| /* |
| * Copyright (C) 2011 Novell Inc. |
| * Copyright (C) 2016 Red Hat, Inc. |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 as published by |
| * the Free Software Foundation. |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/cred.h> |
| #include <linux/namei.h> |
| #include <linux/xattr.h> |
| #include <linux/ratelimit.h> |
| #include <linux/mount.h> |
| #include <linux/exportfs.h> |
| #include "overlayfs.h" |
| #include "ovl_entry.h" |
| |
| struct ovl_lookup_data { |
| struct qstr name; |
| bool is_dir; |
| bool opaque; |
| bool stop; |
| bool last; |
| char *redirect; |
| }; |
| |
| static int ovl_check_redirect(struct dentry *dentry, struct ovl_lookup_data *d, |
| size_t prelen, const char *post) |
| { |
| int res; |
| char *s, *next, *buf = NULL; |
| |
| res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, NULL, 0); |
| if (res < 0) { |
| if (res == -ENODATA || res == -EOPNOTSUPP) |
| return 0; |
| goto fail; |
| } |
| buf = kzalloc(prelen + res + strlen(post) + 1, GFP_KERNEL); |
| if (!buf) |
| return -ENOMEM; |
| |
| if (res == 0) |
| goto invalid; |
| |
| res = vfs_getxattr(dentry, OVL_XATTR_REDIRECT, buf, res); |
| if (res < 0) |
| goto fail; |
| if (res == 0) |
| goto invalid; |
| if (buf[0] == '/') { |
| for (s = buf; *s++ == '/'; s = next) { |
| next = strchrnul(s, '/'); |
| if (s == next) |
| goto invalid; |
| } |
| } else { |
| if (strchr(buf, '/') != NULL) |
| goto invalid; |
| |
| memmove(buf + prelen, buf, res); |
| memcpy(buf, d->name.name, prelen); |
| } |
| |
| strcat(buf, post); |
| kfree(d->redirect); |
| d->redirect = buf; |
| d->name.name = d->redirect; |
| d->name.len = strlen(d->redirect); |
| |
| return 0; |
| |
| err_free: |
| kfree(buf); |
| return 0; |
| fail: |
| pr_warn_ratelimited("overlayfs: failed to get redirect (%i)\n", res); |
| goto err_free; |
| invalid: |
| pr_warn_ratelimited("overlayfs: invalid redirect (%s)\n", buf); |
| goto err_free; |
| } |
| |
| static int ovl_acceptable(void *ctx, struct dentry *dentry) |
| { |
| return 1; |
| } |
| |
| static struct ovl_fh *ovl_get_origin_fh(struct dentry *dentry) |
| { |
| int res; |
| struct ovl_fh *fh = NULL; |
| |
| res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0); |
| if (res < 0) { |
| if (res == -ENODATA || res == -EOPNOTSUPP) |
| return NULL; |
| goto fail; |
| } |
| /* Zero size value means "copied up but origin unknown" */ |
| if (res == 0) |
| return NULL; |
| |
| fh = kzalloc(res, GFP_KERNEL); |
| if (!fh) |
| return ERR_PTR(-ENOMEM); |
| |
| res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, fh, res); |
| if (res < 0) |
| goto fail; |
| |
| if (res < sizeof(struct ovl_fh) || res < fh->len) |
| goto invalid; |
| |
| if (fh->magic != OVL_FH_MAGIC) |
| goto invalid; |
| |
| /* Treat larger version and unknown flags as "origin unknown" */ |
| if (fh->version > OVL_FH_VERSION || fh->flags & ~OVL_FH_FLAG_ALL) |
| goto out; |
| |
| /* Treat endianness mismatch as "origin unknown" */ |
| if (!(fh->flags & OVL_FH_FLAG_ANY_ENDIAN) && |
| (fh->flags & OVL_FH_FLAG_BIG_ENDIAN) != OVL_FH_FLAG_CPU_ENDIAN) |
| goto out; |
| |
| return fh; |
| |
| out: |
| kfree(fh); |
| return NULL; |
| |
| fail: |
| pr_warn_ratelimited("overlayfs: failed to get origin (%i)\n", res); |
| goto out; |
| invalid: |
| pr_warn_ratelimited("overlayfs: invalid origin (%*phN)\n", res, fh); |
| goto out; |
| } |
| |
| static struct dentry *ovl_get_origin(struct dentry *dentry, |
| struct vfsmount *mnt) |
| { |
| struct dentry *origin = NULL; |
| struct ovl_fh *fh = ovl_get_origin_fh(dentry); |
| int bytes; |
| |
| if (IS_ERR_OR_NULL(fh)) |
| return (struct dentry *)fh; |
| |
| /* |
| * Make sure that the stored uuid matches the uuid of the lower |
| * layer where file handle will be decoded. |
| */ |
| if (!uuid_equal(&fh->uuid, &mnt->mnt_sb->s_uuid)) |
| goto out; |
| |
| bytes = (fh->len - offsetof(struct ovl_fh, fid)); |
| origin = exportfs_decode_fh(mnt, (struct fid *)fh->fid, |
| bytes >> 2, (int)fh->type, |
| ovl_acceptable, NULL); |
| if (IS_ERR(origin)) { |
| /* Treat stale file handle as "origin unknown" */ |
| if (origin == ERR_PTR(-ESTALE)) |
| origin = NULL; |
| goto out; |
| } |
| |
| if (ovl_dentry_weird(origin) || |
| ((d_inode(origin)->i_mode ^ d_inode(dentry)->i_mode) & S_IFMT)) |
| goto invalid; |
| |
| out: |
| kfree(fh); |
| return origin; |
| |
| invalid: |
| pr_warn_ratelimited("overlayfs: invalid origin (%pd2)\n", origin); |
| dput(origin); |
| origin = NULL; |
| goto out; |
| } |
| |
| static bool ovl_is_opaquedir(struct dentry *dentry) |
| { |
| return ovl_check_dir_xattr(dentry, OVL_XATTR_OPAQUE); |
| } |
| |
| static int ovl_lookup_single(struct dentry *base, struct ovl_lookup_data *d, |
| const char *name, unsigned int namelen, |
| size_t prelen, const char *post, |
| struct dentry **ret) |
| { |
| struct dentry *this; |
| int err; |
| |
| this = lookup_one_len_unlocked(name, base, namelen); |
| if (IS_ERR(this)) { |
| err = PTR_ERR(this); |
| this = NULL; |
| if (err == -ENOENT || err == -ENAMETOOLONG) |
| goto out; |
| goto out_err; |
| } |
| if (!this->d_inode) |
| goto put_and_out; |
| |
| if (ovl_dentry_weird(this)) { |
| /* Don't support traversing automounts and other weirdness */ |
| err = -EREMOTE; |
| goto out_err; |
| } |
| if (ovl_is_whiteout(this)) { |
| d->stop = d->opaque = true; |
| goto put_and_out; |
| } |
| if (!d_can_lookup(this)) { |
| d->stop = true; |
| if (d->is_dir) |
| goto put_and_out; |
| goto out; |
| } |
| d->is_dir = true; |
| if (!d->last && ovl_is_opaquedir(this)) { |
| d->stop = d->opaque = true; |
| goto out; |
| } |
| err = ovl_check_redirect(this, d, prelen, post); |
| if (err) |
| goto out_err; |
| out: |
| *ret = this; |
| return 0; |
| |
| put_and_out: |
| dput(this); |
| this = NULL; |
| goto out; |
| |
| out_err: |
| dput(this); |
| return err; |
| } |
| |
| static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d, |
| struct dentry **ret) |
| { |
| /* Counting down from the end, since the prefix can change */ |
| size_t rem = d->name.len - 1; |
| struct dentry *dentry = NULL; |
| int err; |
| |
| if (d->name.name[0] != '/') |
| return ovl_lookup_single(base, d, d->name.name, d->name.len, |
| 0, "", ret); |
| |
| while (!IS_ERR_OR_NULL(base) && d_can_lookup(base)) { |
| const char *s = d->name.name + d->name.len - rem; |
| const char *next = strchrnul(s, '/'); |
| size_t thislen = next - s; |
| bool end = !next[0]; |
| |
| /* Verify we did not go off the rails */ |
| if (WARN_ON(s[-1] != '/')) |
| return -EIO; |
| |
| err = ovl_lookup_single(base, d, s, thislen, |
| d->name.len - rem, next, &base); |
| dput(dentry); |
| if (err) |
| return err; |
| dentry = base; |
| if (end) |
| break; |
| |
| rem -= thislen + 1; |
| |
| if (WARN_ON(rem >= d->name.len)) |
| return -EIO; |
| } |
| *ret = dentry; |
| return 0; |
| } |
| |
| |
| static int ovl_check_origin(struct dentry *upperdentry, |
| struct path *lowerstack, unsigned int numlower, |
| struct path **stackp, unsigned int *ctrp) |
| { |
| struct vfsmount *mnt; |
| struct dentry *origin = NULL; |
| int i; |
| |
| |
| for (i = 0; i < numlower; i++) { |
| mnt = lowerstack[i].mnt; |
| origin = ovl_get_origin(upperdentry, mnt); |
| if (IS_ERR(origin)) |
| return PTR_ERR(origin); |
| |
| if (origin) |
| break; |
| } |
| |
| if (!origin) |
| return 0; |
| |
| BUG_ON(*ctrp); |
| if (!*stackp) |
| *stackp = kmalloc(sizeof(struct path), GFP_KERNEL); |
| if (!*stackp) { |
| dput(origin); |
| return -ENOMEM; |
| } |
| **stackp = (struct path) { .dentry = origin, .mnt = mnt }; |
| *ctrp = 1; |
| |
| return 0; |
| } |
| |
| /* |
| * Verify that @fh matches the origin file handle stored in OVL_XATTR_ORIGIN. |
| * Return 0 on match, -ESTALE on mismatch, < 0 on error. |
| */ |
| static int ovl_verify_origin_fh(struct dentry *dentry, const struct ovl_fh *fh) |
| { |
| struct ovl_fh *ofh = ovl_get_origin_fh(dentry); |
| int err = 0; |
| |
| if (!ofh) |
| return -ENODATA; |
| |
| if (IS_ERR(ofh)) |
| return PTR_ERR(ofh); |
| |
| if (fh->len != ofh->len || memcmp(fh, ofh, fh->len)) |
| err = -ESTALE; |
| |
| kfree(ofh); |
| return err; |
| } |
| |
| /* |
| * Verify that an inode matches the origin file handle stored in upper inode. |
| * |
| * If @set is true and there is no stored file handle, encode and store origin |
| * file handle in OVL_XATTR_ORIGIN. |
| * |
| * Return 0 on match, -ESTALE on mismatch, < 0 on error. |
| */ |
| int ovl_verify_origin(struct dentry *dentry, struct vfsmount *mnt, |
| struct dentry *origin, bool is_upper, bool set) |
| { |
| struct inode *inode; |
| struct ovl_fh *fh; |
| int err; |
| |
| fh = ovl_encode_fh(origin, is_upper); |
| err = PTR_ERR(fh); |
| if (IS_ERR(fh)) |
| goto fail; |
| |
| err = ovl_verify_origin_fh(dentry, fh); |
| if (set && err == -ENODATA) |
| err = ovl_do_setxattr(dentry, OVL_XATTR_ORIGIN, fh, fh->len, 0); |
| if (err) |
| goto fail; |
| |
| out: |
| kfree(fh); |
| return err; |
| |
| fail: |
| inode = d_inode(origin); |
| pr_warn_ratelimited("overlayfs: failed to verify origin (%pd2, ino=%lu, err=%i)\n", |
| origin, inode ? inode->i_ino : 0, err); |
| goto out; |
| } |
| |
| /* |
| * Verify that an index entry name matches the origin file handle stored in |
| * OVL_XATTR_ORIGIN and that origin file handle can be decoded to lower path. |
| * Return 0 on match, -ESTALE on mismatch or stale origin, < 0 on error. |
| */ |
| int ovl_verify_index(struct dentry *index, struct path *lowerstack, |
| unsigned int numlower) |
| { |
| struct ovl_fh *fh = NULL; |
| size_t len; |
| struct path origin = { }; |
| struct path *stack = &origin; |
| unsigned int ctr = 0; |
| int err; |
| |
| if (!d_inode(index)) |
| return 0; |
| |
| /* |
| * Directory index entries are going to be used for looking up |
| * redirected upper dirs by lower dir fh when decoding an overlay |
| * file handle of a merge dir. Whiteout index entries are going to be |
| * used as an indication that an exported overlay file handle should |
| * be treated as stale (i.e. after unlink of the overlay inode). |
| * We don't know the verification rules for directory and whiteout |
| * index entries, because they have not been implemented yet, so return |
| * EINVAL if those entries are found to abort the mount to avoid |
| * corrupting an index that was created by a newer kernel. |
| */ |
| err = -EINVAL; |
| if (d_is_dir(index) || ovl_is_whiteout(index)) |
| goto fail; |
| |
| if (index->d_name.len < sizeof(struct ovl_fh)*2) |
| goto fail; |
| |
| err = -ENOMEM; |
| len = index->d_name.len / 2; |
| fh = kzalloc(len, GFP_KERNEL); |
| if (!fh) |
| goto fail; |
| |
| err = -EINVAL; |
| if (hex2bin((u8 *)fh, index->d_name.name, len) || len != fh->len) |
| goto fail; |
| |
| err = ovl_verify_origin_fh(index, fh); |
| if (err) |
| goto fail; |
| |
| err = ovl_check_origin(index, lowerstack, numlower, &stack, &ctr); |
| if (!err && !ctr) |
| err = -ESTALE; |
| if (err) |
| goto fail; |
| |
| /* Check if index is orphan and don't warn before cleaning it */ |
| if (d_inode(index)->i_nlink == 1 && |
| ovl_get_nlink(index, origin.dentry, 0) == 0) |
| err = -ENOENT; |
| |
| dput(origin.dentry); |
| out: |
| kfree(fh); |
| return err; |
| |
| fail: |
| pr_warn_ratelimited("overlayfs: failed to verify index (%pd2, ftype=%x, err=%i)\n", |
| index, d_inode(index)->i_mode & S_IFMT, err); |
| goto out; |
| } |
| |
| /* |
| * Lookup in indexdir for the index entry of a lower real inode or a copy up |
| * origin inode. The index entry name is the hex representation of the lower |
| * inode file handle. |
| * |
| * If the index dentry in negative, then either no lower aliases have been |
| * copied up yet, or aliases have been copied up in older kernels and are |
| * not indexed. |
| * |
| * If the index dentry for a copy up origin inode is positive, but points |
| * to an inode different than the upper inode, then either the upper inode |
| * has been copied up and not indexed or it was indexed, but since then |
| * index dir was cleared. Either way, that index cannot be used to indentify |
| * the overlay inode. |
| */ |
| int ovl_get_index_name(struct dentry *origin, struct qstr *name) |
| { |
| int err; |
| struct ovl_fh *fh; |
| char *n, *s; |
| |
| fh = ovl_encode_fh(origin, false); |
| if (IS_ERR(fh)) |
| return PTR_ERR(fh); |
| |
| err = -ENOMEM; |
| n = kzalloc(fh->len * 2, GFP_KERNEL); |
| if (n) { |
| s = bin2hex(n, fh, fh->len); |
| *name = (struct qstr) QSTR_INIT(n, s - n); |
| err = 0; |
| } |
| kfree(fh); |
| |
| return err; |
| |
| } |
| |
| static struct dentry *ovl_lookup_index(struct dentry *dentry, |
| struct dentry *upper, |
| struct dentry *origin) |
| { |
| struct ovl_fs *ofs = dentry->d_sb->s_fs_info; |
| struct dentry *index; |
| struct inode *inode; |
| struct qstr name; |
| int err; |
| |
| err = ovl_get_index_name(origin, &name); |
| if (err) |
| return ERR_PTR(err); |
| |
| index = lookup_one_len_unlocked(name.name, ofs->indexdir, name.len); |
| if (IS_ERR(index)) { |
| err = PTR_ERR(index); |
| if (err == -ENOENT) { |
| index = NULL; |
| goto out; |
| } |
| pr_warn_ratelimited("overlayfs: failed inode index lookup (ino=%lu, key=%*s, err=%i);\n" |
| "overlayfs: mount with '-o index=off' to disable inodes index.\n", |
| d_inode(origin)->i_ino, name.len, name.name, |
| err); |
| goto out; |
| } |
| |
| inode = d_inode(index); |
| if (d_is_negative(index)) { |
| goto out_dput; |
| } else if (upper && d_inode(upper) != inode) { |
| goto out_dput; |
| } else if (ovl_dentry_weird(index) || ovl_is_whiteout(index) || |
| ((inode->i_mode ^ d_inode(origin)->i_mode) & S_IFMT)) { |
| /* |
| * Index should always be of the same file type as origin |
| * except for the case of a whiteout index. A whiteout |
| * index should only exist if all lower aliases have been |
| * unlinked, which means that finding a lower origin on lookup |
| * whose index is a whiteout should be treated as an error. |
| */ |
| pr_warn_ratelimited("overlayfs: bad index found (index=%pd2, ftype=%x, origin ftype=%x).\n", |
| index, d_inode(index)->i_mode & S_IFMT, |
| d_inode(origin)->i_mode & S_IFMT); |
| goto fail; |
| } |
| |
| out: |
| kfree(name.name); |
| return index; |
| |
| out_dput: |
| dput(index); |
| index = NULL; |
| goto out; |
| |
| fail: |
| dput(index); |
| index = ERR_PTR(-EIO); |
| goto out; |
| } |
| |
| /* |
| * Returns next layer in stack starting from top. |
| * Returns -1 if this is the last layer. |
| */ |
| int ovl_path_next(int idx, struct dentry *dentry, struct path *path) |
| { |
| struct ovl_entry *oe = dentry->d_fsdata; |
| |
| BUG_ON(idx < 0); |
| if (idx == 0) { |
| ovl_path_upper(dentry, path); |
| if (path->dentry) |
| return oe->numlower ? 1 : -1; |
| idx++; |
| } |
| BUG_ON(idx > oe->numlower); |
| *path = oe->lowerstack[idx - 1]; |
| |
| return (idx < oe->numlower) ? idx + 1 : -1; |
| } |
| |
| struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, |
| unsigned int flags) |
| { |
| struct ovl_entry *oe; |
| const struct cred *old_cred; |
| struct ovl_fs *ofs = dentry->d_sb->s_fs_info; |
| struct ovl_entry *poe = dentry->d_parent->d_fsdata; |
| struct ovl_entry *roe = dentry->d_sb->s_root->d_fsdata; |
| struct path *stack = NULL; |
| struct dentry *upperdir, *upperdentry = NULL; |
| struct dentry *index = NULL; |
| unsigned int ctr = 0; |
| struct inode *inode = NULL; |
| bool upperopaque = false; |
| char *upperredirect = NULL; |
| struct dentry *this; |
| unsigned int i; |
| int err; |
| struct ovl_lookup_data d = { |
| .name = dentry->d_name, |
| .is_dir = false, |
| .opaque = false, |
| .stop = false, |
| .last = !poe->numlower, |
| .redirect = NULL, |
| }; |
| |
| if (dentry->d_name.len > ofs->namelen) |
| return ERR_PTR(-ENAMETOOLONG); |
| |
| old_cred = ovl_override_creds(dentry->d_sb); |
| upperdir = ovl_dentry_upper(dentry->d_parent); |
| if (upperdir) { |
| err = ovl_lookup_layer(upperdir, &d, &upperdentry); |
| if (err) |
| goto out; |
| |
| if (upperdentry && unlikely(ovl_dentry_remote(upperdentry))) { |
| dput(upperdentry); |
| err = -EREMOTE; |
| goto out; |
| } |
| if (upperdentry && !d.is_dir) { |
| BUG_ON(!d.stop || d.redirect); |
| /* |
| * Lookup copy up origin by decoding origin file handle. |
| * We may get a disconnected dentry, which is fine, |
| * because we only need to hold the origin inode in |
| * cache and use its inode number. We may even get a |
| * connected dentry, that is not under any of the lower |
| * layers root. That is also fine for using it's inode |
| * number - it's the same as if we held a reference |
| * to a dentry in lower layer that was moved under us. |
| */ |
| err = ovl_check_origin(upperdentry, roe->lowerstack, |
| roe->numlower, &stack, &ctr); |
| if (err) |
| goto out_put_upper; |
| } |
| |
| if (d.redirect) { |
| err = -ENOMEM; |
| upperredirect = kstrdup(d.redirect, GFP_KERNEL); |
| if (!upperredirect) |
| goto out_put_upper; |
| if (d.redirect[0] == '/') |
| poe = roe; |
| } |
| upperopaque = d.opaque; |
| } |
| |
| if (!d.stop && poe->numlower) { |
| err = -ENOMEM; |
| stack = kcalloc(ofs->numlower, sizeof(struct path), |
| GFP_KERNEL); |
| if (!stack) |
| goto out_put_upper; |
| } |
| |
| for (i = 0; !d.stop && i < poe->numlower; i++) { |
| struct path lowerpath = poe->lowerstack[i]; |
| |
| d.last = i == poe->numlower - 1; |
| err = ovl_lookup_layer(lowerpath.dentry, &d, &this); |
| if (err) |
| goto out_put; |
| |
| if (!this) |
| continue; |
| |
| stack[ctr].dentry = this; |
| stack[ctr].mnt = lowerpath.mnt; |
| ctr++; |
| |
| if (d.stop) |
| break; |
| |
| if (d.redirect && d.redirect[0] == '/' && poe != roe) { |
| poe = roe; |
| |
| /* Find the current layer on the root dentry */ |
| for (i = 0; i < poe->numlower; i++) |
| if (poe->lowerstack[i].mnt == lowerpath.mnt) |
| break; |
| if (WARN_ON(i == poe->numlower)) |
| break; |
| } |
| } |
| |
| /* Lookup index by lower inode and verify it matches upper inode */ |
| if (ctr && !d.is_dir && ovl_indexdir(dentry->d_sb)) { |
| struct dentry *origin = stack[0].dentry; |
| |
| index = ovl_lookup_index(dentry, upperdentry, origin); |
| if (IS_ERR(index)) { |
| err = PTR_ERR(index); |
| index = NULL; |
| goto out_put; |
| } |
| } |
| |
| oe = ovl_alloc_entry(ctr); |
| err = -ENOMEM; |
| if (!oe) |
| goto out_put; |
| |
| oe->opaque = upperopaque; |
| memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr); |
| dentry->d_fsdata = oe; |
| |
| if (upperdentry) |
| ovl_dentry_set_upper_alias(dentry); |
| else if (index) |
| upperdentry = dget(index); |
| |
| if (upperdentry || ctr) { |
| inode = ovl_get_inode(dentry, upperdentry, index); |
| err = PTR_ERR(inode); |
| if (IS_ERR(inode)) |
| goto out_free_oe; |
| |
| OVL_I(inode)->redirect = upperredirect; |
| if (index) |
| ovl_set_flag(OVL_INDEX, inode); |
| } |
| |
| revert_creds(old_cred); |
| dput(index); |
| kfree(stack); |
| kfree(d.redirect); |
| d_add(dentry, inode); |
| |
| return NULL; |
| |
| out_free_oe: |
| dentry->d_fsdata = NULL; |
| kfree(oe); |
| out_put: |
| dput(index); |
| for (i = 0; i < ctr; i++) |
| dput(stack[i].dentry); |
| kfree(stack); |
| out_put_upper: |
| dput(upperdentry); |
| kfree(upperredirect); |
| out: |
| kfree(d.redirect); |
| revert_creds(old_cred); |
| return ERR_PTR(err); |
| } |
| |
| bool ovl_lower_positive(struct dentry *dentry) |
| { |
| struct ovl_entry *oe = dentry->d_fsdata; |
| struct ovl_entry *poe = dentry->d_parent->d_fsdata; |
| const struct qstr *name = &dentry->d_name; |
| unsigned int i; |
| bool positive = false; |
| bool done = false; |
| |
| /* |
| * If dentry is negative, then lower is positive iff this is a |
| * whiteout. |
| */ |
| if (!dentry->d_inode) |
| return oe->opaque; |
| |
| /* Negative upper -> positive lower */ |
| if (!ovl_dentry_upper(dentry)) |
| return true; |
| |
| /* Positive upper -> have to look up lower to see whether it exists */ |
| for (i = 0; !done && !positive && i < poe->numlower; i++) { |
| struct dentry *this; |
| struct dentry *lowerdir = poe->lowerstack[i].dentry; |
| |
| this = lookup_one_len_unlocked(name->name, lowerdir, |
| name->len); |
| if (IS_ERR(this)) { |
| switch (PTR_ERR(this)) { |
| case -ENOENT: |
| case -ENAMETOOLONG: |
| break; |
| |
| default: |
| /* |
| * Assume something is there, we just couldn't |
| * access it. |
| */ |
| positive = true; |
| break; |
| } |
| } else { |
| if (this->d_inode) { |
| positive = !ovl_is_whiteout(this); |
| done = true; |
| } |
| dput(this); |
| } |
| } |
| |
| return positive; |
| } |