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| author | Ross Zwisler <ross.zwisler@linux.intel.com> | 2016-01-23 00:10:59 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-23 02:02:18 +0100 |
| commit | eab95db69d334745d3034072f4a7204084136c88 (patch) | |
| tree | 3d54065f19a096d64caaf90793ceec9d527060a2 | |
| parent | xfs: call dax_pfn_mkwrite() for DAX fsync/msync (diff) | |
| download | linux-eab95db69d334745d3034072f4a7204084136c88.tar.xz linux-eab95db69d334745d3034072f4a7204084136c88.zip | |
dax: never rely on bh.b_dev being set by get_block()
Previously in DAX we assumed that calls to get_block() would set
bh.b_bdev, and we would then use that value even in error cases for
debugging. This caused a NULL pointer dereference in __dax_dbg() which
was fixed by a previous commit, but that commit only changed the one
place where we were hitting an error.
Instead, update dax.c so that we always initialize bh.b_bdev as best we
can based on the information that DAX has. get_block() may or may not
update to a new value, but this at least lets us get something helpful
from bh.b_bdev for error messages and not have to worry about whether it
was set by get_block() or not.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reported-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/dax.c | 3 |
1 files changed, 3 insertions, 0 deletions
@@ -246,6 +246,7 @@ ssize_t dax_do_io(struct kiocb *iocb, struct inode *inode, loff_t end = pos + iov_iter_count(iter); memset(&bh, 0, sizeof(bh)); + bh.b_bdev = inode->i_sb->s_bdev; if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ) { struct address_space *mapping = inode->i_mapping; @@ -607,6 +608,7 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, memset(&bh, 0, sizeof(bh)); block = (sector_t)vmf->pgoff << (PAGE_SHIFT - blkbits); + bh.b_bdev = inode->i_sb->s_bdev; bh.b_size = PAGE_SIZE; repeat: @@ -1078,6 +1080,7 @@ int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length, BUG_ON((offset + length) > PAGE_CACHE_SIZE); memset(&bh, 0, sizeof(bh)); + bh.b_bdev = inode->i_sb->s_bdev; bh.b_size = PAGE_CACHE_SIZE; err = get_block(inode, index, &bh, 0); if (err < 0) |