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mkfs should initialize unused fields properly

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we discovered speed setting is (probably unintentionally) initialized to 1 in make_btrfs(), while being initialized to 0 in btrfs_add_to_fsid(). initialization in make_btrfs() is due to reuse of buf after pwrite() without clearing it. consequently, code like

 	btrfs_set_extent_generation(buf, extent_item, 1);

writes to the same location in buf where speed will be placed, later. It may be a good idea to clear buf after each pwrite(), though leaving the struct btrfs_header intact.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Hugo Mills <hugo@carfax.org.uk>
This commit is contained in:
Jan Schmidt 2010-11-19 16:05:27 +01:00 committed by Chris Mason
parent c55248003c
commit 42f9568bfd
1 changed files with 10 additions and 0 deletions
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10
utils.c
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@ -212,6 +212,8 @@ int make_btrfs(int fd, const char *device, const char *label,
BUG_ON(ret != leafsize);
/* create the items for the extent tree */
memset(buf->data+sizeof(struct btrfs_header), 0,
leafsize-sizeof(struct btrfs_header));
nritems = 0;
itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize);
for (i = 1; i < 7; i++) {
@ -257,6 +259,8 @@ int make_btrfs(int fd, const char *device, const char *label,
BUG_ON(ret != leafsize);
/* create the chunk tree */
memset(buf->data+sizeof(struct btrfs_header), 0,
leafsize-sizeof(struct btrfs_header));
nritems = 0;
item_size = sizeof(*dev_item);
itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) - item_size;
@ -338,6 +342,8 @@ int make_btrfs(int fd, const char *device, const char *label,
ret = pwrite(fd, buf->data, leafsize, blocks[3]);
/* create the device tree */
memset(buf->data+sizeof(struct btrfs_header), 0,
leafsize-sizeof(struct btrfs_header));
nritems = 0;
itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) -
sizeof(struct btrfs_dev_extent);
@ -371,6 +377,8 @@ int make_btrfs(int fd, const char *device, const char *label,
ret = pwrite(fd, buf->data, leafsize, blocks[4]);
/* create the FS root */
memset(buf->data+sizeof(struct btrfs_header), 0,
leafsize-sizeof(struct btrfs_header));
btrfs_set_header_bytenr(buf, blocks[5]);
btrfs_set_header_owner(buf, BTRFS_FS_TREE_OBJECTID);
btrfs_set_header_nritems(buf, 0);
@ -379,6 +387,8 @@ int make_btrfs(int fd, const char *device, const char *label,
BUG_ON(ret != leafsize);
/* finally create the csum root */
memset(buf->data+sizeof(struct btrfs_header), 0,
leafsize-sizeof(struct btrfs_header));
btrfs_set_header_bytenr(buf, blocks[6]);
btrfs_set_header_owner(buf, BTRFS_CSUM_TREE_OBJECTID);
btrfs_set_header_nritems(buf, 0);