diff mbox series

[v7,10/11] xfs: make the calculation generic in xfs_sb_validate_fsb_count()

Message ID 20240607145902.1137853-11-kernel@pankajraghav.com (mailing list archive)
State New
Headers show
Series enable bs > ps in XFS | expand

Commit Message

Pankaj Raghav (Samsung) June 7, 2024, 2:59 p.m. UTC 
From: Pankaj Raghav <p.raghav@samsung.com>

Instead of assuming that PAGE_SHIFT is always higher than the blocklog,
make the calculation generic so that page cache count can be calculated
correctly for LBS.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
---
 fs/xfs/xfs_mount.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

Comments

Christoph Hellwig June 13, 2024, 8:45 a.m. UTC | #1 
> +	uint64_t		max_index;
> +	uint64_t		max_bytes;
> +
>  	ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
>  	ASSERT(sbp->sb_blocklog >= BBSHIFT);
>  
> +	if (check_shl_overflow(nblocks, sbp->sb_blocklog, &max_bytes))
> +		return -EFBIG;
> +
>  	/* Limited by ULONG_MAX of page cache index */
> -	if (nblocks >> (PAGE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
> +	max_index = max_bytes >> PAGE_SHIFT;
> +
> +	if (max_index > ULONG_MAX)

Do we really need the max_index variable for a single user here?
Or do you plan to add more uses of it later (can't really think of one
though)?
Pankaj Raghav (Samsung) June 17, 2024, 4:09 p.m. UTC | #2 
On Thu, Jun 13, 2024 at 10:45:45AM +0200, Christoph Hellwig wrote:
> > +	uint64_t		max_index;
> > +	uint64_t		max_bytes;
> > +
> >  	ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
> >  	ASSERT(sbp->sb_blocklog >= BBSHIFT);
> >  
> > +	if (check_shl_overflow(nblocks, sbp->sb_blocklog, &max_bytes))
> > +		return -EFBIG;
> > +
> >  	/* Limited by ULONG_MAX of page cache index */
> > -	if (nblocks >> (PAGE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
> > +	max_index = max_bytes >> PAGE_SHIFT;
> > +
> > +	if (max_index > ULONG_MAX)
> 
> Do we really need the max_index variable for a single user here?
> Or do you plan to add more uses of it later (can't really think of one
> though)?

Yeah, we could just inline it:

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index a99454208807..c6933440f806 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -132,7 +132,6 @@ xfs_sb_validate_fsb_count(
        xfs_sb_t        *sbp,
        uint64_t        nblocks)
 {
-       uint64_t                max_index;
        uint64_t                max_bytes;
 
        ASSERT(sbp->sb_blocklog >= BBSHIFT);
@@ -141,9 +140,7 @@ xfs_sb_validate_fsb_count(
                return -EFBIG;
 
        /* Limited by ULONG_MAX of page cache index */
-       max_index = max_bytes >> PAGE_SHIFT;
-
-       if (max_index > ULONG_MAX)
+       if (max_bytes >> PAGE_SHIFT > ULONG_MAX)
                return -EFBIG;
        return 0;
 }

>
diff mbox series

Patch

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 09eef1721ef4..46cb0384143b 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -132,11 +132,19 @@  xfs_sb_validate_fsb_count(
 	xfs_sb_t	*sbp,
 	uint64_t	nblocks)
 {
+	uint64_t		max_index;
+	uint64_t		max_bytes;
+
 	ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
 	ASSERT(sbp->sb_blocklog >= BBSHIFT);
 
+	if (check_shl_overflow(nblocks, sbp->sb_blocklog, &max_bytes))
+		return -EFBIG;
+
 	/* Limited by ULONG_MAX of page cache index */
-	if (nblocks >> (PAGE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
+	max_index = max_bytes >> PAGE_SHIFT;
+
+	if (max_index > ULONG_MAX)
 		return -EFBIG;
 	return 0;
 }