On Thu, 24 Feb 2011, Li Dongyang wrote:

On Monday, February 21, 2011 09:37:21 PM Lukas Czerner wrote:

quoted

On Mon, 21 Feb 2011, Li Dongyang wrote:

quoted

Here is batched discard support for btrfs, several changes were made:

btrfs_test_opt(root, DISCARD) is moved from btrfs_discard_extent
to callers, as we still want to trim the fs even it's not mounted
with -o discard.
btrfs_discard_extent now reports errors and actual bytes trimmed to
callers, for EOPNOTSUPP, we will try other stripes as an extent
could span SSD and other drives, and we won't return error to
callers unless we failed with all stripes.

And btrfs_discard_extent calls btrfs_map_block with READ, this means
we won't get all stripes mapped for RAID1/DUP/RAID10, I think this
should be fixed, Thanks.

Hello,

First of all thanks for you effort:). I can not really comment on the
btrfs specific code, however I have couple of comments bellow.

Btw, how did you test it ?

Thanks for mentioning trim support checking and discard_granularity, they are
added to V2, I fire fstrim from util-linux, and watch the trim command by blktrace.

You may want to try xfstests test 251 to test it.

-Lukas

quoted

Thanks!
-Lukas

quoted

Signed-off-by: Li Dongyang <redacted>
---

 fs/btrfs/ctree.h            |    3 +-
 fs/btrfs/disk-io.c          |    5 ++-
 fs/btrfs/extent-tree.c      |   81
 ++++++++++++++++++++++++++++++++++++------- fs/btrfs/free-space-cache.c
 |   79 +++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/free-space-cache.h |    2 +
 fs/btrfs/ioctl.c            |   24 +++++++++++++
 6 files changed, 179 insertions(+), 15 deletions(-)

..snip..

quoted

diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h
index e49ca5c..65c3b93 100644
--- a/fs/btrfs/free-space-cache.h
+++ b/fs/btrfs/free-space-cache.h

@@ -68,4 +68,6 @@ u64 btrfs_alloc_from_cluster(struct

btrfs_block_group_cache *block_group,

 int btrfs_return_cluster_to_free_space(
 
 			       struct btrfs_block_group_cache *block_group,
 			       struct btrfs_free_cluster *cluster);

+int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
+			   u64 *trimmed, u64 start, u64 end, u64 minlen);

 #endif

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index be2d4f6..ecd3982 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c

@@ -225,6 +225,28 @@ static int btrfs_ioctl_getversion(struct file *file,

int __user *arg)

 	return put_user(inode->i_generation, arg);
 
 }

+static noinline int btrfs_ioctl_fitrim(struct file *file, void __user
*arg) +{
+	struct btrfs_root *root = fdentry(file)->d_sb->s_fs_info;
+	struct fstrim_range range;
+	int ret;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;

You might want to check whether any of the underlying device does
actually support trim and also adjust the minlen according to the
discard_granularity.

quoted

+
+	if (copy_from_user(&range, arg, sizeof(range)))
+		return -EFAULT;
+
+	ret = btrfs_trim_fs(root, &range);
+	if (ret < 0)
+		return ret;
+
+	if (copy_to_user(arg, &range, sizeof(range)))
+		return -EFAULT;
+
+	return 0;
+}
+

 static noinline int create_subvol(struct btrfs_root *root,
 
 				  struct dentry *dentry,
 				  char *name, int namelen,

@@ -2385,6 +2407,8 @@ long btrfs_ioctl(struct file *file, unsigned int

 		return btrfs_ioctl_setflags(file, argp);
 	
 	case FS_IOC_GETVERSION:
 		return btrfs_ioctl_getversion(file, argp);

+	case FITRIM:
+		return btrfs_ioctl_fitrim(file, argp);

 	case BTRFS_IOC_SNAP_CREATE:
 		return btrfs_ioctl_snap_create(file, argp, 0);
 	
 	case BTRFS_IOC_SNAP_CREATE_V2:

--