[PATCH] Btrfs: check file extent type before anything else

[PATCH] Btrfs: check file extent type before anything else

[Josef Bacik]

I hit this problem with my no holes patch and it made me realize what the
problem was for bz 60834.  If the first item in the leaf is an inline extent and
we try to read anything starting from disk_bytenr onward we will read off the
end of the leaf.  So we need to check to see what it's type is, and if it's not
REG we can just break out.  This should fix this problem.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
---
 fs/btrfs/backref.c |  1 +
 fs/btrfs/send.c    | 10 +++++-----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 3775947..b763f10 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1051,6 +1051,7 @@ static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
 
 	if (ret < 0 && ret != -ENOENT) {
 		free_leaf_list(*leafs);
+		ulist_free(*leafs);
 		return ret;
 	}
 
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 8af536f..629cb9e 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -3943,16 +3943,16 @@ static int is_extent_unchanged(struct send_ctx *sctx,
 	while (key.offset < ekey->offset + left_len) {
 		ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
 		right_type = btrfs_file_extent_type(eb, ei);
-		right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
-		right_len = btrfs_file_extent_num_bytes(eb, ei);
-		right_offset = btrfs_file_extent_offset(eb, ei);
-		right_gen = btrfs_file_extent_generation(eb, ei);
-
 		if (right_type != BTRFS_FILE_EXTENT_REG) {
 			ret = 0;
 			goto out;
 		}
 
+		right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
+		right_len = btrfs_file_extent_num_bytes(eb, ei);
+		right_offset = btrfs_file_extent_offset(eb, ei);
+		right_gen = btrfs_file_extent_generation(eb, ei);
+
 		/*
 		 * Are we at extent 8? If yes, we know the extent is changed.
 		 * This may only happen on the first iteration.
-- 
1.8.3.1

Re: [PATCH] Btrfs: check file extent type before anything else

[Stefan Behrens]

On Thu, 31 Oct 2013 16:50:43 -0400, Josef Bacik wrote:
> I hit this problem with my no holes patch and it made me realize what the
> problem was for bz 60834.  If the first item in the leaf is an inline extent and
> we try to read anything starting from disk_bytenr onward we will read off the
> end of the leaf.  So we need to check to see what it's type is, and if it's not
> REG we can just break out.  This should fix this problem.  Thanks,
> 
> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
> ---
>  fs/btrfs/backref.c |  1 +
>  fs/btrfs/send.c    | 10 +++++-----
>  2 files changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
> index 3775947..b763f10 100644
> --- a/fs/btrfs/backref.c
> +++ b/fs/btrfs/backref.c
> @@ -1051,6 +1051,7 @@ static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
>  
>  	if (ret < 0 && ret != -ENOENT) {
>  		free_leaf_list(*leafs);
> +		ulist_free(*leafs);

An en passant fix for which problem?


>  		return ret;
>  	}
>  
> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> index 8af536f..629cb9e 100644
> --- a/fs/btrfs/send.c
> +++ b/fs/btrfs/send.c
> @@ -3943,16 +3943,16 @@ static int is_extent_unchanged(struct send_ctx *sctx,
>  	while (key.offset < ekey->offset + left_len) {
>  		ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
>  		right_type = btrfs_file_extent_type(eb, ei);
> -		right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
> -		right_len = btrfs_file_extent_num_bytes(eb, ei);
> -		right_offset = btrfs_file_extent_offset(eb, ei);
> -		right_gen = btrfs_file_extent_generation(eb, ei);
> -
>  		if (right_type != BTRFS_FILE_EXTENT_REG) {
>  			ret = 0;
>  			goto out;
>  		}
>  
> +		right_disknr = btrfs_file_extent_disk_bytenr(eb, ei);
> +		right_len = btrfs_file_extent_num_bytes(eb, ei);
> +		right_offset = btrfs_file_extent_offset(eb, ei);
> +		right_gen = btrfs_file_extent_generation(eb, ei);
> +
>  		/*
>  		 * Are we at extent 8? If yes, we know the extent is changed.
>  		 * This may only happen on the first iteration.
> 

Re: [PATCH] Btrfs: check file extent type before anything else

[Josef Bacik]

On Fri, Nov 01, 2013 at 08:30:44AM +0100, Stefan Behrens wrote:
> On Thu, 31 Oct 2013 16:50:43 -0400, Josef Bacik wrote:
> > I hit this problem with my no holes patch and it made me realize what the
> > problem was for bz 60834.  If the first item in the leaf is an inline extent and
> > we try to read anything starting from disk_bytenr onward we will read off the
> > end of the leaf.  So we need to check to see what it's type is, and if it's not
> > REG we can just break out.  This should fix this problem.  Thanks,
> > 
> > Signed-off-by: Josef Bacik <jbacik@fusionio.com>
> > ---
> >  fs/btrfs/backref.c |  1 +
> >  fs/btrfs/send.c    | 10 +++++-----
> >  2 files changed, 6 insertions(+), 5 deletions(-)
> > 
> > diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
> > index 3775947..b763f10 100644
> > --- a/fs/btrfs/backref.c
> > +++ b/fs/btrfs/backref.c
> > @@ -1051,6 +1051,7 @@ static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
> >  
> >  	if (ret < 0 && ret != -ENOENT) {
> >  		free_leaf_list(*leafs);
> > +		ulist_free(*leafs);
> 
> An en passant fix for which problem?
> 

Oops, sorry about that, not a problem just me doing other things, I'll drop that
bit.  Thanks,

Josef