On Wed, Oct 18, 2017 at 12:05 AM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> Presence of OVL_XATTR_METACOPY reflects that file has been copied up
> with metadata only and data needs to be copied up later from lower.
> So this xattr is set when a metadata copy takes place and cleared when
> data copy takes place.
>
> We also use a bit in ovl_inode->flags to cache OVL_METACOPY which reflects
> whether ovl inode has only metadata copied up.
>
> ovl_set_size() code has been taken from Amir's patch.
I waiver this attribution.
In git log history context, it is just noise that adds no information.
Please remove.
>
> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
> ---
> fs/overlayfs/copy_up.c | 59 ++++++++++++++++++++++++++++++++++++++++++------
> fs/overlayfs/inode.c | 3 ++-
> fs/overlayfs/overlayfs.h | 5 +++-
> fs/overlayfs/util.c | 21 +++++++++++++++--
> 4 files changed, 77 insertions(+), 11 deletions(-)
>
> diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
> index cf0b36518a3a..99b7be4ff4fc 100644
> --- a/fs/overlayfs/copy_up.c
> +++ b/fs/overlayfs/copy_up.c
> @@ -196,6 +196,16 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
> return error;
> }
>
> +static int ovl_set_size(struct dentry *upperdentry, struct kstat *stat)
> +{
> + struct iattr attr = {
> + .ia_valid = ATTR_SIZE,
> + .ia_size = stat->size,
> + };
> +
> + return notify_change(upperdentry, &attr, NULL);
> +}
> +
> static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat)
> {
> struct iattr attr = {
> @@ -439,6 +449,27 @@ static int ovl_get_tmpfile(struct ovl_copy_up_ctx *c, struct dentry **tempp)
> goto out;
> }
>
> +/* Copy up data of an inode which was copied up metadata only in the past. */
> +static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
I like the name :)
> +{
> + struct path upperpath;
> + int err;
> +
> + ovl_path_upper(c->dentry, &upperpath);
> + BUG_ON(upperpath.dentry == NULL);
I know this is copied from ovl_copy_up_inode() and Miklos uses BUG_ON often,
but kernel coding style prefers to use
if (WARN_ON())
return -EIO;
> +
> + err = ovl_copy_up_data(&c->lowerpath, &upperpath, c->stat.size);
> + if (err)
> + return err;
> +
> + err= vfs_removexattr(upperpath.dentry, OVL_XATTR_METACOPY);
> + if (err)
> + return err;
> +
> + ovl_clear_flag(OVL_METACOPY, d_inode(c->dentry));
> + return err;
> +}
> +
> static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
> {
> int err;
> @@ -476,13 +507,21 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
> return err;
> }
>
> + if (c->metadata_only) {
> + err = ovl_check_setxattr(c->dentry, temp, OVL_XATTR_METACOPY,
> + NULL, 0, -EOPNOTSUPP);
> + if (err)
> + return err;
> + }
> +
> inode_lock(temp->d_inode);
> - err = ovl_set_attr(temp, &c->stat);
> - inode_unlock(temp->d_inode);
> - if (err)
> - return err;
> + if (c->metadata_only)
> + err = ovl_set_size(temp, &c->stat);
>
> - return 0;
> + if (!err)
> + err = ovl_set_attr(temp, &c->stat);
> + inode_unlock(temp->d_inode);
> + return err;
> }
>
> static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c)
> @@ -510,6 +549,8 @@ static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c)
> if (err)
> goto out_cleanup;
>
> + if (c->metadata_only)
> + ovl_set_flag(OVL_METACOPY, d_inode(c->dentry));
> ovl_inode_update(d_inode(c->dentry), newdentry);
> out:
> dput(temp);
> @@ -637,7 +678,7 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
> }
> ovl_do_check_copy_up(ctx.lowerpath.dentry);
>
> - err = ovl_copy_up_start(dentry);
> + err = ovl_copy_up_start(dentry, flags);
> /* err < 0: interrupted, err > 0: raced with another copy-up */
> if (unlikely(err)) {
> if (err > 0)
> @@ -647,6 +688,8 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
> err = ovl_do_copy_up(&ctx);
> if (!err && !ovl_dentry_has_upper_alias(dentry))
> err = ovl_link_up(&ctx);
> + if (!err && ovl_dentry_needs_data_copy_up(dentry, flags))
> + err = ovl_copy_up_meta_inode_data(&ctx);
> ovl_copy_up_end(dentry);
> }
> do_delayed_call(&done);
> @@ -677,8 +720,10 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
> * with rename.
> */
> if (ovl_dentry_upper(dentry) &&
> - ovl_dentry_has_upper_alias(dentry))
> + ovl_dentry_has_upper_alias(dentry) &&
> + !ovl_dentry_needs_data_copy_up(dentry, flags)) {
> break;
> + }
>
> next = dget(dentry);
> /* find the topmost dentry not yet copied up */
> diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
> index 321511ed8c42..1b4b42c45ed5 100644
> --- a/fs/overlayfs/inode.c
> +++ b/fs/overlayfs/inode.c
> @@ -320,7 +320,8 @@ struct posix_acl *ovl_get_acl(struct inode *inode, int type)
> static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
> {
> if (ovl_dentry_upper(dentry) &&
> - ovl_dentry_has_upper_alias(dentry))
> + ovl_dentry_has_upper_alias(dentry) &&
> + !ovl_dentry_needs_data_copy_up(dentry, flags))
> return false;
>
> if (special_file(d_inode(dentry)->i_mode))
> diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
> index d9a0edd4e57e..dcec9456c654 100644
> --- a/fs/overlayfs/overlayfs.h
> +++ b/fs/overlayfs/overlayfs.h
> @@ -26,10 +26,12 @@ enum ovl_path_type {
> #define OVL_XATTR_ORIGIN OVL_XATTR_PREFIX "origin"
> #define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure"
> #define OVL_XATTR_NLINK OVL_XATTR_PREFIX "nlink"
> +#define OVL_XATTR_METACOPY OVL_XATTR_PREFIX "metacopy"
>
> enum ovl_flag {
> OVL_IMPURE,
> OVL_INDEX,
> + OVL_METACOPY,
> };
>
> /*
> @@ -211,6 +213,7 @@ bool ovl_dentry_is_whiteout(struct dentry *dentry);
> void ovl_dentry_set_opaque(struct dentry *dentry);
> bool ovl_dentry_has_upper_alias(struct dentry *dentry);
> void ovl_dentry_set_upper_alias(struct dentry *dentry);
> +bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
> bool ovl_redirect_dir(struct super_block *sb);
> const char *ovl_dentry_get_redirect(struct dentry *dentry);
> void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
> @@ -221,7 +224,7 @@ void ovl_dentry_version_inc(struct dentry *dentry, bool impurity);
> u64 ovl_dentry_version_get(struct dentry *dentry);
> bool ovl_is_whiteout(struct dentry *dentry);
> struct file *ovl_path_open(struct path *path, int flags);
> -int ovl_copy_up_start(struct dentry *dentry);
> +int ovl_copy_up_start(struct dentry *dentry, int flags);
> void ovl_copy_up_end(struct dentry *dentry);
> bool ovl_check_dir_xattr(struct dentry *dentry, const char *name);
> int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
> diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
> index a4ce1c9944f0..91c542d1a39d 100644
> --- a/fs/overlayfs/util.c
> +++ b/fs/overlayfs/util.c
> @@ -227,6 +227,22 @@ void ovl_dentry_set_upper_alias(struct dentry *dentry)
> oe->has_upper = true;
> }
>
> +bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags) {
Maybe start off with
if (likely(!ovl_test_flag(OVL_METACOPY, d_inode(dentry))
return false;
> + if (!S_ISREG(d_inode(dentry)->i_mode))
> + return false;
> +
> + if (!flags)
> + return false;
> +
> + if (!(OPEN_FMODE(flags) & FMODE_WRITE))
> + return false;
> +
> + if (!ovl_test_flag(OVL_METACOPY, d_inode(dentry)))
> + return false;
> +
> + return true;
> +}
> +
> bool ovl_redirect_dir(struct super_block *sb)
> {
> struct ovl_fs *ofs = sb->s_fs_info;
> @@ -310,13 +326,14 @@ struct file *ovl_path_open(struct path *path, int flags)
> return dentry_open(path, flags | O_NOATIME, current_cred());
> }
>
> -int ovl_copy_up_start(struct dentry *dentry)
> +int ovl_copy_up_start(struct dentry *dentry, int flags)
> {
> struct ovl_inode *oi = OVL_I(d_inode(dentry));
> int err;
>
> err = mutex_lock_interruptible(&oi->lock);
> - if (!err && ovl_dentry_has_upper_alias(dentry)) {
> + if (!err && ovl_dentry_has_upper_alias(dentry) &&
> + !ovl_dentry_needs_data_copy_up(dentry, flags)) {
> err = 1; /* Already copied up */
> mutex_unlock(&oi->lock);
> }
> --
> 2.13.5
>
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