Ocfs2 devel - Oct 2020 - [PATCH 7/7] btrfs: Promote to unsigned long long before multiplying

I caught a bug in my own code where I forgot to cast to loff_t before
shifting.  So I thought I'd grep around and see if I could find any
other occurrences.  I found a few that were clearly bugs, and they're
fixed below.  There are other places where we don't cast, and I think
they're OK.  For example, some places we have a 'nr_pages' being
shifted
by PAGE_SHIFT, and that's probably OK because it's probably a single
I/O.

Also, I didn't touch AFFS or ROMFS or some other filesystems which
probably have never seen a 4GB file in their lives.  Might be worth
fixing to be sure nobody copies bad code from them, but not worth cc'ing
stable for.

I didn't look for SECTOR_SHIFT or SECTOR_SIZE (or bare 9/512), just
PAGE_SIZE and PAGE_SHIFT.

I can't find a GCC warning to enable for this pattern, so I filed
https://urldefense.com/v3/__https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97287__;!!GqivPVa7Brio!JmJRfLO1W1WY_UNpWJIfK5J2F0viNTrZ3l7xIrCKzl03yThvlPmVBeZHbHY6hZu2IJ2u7Q$

Matthew Wilcox (Oracle) (7):
  9P: Cast to loff_t before multiplying
  buffer: Promote to unsigned long long before shifting
  ceph: Promote to unsigned long long before shifting
  ocfs2: Promote to unsigned long long before shifting
  btrfs: Promote to unsigned long long before shifting
  btrfs: Promote to unsigned long long before shifting
  btrfs: Promote to unsigned long long before multiplying

 fs/9p/vfs_file.c  |  4 ++--
 fs/btrfs/ioctl.c  |  6 +++---
 fs/btrfs/raid56.c |  2 +-
 fs/btrfs/scrub.c  | 25 ++++++++++++++++---------
 fs/buffer.c       |  2 +-
 fs/ceph/addr.c    |  2 +-
 fs/ocfs2/alloc.c  |  2 +-
 7 files changed, 25 insertions(+), 18 deletions(-)

-- 
2.28.0

On 32-bit systems, this multiplication will overflow for files larger
than 4GB.

Cc: stable at vger.kernel.org
Fixes: fb89b45cdfdc ("9P: introduction of a new cache=mmap model.")
Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org>
---
 fs/9p/vfs_file.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 3576123d8299..6d97b6b4d34b 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -612,9 +612,9 @@ static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
 	struct writeback_control wbc = {
 		.nr_to_write = LONG_MAX,
 		.sync_mode = WB_SYNC_ALL,
-		.range_start = vma->vm_pgoff * PAGE_SIZE,
+		.range_start = (loff_t)vma->vm_pgoff * PAGE_SIZE,
 		 /* absolute end, byte at end included */
-		.range_end = vma->vm_pgoff * PAGE_SIZE +
+		.range_end = (loff_t)vma->vm_pgoff * PAGE_SIZE +
 			(vma->vm_end - vma->vm_start - 1),
 	};
 
-- 
2.28.0

On 32-bit systems, this shift will overflow for files larger than 4GB.

Cc: stable at vger.kernel.org
Fixes: 5417169026c3 ("[FS] Implement block_page_mkwrite.")
Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org>
---
 fs/buffer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 50bbc99e3d96..66f4765e60ee 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2515,7 +2515,7 @@ int block_page_mkwrite(struct vm_area_struct *vma, struct
vm_fault *vmf,
 	}
 
 	/* page is wholly or partially inside EOF */
-	if (((page->index + 1) << PAGE_SHIFT) > size)
+	if (((page->index + 1ULL) << PAGE_SHIFT) > size)
 		end = size & ~PAGE_MASK;
 	else
 		end = PAGE_SIZE;
-- 
2.28.0

On 32-bit systems, this shift will overflow for files larger than 4GB.

Cc: stable at vger.kernel.org
Fixes: 61f68816211e ("ceph: check caps in filemap_fault and
page_mkwrite")
Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org>
---
 fs/ceph/addr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 6ea761c84494..970e5a094035 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1522,7 +1522,7 @@ static vm_fault_t ceph_filemap_fault(struct vm_fault *vmf)
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_file_info *fi = vma->vm_file->private_data;
 	struct page *pinned_page = NULL;
-	loff_t off = vmf->pgoff << PAGE_SHIFT;
+	loff_t off = (loff_t)vmf->pgoff << PAGE_SHIFT;
 	int want, got, err;
 	sigset_t oldset;
 	vm_fault_t ret = VM_FAULT_SIGBUS;
-- 
2.28.0

On 32-bit systems, this shift will overflow for files larger than 4GB.

Cc: stable at vger.kernel.org
Fixes: 35edec1d52c0 ("ocfs2: update truncate handling of partial
clusters")
Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org>
---
 fs/ocfs2/alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 4c1b90442d6f..26eff79ecb50 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -6867,7 +6867,7 @@ static void ocfs2_zero_cluster_pages(struct inode *inode,
loff_t start,
 		ocfs2_map_and_dirty_page(inode, handle, from, to, page, 1,
 					 &phys);
 
-		start = (page->index + 1) << PAGE_SHIFT;
+		start = (page->index + 1ULL) << PAGE_SHIFT;
 	}
 out:
 	if (pages)
-- 
2.28.0

On 32-bit systems, this shift will overflow for files larger than 4GB.

Cc: stable at vger.kernel.org
Fixes: df480633b891 ("btrfs: extent-tree: Switch to new delalloc space
reserve and release")
Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org>
---
 fs/btrfs/ioctl.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ac45f022b495..4d3b7e4ae53a 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1277,7 +1277,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
 	page_cnt = min_t(u64, (u64)num_pages, (u64)file_end - start_index + 1);
 
 	ret = btrfs_delalloc_reserve_space(BTRFS_I(inode), &data_reserved,
-			start_index << PAGE_SHIFT,
+			(loff_t)start_index << PAGE_SHIFT,
 			page_cnt << PAGE_SHIFT);
 	if (ret)
 		return ret;
@@ -1367,7 +1367,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
 		btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
 		spin_unlock(&BTRFS_I(inode)->lock);
 		btrfs_delalloc_release_space(BTRFS_I(inode), data_reserved,
-				start_index << PAGE_SHIFT,
+				(loff_t)start_index << PAGE_SHIFT,
 				(page_cnt - i_done) << PAGE_SHIFT, true);
 	}
 
@@ -1395,7 +1395,7 @@ static int cluster_pages_for_defrag(struct inode *inode,
 		put_page(pages[i]);
 	}
 	btrfs_delalloc_release_space(BTRFS_I(inode), data_reserved,
-			start_index << PAGE_SHIFT,
+			(loff_t)start_index << PAGE_SHIFT,
 			page_cnt << PAGE_SHIFT, true);
 	btrfs_delalloc_release_extents(BTRFS_I(inode), page_cnt << PAGE_SHIFT);
 	extent_changeset_free(data_reserved);
-- 
2.28.0

On 32-bit systems, this shift will overflow for files larger than 4GB.

Cc: stable at vger.kernel.org
Fixes: 53b381b3abeb ("Btrfs: RAID5 and RAID6")
Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org>
---
 fs/btrfs/raid56.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 255490f42b5d..5ee0a53301bd 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1089,7 +1089,7 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
 	u64 disk_start;
 
 	stripe = &rbio->bbio->stripes[stripe_nr];
-	disk_start = stripe->physical + (page_index << PAGE_SHIFT);
+	disk_start = stripe->physical + ((loff_t)page_index << PAGE_SHIFT);
 
 	/* if the device is missing, just fail this stripe */
 	if (!stripe->dev->bdev)
-- 
2.28.0

On 32-bit systems, these shifts will overflow for files larger than 4GB.
Add helper functions to avoid this problem coming back.

Cc: stable at vger.kernel.org
Fixes: 73ff61dbe5ed ("Btrfs: fix device replace of a missing RAID 5/6
device")
Fixes: be50a8ddaae1 ("Btrfs: Simplify scrub_setup_recheck_block()'s
argument")
Fixes: ff023aac3119 ("Btrfs: add code to scrub to copy read data to another
disk")
Fixes: b5d67f64f9bc ("Btrfs: change scrub to support big blocks")
Fixes: a2de733c78fa ("btrfs: scrub")
Signed-off-by: Matthew Wilcox (Oracle) <willy at infradead.org>
---
 fs/btrfs/scrub.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 354ab9985a34..ccbaf9c6e87a 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1262,12 +1262,17 @@ static inline void scrub_stripe_index_and_offset(u64
logical, u64 map_type,
 	}
 }
 
+static u64 sblock_length(struct scrub_block *sblock)
+{
+	return (u64)sblock->page_count * PAGE_SIZE;
+}
+
 static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
 				     struct scrub_block *sblocks_for_recheck)
 {
 	struct scrub_ctx *sctx = original_sblock->sctx;
 	struct btrfs_fs_info *fs_info = sctx->fs_info;
-	u64 length = original_sblock->page_count * PAGE_SIZE;
+	u64 length = sblock_length(original_sblock);
 	u64 logical = original_sblock->pagev[0]->logical;
 	u64 generation = original_sblock->pagev[0]->generation;
 	u64 flags = original_sblock->pagev[0]->flags;
@@ -1610,6 +1615,11 @@ static void scrub_write_block_to_dev_replace(struct
scrub_block *sblock)
 	}
 }
 
+static u64 sbio_length(struct scrub_bio *sbio)
+{
+	return (u64)sbio->page_count * PAGE_SIZE;
+}
+
 static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
 					   int page_num)
 {
@@ -1659,10 +1669,9 @@ static int scrub_add_page_to_wr_bio(struct scrub_ctx
*sctx,
 		bio->bi_iter.bi_sector = sbio->physical >> 9;
 		bio->bi_opf = REQ_OP_WRITE;
 		sbio->status = 0;
-	} else if (sbio->physical + sbio->page_count * PAGE_SIZE !+	} else if
(sbio->physical + sbio_length(sbio) ! 		   spage->physical_for_dev_replace
||
-		   sbio->logical + sbio->page_count * PAGE_SIZE !-		  
spage->logical) {
+		   sbio->logical + sbio_length(sbio) != spage->logical) {
 		scrub_wr_submit(sctx);
 		goto again;
 	}
@@ -2005,10 +2014,8 @@ static int scrub_add_page_to_rd_bio(struct scrub_ctx
*sctx,
 		bio->bi_iter.bi_sector = sbio->physical >> 9;
 		bio->bi_opf = REQ_OP_READ;
 		sbio->status = 0;
-	} else if (sbio->physical + sbio->page_count * PAGE_SIZE !-		  
spage->physical ||
-		   sbio->logical + sbio->page_count * PAGE_SIZE !-		  
spage->logical ||
+	} else if (sbio->physical + sbio_length(sbio) != spage->physical ||
+		   sbio->logical + sbio_length(sbio) != spage->logical ||
 		   sbio->dev != spage->dev) {
 		scrub_submit(sctx);
 		goto again;
@@ -2094,7 +2101,7 @@ static void scrub_missing_raid56_pages(struct scrub_block
*sblock)
 {
 	struct scrub_ctx *sctx = sblock->sctx;
 	struct btrfs_fs_info *fs_info = sctx->fs_info;
-	u64 length = sblock->page_count * PAGE_SIZE;
+	u64 length = sblock_length(sblock);
 	u64 logical = sblock->pagev[0]->logical;
 	struct btrfs_bio *bbio = NULL;
 	struct bio *bio;
-- 
2.28.0