diff options
Diffstat (limited to 'fs/overlayfs/readdir.c')
-rw-r--r-- | fs/overlayfs/readdir.c | 56 |
1 files changed, 26 insertions, 30 deletions
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index 910553f37aca..ab1e3dcbed95 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -21,9 +21,10 @@ struct ovl_cache_entry { unsigned int len; unsigned int type; u64 ino; - bool is_whiteout; struct list_head l_node; struct rb_node node; + bool is_whiteout; + bool is_cursor; char name[]; }; @@ -92,6 +93,7 @@ static struct ovl_cache_entry *ovl_cache_entry_new(const char *name, int len, p->type = d_type; p->ino = ino; p->is_whiteout = false; + p->is_cursor = false; } return p; @@ -166,7 +168,7 @@ static void ovl_cache_put(struct ovl_dir_file *od, struct dentry *dentry) { struct ovl_dir_cache *cache = od->cache; - list_del(&od->cursor.l_node); + list_del_init(&od->cursor.l_node); WARN_ON(cache->refcount <= 0); cache->refcount--; if (!cache->refcount) { @@ -251,7 +253,7 @@ static int ovl_dir_mark_whiteouts(struct dentry *dir, mutex_lock(&dir->d_inode->i_mutex); list_for_each_entry(p, rdd->list, l_node) { - if (!p->name) + if (p->is_cursor) continue; if (p->type != DT_CHR) @@ -272,11 +274,11 @@ static int ovl_dir_mark_whiteouts(struct dentry *dir, return 0; } -static inline int ovl_dir_read_merged(struct path *upperpath, - struct path *lowerpath, - struct list_head *list) +static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list) { int err; + struct path lowerpath; + struct path upperpath; struct ovl_readdir_data rdd = { .ctx.actor = ovl_fill_merge, .list = list, @@ -284,30 +286,32 @@ static inline int ovl_dir_read_merged(struct path *upperpath, .is_merge = false, }; - if (upperpath->dentry) { - err = ovl_dir_read(upperpath, &rdd); + ovl_path_lower(dentry, &lowerpath); + ovl_path_upper(dentry, &upperpath); + + if (upperpath.dentry) { + err = ovl_dir_read(&upperpath, &rdd); if (err) goto out; - if (lowerpath->dentry) { - err = ovl_dir_mark_whiteouts(upperpath->dentry, &rdd); + if (lowerpath.dentry) { + err = ovl_dir_mark_whiteouts(upperpath.dentry, &rdd); if (err) goto out; } } - if (lowerpath->dentry) { + if (lowerpath.dentry) { /* * Insert lowerpath entries before upperpath ones, this allows * offsets to be reasonably constant */ list_add(&rdd.middle, rdd.list); rdd.is_merge = true; - err = ovl_dir_read(lowerpath, &rdd); + err = ovl_dir_read(&lowerpath, &rdd); list_del(&rdd.middle); } out: return err; - } static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos) @@ -316,7 +320,7 @@ static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos) loff_t off = 0; list_for_each_entry(p, &od->cache->entries, l_node) { - if (!p->name) + if (p->is_cursor) continue; if (off >= pos) break; @@ -328,8 +332,6 @@ static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos) static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry) { int res; - struct path lowerpath; - struct path upperpath; struct ovl_dir_cache *cache; cache = ovl_dir_cache(dentry); @@ -346,10 +348,7 @@ static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry) cache->refcount = 1; INIT_LIST_HEAD(&cache->entries); - ovl_path_lower(dentry, &lowerpath); - ovl_path_upper(dentry, &upperpath); - - res = ovl_dir_read_merged(&upperpath, &lowerpath, &cache->entries); + res = ovl_dir_read_merged(dentry, &cache->entries); if (res) { ovl_cache_free(&cache->entries); kfree(cache); @@ -389,7 +388,7 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) p = list_entry(od->cursor.l_node.next, struct ovl_cache_entry, l_node); /* Skip cursors */ - if (p->name) { + if (!p->is_cursor) { if (!p->is_whiteout) { if (!dir_emit(ctx, p->name, p->len, p->ino, p->type)) break; @@ -451,15 +450,16 @@ static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end, /* * Need to check if we started out being a lower dir, but got copied up */ - if (!od->is_upper && ovl_path_type(dentry) == OVL_PATH_MERGE) { + if (!od->is_upper && ovl_path_type(dentry) != OVL_PATH_LOWER) { struct inode *inode = file_inode(file); - realfile = od->upperfile; + realfile = lockless_dereference(od->upperfile); if (!realfile) { struct path upperpath; ovl_path_upper(dentry, &upperpath); realfile = ovl_path_open(&upperpath, O_RDONLY); + smp_mb__before_spinlock(); mutex_lock(&inode->i_mutex); if (!od->upperfile) { if (IS_ERR(realfile)) { @@ -518,6 +518,7 @@ static int ovl_dir_open(struct inode *inode, struct file *file) od->realfile = realfile; od->is_real = (type != OVL_PATH_MERGE); od->is_upper = (type != OVL_PATH_LOWER); + od->cursor.is_cursor = true; file->private_data = od; return 0; @@ -535,14 +536,9 @@ const struct file_operations ovl_dir_operations = { int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list) { int err; - struct path lowerpath; - struct path upperpath; struct ovl_cache_entry *p; - ovl_path_upper(dentry, &upperpath); - ovl_path_lower(dentry, &lowerpath); - - err = ovl_dir_read_merged(&upperpath, &lowerpath, list); + err = ovl_dir_read_merged(dentry, list); if (err) return err; @@ -569,7 +565,7 @@ void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list) { struct ovl_cache_entry *p; - mutex_lock_nested(&upper->d_inode->i_mutex, I_MUTEX_PARENT); + mutex_lock_nested(&upper->d_inode->i_mutex, I_MUTEX_CHILD); list_for_each_entry(p, list, l_node) { struct dentry *dentry; |