ovl: factor out ovl_check_origin_fh()
Re-factor ovl_check_origin() and ovl_get_origin(), so origin fh xattr is read from upper inode only once during lookup with multiple lower layers and only once when verifying index entry origin. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein
Miklos Szeredi
Родитель
d583ed7d13
Коммит
2e1a532883
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@ -87,9 +87,36 @@ static int ovl_acceptable(void *ctx, struct dentry *dentry)
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return 1;
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}
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/*
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* Check validity of an overlay file handle buffer.
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*
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* Return 0 for a valid file handle.
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* Return -ENODATA for "origin unknown".
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* Return <0 for an invalid file handle.
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*/
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static int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
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{
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if (fh_len < sizeof(struct ovl_fh) || fh_len < fh->len)
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return -EINVAL;
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if (fh->magic != OVL_FH_MAGIC)
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return -EINVAL;
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/* Treat larger version and unknown flags as "origin unknown" */
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if (fh->version > OVL_FH_VERSION || fh->flags & ~OVL_FH_FLAG_ALL)
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return -ENODATA;
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/* Treat endianness mismatch as "origin unknown" */
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if (!(fh->flags & OVL_FH_FLAG_ANY_ENDIAN) &&
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(fh->flags & OVL_FH_FLAG_BIG_ENDIAN) != OVL_FH_FLAG_CPU_ENDIAN)
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return -ENODATA;
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return 0;
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}
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static struct ovl_fh *ovl_get_origin_fh(struct dentry *dentry)
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{
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int res;
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int res, err;
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struct ovl_fh *fh = NULL;
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res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0);
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@ -102,7 +129,7 @@ static struct ovl_fh *ovl_get_origin_fh(struct dentry *dentry)
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if (res == 0)
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return NULL;
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fh = kzalloc(res, GFP_KERNEL);
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fh = kzalloc(res, GFP_KERNEL);
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if (!fh)
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return ERR_PTR(-ENOMEM);
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@ -110,20 +137,12 @@ static struct ovl_fh *ovl_get_origin_fh(struct dentry *dentry)
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if (res < 0)
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goto fail;
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if (res < sizeof(struct ovl_fh) || res < fh->len)
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err = ovl_check_fh_len(fh, res);
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if (err < 0) {
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if (err == -ENODATA)
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goto out;
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goto invalid;
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if (fh->magic != OVL_FH_MAGIC)
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goto invalid;
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/* Treat larger version and unknown flags as "origin unknown" */
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if (fh->version > OVL_FH_VERSION || fh->flags & ~OVL_FH_FLAG_ALL)
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goto out;
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/* Treat endianness mismatch as "origin unknown" */
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if (!(fh->flags & OVL_FH_FLAG_ANY_ENDIAN) &&
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(fh->flags & OVL_FH_FLAG_BIG_ENDIAN) != OVL_FH_FLAG_CPU_ENDIAN)
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goto out;
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}
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return fh;
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@ -139,22 +158,17 @@ invalid:
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goto out;
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}
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static struct dentry *ovl_get_origin(struct dentry *dentry,
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struct vfsmount *mnt)
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static struct dentry *ovl_decode_fh(struct ovl_fh *fh, struct vfsmount *mnt)
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{
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struct dentry *origin = NULL;
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struct ovl_fh *fh = ovl_get_origin_fh(dentry);
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struct dentry *origin;
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int bytes;
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if (IS_ERR_OR_NULL(fh))
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return (struct dentry *)fh;
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/*
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* Make sure that the stored uuid matches the uuid of the lower
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* layer where file handle will be decoded.
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*/
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if (!uuid_equal(&fh->uuid, &mnt->mnt_sb->s_uuid))
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goto out;
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return NULL;
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bytes = (fh->len - offsetof(struct ovl_fh, fid));
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origin = exportfs_decode_fh(mnt, (struct fid *)fh->fid,
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@ -164,22 +178,15 @@ static struct dentry *ovl_get_origin(struct dentry *dentry,
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/* Treat stale file handle as "origin unknown" */
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if (origin == ERR_PTR(-ESTALE))
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origin = NULL;
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goto out;
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return origin;
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}
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if (ovl_dentry_weird(origin) ||
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((d_inode(origin)->i_mode ^ d_inode(dentry)->i_mode) & S_IFMT))
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goto invalid;
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if (ovl_dentry_weird(origin)) {
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dput(origin);
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return NULL;
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}
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out:
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kfree(fh);
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return origin;
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invalid:
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pr_warn_ratelimited("overlayfs: invalid origin (%pd2)\n", origin);
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dput(origin);
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origin = NULL;
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goto out;
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}
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static bool ovl_is_opaquedir(struct dentry *dentry)
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@ -284,9 +291,9 @@ static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d,
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}
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static int ovl_check_origin(struct dentry *upperdentry,
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struct ovl_path *lower, unsigned int numlower,
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struct ovl_path **stackp, unsigned int *ctrp)
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static int ovl_check_origin_fh(struct ovl_fh *fh, struct dentry *upperdentry,
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struct ovl_path *lower, unsigned int numlower,
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struct ovl_path **stackp)
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{
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struct vfsmount *mnt;
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struct dentry *origin = NULL;
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@ -294,18 +301,20 @@ static int ovl_check_origin(struct dentry *upperdentry,
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for (i = 0; i < numlower; i++) {
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mnt = lower[i].layer->mnt;
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origin = ovl_get_origin(upperdentry, mnt);
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if (IS_ERR(origin))
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return PTR_ERR(origin);
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origin = ovl_decode_fh(fh, mnt);
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if (origin)
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break;
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}
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if (!origin)
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return 0;
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return -ESTALE;
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else if (IS_ERR(origin))
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return PTR_ERR(origin);
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if (!ovl_is_whiteout(upperdentry) &&
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((d_inode(origin)->i_mode ^ d_inode(upperdentry)->i_mode) & S_IFMT))
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goto invalid;
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BUG_ON(*ctrp);
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if (!*stackp)
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*stackp = kmalloc(sizeof(struct ovl_path), GFP_KERNEL);
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if (!*stackp) {
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@ -313,9 +322,41 @@ static int ovl_check_origin(struct dentry *upperdentry,
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return -ENOMEM;
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}
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**stackp = (struct ovl_path){.dentry = origin, .layer = lower[i].layer};
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*ctrp = 1;
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return 0;
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invalid:
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pr_warn_ratelimited("overlayfs: invalid origin (%pd2, ftype=%x, origin ftype=%x).\n",
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upperdentry, d_inode(upperdentry)->i_mode & S_IFMT,
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d_inode(origin)->i_mode & S_IFMT);
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dput(origin);
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return -EIO;
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}
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static int ovl_check_origin(struct dentry *upperdentry,
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struct ovl_path *lower, unsigned int numlower,
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struct ovl_path **stackp, unsigned int *ctrp)
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{
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struct ovl_fh *fh = ovl_get_origin_fh(upperdentry);
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int err;
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if (IS_ERR_OR_NULL(fh))
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return PTR_ERR(fh);
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err = ovl_check_origin_fh(fh, upperdentry, lower, numlower, stackp);
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kfree(fh);
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if (err) {
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if (err == -ESTALE)
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return 0;
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return err;
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}
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if (WARN_ON(*ctrp))
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return -EIO;
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*ctrp = 1;
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return 0;
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}
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/*
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@ -389,7 +430,6 @@ int ovl_verify_index(struct dentry *index, struct ovl_path *lower,
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size_t len;
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struct ovl_path origin = { };
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struct ovl_path *stack = &origin;
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unsigned int ctr = 0;
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int err;
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if (!d_inode(index))
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@ -420,16 +460,18 @@ int ovl_verify_index(struct dentry *index, struct ovl_path *lower,
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goto fail;
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err = -EINVAL;
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if (hex2bin((u8 *)fh, index->d_name.name, len) || len != fh->len)
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if (hex2bin((u8 *)fh, index->d_name.name, len))
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goto fail;
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err = ovl_check_fh_len(fh, len);
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if (err)
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goto fail;
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err = ovl_verify_origin_fh(index, fh);
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if (err)
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goto fail;
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err = ovl_check_origin(index, lower, numlower, &stack, &ctr);
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if (!err && !ctr)
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err = -ESTALE;
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err = ovl_check_origin_fh(fh, index, lower, numlower, &stack);
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if (err)
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goto fail;
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