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| author | Miklos Szeredi <mszeredi@suse.cz> | 2014-12-13 00:59:43 +0100 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@suse.cz> | 2014-12-13 00:59:43 +0100 |
| commit | 5ef88da56a77bfb3b9631f5e5775f3bff86b6219 (patch) | |
| tree | d09b7c8612f7652576ae3b75b80f7aaec303143e /fs/overlayfs | |
| parent | ovl: add mutli-layer infrastructure (diff) | |
| download | linux-5ef88da56a77bfb3b9631f5e5775f3bff86b6219.tar.xz linux-5ef88da56a77bfb3b9631f5e5775f3bff86b6219.zip | |
ovl: helper to iterate layers
Add helper to iterate through all the layers, starting from the upper layer
(if exists) and continuing down through the lower layers.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'fs/overlayfs')
| -rw-r--r-- | fs/overlayfs/overlayfs.h | 1 | ||||
| -rw-r--r-- | fs/overlayfs/super.c | 21 |
2 files changed, 22 insertions, 0 deletions
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index d39eaa8f5e47..d176b679f526 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -135,6 +135,7 @@ void ovl_dentry_version_inc(struct dentry *dentry); void ovl_path_upper(struct dentry *dentry, struct path *path); void ovl_path_lower(struct dentry *dentry, struct path *path); enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); +int ovl_path_next(int idx, struct dentry *dentry, struct path *path); struct dentry *ovl_dentry_upper(struct dentry *dentry); struct dentry *ovl_dentry_lower(struct dentry *dentry); struct dentry *ovl_dentry_real(struct dentry *dentry); diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 460d866b97a2..07e4c576e93e 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -305,6 +305,27 @@ static inline struct dentry *ovl_lookup_real(struct dentry *dir, return dentry; } +/* + * Returns next layer in stack starting from top. + * Returns -1 if this is the last layer. + */ +int ovl_path_next(int idx, struct dentry *dentry, struct path *path) +{ + struct ovl_entry *oe = dentry->d_fsdata; + + BUG_ON(idx < 0); + if (idx == 0) { + ovl_path_upper(dentry, path); + if (path->dentry) + return oe->numlower ? 1 : -1; + idx++; + } + BUG_ON(idx > oe->numlower); + *path = oe->lowerstack[idx - 1]; + + return (idx < oe->numlower) ? idx + 1 : -1; +} + struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { |