From 47b71abd58461a67cae71d2f2a9d44379e4e2fcf Mon Sep 17 00:00:00 2001 From: Rajeev Mishra Date: Mon, 18 Aug 2025 18:48:21 +0000 Subject: [PATCH] loop: use vfs_getattr_nosec for accurate file size Use vfs_getattr_nosec() in lo_calculate_size() for getting the file size, rather than just read the cached inode size via i_size_read(). This provides better results than cached inode data, particularly for network filesystems where metadata may be stale. Signed-off-by: Rajeev Mishra Reviewed-by: Yu Kuai Link: https://lore.kernel.org/r/20250818184821.115033-3-rajeevm@hpe.com [axboe: massage commit message] Signed-off-by: Jens Axboe --- 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 */ -- 2.25.1