diff options
Diffstat (limited to 'fs/overlayfs/super.c')
| -rw-r--r-- | fs/overlayfs/super.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 1f1d40fc5e33..53dd094f970e 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -1483,7 +1483,8 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, * free high bits in underlying fs to hold the unique fsid. * If overlayfs does encounter underlying inodes using the high xino * bits reserved for fsid, it emits a warning and uses the original - * inode number. + * inode number or a non persistent inode number allocated from a + * dedicated range. */ if (ofs->numfs - !ofs->upper_mnt == 1) { if (ofs->config.xino == OVL_XINO_ON) @@ -1494,11 +1495,13 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, } else if (ofs->config.xino == OVL_XINO_ON && ofs->xino_mode < 0) { /* * This is a roundup of number of bits needed for encoding - * fsid, where fsid 0 is reserved for upper fs even with - * lower only overlay. + * fsid, where fsid 0 is reserved for upper fs (even with + * lower only overlay) +1 extra bit is reserved for the non + * persistent inode number range that is used for resolving + * xino lower bits overflow. */ - BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 31); - ofs->xino_mode = ilog2(ofs->numfs - 1) + 1; + BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); + ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; } if (ofs->xino_mode > 0) { |