On Thu, Mar 29, 2018 at 10:38 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> If an inode has been copied up metadata only, then we need to query the
> number of blocks from lower and fill up the stat->st_blocks.
>
> We need to be careful about races where we are doing stat on one cpu and
> data copy up is taking place on other cpu. We want to return
> stat->st_blocks either from lower or stable upper and not something in
> between. Hence, ovl_has_upperdata() is called first to figure out whether
> block reporting will take place from lower or upper.
>
> Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
> ---
> fs/overlayfs/inode.c | 17 ++++++++++++++++-
> fs/overlayfs/overlayfs.h | 1 +
> fs/overlayfs/util.c | 16 ++++++++++++++++
> 3 files changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> index e1dbfed0c449..cd03f3e642fd 100644
> --- a/fs/overlayfs/inode.c
> +++ b/fs/overlayfs/inode.c
> @@ -76,6 +76,9 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
> bool is_dir = S_ISDIR(dentry->d_inode->i_mode);
> bool samefs = ovl_same_sb(dentry->d_sb);
> int err;
> + bool metacopy = false;
> +
> + metacopy = ovl_is_metacopy_dentry(dentry);
>
> type = ovl_path_real(dentry, &realpath);
> old_cred = ovl_override_creds(dentry->d_sb);
> @@ -93,7 +96,8 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
> if (!is_dir || samefs) {
> if (OVL_TYPE_ORIGIN(type)) {
> struct kstat lowerstat;
> - u32 lowermask = STATX_INO | (!is_dir ? STATX_NLINK : 0);
> + u32 lowermask = STATX_INO | STATX_BLOCKS |
> + (!is_dir ? STATX_NLINK : 0);
Leftover.
But I think you could do with one vfs_getattr():
if (!is_dir || samefs) {
u32 lowermask = metacopy ? STATX_BLOCKS : 0;
if (OVL_TYPE_ORIGIN(type))
lowermask |= STATX_INO | (!is_dir ? STATX_NLINK : 0);
if (lowermask) {
ovl_path_lower(dentry, &realpath);
err = vfs_getattr(&realpath, &lowerstat,
...
Thanks,
Amir.
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