[PATCH v4 2/2] loop: use vfs_getattr_nosec for accurate file size
From: Rajeev Mishra <hidden>
Date: 2025-08-18 18:49:36
Also in:
lkml
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
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 <redacted> --- 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