root_item,
ctransid, 64);
BTRFS_SETGET_STACK_FUNCS(root_otransid, struct btrfs_root_item,
@@ -2441,6 +2447,14 @@ static inline bool btrfs_root_readonly(struct btrfs_root *root)
{
return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
}
+static inline char * btrfs_root_label(struct btrfs_root *root)
+{
+ return (root->root_item.label);
+}
+static inline void btrfs_root_set_label(struct btrfs_root *root, char *val)
+{
+ memcpy(root->root_item.label,val,BTRFS_LABEL_SIZE);
+}
/* struct btrfs_root_backup */
BTRFS_SETGET_STACK_FUNCS(backup_tree_root, struct btrfs_root_backup,
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index e58bd9d..cce0128 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3725,6 +3725,34 @@ static int btrfs_ioctl_set_label(struct btrfs_root *root, void __user *arg)
return 0;
}
+static int btrfs_ioctl_subvol_getlabel(struct btrfs_root *root,
+ void __user *arg)
+{
+ char *label;
+
+ label = btrfs_root_label(root);
+ if (copy_to_user(arg, label, BTRFS_LABEL_SIZE))
+ return -EFAULT;
+ return 0;
+}
+
+static int btrfs_ioctl_subvol_setlabel(struct btrfs_root *root,
+ void __user *arg)
+{
+ char label[BTRFS_LABEL_SIZE];
+ struct btrfs_trans_handle *trans;
+
+ if (copy_from_user(label, arg, BTRFS_LABEL_SIZE))
+ return -EFAULT;
+ trans = btrfs_start_transaction(root, 1);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+ btrfs_root_set_label(root, label);
+ btrfs_commit_transaction(trans, root);
Why use start/commit instead of join/end here?
+ return 0;
+}
+
long btrfs_ioctl(struct file *file, unsigned int
cmd, unsigned long arg)
{
@@ -3827,6 +3855,10 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_get_label(root, argp);
case BTRFS_IOC_SET_LABEL:
return btrfs_ioctl_set_label(root, argp);
+ case BTRFS_IOC_SUBVOL_GETLABEL:
+ return btrfs_ioctl_subvol_getlabel(root, argp);
+ case BTRFS_IOC_SUBVOL_SETLABEL:
+ return btrfs_ioctl_subvol_setlabel(root, argp);
}
return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 0c60fcb..1009a0c 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -455,4 +455,6 @@ struct btrfs_ioctl_send_args {
struct btrfs_ioctl_get_dev_stats)
#define BTRFS_IOC_GET_LABEL _IOR(BTRFS_IOCTL_MAGIC, 53, __u64)
#define BTRFS_IOC_SET_LABEL _IOW(BTRFS_IOCTL_MAGIC, 54, __u64)
+#define BTRFS_IOC_SUBVOL_GETLABEL _IOWR(BTRFS_IOCTL_MAGIC, 55, __u64)
+#define BTRFS_IOC_SUBVOL_SETLABEL _IOW(BTRFS_IOCTL_MAGIC, 56, __u64)
#endif
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index eb923d0..2a9ae5f 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -35,32 +35,34 @@ void btrfs_read_root_item(struct btrfs_root *root,
{
uuid_le uuid;
int len;
- int need_reset = 0;
len = btrfs_item_size_nr(eb, slot);
read_extent_buffer(eb, item, btrfs_item_ptr_offset(eb, slot),
min_t(int, len, (int)sizeof(*item)));
- if (len < sizeof(*item))
- need_reset = 1;
- if (!need_reset && btrfs_root_generation(item)
- != btrfs_root_generation_v2(item)) {
- if (btrfs_root_generation_v2(item) != 0) {
- printk(KERN_WARNING "btrfs: mismatching "
- "generation and generation_v2 "
- "found in root item. This root "
- "was probably mounted with an "
- "older kernel. Resetting all "
- "new fields.\n");
Please argue why removing this without replacement should be a good idea.
- }
- need_reset = 1;
- }
- if (need_reset) {
- memset(&item->generation_v2, 0,
- sizeof(*item) - offsetof(struct btrfs_root_item,
- generation_v2));
- uuid_le_gen(&uuid);
- memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
+ /* when len is gt sizeof(*item) that means its downgrade and
+ the new members won't be touched anyways
+ if len is lt sizeof(*item) its upgrade, we need to take
+ care to set/reset newer members.
+ */
+ if (len < sizeof(*item)) {
+ /* there is an upgrade need to set/reset the new members
+ assume v1 v2 v3 it can be upgrade from
+ v1 to v2 (set/reset only new members of v2)
+ v2 to v3 (set/reset only new members of v3)
+ v1 to v3 (set/reset new to v1)
+ */
+ if (btrfs_root_generation(item) != btrfs_root_generation_v2(item)) {
+ //memset(&item->generation_v2, 0,
+ //sizeof(*item) - offsetof(struct btrfs_root_item, generation_v2));
+ memset(&item->generation_v2, 0, sizeof(*item) - len);
+ uuid_le_gen(&uuid);
+ memcpy(item->uuid, uuid.b, BTRFS_UUID_SIZE);
+ } else if (btrfs_root_generation_v2(item) != btrfs_root_generation_v3(item)) {
+ //memset(&item->generation_v3, 0,
+ // sizeof(*item) - offsetof(struct btrfs_root_item, generation_v3));
+ memset(&item->generation_v3, 0, sizeof(*item) - len);
+ }
}
}
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 04bbfb1..45bff43 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1116,6 +1116,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
btrfs_set_root_otransid(new_root_item, trans->transid);
memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
+ memset(new_root_item->label, 0, BTRFS_LABEL_SIZE);
btrfs_set_root_stransid(new_root_item, 0);
btrfs_set_root_rtransid(new_root_item, 0);
-Jan
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