diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c index 092e6e8c9258..b65ea49de457 100644 --- a/fs/overlayfs/export.c +++ b/fs/overlayfs/export.c @@ -294,6 +294,10 @@ fail: goto out; } +static struct dentry *ovl_lookup_real(struct super_block *sb, + struct dentry *real, + struct ovl_layer *layer); + /* * Lookup an indexed or hashed overlay dentry by real inode. */ @@ -301,9 +305,16 @@ static struct dentry *ovl_lookup_real_inode(struct super_block *sb, struct dentry *real, struct ovl_layer *layer) { + struct ovl_fs *ofs = sb->s_fs_info; + struct ovl_layer upper_layer = { .mnt = ofs->upper_mnt }; + struct dentry *index = NULL; struct dentry *this = NULL; struct inode *inode; + /* + * Decoding upper dir from index is expensive, so first try to lookup + * overlay dentry in inode/dcache. + */ inode = ovl_lookup_inode(sb, real, !layer->idx); if (IS_ERR(inode)) return ERR_CAST(inode); @@ -312,7 +323,35 @@ static struct dentry *ovl_lookup_real_inode(struct super_block *sb, iput(inode); } - /* TODO: use index when looking up by origin inode */ + /* + * For decoded lower dir file handle, lookup index by origin to check + * if lower dir was copied up and and/or removed. + */ + if (!this && layer->idx && ofs->indexdir && !WARN_ON(!d_is_dir(real))) { + index = ovl_lookup_index(ofs, NULL, real, false); + if (IS_ERR(index)) + return index; + } + + /* Get connected upper overlay dir from index */ + if (index) { + struct dentry *upper = ovl_index_upper(ofs, index); + + dput(index); + if (IS_ERR_OR_NULL(upper)) + return upper; + + /* + * ovl_lookup_real() in lower layer may call recursively once to + * ovl_lookup_real() in upper layer. The first level call walks + * back lower parents to the topmost indexed parent. The second + * recursive call walks back from indexed upper to the topmost + * connected/hashed upper parent (or up to root). + */ + this = ovl_lookup_real(sb, upper, &upper_layer); + dput(upper); + } + if (!this) return NULL; diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 6199bf7a77c7..c5449efd96d5 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -661,11 +661,9 @@ struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh) return ERR_PTR(err); } -static struct dentry *ovl_lookup_index(struct dentry *dentry, - struct dentry *upper, - struct dentry *origin) +struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, + struct dentry *origin, bool verify) { - struct ovl_fs *ofs = dentry->d_sb->s_fs_info; struct dentry *index; struct inode *inode; struct qstr name; @@ -693,6 +691,16 @@ static struct dentry *ovl_lookup_index(struct dentry *dentry, inode = d_inode(index); if (d_is_negative(index)) { goto out_dput; + } else if (ovl_is_whiteout(index) && !verify) { + /* + * When index lookup is called with !verify for decoding an + * overlay file handle, a whiteout index implies that decode + * should treat file handle as stale and no need to print a + * warning about it. + */ + dput(index); + index = ERR_PTR(-ESTALE); + goto out; } else if (ovl_dentry_weird(index) || ovl_is_whiteout(index) || ((inode->i_mode ^ d_inode(origin)->i_mode) & S_IFMT)) { /* @@ -706,7 +714,7 @@ static struct dentry *ovl_lookup_index(struct dentry *dentry, index, d_inode(index)->i_mode & S_IFMT, d_inode(origin)->i_mode & S_IFMT); goto fail; - } else if (is_dir) { + } else if (is_dir && verify) { if (!upper) { pr_warn_ratelimited("overlayfs: suspected uncovered redirected dir found (origin=%pd2, index=%pd2).\n", origin, index); @@ -943,7 +951,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, if (origin && ovl_indexdir(dentry->d_sb) && (!d.is_dir || ovl_index_all(dentry->d_sb))) { - index = ovl_lookup_index(dentry, upperdentry, origin); + index = ovl_lookup_index(ofs, upperdentry, origin, true); if (IS_ERR(index)) { err = PTR_ERR(index); index = NULL; diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index bf17bf97c50f..0df25a9c94bd 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -274,6 +274,8 @@ struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index); int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); int ovl_get_index_name(struct dentry *origin, struct qstr *name); struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); +struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, + struct dentry *origin, bool verify); int ovl_path_next(int idx, struct dentry *dentry, struct path *path); struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);