On Thu, 18 Aug 2011, David Sterba wrote:
> Hi,
>
> I see you are mixing a cleanup while adding a new feature.
>
> On Thu, Aug 18, 2011 at 02:18:26PM +0200, Lukas Czerner wrote:
> > Register fs netlink interface and send proper warning if ENOSPC is
> > encountered. Note that we differentiate between enospc for metadata and
> > enospc for data.
> >
> > Signed-off-by: Lukas Czerner <lczer...@redhat.com>
> > Cc: Chris Mason <chris.ma...@oracle.com>
> > Cc: linux-btrfs@vger.kernel.org
> > ---
> > fs/btrfs/extent-tree.c | 13 ++++++++++---
> > fs/btrfs/super.c | 1 +
> > 2 files changed, 11 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> > index 66bac22..a47d9b9 100644
> > --- a/fs/btrfs/extent-tree.c
> > +++ b/fs/btrfs/extent-tree.c
> > @@ -3029,13 +3029,14 @@ int btrfs_check_data_free_space(struct inode
> > *inode, u64 bytes)
>
> hm, if diff is correct with the context, you are changing function
> btrfs_check_data_free_space and reporting it as metadata ENOSPC later.
> Although it's called for metadata (or I should say non-user file blocks,
> like space cache, ino cache) block allocation, it's called from
> btrfs_fallocate too. Seems that there has to be additional flag to say
> if it's really metadata or data.
Actually diff got the context wrong. Sometimes it has some difficulties
if there are labels involved.
>
> > {
> > struct btrfs_space_info *data_sinfo;
> > struct btrfs_root *root = BTRFS_I(inode)->root;
> > + struct btrfs_fs_info *fs_info = root->fs_info;
>
> change unrealated to ENOSPC-netlink
Not really. I am using fs_info to get reference to the last_bdev and
it is useful for other places as well.
>
> > u64 used;
> > int ret = 0, committed = 0, alloc_chunk = 1;
> >
> > /* make sure bytes are sectorsize aligned */
> > bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
> >
> > - if (root == root->fs_info->tree_root ||
> > + if (root == fs_info->tree_root ||
>
> here
>
> > BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
> > alloc_chunk = 0;
> > committed = 1;
> > @@ -3070,7 +3071,7 @@ alloc:
> > if (IS_ERR(trans))
> > return PTR_ERR(trans);
> >
> > - ret = do_chunk_alloc(trans, root->fs_info->extent_root,
> > + ret = do_chunk_alloc(trans, fs_info->extent_root,
>
> here
>
> > bytes + 2 * 1024 * 1024,
> > alloc_target,
> > CHUNK_ALLOC_NO_FORCE);
> > @@ -3100,7 +3101,7 @@ alloc:
> > /* commit the current transaction and try again */
> > commit_trans:
> > if (!committed &&
> > - !atomic_read(&root->fs_info->open_ioctl_trans)) {
> > + !atomic_read(&fs_info->open_ioctl_trans)) {
>
> here
>
> > committed = 1;
> > trans = btrfs_join_transaction(root);
> > if (IS_ERR(trans))
> > @@ -3111,6 +3112,8 @@ commit_trans:
> > goto again;
> > }
> >
> > + fs_nl_send_warning(fs_info->fs_devices->latest_bdev->bd_dev,
> > + FS_NL_ENOSPC_WARN);
>
> or is it due to this line being too long with root-> ? :)
exactly :) But as I said fs_info is referenced on other paces as well so
it is useful anyway.
>
> > return -ENOSPC;
> > }
> > data_sinfo->bytes_may_use += bytes;
> > @@ -3522,6 +3525,10 @@ again:
> > }
> >
> > out:
> > + if (unlikely(-ENOSPC == ret)) {
>
> 'unlikely' is not needed here, it does not bring anything compiler
> wouldn't know, static branch prediction will give low probabiliy to this
> check anyway
Ok, but I would like to know why do you think that. It is not only in
the error path and there are actually several paths to this condition so
maybe I am being dense, could you explain it a bit for me ?
Thanks!
-Lukas
>
> > + dev_t bdev = root->fs_info->fs_devices->latest_bdev->bd_dev;
> > + fs_nl_send_warning(bdev, FS_NL_META_ENOSPC_WARN);
> > + }
> > if (flushing) {
> > spin_lock(&space_info->lock);
> > space_info->flush = 0;
> > diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
> > index 15634d4..8ac9e01 100644
> > --- a/fs/btrfs/super.c
> > +++ b/fs/btrfs/super.c
> > @@ -1266,6 +1266,7 @@ static int __init init_btrfs_fs(void)
> > if (err)
> > goto unregister_ioctl;
> >
> > + init_fs_nl_family();
> > printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
> > return 0;
>
>
> david
>
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