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* [PATCH 1/2] btrfs: Make btrfs_start_delalloc_root's nr argument a long
@ 2021-01-11 10:58 Nikolay Borisov
  2021-01-11 10:58 ` [PATCH 2/2] btrfs: Remove always true condition in btrfs_start_delalloc_roots Nikolay Borisov
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Nikolay Borisov @ 2021-01-11 10:58 UTC (permalink / raw)
  To: dsterba; +Cc: linux-btrfs, Nikolay Borisov

It's currently u64 which gets instantly translated either to LONG_MAX
(if U64_MAX is passed) or casted to an unsigned long (which is in fact,
wrong because iwriteback_control::nr_to_write is a signed, long type).

Just convert the function's argument to be long time which obviates the
need to manually convert u64 value to a long. Adjust all call sites
which pass U64_MAX to pass LONG_MAX. Finally ensure that in
shrink_delalloc the u64 is converted to a long without overflowing,
resulting in a negative number.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
David,

Here are 2 patches which I believe should be folded into
"btrfs: shrink delalloc pages instead of full inodes" so as to avoid needless
casts and a possible overflow, resulting in negative nr_to_write value.

 fs/btrfs/ctree.h       | 2 +-
 fs/btrfs/dev-replace.c | 2 +-
 fs/btrfs/inode.c       | 6 +++---
 fs/btrfs/ioctl.c       | 2 +-
 fs/btrfs/space-info.c  | 3 ++-
 5 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 05f009fbbd55..3dc67f241919 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3101,7 +3101,7 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 			       u32 min_type);

 int btrfs_start_delalloc_snapshot(struct btrfs_root *root);
-int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, u64 nr,
+int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, long nr,
 			       bool in_reclaim_context);
 int btrfs_set_extent_delalloc(struct btrfs_inode *inode, u64 start, u64 end,
 			      unsigned int extra_bits,
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 324f646d6e5e..bc73f798ce3a 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -715,7 +715,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 	 * flush all outstanding I/O and inode extent mappings before the
 	 * copy operation is declared as being finished
 	 */
-	ret = btrfs_start_delalloc_roots(fs_info, U64_MAX, false);
+	ret = btrfs_start_delalloc_roots(fs_info, LONG_MAX, false);
 	if (ret) {
 		mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
 		return ret;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 5c173a30a97a..69e24341afc0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9474,11 +9474,11 @@ int btrfs_start_delalloc_snapshot(struct btrfs_root *root)
 	return start_delalloc_inodes(root, &wbc, true, false);
 }

-int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, u64 nr,
+int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, long nr,
 			       bool in_reclaim_context)
 {
 	struct writeback_control wbc = {
-		.nr_to_write = (nr == U64_MAX) ? LONG_MAX : (unsigned long)nr,
+		.nr_to_write = nr,
 		.sync_mode = WB_SYNC_NONE,
 		.range_start = 0,
 		.range_end = LLONG_MAX,
@@ -9500,7 +9500,7 @@ int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, u64 nr,
 		 * Reset nr_to_write here so we know that we're doing a full
 		 * flush.
 		 */
-		if (nr == U64_MAX)
+		if (nr == LONG_MAX)
 			wbc.nr_to_write = LONG_MAX;

 		root = list_first_entry(&splice, struct btrfs_root,
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index db29c1b54daa..998ea561d934 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4973,7 +4973,7 @@ long btrfs_ioctl(struct file *file, unsigned int
 	case BTRFS_IOC_SYNC: {
 		int ret;

-		ret = btrfs_start_delalloc_roots(fs_info, U64_MAX, false);
+		ret = btrfs_start_delalloc_roots(fs_info, LONG_MAX, false);
 		if (ret)
 			return ret;
 		ret = btrfs_sync_fs(inode->i_sb, 1);
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index e8347461c8dd..84fb94e78a8f 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -532,7 +532,8 @@ static void shrink_delalloc(struct btrfs_fs_info *fs_info,

 	loops = 0;
 	while ((delalloc_bytes || dio_bytes) && loops < 3) {
-		u64 nr_pages = min(delalloc_bytes, to_reclaim) >> PAGE_SHIFT;
+		u64 temp = min(delalloc_bytes, to_reclaim) >> PAGE_SHIFT;
+		long nr_pages = min_t(u64, temp, LONG_MAX);

 		btrfs_start_delalloc_roots(fs_info, nr_pages, true);

--
2.25.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [PATCH 2/2] btrfs: Remove always true condition in btrfs_start_delalloc_roots
  2021-01-11 10:58 [PATCH 1/2] btrfs: Make btrfs_start_delalloc_root's nr argument a long Nikolay Borisov
@ 2021-01-11 10:58 ` Nikolay Borisov
  2021-01-11 15:48 ` [PATCH 1/2] btrfs: Make btrfs_start_delalloc_root's nr argument a long Josef Bacik
  2021-01-11 21:39 ` David Sterba
  2 siblings, 0 replies; 4+ messages in thread
From: Nikolay Borisov @ 2021-01-11 10:58 UTC (permalink / raw)
  To: dsterba; +Cc: linux-btrfs, Nikolay Borisov

Following the rework in
"btrfs: shrink delalloc pages instead of full inodes" the nr variable
is no longer passed by reference to start_delalloc_inodes hence it
cannot change. Additionally we are always guaranteed for it to be
positive number hence it's redundant to have it as a condition in the
loop. Simply remove that usage.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/inode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 69e24341afc0..eb0a25e75126 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9495,7 +9495,7 @@ int btrfs_start_delalloc_roots(struct btrfs_fs_info *fs_info, long nr,
 	mutex_lock(&fs_info->delalloc_root_mutex);
 	spin_lock(&fs_info->delalloc_root_lock);
 	list_splice_init(&fs_info->delalloc_roots, &splice);
-	while (!list_empty(&splice) && nr) {
+	while (!list_empty(&splice)) {
 		/*
 		 * Reset nr_to_write here so we know that we're doing a full
 		 * flush.
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH 1/2] btrfs: Make btrfs_start_delalloc_root's nr argument a long
  2021-01-11 10:58 [PATCH 1/2] btrfs: Make btrfs_start_delalloc_root's nr argument a long Nikolay Borisov
  2021-01-11 10:58 ` [PATCH 2/2] btrfs: Remove always true condition in btrfs_start_delalloc_roots Nikolay Borisov
@ 2021-01-11 15:48 ` Josef Bacik
  2021-01-11 21:39 ` David Sterba
  2 siblings, 0 replies; 4+ messages in thread
From: Josef Bacik @ 2021-01-11 15:48 UTC (permalink / raw)
  To: Nikolay Borisov, dsterba; +Cc: linux-btrfs

On 1/11/21 5:58 AM, Nikolay Borisov wrote:
> It's currently u64 which gets instantly translated either to LONG_MAX
> (if U64_MAX is passed) or casted to an unsigned long (which is in fact,
> wrong because iwriteback_control::nr_to_write is a signed, long type).
> 
> Just convert the function's argument to be long time which obviates the
> need to manually convert u64 value to a long. Adjust all call sites
> which pass U64_MAX to pass LONG_MAX. Finally ensure that in
> shrink_delalloc the u64 is converted to a long without overflowing,
> resulting in a negative number.
> 
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>

You can add

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

to both patches, thanks,

Josef

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH 1/2] btrfs: Make btrfs_start_delalloc_root's nr argument a long
  2021-01-11 10:58 [PATCH 1/2] btrfs: Make btrfs_start_delalloc_root's nr argument a long Nikolay Borisov
  2021-01-11 10:58 ` [PATCH 2/2] btrfs: Remove always true condition in btrfs_start_delalloc_roots Nikolay Borisov
  2021-01-11 15:48 ` [PATCH 1/2] btrfs: Make btrfs_start_delalloc_root's nr argument a long Josef Bacik
@ 2021-01-11 21:39 ` David Sterba
  2 siblings, 0 replies; 4+ messages in thread
From: David Sterba @ 2021-01-11 21:39 UTC (permalink / raw)
  To: Nikolay Borisov; +Cc: dsterba, linux-btrfs

On Mon, Jan 11, 2021 at 12:58:11PM +0200, Nikolay Borisov wrote:
> It's currently u64 which gets instantly translated either to LONG_MAX
> (if U64_MAX is passed) or casted to an unsigned long (which is in fact,
> wrong because iwriteback_control::nr_to_write is a signed, long type).
> 
> Just convert the function's argument to be long time which obviates the
> need to manually convert u64 value to a long. Adjust all call sites
> which pass U64_MAX to pass LONG_MAX. Finally ensure that in
> shrink_delalloc the u64 is converted to a long without overflowing,
> resulting in a negative number.
> 
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> ---
> David,
> 
> Here are 2 patches which I believe should be folded into
> "btrfs: shrink delalloc pages instead of full inodes"

That patch is about to be merged to Linus' tree so I'll apply your
patches separately.

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-01-11 21:41 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-01-11 10:58 [PATCH 1/2] btrfs: Make btrfs_start_delalloc_root's nr argument a long Nikolay Borisov
2021-01-11 10:58 ` [PATCH 2/2] btrfs: Remove always true condition in btrfs_start_delalloc_roots Nikolay Borisov
2021-01-11 15:48 ` [PATCH 1/2] btrfs: Make btrfs_start_delalloc_root's nr argument a long Josef Bacik
2021-01-11 21:39 ` David Sterba

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