Btrfs: send, use the right limits for xattr names and values (7e3ae33e) · Commits · 戴 / test

We were limiting the sum of the xattr name and value lengths to PATH_MAX, which is not correct, specially on filesystems created with btrfs-progs v3.12 or higher, where the default leaf size is max(16384, PAGE_SIZE), or systems with page sizes larger than 4096 bytes. Xattrs have their own specific maximum name and value lengths, which depend on the leaf size, therefore use these limits to be able to send xattrs with sizes larger than PATH_MAX. A test case for xfstests follows. Signed-off-by:

Filipe David Borba Manana <fdmanana@gmail.com> Signed-off-by:

Chris Mason <clm@fb.com>

fs/btrfs/send.c

+23 −7

Original line number	Diff line number	Diff line
		@@ -975,7 +975,7 @@ static int iterate_dir_item(struct btrfs_root root, struct btrfs_path path,
		struct btrfs_dir_item *di;
		struct btrfs_key di_key;
		char *buf = NULL;
		const int buf_len = PATH_MAX;
		int buf_len;
		u32 name_len;
		u32 data_len;
		u32 cur;
		@@ -985,6 +985,11 @@ static int iterate_dir_item(struct btrfs_root root, struct btrfs_path path,
		int num;
		u8 type;

		if (found_key->type == BTRFS_XATTR_ITEM_KEY)
		buf_len = BTRFS_MAX_XATTR_SIZE(root);
		else
		buf_len = PATH_MAX;

		buf = kmalloc(buf_len, GFP_NOFS);
		if (!buf) {
		ret = -ENOMEM;
		@@ -1006,6 +1011,16 @@ static int iterate_dir_item(struct btrfs_root root, struct btrfs_path path,
		type = btrfs_dir_type(eb, di);
		btrfs_dir_item_key_to_cpu(eb, di, &di_key);

		if (type == BTRFS_FT_XATTR) {
		if (name_len > XATTR_NAME_MAX) {
		ret = -ENAMETOOLONG;
		goto out;
		}
		if (name_len + data_len > buf_len) {
		ret = -E2BIG;
		goto out;
		}
		} else {
		/*
		* Path too long
		*/
		@@ -1013,6 +1028,7 @@ static int iterate_dir_item(struct btrfs_root root, struct btrfs_path path,
		ret = -ENAMETOOLONG;
		goto out;
		}
		}

		read_extent_buffer(eb, buf, (unsigned long)(di + 1),
		name_len + data_len);

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