On Wed, 15 Aug 2007 17:52:28 +0400 Dmitry Monakhov <[EMAIL PROTECTED]> wrote:
> Currently block device size calculated regardless its > bd_block_size. This may result attempt to write outside > block device if i_size not aligned to bdev->bd_block_size > and result in EIO. > > #### TEST_CASE_BEGIN > # fdisk -l /dev/sdc > Disk /dev/sdc: 36.7 GB, 36703918080 bytes > 255 heads, 63 sectors/track, 4462 cylinders > Units = cylinders of 16065 * 512 = 8225280 bytes > > Device Boot Start End Blocks Id System > /dev/sdc1 * 1 254 2040223+ 83 Ldinux > /dev/sdc2 255 379 1004062+ 83 Linux > #### > #### /dev/sdc2 size not aligned to 4K > > #### at this time bd_block_size == 512 so generic_write_check > #### performed correctly > # dd if=/dev/zero of=/dev/sdc2 bs=1k count=7 seek=1004058 > dd: writing `/dev/sdc2': No space left on device > 5+0 records in > 4+0 records out > > #### this bdev contain ext4fs with blksize = 4K > # mount /dev/sdc2 /mnt/ > #### after we mounted this bdev bd_block_size == fsblksize == 4K > > #### the same write operation failed with EIO > # dd if=/dev/zero of=/dev/sdc2 bs=1k count=7 seek=1004058 > dd: writing `/dev/sdc2': Input/output error > 3+0 records in > 2+0 records out > #### Attempt to write whole fsblock result write access outside > #### blkdevice and cause -EIO (returned by blkdev_get_block) > #### TEST_CASE_END > > Signed-off-by: Dmitry Monakhov <[EMAIL PROTECTED]> > --- > mm/filemap.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/mm/filemap.c b/mm/filemap.c > index 2c8776b..a23ee8a 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -1867,9 +1867,11 @@ inline int generic_write_checks(struct file *file, > loff_t *pos, size_t *count, i > } else { > #ifdef CONFIG_BLOCK > loff_t isize; > + unsigned int blksize; > if (bdev_read_only(I_BDEV(inode))) > return -EPERM; > - isize = i_size_read(inode); > + blksize = block_size(I_BDEV(inode)); > + isize = i_size_read(inode) & ~(blksize - 1); > if (*pos >= isize) { > if (*count || *pos > isize) > return -ENOSPC; Can't say I really like the idea of adding additional overhead in this hotpath for such an odd case. Is there a faster way of doing it? Maybe adjust i_size, perhaps when the blocksize gets changed? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/