Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs (983a5f84) · Commits · 戴 / test

Documentation/filesystems/btrfs.txt

+173 −7

Original line number	Diff line number	Diff line
		@@ -2,7 +2,7 @@
		BTRFS
		=====

		Btrfs is a new copy on write filesystem for Linux aimed at
		Btrfs is a copy on write filesystem for Linux aimed at
		implementing advanced features while focusing on fault tolerance,
		repair and easy administration. Initially developed by Oracle, Btrfs
		is licensed under the GPL and open for contribution from anyone.
		@@ -34,6 +34,172 @@ The main Btrfs features include:
		* Online filesystem defragmentation


		Mount Options
		=============

		When mounting a btrfs filesystem, the following option are accepted.
		Unless otherwise specified, all options default to off.

		alloc_start=<bytes>
		Debugging option to force all block allocations above a certain
		byte threshold on each block device. The value is specified in
		bytes, optionally with a K, M, or G suffix, case insensitive.
		Default is 1MB.

		autodefrag
		Detect small random writes into files and queue them up for the
		defrag process. Works best for small files; Not well suited for
		large database workloads.

		check_int
		check_int_data
		check_int_print_mask=<value>
		These debugging options control the behavior of the integrity checking
		module (the BTRFS_FS_CHECK_INTEGRITY config option required).

		check_int enables the integrity checker module, which examines all
		block write requests to ensure on-disk consistency, at a large
		memory and CPU cost.

		check_int_data includes extent data in the integrity checks, and
		implies the check_int option.

		check_int_print_mask takes a bitmask of BTRFSIC_PRINT_MASK_* values
		as defined in fs/btrfs/check-integrity.c, to control the integrity
		checker module behavior.

		See comments at the top of fs/btrfs/check-integrity.c for more info.

		compress
		compress=<type>
		compress-force
		compress-force=<type>
		Control BTRFS file data compression. Type may be specified as "zlib"
		"lzo" or "no" (for no compression, used for remounting). If no type
		is specified, zlib is used. If compress-force is specified,
		all files will be compressed, whether or not they compress well.
		If compression is enabled, nodatacow and nodatasum are disabled.

		degraded
		Allow mounts to continue with missing devices. A read-write mount may
		fail with too many devices missing, for example if a stripe member
		is completely missing.

		device=<devicepath>
		Specify a device during mount so that ioctls on the control device
		can be avoided. Especialy useful when trying to mount a multi-device
		setup as root. May be specified multiple times for multiple devices.

		discard
		Issue frequent commands to let the block device reclaim space freed by
		the filesystem. This is useful for SSD devices, thinly provisioned
		LUNs and virtual machine images, but may have a significant
		performance impact. (The fstrim command is also available to
		initiate batch trims from userspace).

		enospc_debug
		Debugging option to be more verbose in some ENOSPC conditions.

		fatal_errors=<action>
		Action to take when encountering a fatal error:
		"bug" - BUG() on a fatal error. This is the default.
		"panic" - panic() on a fatal error.

		flushoncommit
		The 'flushoncommit' mount option forces any data dirtied by a write in a
		prior transaction to commit as part of the current commit. This makes
		the committed state a fully consistent view of the file system from the
		application's perspective (i.e., it includes all completed file system
		operations). This was previously the behavior only when a snapshot is
		created.

		inode_cache
		Enable free inode number caching. Defaults to off due to an overflow
		problem when the free space crcs don't fit inside a single page.

		max_inline=<bytes>
		Specify the maximum amount of space, in bytes, that can be inlined in
		a metadata B-tree leaf. The value is specified in bytes, optionally
		with a K, M, or G suffix, case insensitive. In practice, this value
		is limited by the root sector size, with some space unavailable due
		to leaf headers. For a 4k sectorsize, max inline data is ~3900 bytes.

		metadata_ratio=<value>
		Specify that 1 metadata chunk should be allocated after every <value>
		data chunks. Off by default.

		noacl
		Disable support for Posix Access Control Lists (ACLs). See the
		acl(5) manual page for more information about ACLs.

		nobarrier
		Disables the use of block layer write barriers. Write barriers ensure
		that certain IOs make it through the device cache and are on persistent
		storage. If used on a device with a volatile (non-battery-backed)
		write-back cache, this option will lead to filesystem corruption on a
		system crash or power loss.

		nodatacow
		Disable data copy-on-write for newly created files. Implies nodatasum,
		and disables all compression.

		nodatasum
		Disable data checksumming for newly created files.

		notreelog
		Disable the tree logging used for fsync and O_SYNC writes.

		recovery
		Enable autorecovery attempts if a bad tree root is found at mount time.
		Currently this scans a list of several previous tree roots and tries to
		use the first readable.

		skip_balance
		Skip automatic resume of interrupted balance operation after mount.
		May be resumed with "btrfs balance resume."

		space_cache (*)
		Enable the on-disk freespace cache.
		nospace_cache
		Disable freespace cache loading without clearing the cache.
		clear_cache
		Force clearing and rebuilding of the disk space cache if something
		has gone wrong.

		ssd
		nossd
		ssd_spread
		Options to control ssd allocation schemes. By default, BTRFS will
		enable or disable ssd allocation heuristics depending on whether a
		rotational or nonrotational disk is in use. The ssd and nossd options
		can override this autodetection.

		The ssd_spread mount option attempts to allocate into big chunks
		of unused space, and may perform better on low-end ssds. ssd_spread
		implies ssd, enabling all other ssd heuristics as well.

		subvol=<path>
		Mount subvolume at <path> rather than the root subvolume. <path> is
		relative to the top level subvolume.

		subvolid=<ID>
		Mount subvolume specified by an ID number rather than the root subvolume.
		This allows mounting of subvolumes which are not in the root of the mounted
		filesystem.
		You can use "btrfs subvolume list" to see subvolume ID numbers.

		subvolrootid=<objectid> (deprecated)
		Mount subvolume specified by <objectid> rather than the root subvolume.
		This allows mounting of subvolumes which are not in the root of the mounted
		filesystem.
		You can use "btrfs subvolume show " to see the object ID for a subvolume.

		thread_pool=<number>
		The number of worker threads to allocate. The default number is equal
		to the number of CPUs + 2, or 8, whichever is smaller.

		user_subvol_rm_allowed
		Allow subvolumes to be deleted by a non-root user. Use with caution.

		MAILING LIST
		============

fs/btrfs/Kconfig

+21 −1

Original line number	Diff line number	Diff line
		config BTRFS_FS
		tristate "Btrfs filesystem Unstable disk format"
		tristate "Btrfs filesystem support"
		select LIBCRC32C
		select ZLIB_INFLATE
		select ZLIB_DEFLATE
		@@ -52,3 +52,23 @@ config BTRFS_FS_CHECK_INTEGRITY
		In most cases, unless you are a btrfs developer who needs
		to verify the integrity of (super)-block write requests
		during the run of a regression test, say N

		config BTRFS_FS_RUN_SANITY_TESTS
		bool "Btrfs will run sanity tests upon loading"
		depends on BTRFS_FS
		help
		This will run some basic sanity tests on the free space cache
		code to make sure it is acting as it should. These are mostly
		regression tests and are only really interesting to btrfs devlopers.

		If unsure, say N.

		config BTRFS_DEBUG
		bool "Btrfs debugging support"
		depends on BTRFS_FS
		help
		Enable run-time debugging support for the btrfs filesystem. This may
		enable additional and expensive checks with negative impact on
		performance, or export extra information via sysfs.

		If unsure, say N.

fs/btrfs/backref.c

+40 −47

Original line number	Diff line number	Diff line
		@@ -352,6 +352,8 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
		err = __resolve_indirect_ref(fs_info, search_commit_root,
		time_seq, ref, parents,
		extent_item_pos);
		if (err == -ENOMEM)
		goto out;
		if (err)
		continue;

		@@ -367,7 +369,7 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
		new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS);
		if (!new_ref) {
		ret = -ENOMEM;
		break;
		goto out;
		}
		memcpy(new_ref, ref, sizeof(*ref));
		new_ref->parent = node->val;
		@@ -377,7 +379,7 @@ static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
		}
		ulist_reinit(parents);
		}

		out:
		ulist_free(parents);
		return ret;
		}
		@@ -421,7 +423,10 @@ static int __add_missing_keys(struct btrfs_fs_info *fs_info,
		BUG_ON(!ref->wanted_disk_byte);
		eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
		fs_info->tree_root->leafsize, 0);
		BUG_ON(!eb);
		if (!eb \|\| !extent_buffer_uptodate(eb)) {
		free_extent_buffer(eb);
		return -EIO;
		}
		btrfs_tree_read_lock(eb);
		if (btrfs_header_level(eb) == 0)
		btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
		@@ -443,7 +448,7 @@ static int __add_missing_keys(struct btrfs_fs_info *fs_info,
		* having a parent).
		* mode = 2: merge identical parents
		*/
		static int __merge_refs(struct list_head *head, int mode)
		static void __merge_refs(struct list_head *head, int mode)
		{
		struct list_head *pos1;

		@@ -489,7 +494,6 @@ static int __merge_refs(struct list_head *head, int mode)
		}

		}
		return 0;
		}

		/*
		@@ -582,7 +586,8 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
		default:
		WARN_ON(1);
		}
		BUG_ON(ret);
		if (ret)
		return ret;
		}

		return 0;
		@@ -680,7 +685,8 @@ static int __add_inline_refs(struct btrfs_fs_info *fs_info,
		default:
		WARN_ON(1);
		}
		BUG_ON(ret);
		if (ret)
		return ret;
		ptr += btrfs_extent_inline_ref_size(type);
		}

		@@ -762,7 +768,9 @@ static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
		default:
		WARN_ON(1);
		}
		BUG_ON(ret);
		if (ret)
		return ret;

		}

		return ret;
		@@ -880,18 +888,14 @@ again:
		if (ret)
		goto out;

		ret = __merge_refs(&prefs, 1);
		if (ret)
		goto out;
		__merge_refs(&prefs, 1);

		ret = __resolve_indirect_refs(fs_info, search_commit_root, time_seq,
		&prefs, extent_item_pos);
		if (ret)
		goto out;

		ret = __merge_refs(&prefs, 2);
		if (ret)
		goto out;
		__merge_refs(&prefs, 2);

		while (!list_empty(&prefs)) {
		ref = list_first_entry(&prefs, struct __prelim_ref, list);
		@@ -900,7 +904,8 @@ again:
		if (ref->count && ref->root_id && ref->parent == 0) {
		/* no parent == root of tree */
		ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
		BUG_ON(ret < 0);
		if (ret < 0)
		goto out;
		}
		if (ref->count && ref->parent) {
		struct extent_inode_elem *eie = NULL;
		@@ -911,7 +916,10 @@ again:
		info_level);
		eb = read_tree_block(fs_info->extent_root,
		ref->parent, bsz, 0);
		BUG_ON(!eb);
		if (!eb \|\| !extent_buffer_uptodate(eb)) {
		free_extent_buffer(eb);
		return -EIO;
		}
		ret = find_extent_in_eb(eb, bytenr,
		*extent_item_pos, &eie);
		ref->inode_list = eie;
		@@ -920,6 +928,8 @@ again:
		ret = ulist_add_merge(refs, ref->parent,
		(uintptr_t)ref->inode_list,
		(u64 *)&eie, GFP_NOFS);
		if (ret < 0)
		goto out;
		if (!ret && extent_item_pos) {
		/*
		* we've recorded that parent, so we must extend
		@@ -930,7 +940,6 @@ again:
		eie = eie->next;
		eie->next = ref->inode_list;
		}
		BUG_ON(ret < 0);
		}
		kfree(ref);
		}
		@@ -1180,6 +1189,20 @@ int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
		return ret;
		}

		/*
		* this iterates to turn a name (from iref/extref) into a full filesystem path.
		* Elements of the path are separated by '/' and the path is guaranteed to be
		* 0-terminated. the path is only given within the current file system.
		* Therefore, it never starts with a '/'. the caller is responsible to provide
		* "size" bytes in "dest". the dest buffer will be filled backwards. finally,
		* the start point of the resulting string is returned. this pointer is within
		* dest, normally.
		* in case the path buffer would overflow, the pointer is decremented further
		* as if output was written to the buffer, though no more output is actually
		* generated. that way, the caller can determine how much space would be
		* required for the path to fit into the buffer. in that case, the returned
		* value will be smaller than dest. callers must check this!
		*/
		char btrfs_ref_to_path(struct btrfs_root fs_root, struct btrfs_path *path,
		u32 name_len, unsigned long name_off,
		struct extent_buffer *eb_in, u64 parent,
		@@ -1248,32 +1271,6 @@ char btrfs_ref_to_path(struct btrfs_root fs_root, struct btrfs_path *path,
		return dest + bytes_left;
		}

		/*
		* this iterates to turn a btrfs_inode_ref into a full filesystem path. elements
		* of the path are separated by '/' and the path is guaranteed to be
		* 0-terminated. the path is only given within the current file system.
		* Therefore, it never starts with a '/'. the caller is responsible to provide
		* "size" bytes in "dest". the dest buffer will be filled backwards. finally,
		* the start point of the resulting string is returned. this pointer is within
		* dest, normally.
		* in case the path buffer would overflow, the pointer is decremented further
		* as if output was written to the buffer, though no more output is actually
		* generated. that way, the caller can determine how much space would be
		* required for the path to fit into the buffer. in that case, the returned
		* value will be smaller than dest. callers must check this!
		*/
		char btrfs_iref_to_path(struct btrfs_root fs_root,
		struct btrfs_path *path,
		struct btrfs_inode_ref *iref,
		struct extent_buffer *eb_in, u64 parent,
		char *dest, u32 size)
		{
		return btrfs_ref_to_path(fs_root, path,
		btrfs_inode_ref_name_len(eb_in, iref),
		(unsigned long)(iref + 1),
		eb_in, parent, dest, size);
		}

		/*
		* this makes the path point to (logical EXTENT_ITEM *)
		* returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
		@@ -1461,8 +1458,6 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
		iterate_extent_inodes_t iterate, void ctx)
		{
		int ret;
		struct list_head data_refs = LIST_HEAD_INIT(data_refs);
		struct list_head shared_refs = LIST_HEAD_INIT(shared_refs);
		struct btrfs_trans_handle *trans;
		struct ulist *refs = NULL;
		struct ulist *roots = NULL;
		@@ -1508,11 +1503,9 @@ int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
		iterate, ctx);
		}
		ulist_free(roots);
		roots = NULL;
		}

		free_leaf_list(refs);
		ulist_free(roots);
		out:
		if (!search_commit_root) {
		btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);

fs/btrfs/backref.h

+0 −3

Original line number	Diff line number	Diff line
		@@ -59,9 +59,6 @@ int paths_from_inode(u64 inum, struct inode_fs_paths *ipath);
		int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
		struct btrfs_fs_info *fs_info, u64 bytenr,
		u64 time_seq, struct ulist **roots);
		char btrfs_iref_to_path(struct btrfs_root fs_root, struct btrfs_path *path,
		struct btrfs_inode_ref iref, struct extent_buffer eb,
		u64 parent, char *dest, u32 size);
		char btrfs_ref_to_path(struct btrfs_root fs_root, struct btrfs_path *path,
		u32 name_len, unsigned long name_off,
		struct extent_buffer *eb_in, u64 parent,

fs/btrfs/btrfs_inode.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -93,7 +93,7 @@ struct btrfs_inode {

		unsigned long runtime_flags;

		/* Keep track of who's O_SYNC/fsycing currently */
		/* Keep track of who's O_SYNC/fsyncing currently */
		atomic_t sync_writers;

		/* full 64 bit generation number, struct vfs_inode doesn't have a big

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