| Message ID | 20180704171045.9814-1-marek.behun@nic.cz |
|---|---|
| State | Superseded |
| Delegated to: | Tom Rini |
| Headers | show |
| Series | [U-Boot] fs: btrfs: Fix wrong comparison in logical to physical mapping | expand |
On Wed, 2018-07-04 at 19:10 +0200, Marek Behún wrote: > CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe. > > > The comparison > logical > item->logical + item->length > in btrfs_map_logical_to_physical is wrong and should be instead > logical >= item->logical + item->length > For example, if > item->logical = 4096 > item->length = 4096 > and we are looking for logical = 8192, it is not part of item (item is > [4096, 8191]). But the comparison is false and we think we have found > the correct item, although we should be searing in the right subtree. > > This fixes some bugs I encountered. > > Signed-off-by: Marek Behun <marek.behun@nic.cz> > --- > fs/btrfs/chunk-map.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/btrfs/chunk-map.c b/fs/btrfs/chunk-map.c > index beb6a4bb92..31619f6241 100644 > --- a/fs/btrfs/chunk-map.c > +++ b/fs/btrfs/chunk-map.c > @@ -78,7 +78,7 @@ u64 btrfs_map_logical_to_physical(u64 logical) > > if (item->logical > logical) > node = node->rb_left; > - else if (logical > item->logical + item->length) > + else if (logical > item->logical + item->length - 1) maybe logical >= item->logical + item->length ? > node = node->rb_right;
On Wed, 4 Jul 2018 17:48:30 +0000
Joakim Tjernlund <Joakim.Tjernlund@infinera.com> wrote:
> maybe logical >= item->logical + item->length ?
You're right, i did it correctly in the commit message but not in the
code :)
diff --git a/fs/btrfs/chunk-map.c b/fs/btrfs/chunk-map.c index beb6a4bb92..31619f6241 100644 --- a/fs/btrfs/chunk-map.c +++ b/fs/btrfs/chunk-map.c @@ -78,7 +78,7 @@ u64 btrfs_map_logical_to_physical(u64 logical) if (item->logical > logical) node = node->rb_left; - else if (logical > item->logical + item->length) + else if (logical > item->logical + item->length - 1) node = node->rb_right; else return item->physical + logical - item->logical;
The comparison logical > item->logical + item->length in btrfs_map_logical_to_physical is wrong and should be instead logical >= item->logical + item->length For example, if item->logical = 4096 item->length = 4096 and we are looking for logical = 8192, it is not part of item (item is [4096, 8191]). But the comparison is false and we think we have found the correct item, although we should be searing in the right subtree. This fixes some bugs I encountered. Signed-off-by: Marek Behun <marek.behun@nic.cz> --- fs/btrfs/chunk-map.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)