* [PATCH] Btrfs: fix unexpected return value of fiemap
@ 2016-05-18 0:21 Liu Bo
2016-05-18 9:41 ` David Sterba
0 siblings, 1 reply; 4+ messages in thread
From: Liu Bo @ 2016-05-18 0:21 UTC (permalink / raw)
To: linux-btrfs
btrfs's fiemap is supposed to return 0 on success and
return < 0 on error, however, ret becomes 1 after looking
up the last file extent, and if the offset is beyond EOF,
we can return 1.
This may confuse applications using ioctl(FIEL_IOC_FIEMAP).
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
fs/btrfs/extent_io.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index d247fc0..16ece52 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4379,8 +4379,12 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
if (ret < 0) {
btrfs_free_path(path);
return ret;
+ } else {
+ WARN_ON(!ret);
+ if (ret == 1)
+ ret = 0;
}
- WARN_ON(!ret);
+
path->slots[0]--;
btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
found_type = found_key.type;
--
2.5.5
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] Btrfs: fix unexpected return value of fiemap
2016-05-18 0:21 [PATCH] Btrfs: fix unexpected return value of fiemap Liu Bo
@ 2016-05-18 9:41 ` David Sterba
2016-05-18 17:52 ` Liu Bo
0 siblings, 1 reply; 4+ messages in thread
From: David Sterba @ 2016-05-18 9:41 UTC (permalink / raw)
To: Liu Bo; +Cc: linux-btrfs
On Tue, May 17, 2016 at 05:21:48PM -0700, Liu Bo wrote:
> btrfs's fiemap is supposed to return 0 on success and
> return < 0 on error, however, ret becomes 1 after looking
> up the last file extent, and if the offset is beyond EOF,
> we can return 1.
>
> This may confuse applications using ioctl(FIEL_IOC_FIEMAP).
>
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
> ---
> fs/btrfs/extent_io.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index d247fc0..16ece52 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -4379,8 +4379,12 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
> if (ret < 0) {
> btrfs_free_path(path);
> return ret;
> + } else {
> + WARN_ON(!ret);
> + if (ret == 1)
> + ret = 0;
> }
So, ret == 1 can end up here from btrfs_lookup_file_extent ->
btrfs_search_slot(..., ins_len=0, cow=0) and the offset does not exist,
we'll get path pointed to the slot where it would be inserted and ret is 1.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Btrfs: fix unexpected return value of fiemap
2016-05-18 9:41 ` David Sterba
@ 2016-05-18 17:52 ` Liu Bo
2016-05-23 12:11 ` David Sterba
0 siblings, 1 reply; 4+ messages in thread
From: Liu Bo @ 2016-05-18 17:52 UTC (permalink / raw)
To: dsterba, linux-btrfs
On Wed, May 18, 2016 at 11:41:05AM +0200, David Sterba wrote:
> On Tue, May 17, 2016 at 05:21:48PM -0700, Liu Bo wrote:
> > btrfs's fiemap is supposed to return 0 on success and
> > return < 0 on error, however, ret becomes 1 after looking
> > up the last file extent, and if the offset is beyond EOF,
> > we can return 1.
> >
> > This may confuse applications using ioctl(FIEL_IOC_FIEMAP).
> >
> > Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
>
> Reviewed-by: David Sterba <dsterba@suse.com>
>
> > ---
> > fs/btrfs/extent_io.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> > index d247fc0..16ece52 100644
> > --- a/fs/btrfs/extent_io.c
> > +++ b/fs/btrfs/extent_io.c
> > @@ -4379,8 +4379,12 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
> > if (ret < 0) {
> > btrfs_free_path(path);
> > return ret;
> > + } else {
> > + WARN_ON(!ret);
> > + if (ret == 1)
> > + ret = 0;
> > }
>
> So, ret == 1 can end up here from btrfs_lookup_file_extent ->
> btrfs_search_slot(..., ins_len=0, cow=0) and the offset does not exist,
> we'll get path pointed to the slot where it would be inserted and ret is 1.
Sounds better than the commit log, would you like me to update it?
Thanks,
-liubo
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Btrfs: fix unexpected return value of fiemap
2016-05-18 17:52 ` Liu Bo
@ 2016-05-23 12:11 ` David Sterba
0 siblings, 0 replies; 4+ messages in thread
From: David Sterba @ 2016-05-23 12:11 UTC (permalink / raw)
To: Liu Bo; +Cc: dsterba, linux-btrfs
On Wed, May 18, 2016 at 10:52:25AM -0700, Liu Bo wrote:
> On Wed, May 18, 2016 at 11:41:05AM +0200, David Sterba wrote:
> > On Tue, May 17, 2016 at 05:21:48PM -0700, Liu Bo wrote:
> > > btrfs's fiemap is supposed to return 0 on success and
> > > return < 0 on error, however, ret becomes 1 after looking
> > > up the last file extent, and if the offset is beyond EOF,
> > > we can return 1.
> > >
> > > This may confuse applications using ioctl(FIEL_IOC_FIEMAP).
> > >
> > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> >
> > Reviewed-by: David Sterba <dsterba@suse.com>
> >
> > > ---
> > > fs/btrfs/extent_io.c | 6 +++++-
> > > 1 file changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> > > index d247fc0..16ece52 100644
> > > --- a/fs/btrfs/extent_io.c
> > > +++ b/fs/btrfs/extent_io.c
> > > @@ -4379,8 +4379,12 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
> > > if (ret < 0) {
> > > btrfs_free_path(path);
> > > return ret;
> > > + } else {
> > > + WARN_ON(!ret);
> > > + if (ret == 1)
> > > + ret = 0;
> > > }
> >
> > So, ret == 1 can end up here from btrfs_lookup_file_extent ->
> > btrfs_search_slot(..., ins_len=0, cow=0) and the offset does not exist,
> > we'll get path pointed to the slot where it would be inserted and ret is 1.
>
> Sounds better than the commit log, would you like me to update it?
Done.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2016-05-18 0:21 [PATCH] Btrfs: fix unexpected return value of fiemap Liu Bo
2016-05-18 9:41 ` David Sterba
2016-05-18 17:52 ` Liu Bo
2016-05-23 12:11 ` David Sterba
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