Currently we hold the transaction mutex and the cleaner mutex when we do a
freeze, but the cleaner kthread does a vfs_check_frozen() to make sure it
doesn''t run while the fs is frozen, so the only thing thats left is the
transaction stuff. So add a vfs_check_frozen() into start_transaction and then
make the freeze functions just return, since vfs_check_frozen() covers us in all
the cases. This works because the vfs freezer function sync''s the
filesystem
first, and then sets SB_FREEZE_TRANS, so no transaction started after
SB_FREEZE_TRANS is set should be allowed to complete, including people calling
btrfs_join_transaction. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
---
fs/btrfs/super.c | 6 ------
fs/btrfs/transaction.c | 2 ++
2 files changed, 2 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 9ac612e..c9ded47 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -811,17 +811,11 @@ static long btrfs_control_ioctl(struct file *file,
unsigned int cmd,
static int btrfs_freeze(struct super_block *sb)
{
- struct btrfs_root *root = btrfs_sb(sb);
- mutex_lock(&root->fs_info->transaction_kthread_mutex);
- mutex_lock(&root->fs_info->cleaner_mutex);
return 0;
}
static int btrfs_unfreeze(struct super_block *sb)
{
- struct btrfs_root *root = btrfs_sb(sb);
- mutex_unlock(&root->fs_info->cleaner_mutex);
- mutex_unlock(&root->fs_info->transaction_kthread_mutex);
return 0;
}
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 2d654c1..c3bc9ba 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -176,6 +176,8 @@ static struct btrfs_trans_handle *start_transaction(struct
btrfs_root *root,
kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
int ret;
+ vfs_check_frozen(root->fs_info->sb, SB_FREEZE_TRANS);
+
mutex_lock(&root->fs_info->trans_mutex);
if (!root->fs_info->log_root_recovering &&
((type == TRANS_START && !root->fs_info->open_ioctl_trans)
||
--
1.6.6.1
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Hi, If the only thing is returning 0 in the freeze/unfreeze member functions, why not just remove the two functions? regards, wengang. On 10-03-23 10:28, Josef Bacik wrote:> Currently we hold the transaction mutex and the cleaner mutex when we do a > freeze, but the cleaner kthread does a vfs_check_frozen() to make sure it > doesn''t run while the fs is frozen, so the only thing thats left is the > transaction stuff. So add a vfs_check_frozen() into start_transaction and then > make the freeze functions just return, since vfs_check_frozen() covers us in all > the cases. This works because the vfs freezer function sync''s the filesystem > first, and then sets SB_FREEZE_TRANS, so no transaction started after > SB_FREEZE_TRANS is set should be allowed to complete, including people calling > btrfs_join_transaction. Thanks, > > Signed-off-by: Josef Bacik <josef@redhat.com> > --- > fs/btrfs/super.c | 6 ------ > fs/btrfs/transaction.c | 2 ++ > 2 files changed, 2 insertions(+), 6 deletions(-) > > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c > index 9ac612e..c9ded47 100644 > --- a/fs/btrfs/super.c > +++ b/fs/btrfs/super.c > @@ -811,17 +811,11 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, > > static int btrfs_freeze(struct super_block *sb) > { > - struct btrfs_root *root = btrfs_sb(sb); > - mutex_lock(&root->fs_info->transaction_kthread_mutex); > - mutex_lock(&root->fs_info->cleaner_mutex); > return 0; > } > > static int btrfs_unfreeze(struct super_block *sb) > { > - struct btrfs_root *root = btrfs_sb(sb); > - mutex_unlock(&root->fs_info->cleaner_mutex); > - mutex_unlock(&root->fs_info->transaction_kthread_mutex); > return 0; > } > > diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c > index 2d654c1..c3bc9ba 100644 > --- a/fs/btrfs/transaction.c > +++ b/fs/btrfs/transaction.c > @@ -176,6 +176,8 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root, > kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS); > int ret; > > + vfs_check_frozen(root->fs_info->sb, SB_FREEZE_TRANS); > + > mutex_lock(&root->fs_info->trans_mutex); > if (!root->fs_info->log_root_recovering && > ((type == TRANS_START && !root->fs_info->open_ioctl_trans) || > -- > 1.6.6.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Mar 23, 2010 at 10:54:08PM +0800, Wengang Wang wrote:> Hi, > > If the only thing is returning 0 in the freeze/unfreeze member functions, why > not just remove the two functions? >Because if the fs doesn''t provide a freeze/unfreeze function, trying to do a freeze will return -EOPNOTSUPP, which is not what we want. Thanks, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10-03-23 11:03, Josef Bacik wrote:> On Tue, Mar 23, 2010 at 10:54:08PM +0800, Wengang Wang wrote: > > Hi, > > > > If the only thing is returning 0 in the freeze/unfreeze member functions, why > > not just remove the two functions? > > > > Because if the fs doesn''t provide a freeze/unfreeze function, trying to do a > freeze will return -EOPNOTSUPP, which is not what we want. Thanks,How does freeze_fs()/unfreeze_fs() get called in btrfs? I think they called by freeze_bdev()/unfreeze_fs() respectively. And I don''t see -EOPNOTSUPP is returned in the later two functions. regards, wengang. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Mar 23, 2010 at 11:25:18PM +0800, Wengang Wang wrote:> On 10-03-23 11:03, Josef Bacik wrote: > > On Tue, Mar 23, 2010 at 10:54:08PM +0800, Wengang Wang wrote: > > > Hi, > > > > > > If the only thing is returning 0 in the freeze/unfreeze member functions, why > > > not just remove the two functions? > > > > > > > Because if the fs doesn''t provide a freeze/unfreeze function, trying to do a > > freeze will return -EOPNOTSUPP, which is not what we want. Thanks, > > How does freeze_fs()/unfreeze_fs() get called in btrfs? I think they > called by freeze_bdev()/unfreeze_fs() respectively. And I don''t see > -EOPNOTSUPP is returned in the later two functions. >its in ioctl_fsfreeze, /* If filesystem doesn''t support freeze feature, return. */ if (sb->s_op->freeze_fs == NULL) return -EOPNOTSUPP; Thanks, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10-03-23 23:25, Wengang Wang wrote:> On 10-03-23 11:03, Josef Bacik wrote: > > On Tue, Mar 23, 2010 at 10:54:08PM +0800, Wengang Wang wrote: > > > Hi, > > > > > > If the only thing is returning 0 in the freeze/unfreeze member functions, why > > > not just remove the two functions? > > > > > > > Because if the fs doesn''t provide a freeze/unfreeze function, trying to do a > > freeze will return -EOPNOTSUPP, which is not what we want. Thanks, > > How does freeze_fs()/unfreeze_fs() get called in btrfs? I think they > called by freeze_bdev()/unfreeze_fs() respectively. And I don''t seesorry, I meant called by freeze_bdev()/unfreeze_bdev() respectively.> -EOPNOTSUPP is returned in the later two functions. > > regards, > wengang.-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10-03-23 11:27, Josef Bacik wrote:> On Tue, Mar 23, 2010 at 11:25:18PM +0800, Wengang Wang wrote: > > On 10-03-23 11:03, Josef Bacik wrote: > > > On Tue, Mar 23, 2010 at 10:54:08PM +0800, Wengang Wang wrote: > > > > Hi, > > > > > > > > If the only thing is returning 0 in the freeze/unfreeze member functions, why > > > > not just remove the two functions? > > > > > > > > > > Because if the fs doesn''t provide a freeze/unfreeze function, trying to do a > > > freeze will return -EOPNOTSUPP, which is not what we want. Thanks, > > > > How does freeze_fs()/unfreeze_fs() get called in btrfs? I think they > > called by freeze_bdev()/unfreeze_fs() respectively. And I don''t see > > -EOPNOTSUPP is returned in the later two functions. > > > > its in ioctl_fsfreeze, > > /* If filesystem doesn''t support freeze feature, return. */ > if (sb->s_op->freeze_fs == NULL) > return -EOPNOTSUPP; >Yes, it''s there. Thanks for your explanation! regards, wengang. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html