Add extra limitation explained for --rootdir option, including: 1) Size limitation Now I decide to follow "mkfs.ext4 -d" behavior, so we user is responsible to make sure the block device/file is large enough. 2) Read permission If user can't read the content, mkfs will just fail. So user is also responsible to make sure to have enough privilege. 3) Extra warning about the behavior change Since we we don't shrink fs the create file image, add such warning in documentation. Signed-off-by: Qu Wenruo <quwenruo.btrfs@xxxxxxx> --- Documentation/mkfs.btrfs.asciidoc | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/Documentation/mkfs.btrfs.asciidoc b/Documentation/mkfs.btrfs.asciidoc index d53d9e26..843e25cd 100644 --- a/Documentation/mkfs.btrfs.asciidoc +++ b/Documentation/mkfs.btrfs.asciidoc @@ -106,6 +106,17 @@ Please see the mount option 'discard' for that in `btrfs`(5). *-r|--rootdir <rootdir>*:: Populate the toplevel subvolume with files from 'rootdir'. This does not require root permissions and does not mount the filesystem. ++ +With this option, only one device can be specified. ++ +NOTE: User should make sure the block device/file has large enough space to +contain the source directory and has enough previllege to read source directory. +Or mkfs will just fail. ++ +WARNING: Before v4.14 btrfs-progs, *--rootdir* will shrink the filesystem, +prevent user to make use of the remaining space. +In v4.14 btrfs-progs, this behavior is changed, and will not shrink the fs. +The result should be the same as `mkfs`, `mount` and then `cp -r`. *-O|--features <feature1>[,<feature2>...]*:: A list of filesystem features turned on at mkfs time. Not all features are -- 2.14.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
