[PATCH v3 0/2] iomap: swapfile tweaks

[PATCH v3 0/2] iomap: swapfile tweaks

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

Changes from v2:

- Move up inline flag check, which Christoph is going to turn into a
  type at some point
- Remove null address check, since it doesn't make sense for
  IOMAP_MAPPED or IOMAP_UNWRITTEN

Omar Sandoval (2):
  iomap: provide more useful errors for invalid swap files
  iomap: don't allow holes in swapfiles

 fs/iomap.c | 43 +++++++++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 20 deletions(-)

-- 
2.17.0

[PATCH v3 1/2] iomap: provide more useful errors for invalid swap files

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

Currently, for an invalid swap file, we print the same error message
regardless of the reason. This isn't very useful for an admin, who will
likely want to know why exactly they can't use their swap file. So,
let's add specific error messages for each reason, and also move the
bdev check after the flags checks, since the latter are more
fundamental.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/iomap.c | 40 ++++++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/fs/iomap.c b/fs/iomap.c
index d193390a1c20..89517442e296 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -1214,26 +1214,37 @@ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
 	struct iomap_swapfile_info *isi = data;
 	int error;
 
+	/* No inline data. */
+	if (iomap->flags & IOMAP_F_DATA_INLINE) {
+		pr_err("swapon: file is inline\n");
+		return -EINVAL;
+	}
+
 	/* Skip holes. */
 	if (iomap->type == IOMAP_HOLE)
 		goto out;
 
-	/* Only one bdev per swap file. */
-	if (iomap->bdev != isi->sis->bdev)
-		goto err;
-
 	/* Only real or unwritten extents. */
-	if (iomap->type != IOMAP_MAPPED && iomap->type != IOMAP_UNWRITTEN)
-		goto err;
+	if (iomap->type != IOMAP_MAPPED && iomap->type != IOMAP_UNWRITTEN) {
+		pr_err("swapon: file has unallocated extents\n");
+		return -EINVAL;
+	}
 
-	/* No uncommitted metadata or shared blocks or inline data. */
-	if (iomap->flags & (IOMAP_F_DIRTY | IOMAP_F_SHARED |
-			    IOMAP_F_DATA_INLINE))
-		goto err;
+	/* No uncommitted metadata or shared blocks. */
+	if (iomap->flags & IOMAP_F_DIRTY) {
+		pr_err("swapon: file is not committed\n");
+		return -EINVAL;
+	}
+	if (iomap->flags & IOMAP_F_SHARED) {
+		pr_err("swapon: file has shared extents\n");
+		return -EINVAL;
+	}
 
-	/* No null physical addresses. */
-	if (iomap->addr == IOMAP_NULL_ADDR)
-		goto err;
+	/* Only one bdev per swap file. */
+	if (iomap->bdev != isi->sis->bdev) {
+		pr_err("swapon: file is on multiple devices\n");
+		return -EINVAL;
+	}
 
 	if (isi->iomap.length == 0) {
 		/* No accumulated extent, so just store it. */
@@ -1250,9 +1261,6 @@ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
 	}
 out:
 	return count;
-err:
-	pr_err("swapon: file cannot be used for swap\n");
-	return -EINVAL;
 }
 
 /*
-- 
2.17.0

[PATCH v3 2/2] iomap: don't allow holes in swapfiles

[Omar Sandoval]

From: Omar Sandoval <osandov@fb.com>

generic_swapfile_activate() doesn't allow holes, so we should be
consistent here. This is also a bit safer: if the user creates a
swapfile with, say, truncate -s $SIZE followed by mkswap, they should
really get an error and not much less swap space than they expected.
swapon(8) will error out before calling swapon(2) if the file has holes,
anyways.

Fixes: 9d93388b0afe ("iomap: add a swapfile activation function")
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
---
 fs/iomap.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/fs/iomap.c b/fs/iomap.c
index 89517442e296..f2456d0d8ddd 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -1220,10 +1220,6 @@ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
 		return -EINVAL;
 	}
 
-	/* Skip holes. */
-	if (iomap->type == IOMAP_HOLE)
-		goto out;
-
 	/* Only real or unwritten extents. */
 	if (iomap->type != IOMAP_MAPPED && iomap->type != IOMAP_UNWRITTEN) {
 		pr_err("swapon: file has unallocated extents\n");
@@ -1259,7 +1255,6 @@ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
 			return error;
 		memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
 	}
-out:
 	return count;
 }
 
-- 
2.17.0

Re: [PATCH v3 1/2] iomap: provide more useful errors for invalid swap files

[Christoph Hellwig]

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH v3 2/2] iomap: don't allow holes in swapfiles

[Christoph Hellwig]

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

And now lets get the series merged quickly so that I can rebase my
iomap series on top of this :)

Re: [PATCH v3 1/2] iomap: provide more useful errors for invalid swap files

[Jan Kara]

On Wed 16-05-18 10:54:10, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> Currently, for an invalid swap file, we print the same error message
> regardless of the reason. This isn't very useful for an admin, who will
> likely want to know why exactly they can't use their swap file. So,
> let's add specific error messages for each reason, and also move the
> bdev check after the flags checks, since the latter are more
> fundamental.
> 
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
> Signed-off-by: Omar Sandoval <osandov@fb.com>

Yup, looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/iomap.c | 40 ++++++++++++++++++++++++----------------
>  1 file changed, 24 insertions(+), 16 deletions(-)
> 
> diff --git a/fs/iomap.c b/fs/iomap.c
> index d193390a1c20..89517442e296 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -1214,26 +1214,37 @@ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
>  	struct iomap_swapfile_info *isi = data;
>  	int error;
>  
> +	/* No inline data. */
> +	if (iomap->flags & IOMAP_F_DATA_INLINE) {
> +		pr_err("swapon: file is inline\n");
> +		return -EINVAL;
> +	}
> +
>  	/* Skip holes. */
>  	if (iomap->type == IOMAP_HOLE)
>  		goto out;
>  
> -	/* Only one bdev per swap file. */
> -	if (iomap->bdev != isi->sis->bdev)
> -		goto err;
> -
>  	/* Only real or unwritten extents. */
> -	if (iomap->type != IOMAP_MAPPED && iomap->type != IOMAP_UNWRITTEN)
> -		goto err;
> +	if (iomap->type != IOMAP_MAPPED && iomap->type != IOMAP_UNWRITTEN) {
> +		pr_err("swapon: file has unallocated extents\n");
> +		return -EINVAL;
> +	}
>  
> -	/* No uncommitted metadata or shared blocks or inline data. */
> -	if (iomap->flags & (IOMAP_F_DIRTY | IOMAP_F_SHARED |
> -			    IOMAP_F_DATA_INLINE))
> -		goto err;
> +	/* No uncommitted metadata or shared blocks. */
> +	if (iomap->flags & IOMAP_F_DIRTY) {
> +		pr_err("swapon: file is not committed\n");
> +		return -EINVAL;
> +	}
> +	if (iomap->flags & IOMAP_F_SHARED) {
> +		pr_err("swapon: file has shared extents\n");
> +		return -EINVAL;
> +	}
>  
> -	/* No null physical addresses. */
> -	if (iomap->addr == IOMAP_NULL_ADDR)
> -		goto err;
> +	/* Only one bdev per swap file. */
> +	if (iomap->bdev != isi->sis->bdev) {
> +		pr_err("swapon: file is on multiple devices\n");
> +		return -EINVAL;
> +	}
>  
>  	if (isi->iomap.length == 0) {
>  		/* No accumulated extent, so just store it. */
> @@ -1250,9 +1261,6 @@ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
>  	}
>  out:
>  	return count;
> -err:
> -	pr_err("swapon: file cannot be used for swap\n");
> -	return -EINVAL;
>  }
>  
>  /*
> -- 
> 2.17.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH v3 2/2] iomap: don't allow holes in swapfiles

[Jan Kara]

On Wed 16-05-18 10:54:11, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> generic_swapfile_activate() doesn't allow holes, so we should be
> consistent here. This is also a bit safer: if the user creates a
> swapfile with, say, truncate -s $SIZE followed by mkswap, they should
> really get an error and not much less swap space than they expected.
> swapon(8) will error out before calling swapon(2) if the file has holes,
> anyways.
> 
> Fixes: 9d93388b0afe ("iomap: add a swapfile activation function")
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
> Signed-off-by: Omar Sandoval <osandov@fb.com>

Good catch. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/iomap.c | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/fs/iomap.c b/fs/iomap.c
> index 89517442e296..f2456d0d8ddd 100644
> --- a/fs/iomap.c
> +++ b/fs/iomap.c
> @@ -1220,10 +1220,6 @@ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
>  		return -EINVAL;
>  	}
>  
> -	/* Skip holes. */
> -	if (iomap->type == IOMAP_HOLE)
> -		goto out;
> -
>  	/* Only real or unwritten extents. */
>  	if (iomap->type != IOMAP_MAPPED && iomap->type != IOMAP_UNWRITTEN) {
>  		pr_err("swapon: file has unallocated extents\n");
> @@ -1259,7 +1255,6 @@ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos,
>  			return error;
>  		memcpy(&isi->iomap, iomap, sizeof(isi->iomap));
>  	}
> -out:
>  	return count;
>  }
>  
> -- 
> 2.17.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH v3 0/2] iomap: swapfile tweaks

[Darrick J. Wong]

On Wed, May 16, 2018 at 10:54:09AM -0700, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> Changes from v2:
> 
> - Move up inline flag check, which Christoph is going to turn into a
>   type at some point
> - Remove null address check, since it doesn't make sense for
>   IOMAP_MAPPED or IOMAP_UNWRITTEN
> 
> Omar Sandoval (2):
>   iomap: provide more useful errors for invalid swap files
>   iomap: don't allow holes in swapfiles
> 
>  fs/iomap.c | 43 +++++++++++++++++++++++--------------------

Tested ok overnight, so:
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

>  1 file changed, 23 insertions(+), 20 deletions(-)
> 
> -- 
> 2.17.0
> 
> --
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