diff options
Diffstat (limited to 'fs/overlayfs/namei.c')
| -rw-r--r-- | fs/overlayfs/namei.c | 56 |
1 files changed, 49 insertions, 7 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 605108f0dbe9..b3b40bc9a5ab 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -889,6 +889,52 @@ static int ovl_fix_origin(struct ovl_fs *ofs, struct dentry *dentry, return err; } +/* Lazy lookup of lowerdata */ +int ovl_maybe_lookup_lowerdata(struct dentry *dentry) +{ + struct inode *inode = d_inode(dentry); + const char *redirect = ovl_lowerdata_redirect(inode); + struct ovl_path datapath = {}; + const struct cred *old_cred; + int err; + + if (!redirect || ovl_dentry_lowerdata(dentry)) + return 0; + + if (redirect[0] != '/') + return -EIO; + + err = ovl_inode_lock_interruptible(inode); + if (err) + return err; + + err = 0; + /* Someone got here before us? */ + if (ovl_dentry_lowerdata(dentry)) + goto out; + + old_cred = ovl_override_creds(dentry->d_sb); + err = ovl_lookup_data_layers(dentry, redirect, &datapath); + revert_creds(old_cred); + if (err) + goto out_err; + + err = ovl_dentry_set_lowerdata(dentry, &datapath); + if (err) + goto out_err; + +out: + ovl_inode_unlock(inode); + dput(datapath.dentry); + + return err; + +out_err: + pr_warn_ratelimited("lazy lowerdata lookup failed (%pd2, err=%i)\n", + dentry, err); + goto out; +} + struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { @@ -1072,14 +1118,10 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, } } - /* Lookup absolute redirect from lower metacopy in data-only layers */ + /* Defer lookup of lowerdata in data-only layers to first access */ 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++; - } + d.metacopy = false; + ctr++; } /* |