path: root/fs/ioctl.c
diff options
authorJosef Bacik <josef@redhat.com>2010-03-23 10:34:56 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2010-05-21 18:31:18 -0400
commit18e9e5104fcd9a973ffe3eed3816c87f2a1b6cd2 (patch)
tree635369c866fcb384223618c878e0b4c317790634 /fs/ioctl.c
parente1e46bf1866317d4f86f66bf18d3f07317d9f9ee (diff)
Introduce freeze_super and thaw_super for the fsfreeze ioctl
Currently the way we do freezing is by passing sb>s_bdev to freeze_bdev and then letting it do all the work. But freezing is more of an fs thing, and doesn't really have much to do with the bdev at all, all the work gets done with the super. In btrfs we do not populate s_bdev, since we can have multiple bdev's for one fs and setting s_bdev makes removing devices from a pool kind of tricky. This means that freezing a btrfs filesystem fails, which causes us to corrupt with things like tux-on-ice which use the fsfreeze mechanism. So instead of populating sb->s_bdev with a random bdev in our pool, I've broken the actual fs freezing stuff into freeze_super and thaw_super. These just take the super_block that we're freezing and does the appropriate work. It's basically just copy and pasted from freeze_bdev. I've then converted freeze_bdev over to use the new super helpers. I've tested this with ext4 and btrfs and verified everything continues to work the same as before. The only new gotcha is multiple calls to the fsfreeze ioctl will return EBUSY if the fs is already frozen. I thought this was a better solution than adding a freeze counter to the super_block, but if everybody hates this idea I'm open to suggestions. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/ioctl.c')
1 files changed, 2 insertions, 13 deletions
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 7faefb4da93..2d140a71386 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -525,15 +525,8 @@ static int ioctl_fsfreeze(struct file *filp)
if (sb->s_op->freeze_fs == NULL)
- /* If a blockdevice-backed filesystem isn't specified, return. */
- if (sb->s_bdev == NULL)
- return -EINVAL;
/* Freeze */
- sb = freeze_bdev(sb->s_bdev);
- if (IS_ERR(sb))
- return PTR_ERR(sb);
- return 0;
+ return freeze_super(sb);
static int ioctl_fsthaw(struct file *filp)
@@ -543,12 +536,8 @@ static int ioctl_fsthaw(struct file *filp)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- /* If a blockdevice-backed filesystem isn't specified, return EINVAL. */
- if (sb->s_bdev == NULL)
- return -EINVAL;
/* Thaw */
- return thaw_bdev(sb->s_bdev, sb);
+ return thaw_super(sb);