fixed commit message

fixed commit message

[Rajeev Mishra]

fixed the commit message
Rajeev Mishra (2):
  loop: Consolidate size calculation logic into lo_calculate_size()
  loop: use vfs_getattr_nosec for accurate file size

 drivers/block/loop.c | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)

-- 
2.43.7

[PATCH v4 1/2] loop: Consolidate size calculation logic into lo_calculate_size()

[Rajeev Mishra]

Renamed get_size to lo_calculate_size and merged the logic from
get_size and get_loop_size into a single function.
Updated all callers to use lo_calculate_size

Signed-off-by: Rajeev Mishra <rajeevm@hpe.com>
---
 drivers/block/loop.c | 26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 1b6ee91f8eb9..0e1b9eb9db10 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -137,20 +137,18 @@ static void loop_global_unlock(struct loop_device *lo, bool global)
 static int max_part;
 static int part_shift;
 
-static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)
+static loff_t lo_calculate_size(struct loop_device *lo, struct file *file)
 {
 	loff_t loopsize;
-
 	/* Compute loopsize in bytes */
 	loopsize = i_size_read(file->f_mapping->host);
-	if (offset > 0)
-		loopsize -= offset;
+	if (lo->lo_offset > 0)
+		loopsize -= lo->lo_offset;
 	/* offset is beyond i_size, weird but possible */
 	if (loopsize < 0)
 		return 0;
-
-	if (sizelimit > 0 && sizelimit < loopsize)
-		loopsize = sizelimit;
+	if (lo->lo_sizelimit > 0 && lo->lo_sizelimit < loopsize)
+		loopsize = lo->lo_sizelimit;
 	/*
 	 * Unfortunately, if we want to do I/O on the device,
 	 * the number of 512-byte sectors has to fit into a sector_t.
@@ -158,11 +156,6 @@ static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)
 	return loopsize >> 9;
 }
 
-static loff_t get_loop_size(struct loop_device *lo, struct file *file)
-{
-	return get_size(lo->lo_offset, lo->lo_sizelimit, file);
-}
-
 /*
  * We support direct I/O only if lo_offset is aligned with the logical I/O size
  * of backing device, and the logical block size of loop is bigger than that of
@@ -569,7 +562,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
 	error = -EINVAL;
 
 	/* size of the new backing store needs to be the same */
-	if (get_loop_size(lo, file) != get_loop_size(lo, old_file))
+	if (lo_calculate_size(lo, file) != lo_calculate_size(lo, old_file))
 		goto out_err;
 
 	/*
@@ -1063,7 +1056,7 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode,
 	loop_update_dio(lo);
 	loop_sysfs_init(lo);
 
-	size = get_loop_size(lo, file);
+	size = lo_calculate_size(lo, file);
 	loop_set_size(lo, size);
 
 	/* Order wrt reading lo_state in loop_validate_file(). */
@@ -1255,8 +1248,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 	if (partscan)
 		clear_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state);
 	if (!err && size_changed) {
-		loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit,
-					   lo->lo_backing_file);
+		loff_t new_size = lo_calculate_size(lo, lo->lo_backing_file);
 		loop_set_size(lo, new_size);
 	}
 out_unlock:
@@ -1399,7 +1391,7 @@ static int loop_set_capacity(struct loop_device *lo)
 	if (unlikely(lo->lo_state != Lo_bound))
 		return -ENXIO;
 
-	size = get_loop_size(lo, lo->lo_backing_file);
+	size = lo_calculate_size(lo, lo->lo_backing_file);
 	loop_set_size(lo, size);
 
 	return 0;
-- 
2.43.7

[PATCH v4 2/2] loop: use vfs_getattr_nosec for accurate file size

[Rajeev Mishra]

In lo_calculate_size, use vfs_getattr_nosec() instead of
i_size_read(), which improves accuracy for network and
distributed filesystems.

Signed-off-by: Rajeev Mishra <rajeevm@hpe.com>
---
 drivers/block/loop.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 0e1b9eb9db10..57263c273f0f 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -139,9 +139,20 @@ static int part_shift;
 
 static loff_t lo_calculate_size(struct loop_device *lo, struct file *file)
 {
+	struct kstat stat;
 	loff_t loopsize;
-	/* Compute loopsize in bytes */
-	loopsize = i_size_read(file->f_mapping->host);
+	int ret;
+
+	/*
+	 * Get the accurate file size. This provides better results than
+	 * cached inode data, particularly for network filesystems where
+	 * metadata may be stale.
+	 */
+	ret = vfs_getattr_nosec(&file->f_path, &stat, STATX_SIZE, 0);
+	if (ret)
+		return 0;
+
+	loopsize = stat.size;
 	if (lo->lo_offset > 0)
 		loopsize -= lo->lo_offset;
 	/* offset is beyond i_size, weird but possible */
-- 
2.43.7

Re: fixed commit message

[Jens Axboe]

On 8/18/25 12:48 PM, Rajeev Mishra wrote:
> fixed the commit message

Still leaves something to be desired - a nit is the line length,
but most in terms of why the change is necessary. At least the
comment in the code explains why this is a needed change, but
the commit message is pretty vague.

I'll fix them up and re-add Yu's review.

-- 
Jens Axboe

Re: fixed commit message

[Jens Axboe]

On Mon, 18 Aug 2025 18:48:19 +0000, Rajeev Mishra wrote:
> fixed the commit message
> Rajeev Mishra (2):
>   loop: Consolidate size calculation logic into lo_calculate_size()
>   loop: use vfs_getattr_nosec for accurate file size
> 
> drivers/block/loop.c | 39 +++++++++++++++++++++------------------
>  1 file changed, 21 insertions(+), 18 deletions(-)
> 
> [...]

Applied, thanks!

[1/2] loop: Consolidate size calculation logic into lo_calculate_size()
      commit: 8aa5a3b68ad144da49a3d17f165e6561255e3529
[2/2] loop: use vfs_getattr_nosec for accurate file size
      commit: 47b71abd58461a67cae71d2f2a9d44379e4e2fcf

Best regards,
-- 
Jens Axboe