diff options
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/overlayfs/inode.c | 88 | ||||
| -rw-r--r-- | fs/overlayfs/overlayfs.h | 1 | ||||
| -rw-r--r-- | fs/overlayfs/util.c | 7 |
3 files changed, 57 insertions, 39 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 29069f29b3a6..8a283ec21e34 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -16,13 +16,6 @@ #include "overlayfs.h" -static dev_t ovl_get_pseudo_dev(struct dentry *dentry) -{ - struct ovl_entry *oe = dentry->d_fsdata; - - return oe->lowerstack[0].layer->pseudo_dev; -} - int ovl_setattr(struct dentry *dentry, struct iattr *attr) { int err; @@ -66,6 +59,43 @@ out: return err; } +static int ovl_map_dev_ino(struct dentry *dentry, struct kstat *stat, + struct ovl_layer *lower_layer) +{ + bool samefs = ovl_same_sb(dentry->d_sb); + + if (samefs) { + /* + * When all layers are on the same fs, all real inode + * number are unique, so we use the overlay st_dev, + * which is friendly to du -x. + */ + stat->dev = dentry->d_sb->s_dev; + } else if (S_ISDIR(dentry->d_inode->i_mode)) { + /* + * Always use the overlay st_dev for directories, so 'find + * -xdev' will scan the entire overlay mount and won't cross the + * overlay mount boundaries. + * + * If not all layers are on the same fs the pair {real st_ino; + * overlay st_dev} is not unique, so use the non persistent + * overlay st_ino for directories. + */ + stat->dev = dentry->d_sb->s_dev; + stat->ino = dentry->d_inode->i_ino; + } else if (lower_layer) { + /* + * For non-samefs setup, if we cannot map all layers st_ino + * to a unified address space, we need to make sure that st_dev + * is unique per layer. Upper layer uses real st_dev and lower + * layers use the unique anonymous bdev. + */ + stat->dev = lower_layer->pseudo_dev; + } + + return 0; +} + int ovl_getattr(const struct path *path, struct kstat *stat, u32 request_mask, unsigned int flags) { @@ -75,6 +105,7 @@ int ovl_getattr(const struct path *path, struct kstat *stat, const struct cred *old_cred; bool is_dir = S_ISDIR(dentry->d_inode->i_mode); bool samefs = ovl_same_sb(dentry->d_sb); + struct ovl_layer *lower_layer = NULL; int err; type = ovl_path_real(dentry, &realpath); @@ -84,14 +115,16 @@ int ovl_getattr(const struct path *path, struct kstat *stat, goto out; /* - * For non-dir or same fs, we use st_ino of the copy up origin, if we - * know it. This guaranties constant st_dev/st_ino across copy up. + * For non-dir or same fs, we use st_ino of the copy up origin. + * This guaranties constant st_dev/st_ino across copy up. * - * If filesystem supports NFS export ops, this also guaranties + * If lower filesystem supports NFS file handles, this also guaranties * persistent st_ino across mount cycle. */ if (!is_dir || samefs) { - if (OVL_TYPE_ORIGIN(type)) { + if (!OVL_TYPE_UPPER(type)) { + lower_layer = ovl_layer_lower(dentry); + } else if (OVL_TYPE_ORIGIN(type)) { struct kstat lowerstat; u32 lowermask = STATX_INO | (!is_dir ? STATX_NLINK : 0); @@ -120,38 +153,15 @@ int ovl_getattr(const struct path *path, struct kstat *stat, (!ovl_verify_lower(dentry->d_sb) && (is_dir || lowerstat.nlink == 1))) { stat->ino = lowerstat.ino; - stat->dev = ovl_get_pseudo_dev(dentry); + lower_layer = ovl_layer_lower(dentry); } } - if (samefs) { - /* - * When all layers are on the same fs, all real inode - * number are unique, so we use the overlay st_dev, - * which is friendly to du -x. - */ - stat->dev = dentry->d_sb->s_dev; - } else if (!OVL_TYPE_UPPER(type)) { - /* - * For non-samefs setup, to make sure that st_dev/st_ino - * pair is unique across the system, we use a unique - * anonymous st_dev for lower layer inode. - */ - stat->dev = ovl_get_pseudo_dev(dentry); - } - } else { - /* - * Always use the overlay st_dev for directories, so 'find - * -xdev' will scan the entire overlay mount and won't cross the - * overlay mount boundaries. - * - * If not all layers are on the same fs the pair {real st_ino; - * overlay st_dev} is not unique, so use the non persistent - * overlay st_ino for directories. - */ - stat->dev = dentry->d_sb->s_dev; - stat->ino = dentry->d_inode->i_ino; } + err = ovl_map_dev_ino(dentry, stat, lower_layer); + if (err) + goto out; + /* * It's probably not worth it to count subdirs to get the * correct link count. nlink=1 seems to pacify 'find' and diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index b51613b355c5..09779f9111a8 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -215,6 +215,7 @@ void ovl_path_lower(struct dentry *dentry, struct path *path); enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); struct dentry *ovl_dentry_upper(struct dentry *dentry); struct dentry *ovl_dentry_lower(struct dentry *dentry); +struct ovl_layer *ovl_layer_lower(struct dentry *dentry); struct dentry *ovl_dentry_real(struct dentry *dentry); struct dentry *ovl_i_dentry_upper(struct inode *inode); struct inode *ovl_inode_upper(struct inode *inode); diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 493f9b76fbf6..5042293d2078 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -172,6 +172,13 @@ struct dentry *ovl_dentry_lower(struct dentry *dentry) return oe->numlower ? oe->lowerstack[0].dentry : NULL; } +struct ovl_layer *ovl_layer_lower(struct dentry *dentry) +{ + struct ovl_entry *oe = dentry->d_fsdata; + + return oe->numlower ? oe->lowerstack[0].layer : NULL; +} + struct dentry *ovl_dentry_real(struct dentry *dentry) { return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry); |