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authorPatrick McHardy <kaber@trash.net>2013-03-31 18:10:34 +0200
committerPatrick McHardy <kaber@trash.net>2013-03-31 18:10:34 +0200
commit70711d223510ba1773cfe1d7770a56141c815ff8 (patch)
tree4a71f38a3a554ddecaa31b7d8c6bc49b7d1705b4 /fs/btrfs/root-tree.c
parentd53b4ed072d9779cdf53582c46436dec06d0961f (diff)
parent19f949f52599ba7c3f67a5897ac6be14bfcb1200 (diff)
Merge tag 'v3.8' of /home/kaber/src/repos/linux
Linux 3.8 Signed-off-by: Patrick McHardy <kaber@trash.net> Conflicts: include/linux/Kbuild include/linux/netlink.h
Diffstat (limited to 'fs/btrfs/root-tree.c')
-rw-r--r--fs/btrfs/root-tree.c104
1 files changed, 102 insertions, 2 deletions
diff --git a/fs/btrfs/root-tree.c b/fs/btrfs/root-tree.c
index 24fb8ce4e07..668af537a3e 100644
--- a/fs/btrfs/root-tree.c
+++ b/fs/btrfs/root-tree.c
@@ -16,12 +16,55 @@
* Boston, MA 021110-1307, USA.
*/
+#include <linux/uuid.h>
#include "ctree.h"
#include "transaction.h"
#include "disk-io.h"
#include "print-tree.h"
/*
+ * Read a root item from the tree. In case we detect a root item smaller then
+ * sizeof(root_item), we know it's an old version of the root structure and
+ * initialize all new fields to zero. The same happens if we detect mismatching
+ * generation numbers as then we know the root was once mounted with an older
+ * kernel that was not aware of the root item structure change.
+ */
+void btrfs_read_root_item(struct btrfs_root *root,
+ struct extent_buffer *eb, int slot,
+ struct btrfs_root_item *item)
+{
+ 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");
+ }
+ 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);
+ }
+}
+
+/*
* lookup the root with the highest offset for a given objectid. The key we do
* find is copied into 'key'. If we find something return 0, otherwise 1, < 0
* on error.
@@ -61,10 +104,10 @@ int btrfs_find_last_root(struct btrfs_root *root, u64 objectid,
goto out;
}
if (item)
- read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot),
- sizeof(*item));
+ btrfs_read_root_item(root, l, slot, item);
if (key)
memcpy(key, &found_key, sizeof(found_key));
+
ret = 0;
out:
btrfs_free_path(path);
@@ -91,6 +134,7 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
int ret;
int slot;
unsigned long ptr;
+ int old_len;
path = btrfs_alloc_path();
if (!path)
@@ -113,6 +157,45 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
l = path->nodes[0];
slot = path->slots[0];
ptr = btrfs_item_ptr_offset(l, slot);
+ old_len = btrfs_item_size_nr(l, slot);
+
+ /*
+ * If this is the first time we update the root item which originated
+ * from an older kernel, we need to enlarge the item size to make room
+ * for the added fields.
+ */
+ if (old_len < sizeof(*item)) {
+ btrfs_release_path(path);
+ ret = btrfs_search_slot(trans, root, key, path,
+ -1, 1);
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, root, ret);
+ goto out;
+ }
+
+ ret = btrfs_del_item(trans, root, path);
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, root, ret);
+ goto out;
+ }
+ btrfs_release_path(path);
+ ret = btrfs_insert_empty_item(trans, root, path,
+ key, sizeof(*item));
+ if (ret < 0) {
+ btrfs_abort_transaction(trans, root, ret);
+ goto out;
+ }
+ l = path->nodes[0];
+ slot = path->slots[0];
+ ptr = btrfs_item_ptr_offset(l, slot);
+ }
+
+ /*
+ * Update generation_v2 so at the next mount we know the new root
+ * fields are valid.
+ */
+ btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
+
write_extent_buffer(l, item, ptr, sizeof(*item));
btrfs_mark_buffer_dirty(path->nodes[0]);
out:
@@ -123,6 +206,10 @@ out:
int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_key *key, struct btrfs_root_item *item)
{
+ /*
+ * Make sure generation v1 and v2 match. See update_root for details.
+ */
+ btrfs_set_root_generation_v2(item, btrfs_root_generation(item));
return btrfs_insert_item(trans, root, key, item, sizeof(*item));
}
@@ -454,3 +541,16 @@ void btrfs_check_and_init_root_item(struct btrfs_root_item *root_item)
root_item->byte_limit = 0;
}
}
+
+void btrfs_update_root_times(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root)
+{
+ struct btrfs_root_item *item = &root->root_item;
+ struct timespec ct = CURRENT_TIME;
+
+ spin_lock(&root->root_item_lock);
+ item->ctransid = cpu_to_le64(trans->transid);
+ item->ctime.sec = cpu_to_le64(ct.tv_sec);
+ item->ctime.nsec = cpu_to_le32(ct.tv_nsec);
+ spin_unlock(&root->root_item_lock);
+}