Recent 2.5 kernels break loop devices using files on NFS, because
inode->i_sb->s_bdev is NULL, so you get an oops in loop_set_fd.
The patch below fixes this. Note that I'm not entirely sure
whether using i_blksize is really correct. The patch is for
2.5.24.
This patch also removes redundant setting of LO_FLAGS_READ_ONLY
- Werner
---------------------------------- cut here -----------------------------------
--- drivers/block/loop.c.orig Sun Jun 23 09:09:10 2002
+++ drivers/block/loop.c Sun Jun 23 11:41:19 2002
@@ -336,7 +336,10 @@ lo_receive(struct loop_device *lo, struc
static inline int loop_get_bs(struct loop_device *lo)
{
- return block_size(lo->lo_device);
+ if (lo->lo_device)
+ return block_size(lo->lo_device);
+ /* @@@ is this correct ? */
+ return lo->lo_backing_file->f_dentry->d_inode->i_blksize;
}
static inline unsigned long loop_get_iv(struct loop_device *lo,
@@ -662,9 +665,6 @@ static int loop_set_fd(struct loop_devic
error = -EINVAL;
inode = file->f_dentry->d_inode;
- if (!(file->f_mode & FMODE_WRITE))
- lo_flags |= LO_FLAGS_READ_ONLY;
-
if (S_ISBLK(inode->i_mode)) {
lo_device = inode->i_bdev;
if (lo_device == bdev) {
@@ -691,7 +691,7 @@ static int loop_set_fd(struct loop_devic
get_file(file);
- if (IS_RDONLY (inode) || bdev_read_only(lo_device)
+ if (IS_RDONLY (inode) || (lo_device && bdev_read_only(lo_device))
|| !(lo_file->f_mode & FMODE_WRITE))
lo_flags |= LO_FLAGS_READ_ONLY;
@@ -706,7 +706,7 @@ static int loop_set_fd(struct loop_devic
lo->old_gfp_mask = inode->i_mapping->gfp_mask;
inode->i_mapping->gfp_mask = GFP_NOIO;
- set_blocksize(bdev, block_size(lo_device));
+ set_blocksize(bdev, loop_get_bs(lo));
lo->lo_bio = lo->lo_biotail = NULL;
kernel_thread(loop_thread, lo, CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
--
_________________________________________________________________________
/ Werner Almesberger, Buenos Aires, Argentina [email protected] /
/_http://icapeople.epfl.ch/almesber/_____________________________________/