diff options
author | hujianyang <hujianyang@huawei.com> | 2014-12-11 10:30:18 +0800 |
---|---|---|
committer | Miklos Szeredi <mszeredi@suse.cz> | 2015-01-09 14:55:57 +0100 |
commit | 4330397e4e8a662f36d101659e2a59ce32e76ff4 (patch) | |
tree | 77ad4a8e29eaa3a02a88ab358569817e7991ab5f /fs/overlayfs/readdir.c | |
parent | 6d900f5a33393067e370736d39798f814f5e25cc (diff) | |
download | linux-4330397e4e8a662f36d101659e2a59ce32e76ff4.tar.bz2 |
ovl: discard independent cursor in readdir()
Since the ovl_dir_cache is stable during a directory reading, the cursor
of struct ovl_dir_file don't need to be an independent entry in the list
of a merged directory.
This patch changes *cursor* to a pointer which points to the entry in the
ovl_dir_cache. After this, we don't need to check *is_cursor* either.
Signed-off-by: hujianyang <hujianyang@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'fs/overlayfs/readdir.c')
-rw-r--r-- | fs/overlayfs/readdir.c | 38 |
1 files changed, 14 insertions, 24 deletions
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index 9df848f2e622..dcf1d412888d 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -24,7 +24,6 @@ struct ovl_cache_entry { struct list_head l_node; struct rb_node node; bool is_whiteout; - bool is_cursor; char name[]; }; @@ -49,7 +48,7 @@ struct ovl_dir_file { bool is_real; bool is_upper; struct ovl_dir_cache *cache; - struct ovl_cache_entry cursor; + struct list_head *cursor; struct file *realfile; struct file *upperfile; }; @@ -97,7 +96,6 @@ static struct ovl_cache_entry *ovl_cache_entry_new(struct dentry *dir, p->type = d_type; p->ino = ino; p->is_whiteout = false; - p->is_cursor = false; if (d_type == DT_CHR) { struct dentry *dentry; @@ -196,7 +194,6 @@ static void ovl_cache_put(struct ovl_dir_file *od, struct dentry *dentry) { struct ovl_dir_cache *cache = od->cache; - list_del_init(&od->cursor.l_node); WARN_ON(cache->refcount <= 0); cache->refcount--; if (!cache->refcount) { @@ -254,6 +251,7 @@ static void ovl_dir_reset(struct file *file) if (cache && ovl_dentry_version_get(dentry) != cache->version) { ovl_cache_put(od, dentry); od->cache = NULL; + od->cursor = NULL; } WARN_ON(!od->is_real && !OVL_TYPE_MERGE(type)); if (od->is_real && OVL_TYPE_MERGE(type)) @@ -295,17 +293,16 @@ static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list) static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos) { - struct ovl_cache_entry *p; + struct list_head *p; loff_t off = 0; - list_for_each_entry(p, &od->cache->entries, l_node) { - if (p->is_cursor) - continue; + list_for_each(p, &od->cache->entries) { if (off >= pos) break; off++; } - list_move_tail(&od->cursor.l_node, &p->l_node); + /* Cursor is safe since the cache is stable */ + od->cursor = p; } static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry) @@ -344,6 +341,7 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) { struct ovl_dir_file *od = file->private_data; struct dentry *dentry = file->f_path.dentry; + struct ovl_cache_entry *p; if (!ctx->pos) ovl_dir_reset(file); @@ -362,19 +360,13 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) ovl_seek_cursor(od, ctx->pos); } - while (od->cursor.l_node.next != &od->cache->entries) { - struct ovl_cache_entry *p; - - p = list_entry(od->cursor.l_node.next, struct ovl_cache_entry, l_node); - /* Skip cursors */ - if (!p->is_cursor) { - if (!p->is_whiteout) { - if (!dir_emit(ctx, p->name, p->len, p->ino, p->type)) - break; - } - ctx->pos++; - } - list_move(&od->cursor.l_node, &p->l_node); + while (od->cursor != &od->cache->entries) { + p = list_entry(od->cursor, struct ovl_cache_entry, l_node); + if (!p->is_whiteout) + if (!dir_emit(ctx, p->name, p->len, p->ino, p->type)) + break; + od->cursor = p->l_node.next; + ctx->pos++; } return 0; } @@ -493,11 +485,9 @@ static int ovl_dir_open(struct inode *inode, struct file *file) kfree(od); return PTR_ERR(realfile); } - INIT_LIST_HEAD(&od->cursor.l_node); od->realfile = realfile; od->is_real = !OVL_TYPE_MERGE(type); od->is_upper = OVL_TYPE_UPPER(type); - od->cursor.is_cursor = true; file->private_data = od; return 0; |