The maximum IO size that a block device can read as a single block is based on the min folio order and not the PAGE_SIZE as we have bs > ps support for block devices[1]. Calculate the upper limit based on the on min folio order. [1] https://lore.kernel.org/linux-block/20250221223823.1680616-1-mcgrof@xxxxxxxxxx/ Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx> --- I found this while I was adding bs > ps support to ext4. Ext4 uses this routine to read the superblock. fs/buffer.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index 8cf4a1dc481e..98f90da69a0a 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1121,10 +1121,11 @@ __getblk_slow(struct block_device *bdev, sector_t block, unsigned size, gfp_t gfp) { bool blocking = gfpflags_allow_blocking(gfp); + int blocklog = PAGE_SHIFT + mapping_min_folio_order(bdev->bd_mapping); /* Size must be multiple of hard sectorsize */ - if (unlikely(size & (bdev_logical_block_size(bdev)-1) || - (size < 512 || size > PAGE_SIZE))) { + if (unlikely(size & (bdev_logical_block_size(bdev) - 1) || + (size < 512 || size > (1U << blocklog)))) { printk(KERN_ERR "getblk(): invalid block size %d requested\n", size); printk(KERN_ERR "logical block size: %d\n", base-commit: e04c78d86a9699d136910cfc0bdcf01087e3267e -- 2.49.0
