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author | Josef Bacik <josef@redhat.com> | 2011-05-27 12:06:11 -0400 |
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committer | Josef Bacik <josef@redhat.com> | 2011-07-11 09:58:45 -0400 |
commit | fa09200b8334f9a6af3f656edae924a98d85630f (patch) | |
tree | 9213ac48212f70d86fb60834beb464d68be332ba /fs/btrfs/xattr.c | |
parent | 149e2d76b4886c4c7ff5e077646a8ba3563c8026 (diff) | |
download | linux-stable-fa09200b8334f9a6af3f656edae924a98d85630f.tar.gz linux-stable-fa09200b8334f9a6af3f656edae924a98d85630f.tar.bz2 linux-stable-fa09200b8334f9a6af3f656edae924a98d85630f.zip |
Btrfs: try to only do one btrfs_search_slot in do_setxattr
I've been watching how many btrfs_search_slot()'s we do and I noticed that when
we create a file with selinux enabled we were doing 2 each time we initialize
the security context. That's because we lookup the xattr first so we can delete
it if we're setting a new value to an existing xattr. But in the create case we
don't have any xattrs, so it is completely useless to have the extra lookup. So
re-arrange things so that we only lookup first if we specifically have
XATTR_REPLACE. That way in the basic case we only do 1 search, and in the more
complicated case we do the normal 2 lookups. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Diffstat (limited to 'fs/btrfs/xattr.c')
-rw-r--r-- | fs/btrfs/xattr.c | 66 |
1 files changed, 40 insertions, 26 deletions
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c index 5366fe452ab0..d733b9cfea34 100644 --- a/fs/btrfs/xattr.c +++ b/fs/btrfs/xattr.c @@ -102,43 +102,57 @@ static int do_setxattr(struct btrfs_trans_handle *trans, if (!path) return -ENOMEM; - /* first lets see if we already have this xattr */ - di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name, - strlen(name), -1); - if (IS_ERR(di)) { - ret = PTR_ERR(di); - goto out; - } - - /* ok we already have this xattr, lets remove it */ - if (di) { - /* if we want create only exit */ - if (flags & XATTR_CREATE) { - ret = -EEXIST; + if (flags & XATTR_REPLACE) { + di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), name, + name_len, -1); + if (IS_ERR(di)) { + ret = PTR_ERR(di); + goto out; + } else if (!di) { + ret = -ENODATA; goto out; } - ret = btrfs_delete_one_dir_name(trans, root, path, di); - BUG_ON(ret); + if (ret) + goto out; btrfs_release_path(path); + } - /* if we don't have a value then we are removing the xattr */ - if (!value) +again: + ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode), + name, name_len, value, size); + if (ret == -EEXIST) { + if (flags & XATTR_CREATE) goto out; - } else { + /* + * We can't use the path we already have since we won't have the + * proper locking for a delete, so release the path and + * re-lookup to delete the thing. + */ btrfs_release_path(path); + di = btrfs_lookup_xattr(trans, root, path, btrfs_ino(inode), + name, name_len, -1); + if (IS_ERR(di)) { + ret = PTR_ERR(di); + goto out; + } else if (!di) { + /* Shouldn't happen but just in case... */ + btrfs_release_path(path); + goto again; + } - if (flags & XATTR_REPLACE) { - /* we couldn't find the attr to replace */ - ret = -ENODATA; + ret = btrfs_delete_one_dir_name(trans, root, path, di); + if (ret) goto out; + + /* + * We have a value to set, so go back and try to insert it now. + */ + if (value) { + btrfs_release_path(path); + goto again; } } - - /* ok we have to create a completely new xattr */ - ret = btrfs_insert_xattr_item(trans, root, path, btrfs_ino(inode), - name, name_len, value, size); - BUG_ON(ret); out: btrfs_free_path(path); return ret; |