diff options
| -rw-r--r-- | fs/overlayfs/namei.c | 73 |
1 files changed, 72 insertions, 1 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 5c1b0397c8ce..517f31a28f72 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -14,6 +14,8 @@ #include <linux/exportfs.h> #include "overlayfs.h" +#include "../internal.h" /* for vfs_path_lookup */ + struct ovl_lookup_data { struct super_block *sb; struct vfsmount *mnt; @@ -24,6 +26,8 @@ struct ovl_lookup_data { bool last; char *redirect; bool metacopy; + /* Referring to last redirect xattr */ + bool absolute_redirect; }; static int ovl_check_redirect(const struct path *path, struct ovl_lookup_data *d, @@ -33,11 +37,13 @@ static int ovl_check_redirect(const struct path *path, struct ovl_lookup_data *d char *buf; struct ovl_fs *ofs = OVL_FS(d->sb); + d->absolute_redirect = false; buf = ovl_get_redirect_xattr(ofs, path, prelen + strlen(post)); if (IS_ERR_OR_NULL(buf)) return PTR_ERR(buf); if (buf[0] == '/') { + d->absolute_redirect = true; /* * One of the ancestor path elements in an absolute path * lookup in ovl_lookup_layer() could have been opaque and @@ -349,6 +355,61 @@ static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d, return 0; } +static int ovl_lookup_data_layer(struct dentry *dentry, const char *redirect, + const struct ovl_layer *layer, + struct path *datapath) +{ + int err; + + err = vfs_path_lookup(layer->mnt->mnt_root, layer->mnt, redirect, + LOOKUP_BENEATH | LOOKUP_NO_SYMLINKS | LOOKUP_NO_XDEV, + datapath); + pr_debug("lookup lowerdata (%pd2, redirect=\"%s\", layer=%d, err=%i)\n", + dentry, redirect, layer->idx, err); + + if (err) + return err; + + err = -EREMOTE; + if (ovl_dentry_weird(datapath->dentry)) + goto out_path_put; + + err = -ENOENT; + /* Only regular file is acceptable as lower data */ + if (!d_is_reg(datapath->dentry)) + goto out_path_put; + + return 0; + +out_path_put: + path_put(datapath); + + return err; +} + +/* Lookup in data-only layers by absolute redirect to layer root */ +static int ovl_lookup_data_layers(struct dentry *dentry, const char *redirect, + struct ovl_path *lowerdata) +{ + struct ovl_fs *ofs = OVL_FS(dentry->d_sb); + const struct ovl_layer *layer; + struct path datapath; + int err = -ENOENT; + int i; + + layer = &ofs->layers[ofs->numlayer - ofs->numdatalayer]; + for (i = 0; i < ofs->numdatalayer; i++, layer++) { + err = ovl_lookup_data_layer(dentry, redirect, layer, &datapath); + if (!err) { + mntput(datapath.mnt); + lowerdata->dentry = datapath.dentry; + lowerdata->layer = layer; + return 0; + } + } + + return err; +} int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, struct dentry *upperdentry, struct ovl_path **stackp) @@ -917,7 +978,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, if (!ofs->config.redirect_follow) d.last = i == ovl_numlower(poe) - 1; - else + else if (d.is_dir || !ofs->numdatalayer) d.last = lower.layer->idx == ovl_numlower(roe); d.mnt = lower.layer->mnt; @@ -1011,6 +1072,16 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, } } + /* Lookup absolute redirect from lower metacopy in data-only layers */ + if (d.metacopy && ctr && ofs->numdatalayer && d.absolute_redirect) { + err = ovl_lookup_data_layers(dentry, d.redirect, + &stack[ctr]); + if (!err) { + d.metacopy = false; + ctr++; + } + } + /* * For regular non-metacopy upper dentries, there is no lower * path based lookup, hence ctr will be zero. If a dentry is found |