Messages in this thread | | | Date | Tue, 26 Feb 2008 15:49:48 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] mm: fix blkdev size calculation in generic_write_checks |
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On Wed, 15 Aug 2007 17:52:28 +0400 Dmitry Monakhov <dmonakhov@openvz.org> 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 <dmonakhov@openvz.org> > --- > 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;
I'm trying to work out how the heck we fixed http://bugzilla.kernel.org/show_bug.cgi?id=10116
We never merged your patch because it introduced problems. But did we merge some alternative fix, or does the bug remain in there?
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