diff options
Diffstat (limited to 'fs/overlayfs/inode.c')
| -rw-r--r-- | fs/overlayfs/inode.c | 31 |
1 files changed, 29 insertions, 2 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index cfccd91c51e3..51d780898d89 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -63,6 +63,7 @@ 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); + unsigned int xinobits = ovl_xino_bits(dentry->d_sb); if (samefs) { /* @@ -71,7 +72,31 @@ static int ovl_map_dev_ino(struct dentry *dentry, struct kstat *stat, * which is friendly to du -x. */ stat->dev = dentry->d_sb->s_dev; - } else if (S_ISDIR(dentry->d_inode->i_mode)) { + return 0; + } else if (xinobits) { + unsigned int shift = 64 - xinobits; + /* + * All inode numbers of underlying fs should not be using the + * high xinobits, so we use high xinobits to partition the + * overlay st_ino address space. The high bits holds the fsid + * (upper fsid is 0). This way overlay inode numbers are unique + * and all inodes use overlay st_dev. Inode numbers are also + * persistent for a given layer configuration. + */ + if (stat->ino >> shift) { + pr_warn_ratelimited("overlayfs: inode number too big (%pd2, ino=%llu, xinobits=%d)\n", + dentry, stat->ino, xinobits); + } else { + if (lower_layer) + stat->ino |= ((u64)lower_layer->fsid) << shift; + + stat->dev = dentry->d_sb->s_dev; + return 0; + } + } + + /* The inode could not be mapped to a unified st_ino address space */ + 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 @@ -118,11 +143,13 @@ int ovl_getattr(const struct path *path, struct kstat *stat, /* * 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. + * With xino feature and non-samefs, we use st_ino of the copy up + * origin masked with high bits that represent the layer id. * * If lower filesystem supports NFS file handles, this also guaranties * persistent st_ino across mount cycle. */ - if (!is_dir || samefs) { + if (!is_dir || samefs || ovl_xino_bits(dentry->d_sb)) { if (!OVL_TYPE_UPPER(type)) { lower_layer = ovl_layer_lower(dentry); } else if (OVL_TYPE_ORIGIN(type)) { |