Prepare to allow ovl_lookup() to leave the last entry in a non-dir
lowerstack empty to signify lazy lowerdata lookup.
In this case, ovl_lookup() stores the redirect path from metacopy to
lowerdata in ovl_inode, which is going to be used later to perform the
lazy lowerdata lookup.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/inode.c | 2 ++
fs/overlayfs/namei.c | 5 +++++
fs/overlayfs/overlayfs.h | 2 ++
fs/overlayfs/ovl_entry.h | 3 ++-
fs/overlayfs/super.c | 3 +++
fs/overlayfs/util.c | 13 ++++++++++---
6 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 62027e60a936..a7529b6a86e6 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -1006,6 +1006,7 @@ void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
oi->__upperdentry = oip->upperdentry;
oi->oe = oip->oe;
oi->redirect = oip->redirect;
+ oi->lowerdata_redirect = oip->lowerdata_redirect;
realinode = ovl_inode_real(inode);
ovl_copyattr(inode);
@@ -1366,6 +1367,7 @@ struct inode *ovl_get_inode(struct super_block *sb,
dput(upperdentry);
ovl_free_entry(oip->oe);
kfree(oip->redirect);
+ kfree(oip->lowerdata_redirect);
goto out;
}
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 1ed64ff129d9..6df9a349cd04 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -1181,6 +1181,11 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
.redirect = upperredirect,
};
+ /* Store lowerdata redirect for lazy lookup */
+ if (ctr > 1 && !d.is_dir && !stack[ctr - 1].dentry) {
+ oip.lowerdata_redirect = d.redirect;
+ d.redirect = NULL;
+ }
inode = ovl_get_inode(dentry->d_sb, &oip);
err = PTR_ERR(inode);
if (IS_ERR(inode))
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 93ebc0edf4ef..cb0135ff6249 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -405,6 +405,7 @@ struct inode *ovl_inode_lower(struct inode *inode);
struct inode *ovl_inode_lowerdata(struct inode *inode);
struct inode *ovl_inode_real(struct inode *inode);
struct inode *ovl_inode_realdata(struct inode *inode);
+const char *ovl_lowerdata_redirect(struct inode *inode);
struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
@@ -656,6 +657,7 @@ struct ovl_inode_params {
struct ovl_entry *oe;
bool index;
char *redirect;
+ char *lowerdata_redirect;
};
void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
unsigned long ino, int fsid);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 93ff299da0dd..513c2c499e41 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -141,6 +141,7 @@ static inline struct ovl_path *ovl_lowerdata(struct ovl_entry *oe)
return lowerstack ? &lowerstack[oe->__numlower - 1] : NULL;
}
+/* May return NULL if lazy lookup of lowerdata is needed */
static inline struct dentry *ovl_lowerdata_dentry(struct ovl_entry *oe)
{
struct ovl_path *lowerdata = ovl_lowerdata(oe);
@@ -157,7 +158,7 @@ static inline unsigned long *OVL_E_FLAGS(struct dentry *dentry)
struct ovl_inode {
union {
struct ovl_dir_cache *cache; /* directory */
- /* place holder for non-dir */ /* regular file */
+ const char *lowerdata_redirect; /* regular file */
};
const char *redirect;
u64 version;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 988edb9e9d23..b960b9d84b66 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -171,6 +171,7 @@ static struct inode *ovl_alloc_inode(struct super_block *sb)
oi->version = 0;
oi->flags = 0;
oi->__upperdentry = NULL;
+ oi->lowerdata_redirect = NULL;
oi->oe = NULL;
mutex_init(&oi->lock);
@@ -194,6 +195,8 @@ static void ovl_destroy_inode(struct inode *inode)
ovl_free_entry(oi->oe);
if (S_ISDIR(inode->i_mode))
ovl_dir_cache_free(inode);
+ else
+ kfree(oi->lowerdata_redirect);
}
static void ovl_free_fs(struct ovl_fs *ofs)
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 7495b4d378b0..ad93a3132495 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -226,10 +226,11 @@ void ovl_path_lowerdata(struct dentry *dentry, struct path *path)
{
struct ovl_entry *oe = OVL_E(dentry);
struct ovl_path *lowerdata = ovl_lowerdata(oe);
+ struct dentry *lowerdata_dentry = ovl_lowerdata_dentry(oe);
- if (ovl_numlower(oe)) {
+ if (lowerdata_dentry) {
path->mnt = lowerdata->layer->mnt;
- path->dentry = lowerdata->dentry;
+ path->dentry = lowerdata_dentry;
} else {
*path = (struct path) { };
}
@@ -356,9 +357,15 @@ struct inode *ovl_inode_realdata(struct inode *inode)
return ovl_inode_lowerdata(inode);
}
+const char *ovl_lowerdata_redirect(struct inode *inode)
+{
+ return inode && S_ISREG(inode->i_mode) ?
+ OVL_I(inode)->lowerdata_redirect : NULL;
+}
+
struct ovl_dir_cache *ovl_dir_cache(struct inode *inode)
{
- return OVL_I(inode)->cache;
+ return inode && S_ISDIR(inode->i_mode) ? OVL_I(inode)->cache : NULL;
}
void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache)
--
2.34.1
