From 2b21da920866ad20b5e3119f3b8d2267774b7b0a Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Thu, 27 Apr 2023 12:21:46 +0300 Subject: ovl: prepare to store lowerdata redirect for lazy lowerdata lookup 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 Signed-off-by: Miklos Szeredi --- 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(-) (limited to 'fs/overlayfs') diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 5239a5bfc6d1..552059e759b6 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -1005,6 +1005,7 @@ 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); @@ -1365,6 +1366,7 @@ 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 517f31a28f72..605108f0dbe9 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -1183,6 +1183,11 @@ 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 2ccd6326c2c7..5cc03b8d7b25 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 be2bdf37b0d5..9de02ca2387e 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 b6e66bf8135f..72f565f640fa 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) { }; } @@ -358,9 +359,15 @@ 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) -- cgit v1.2.3