2020-08-17 18:58:43

by Greg Kroah-Hartman

Subject: [PATCH 5.7 188/393] iomap: Make sure iomap_end is called after iomap_begin

From: Andreas Gruenbacher <[email protected]>

[ Upstream commit 856473cd5d17dbbf3055710857c67a4af6d9fcc0 ]

Make sure iomap_end is always called when iomap_begin succeeds.

Without this fix, iomap_end won't be called when a filesystem's
iomap_begin operation returns an invalid mapping, bypassing any
unlocking done in iomap_end. With this fix, the unlocking will still
happen.

This bug was found by Bob Peterson during code review. It's unlikely
that such iomap_begin bugs will survive to affect users, so backporting
this fix seems unnecessary.

Fixes: ae259a9c8593 ("fs: introduce iomap infrastructure")
Signed-off-by: Andreas Gruenbacher <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Darrick J. Wong <[email protected]>
Signed-off-by: Darrick J. Wong <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
fs/iomap/apply.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c
index 76925b40b5fd2..26ab6563181fc 100644
--- a/fs/iomap/apply.c
+++ b/fs/iomap/apply.c
@@ -46,10 +46,14 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
ret = ops->iomap_begin(inode, pos, length, flags, &iomap, &srcmap);
if (ret)
return ret;
- if (WARN_ON(iomap.offset > pos))
- return -EIO;
- if (WARN_ON(iomap.length == 0))
- return -EIO;
+ if (WARN_ON(iomap.offset > pos)) {
+ written = -EIO;
+ goto out;
+ }
+ if (WARN_ON(iomap.length == 0)) {
+ written = -EIO;
+ goto out;
+ }

trace_iomap_apply_dstmap(inode, &iomap);
if (srcmap.type != IOMAP_HOLE)
@@ -80,6 +84,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
written = actor(inode, pos, length, data, &iomap,
srcmap.type != IOMAP_HOLE ? &srcmap : &iomap);

+out:
/*
* Now the data has been copied, commit the range we've copied. This
* should not fail unless the filesystem has had a fatal error.
--
2.25.1

2020-08-17 19:59:23

by Andreas Grünbacher

Subject: Re: [PATCH 5.7 188/393] iomap: Make sure iomap_end is called after iomap_begin

Greg,

Am Mo., 17. Aug. 2020 um 21:01 Uhr schrieb Greg Kroah-Hartman
<[email protected]>:
> From: Andreas Gruenbacher <[email protected]>
>
> [ Upstream commit 856473cd5d17dbbf3055710857c67a4af6d9fcc0 ]
>
> Make sure iomap_end is always called when iomap_begin succeeds.
>
> Without this fix, iomap_end won't be called when a filesystem's
> iomap_begin operation returns an invalid mapping, bypassing any
> unlocking done in iomap_end. With this fix, the unlocking will still
> happen.
>
> This bug was found by Bob Peterson during code review. It's unlikely
> that such iomap_begin bugs will survive to affect users, so backporting
> this fix seems unnecessary.

this doesn't need to be backported.

Thanks,
Andreas


> Fixes: ae259a9c8593 ("fs: introduce iomap infrastructure")
> Signed-off-by: Andreas Gruenbacher <[email protected]>
> Reviewed-by: Christoph Hellwig <[email protected]>
> Reviewed-by: Darrick J. Wong <[email protected]>
> Signed-off-by: Darrick J. Wong <[email protected]>
> Signed-off-by: Sasha Levin <[email protected]>
> ---
> fs/iomap/apply.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/fs/iomap/apply.c b/fs/iomap/apply.c
> index 76925b40b5fd2..26ab6563181fc 100644
> --- a/fs/iomap/apply.c
> +++ b/fs/iomap/apply.c
> @@ -46,10 +46,14 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
> ret = ops->iomap_begin(inode, pos, length, flags, &iomap, &srcmap);
> if (ret)
> return ret;
> - if (WARN_ON(iomap.offset > pos))
> - return -EIO;
> - if (WARN_ON(iomap.length == 0))
> - return -EIO;
> + if (WARN_ON(iomap.offset > pos)) {
> + written = -EIO;
> + goto out;
> + }
> + if (WARN_ON(iomap.length == 0)) {
> + written = -EIO;
> + goto out;
> + }
>
> trace_iomap_apply_dstmap(inode, &iomap);
> if (srcmap.type != IOMAP_HOLE)
> @@ -80,6 +84,7 @@ iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
> written = actor(inode, pos, length, data, &iomap,
> srcmap.type != IOMAP_HOLE ? &srcmap : &iomap);
>
> +out:
> /*
> * Now the data has been copied, commit the range we've copied. This
> * should not fail unless the filesystem has had a fatal error.
> --
> 2.25.1
>
>
>