[3/6] f2fs: skip truncate when verity in progress in ->write_begin()
diff mbox series

Message ID 20190811213557.1970-4-ebiggers@kernel.org
State Accepted
Headers show
Series
  • fs-verity fixups
Related show

Commit Message

Eric Biggers Aug. 11, 2019, 9:35 p.m. UTC
From: Eric Biggers <ebiggers@google.com>

When an error (e.g. ENOSPC) occurs during f2fs_write_begin() when called
from f2fs_write_merkle_tree_block(), skip truncating the file.  i_size
is not meaningful in this case, and the truncation is handled by
f2fs_end_enable_verity() instead.

Fixes: 60d7bf0f790f ("f2fs: add fs-verity support")
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/f2fs/data.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Chao Yu Aug. 12, 2019, 12:25 p.m. UTC | #1
Hi Eric,

On 2019/8/12 5:35, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> When an error (e.g. ENOSPC) occurs during f2fs_write_begin() when called
> from f2fs_write_merkle_tree_block(), skip truncating the file.  i_size
> is not meaningful in this case, and the truncation is handled by
> f2fs_end_enable_verity() instead.
> 
> Fixes: 60d7bf0f790f ("f2fs: add fs-verity support")
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
>  fs/f2fs/data.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 3f525f8a3a5fa..00b03fb87bd9b 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2476,7 +2476,7 @@ static void f2fs_write_failed(struct address_space *mapping, loff_t to)
>  	struct inode *inode = mapping->host;
>  	loff_t i_size = i_size_read(inode);
>  
> -	if (to > i_size) {

Maybe adding one single line comment to mention that it's redundant/unnecessary
truncation here is better, if I didn't misunderstand this.

Thanks,

> +	if (to > i_size && !f2fs_verity_in_progress(inode)) {
>  		down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
>  		down_write(&F2FS_I(inode)->i_mmap_sem);
>  
>
Eric Biggers Aug. 12, 2019, 10:58 p.m. UTC | #2
Hi Chao,

On Mon, Aug 12, 2019 at 08:25:33PM +0800, Chao Yu wrote:
> Hi Eric,
> 
> On 2019/8/12 5:35, Eric Biggers wrote:
> > From: Eric Biggers <ebiggers@google.com>
> > 
> > When an error (e.g. ENOSPC) occurs during f2fs_write_begin() when called
> > from f2fs_write_merkle_tree_block(), skip truncating the file.  i_size
> > is not meaningful in this case, and the truncation is handled by
> > f2fs_end_enable_verity() instead.
> > 
> > Fixes: 60d7bf0f790f ("f2fs: add fs-verity support")
> > Signed-off-by: Eric Biggers <ebiggers@google.com>
> > ---
> >  fs/f2fs/data.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index 3f525f8a3a5fa..00b03fb87bd9b 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -2476,7 +2476,7 @@ static void f2fs_write_failed(struct address_space *mapping, loff_t to)
> >  	struct inode *inode = mapping->host;
> >  	loff_t i_size = i_size_read(inode);
> >  
> > -	if (to > i_size) {
> 
> Maybe adding one single line comment to mention that it's redundant/unnecessary
> truncation here is better, if I didn't misunderstand this.
> 
> Thanks,
> 
> > +	if (to > i_size && !f2fs_verity_in_progress(inode)) {
> >  		down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
> >  		down_write(&F2FS_I(inode)->i_mmap_sem);
> >  

Do you mean add a comment instead of the !f2fs_verity_in_progress() check, or in
addition to it?  ->write_begin(), ->writepages(), and ->write_end() are all
supposed to ignore i_size when verity is in progress, so I don't think this
particular part should be different, even if technically it's still correct to
truncate twice.  Also, ext4 needs this check in its ->write_begin() for locking
reasons; we should keep f2fs similar.

How about having both a comment and the check, like:

        /* In the fs-verity case, f2fs_end_enable_verity() does the truncate */
        if (to > i_size && !f2fs_verity_in_progress(inode)) {

- Eric
Chao Yu Aug. 13, 2019, 2:40 a.m. UTC | #3
Hi Eric,

On 2019/8/13 6:58, Eric Biggers wrote:
> Hi Chao,
> 
> On Mon, Aug 12, 2019 at 08:25:33PM +0800, Chao Yu wrote:
>> Hi Eric,
>>
>> On 2019/8/12 5:35, Eric Biggers wrote:
>>> From: Eric Biggers <ebiggers@google.com>
>>>
>>> When an error (e.g. ENOSPC) occurs during f2fs_write_begin() when called
>>> from f2fs_write_merkle_tree_block(), skip truncating the file.  i_size
>>> is not meaningful in this case, and the truncation is handled by
>>> f2fs_end_enable_verity() instead.
>>>
>>> Fixes: 60d7bf0f790f ("f2fs: add fs-verity support")
>>> Signed-off-by: Eric Biggers <ebiggers@google.com>
>>> ---
>>>  fs/f2fs/data.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index 3f525f8a3a5fa..00b03fb87bd9b 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -2476,7 +2476,7 @@ static void f2fs_write_failed(struct address_space *mapping, loff_t to)
>>>  	struct inode *inode = mapping->host;
>>>  	loff_t i_size = i_size_read(inode);
>>>  
>>> -	if (to > i_size) {
>>
>> Maybe adding one single line comment to mention that it's redundant/unnecessary
>> truncation here is better, if I didn't misunderstand this.
>>
>> Thanks,
>>
>>> +	if (to > i_size && !f2fs_verity_in_progress(inode)) {
>>>  		down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
>>>  		down_write(&F2FS_I(inode)->i_mmap_sem);
>>>  
> 
> Do you mean add a comment instead of the !f2fs_verity_in_progress() check, or in
> addition to it?  ->write_begin(), ->writepages(), and ->write_end() are all

Sorry, I didn't make this very clear, I meant adding the comment in addition on
above change.

> supposed to ignore i_size when verity is in progress, so I don't think this
> particular part should be different, even if technically it's still correct to
> truncate twice.  Also, ext4 needs this check in its ->write_begin() for locking
> reasons; we should keep f2fs similar.

Agreed.

> 
> How about having both a comment and the check, like:
> 
>         /* In the fs-verity case, f2fs_end_enable_verity() does the truncate */
>         if (to > i_size && !f2fs_verity_in_progress(inode)) {

The comment looks good to me. :)

Thanks,

> 
> - Eric
> .
>
Eric Biggers Aug. 18, 2019, 8:24 p.m. UTC | #4
On Tue, Aug 13, 2019 at 10:40:39AM +0800, Chao Yu wrote:
> Hi Eric,
> 
> On 2019/8/13 6:58, Eric Biggers wrote:
> > Hi Chao,
> > 
> > On Mon, Aug 12, 2019 at 08:25:33PM +0800, Chao Yu wrote:
> >> Hi Eric,
> >>
> >> On 2019/8/12 5:35, Eric Biggers wrote:
> >>> From: Eric Biggers <ebiggers@google.com>
> >>>
> >>> When an error (e.g. ENOSPC) occurs during f2fs_write_begin() when called
> >>> from f2fs_write_merkle_tree_block(), skip truncating the file.  i_size
> >>> is not meaningful in this case, and the truncation is handled by
> >>> f2fs_end_enable_verity() instead.
> >>>
> >>> Fixes: 60d7bf0f790f ("f2fs: add fs-verity support")
> >>> Signed-off-by: Eric Biggers <ebiggers@google.com>
> >>> ---
> >>>  fs/f2fs/data.c | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> >>> index 3f525f8a3a5fa..00b03fb87bd9b 100644
> >>> --- a/fs/f2fs/data.c
> >>> +++ b/fs/f2fs/data.c
> >>> @@ -2476,7 +2476,7 @@ static void f2fs_write_failed(struct address_space *mapping, loff_t to)
> >>>  	struct inode *inode = mapping->host;
> >>>  	loff_t i_size = i_size_read(inode);
> >>>  
> >>> -	if (to > i_size) {
> >>
> >> Maybe adding one single line comment to mention that it's redundant/unnecessary
> >> truncation here is better, if I didn't misunderstand this.
> >>
> >> Thanks,
> >>
> >>> +	if (to > i_size && !f2fs_verity_in_progress(inode)) {
> >>>  		down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
> >>>  		down_write(&F2FS_I(inode)->i_mmap_sem);
> >>>  
> > 
> > Do you mean add a comment instead of the !f2fs_verity_in_progress() check, or in
> > addition to it?  ->write_begin(), ->writepages(), and ->write_end() are all
> 
> Sorry, I didn't make this very clear, I meant adding the comment in addition on
> above change.
> 
> > supposed to ignore i_size when verity is in progress, so I don't think this
> > particular part should be different, even if technically it's still correct to
> > truncate twice.  Also, ext4 needs this check in its ->write_begin() for locking
> > reasons; we should keep f2fs similar.
> 
> Agreed.
> 
> > 
> > How about having both a comment and the check, like:
> > 
> >         /* In the fs-verity case, f2fs_end_enable_verity() does the truncate */
> >         if (to > i_size && !f2fs_verity_in_progress(inode)) {
> 
> The comment looks good to me. :)
> 
> Thanks,
> 
> > 
> > - Eric
> > .
> > 
> 

Okay, this is what I applied:

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 3f525f8a3a5f..54cad80acb7d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2476,7 +2476,8 @@ static void f2fs_write_failed(struct address_space *mapping, loff_t to)
 	struct inode *inode = mapping->host;
 	loff_t i_size = i_size_read(inode);
 
-	if (to > i_size) {
+	/* In the fs-verity case, f2fs_end_enable_verity() does the truncate */
+	if (to > i_size && !f2fs_verity_in_progress(inode)) {
 		down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 		down_write(&F2FS_I(inode)->i_mmap_sem);

Patch
diff mbox series

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 3f525f8a3a5fa..00b03fb87bd9b 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2476,7 +2476,7 @@  static void f2fs_write_failed(struct address_space *mapping, loff_t to)
 	struct inode *inode = mapping->host;
 	loff_t i_size = i_size_read(inode);
 
-	if (to > i_size) {
+	if (to > i_size && !f2fs_verity_in_progress(inode)) {
 		down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
 		down_write(&F2FS_I(inode)->i_mmap_sem);