[PATCH 0/4] Btrfs updates for 3.14-rc - sysfs, ioctl

[PATCH 0/4] Btrfs updates for 3.14-rc - sysfs, ioctl

[David Sterba]

Two minor fixes to the new sysfs code and a RFC change to replace the
GLOBAL_RSV ioctl with the same information exported through SPACE_INFO ioctl.

This requires to reserve a blockgroup type that will become part of ABI.

David Sterba (3):
  btrfs: reserve no transaction units in btrfs_ioctl_set_features
  btrfs: export global block reserve size as space_info
  Revert "btrfs: add ioctl to export size of global metadata
    reservation"

Jeff Mahoney (1):
  btrfs: commit transaction after setting label and features

 fs/btrfs/ctree.h           |  9 ++++++++-
 fs/btrfs/ioctl.c           | 42 +++++++++++++++++++++++-------------------
 include/uapi/linux/btrfs.h |  1 -
 3 files changed, 31 insertions(+), 21 deletions(-)

-- 
1.8.5.2

[PATCH 1/4] btrfs: commit transaction after setting label and features

[David Sterba]

From: Jeff Mahoney <jeffm@suse.com>

The set_fslabel ioctl uses btrfs_end_transaction, which means it's
possible that the change will be lost if the system crashes, same for
the newly set features. Let's use btrfs_commit_transaction instead.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
---
 fs/btrfs/ioctl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b0134892dc70..8e48b81e1515 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4525,7 +4525,7 @@ static int btrfs_ioctl_set_fslabel(struct file *file, void __user *arg)
 	spin_lock(&root->fs_info->super_lock);
 	strcpy(super_block->label, label);
 	spin_unlock(&root->fs_info->super_lock);
-	ret = btrfs_end_transaction(trans, root);
+	ret = btrfs_commit_transaction(trans, root);
 
 out_unlock:
 	mnt_drop_write_file(file);
@@ -4689,7 +4689,7 @@ static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
 	btrfs_set_super_incompat_flags(super_block, newflags);
 	spin_unlock(&root->fs_info->super_lock);
 
-	return btrfs_end_transaction(trans, root);
+	return btrfs_commit_transaction(trans, root);
 }
 
 long btrfs_ioctl(struct file *file, unsigned int
-- 
1.8.5.2

[PATCH 2/4] btrfs: reserve no transaction units in btrfs_ioctl_set_features

[David Sterba]

Added in patch "btrfs: add ioctls to query/change feature bits online"
modifications to superblock don't need to reserve metadata blocks when
starting a transaction.

Signed-off-by: David Sterba <dsterba@suse.cz>
---
 fs/btrfs/ioctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 8e48b81e1515..383ab455bfa7 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4668,7 +4668,7 @@ static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
 	if (ret)
 		return ret;
 
-	trans = btrfs_start_transaction(root, 1);
+	trans = btrfs_start_transaction(root, 0);
 	if (IS_ERR(trans))
 		return PTR_ERR(trans);
 
-- 
1.8.5.2

[PATCH 3/4][RFC] btrfs: export global block reserve size as space_info

[David Sterba]

Introduce a block group type bit for a global reserve and fill the space
info for SPACE_INFO ioctl. This should replace the newly added ioctl
(01e219e8069516cdb98594d417b8bb8d906ed30d) to get just the 'size' part
of the global reserve, while the actual usage can be now visible in the
'btrfs fi df' output during ENOSPC stress.

The unpatched userspace tools will show the blockgroup as 'unknown'.

CC: Jeff Mahoney <jeffm@suse.com>
CC: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
---
 fs/btrfs/ctree.h |  9 ++++++++-
 fs/btrfs/ioctl.c | 20 ++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 2c1a42ca519f..8bf1890ea21f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -985,7 +985,8 @@ struct btrfs_dev_replace_item {
 #define BTRFS_BLOCK_GROUP_RAID10	(1ULL << 6)
 #define BTRFS_BLOCK_GROUP_RAID5         (1ULL << 7)
 #define BTRFS_BLOCK_GROUP_RAID6         (1ULL << 8)
-#define BTRFS_BLOCK_GROUP_RESERVED	BTRFS_AVAIL_ALLOC_BIT_SINGLE
+#define BTRFS_BLOCK_GROUP_RESERVED	(BTRFS_AVAIL_ALLOC_BIT_SINGLE | \
+					 BTRFS_SPACE_INFO_GLOBAL_RSV)
 
 enum btrfs_raid_types {
 	BTRFS_RAID_RAID10,
@@ -1017,6 +1018,12 @@ enum btrfs_raid_types {
  */
 #define BTRFS_AVAIL_ALLOC_BIT_SINGLE	(1ULL << 48)
 
+/*
+ * A fake block group type that is used to communicate global block reserve
+ * size to userspace via the SPACE_INFO ioctl.
+ */
+#define BTRFS_SPACE_INFO_GLOBAL_RSV	(1ULL << 49)
+
 #define BTRFS_EXTENDED_PROFILE_MASK	(BTRFS_BLOCK_GROUP_PROFILE_MASK | \
 					 BTRFS_AVAIL_ALLOC_BIT_SINGLE)
 
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 383ab455bfa7..0d938f8f173e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3465,6 +3465,11 @@ static long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
 		up_read(&info->groups_sem);
 	}
 
+	/*
+	 * Global block reserve, exported as a space_info
+	 */
+	slot_count++;
+
 	/* space_slots == 0 means they are asking for a count */
 	if (space_args.space_slots == 0) {
 		space_args.total_spaces = slot_count;
@@ -3523,6 +3528,21 @@ static long btrfs_ioctl_space_info(struct btrfs_root *root, void __user *arg)
 		up_read(&info->groups_sem);
 	}
 
+	/*
+	 * Add global block reserve
+	 */
+	if (slot_count) {
+		struct btrfs_block_rsv *block_rsv = &root->fs_info->global_block_rsv;
+
+		spin_lock(&block_rsv->lock);
+		space.total_bytes = block_rsv->size;
+		space.used_bytes = block_rsv->size - block_rsv->reserved;
+		spin_unlock(&block_rsv->lock);
+		space.flags = BTRFS_SPACE_INFO_GLOBAL_RSV;
+		memcpy(dest, &space, sizeof(space));
+		space_args.total_spaces++;
+	}
+
 	user_dest = (struct btrfs_ioctl_space_info __user *)
 		(arg + sizeof(struct btrfs_ioctl_space_args));
 
-- 
1.8.5.2

Re: [PATCH 3/4][RFC] btrfs: export global block reserve size as space_info

[Chris Mason]

On 02/07/2014 08:34 AM, David Sterba wrote:
> Introduce a block group type bit for a global reserve and fill the space
> info for SPACE_INFO ioctl. This should replace the newly added ioctl
> (01e219e8069516cdb98594d417b8bb8d906ed30d) to get just the 'size' part
> of the global reserve, while the actual usage can be now visible in the
> 'btrfs fi df' output during ENOSPC stress.
>
> The unpatched userspace tools will show the blockgroup as 'unknown'.
>

This wasn't in my rc2 pull because I wanted to sync up with Jeff on it. 
  I like the idea of combining this into SPACE_INFO, any objections?

-chris

Re: [PATCH 3/4][RFC] btrfs: export global block reserve size as space_info

[Jeff Mahoney]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 2/10/14, 12:03 PM, Chris Mason wrote:
> On 02/07/2014 08:34 AM, David Sterba wrote:
>> Introduce a block group type bit for a global reserve and fill
>> the space info for SPACE_INFO ioctl. This should replace the
>> newly added ioctl (01e219e8069516cdb98594d417b8bb8d906ed30d) to
>> get just the 'size' part of the global reserve, while the actual
>> usage can be now visible in the 'btrfs fi df' output during
>> ENOSPC stress.
>> 
>> The unpatched userspace tools will show the blockgroup as
>> 'unknown'.
>> 
> 
> This wasn't in my rc2 pull because I wanted to sync up with Jeff on
> it. I like the idea of combining this into SPACE_INFO, any
> objections?

Sorry, was on vacation when this went by and just got the ping. Yeah,
I have no objections here.

- -Jeff

- -- 
Jeff Mahoney
SUSE Labs
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[PATCH 4/4] Revert "btrfs: add ioctl to export size of global metadata reservation"

[David Sterba]

This reverts commit 01e219e8069516cdb98594d417b8bb8d906ed30d.

The information from the removed ioctl is newly provided by the existing
SPACE_INFO ioctl where it logically belongs and needs only minor changes
to the userspace code.

The GLOBAL_RSV ioctl hasn't been used anywhere yet, introduced only in
3.14-rc1 so there is no userspace ABI breakage.

CC: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
---
 fs/btrfs/ioctl.c           | 16 ----------------
 include/uapi/linux/btrfs.h |  1 -
 2 files changed, 17 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0d938f8f173e..dc64cc28af29 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3557,20 +3557,6 @@ out:
 	return ret;
 }
 
-static long btrfs_ioctl_global_rsv(struct btrfs_root *root, void __user *arg)
-{
-	struct btrfs_block_rsv *block_rsv = &root->fs_info->global_block_rsv;
-	u64 reserved;
-
-	spin_lock(&block_rsv->lock);
-	reserved = block_rsv->reserved;
-	spin_unlock(&block_rsv->lock);
-
-	if (arg && copy_to_user(arg, &reserved, sizeof(reserved)))
-		return -EFAULT;
-	return 0;
-}
-
 /*
  * there are many ways the trans_start and trans_end ioctls can lead
  * to deadlocks.  They should only be used by applications that
@@ -4777,8 +4763,6 @@ long btrfs_ioctl(struct file *file, unsigned int
 		return btrfs_ioctl_logical_to_ino(root, argp);
 	case BTRFS_IOC_SPACE_INFO:
 		return btrfs_ioctl_space_info(root, argp);
-	case BTRFS_IOC_GLOBAL_RSV:
-		return btrfs_ioctl_global_rsv(root, argp);
 	case BTRFS_IOC_SYNC: {
 		int ret;
 
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index 1b8a0f4c9590..b4d69092fbdb 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -558,7 +558,6 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code)
 #define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, __u64)
 #define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
 				    struct btrfs_ioctl_space_args)
-#define BTRFS_IOC_GLOBAL_RSV _IOR(BTRFS_IOCTL_MAGIC, 20, __u64)
 #define BTRFS_IOC_START_SYNC _IOR(BTRFS_IOCTL_MAGIC, 24, __u64)
 #define BTRFS_IOC_WAIT_SYNC  _IOW(BTRFS_IOCTL_MAGIC, 22, __u64)
 #define BTRFS_IOC_SNAP_CREATE_V2 _IOW(BTRFS_IOCTL_MAGIC, 23, \
-- 
1.8.5.2