Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 (395d7341) · Commits · 戴 / test

Documentation/ABI/testing/sysfs-fs-ext4

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+81 −0

Original line number	Diff line number	Diff line
		What: /sys/fs/ext4/<disk>/mb_stats
		Date: March 2008
		Contact: "Theodore Ts'o" <tytso@mit.edu>
		Description:
		Controls whether the multiblock allocator should
		collect statistics, which are shown during the unmount.
		1 means to collect statistics, 0 means not to collect
		statistics

		What: /sys/fs/ext4/<disk>/mb_group_prealloc
		Date: March 2008
		Contact: "Theodore Ts'o" <tytso@mit.edu>
		Description:
		The multiblock allocator will round up allocation
		requests to a multiple of this tuning parameter if the
		stripe size is not set in the ext4 superblock

		What: /sys/fs/ext4/<disk>/mb_max_to_scan
		Date: March 2008
		Contact: "Theodore Ts'o" <tytso@mit.edu>
		Description:
		The maximum number of extents the multiblock allocator
		will search to find the best extent

		What: /sys/fs/ext4/<disk>/mb_min_to_scan
		Date: March 2008
		Contact: "Theodore Ts'o" <tytso@mit.edu>
		Description:
		The minimum number of extents the multiblock allocator
		will search to find the best extent

		What: /sys/fs/ext4/<disk>/mb_order2_req
		Date: March 2008
		Contact: "Theodore Ts'o" <tytso@mit.edu>
		Description:
		Tuning parameter which controls the minimum size for
		requests (as a power of 2) where the buddy cache is
		used

		What: /sys/fs/ext4/<disk>/mb_stream_req
		Date: March 2008
		Contact: "Theodore Ts'o" <tytso@mit.edu>
		Description:
		Files which have fewer blocks than this tunable
		parameter will have their blocks allocated out of a
		block group specific preallocation pool, so that small
		files are packed closely together. Each large file
		will have its blocks allocated out of its own unique
		preallocation pool.

		What: /sys/fs/ext4/<disk>/inode_readahead
		Date: March 2008
		Contact: "Theodore Ts'o" <tytso@mit.edu>
		Description:
		Tuning parameter which controls the maximum number of
		inode table blocks that ext4's inode table readahead
		algorithm will pre-read into the buffer cache

		What: /sys/fs/ext4/<disk>/delayed_allocation_blocks
		Date: March 2008
		Contact: "Theodore Ts'o" <tytso@mit.edu>
		Description:
		This file is read-only and shows the number of blocks
		that are dirty in the page cache, but which do not
		have their location in the filesystem allocated yet.

		What: /sys/fs/ext4/<disk>/lifetime_write_kbytes
		Date: March 2008
		Contact: "Theodore Ts'o" <tytso@mit.edu>
		Description:
		This file is read-only and shows the number of kilobytes
		of data that have been written to this filesystem since it was
		created.

		What: /sys/fs/ext4/<disk>/session_write_kbytes
		Date: March 2008
		Contact: "Theodore Ts'o" <tytso@mit.edu>
		Description:
		This file is read-only and shows the number of
		kilobytes of data that have been written to this
		filesystem since it was mounted.

Documentation/filesystems/ext4.txt

+27 −3

Original line number	Diff line number	Diff line
		@@ -85,7 +85,7 @@ Note: More extensive information for getting started with ext4 can be
		* extent format more robust in face of on-disk corruption due to magics,
		* internal redundancy in tree
		* improved file allocation (multi-block alloc)
		* fix 32000 subdirectory limit
		* lift 32000 subdirectory limit imposed by i_links_count[1]
		* nsec timestamps for mtime, atime, ctime, create time
		* inode version field on disk (NFSv4, Lustre)
		* reduced e2fsck time via uninit_bg feature
		@@ -100,6 +100,9 @@ Note: More extensive information for getting started with ext4 can be
		* efficent new ordered mode in JBD2 and ext4(avoid using buffer head to force
		the ordering)

		[1] Filesystems with a block size of 1k may see a limit imposed by the
		directory hash tree having a maximum depth of two.

		2.2 Candidate features for future inclusion

		* Online defrag (patches available but not well tested)
		@@ -180,8 +183,8 @@ commit=nrsec (*) Ext4 can be told to sync all its data and metadata
		performance.

		barrier=<0\|1(*)> This enables/disables the use of write barriers in
		the jbd code. barrier=0 disables, barrier=1 enables.
		This also requires an IO stack which can support
		barrier(*) the jbd code. barrier=0 disables, barrier=1 enables.
		nobarrier This also requires an IO stack which can support
		barriers, and if jbd gets an error on a barrier
		write, it will disable again with a warning.
		Write barriers enforce proper on-disk ordering
		@@ -189,6 +192,9 @@ barrier=<0\|1(*)> This enables/disables the use of write barriers in
		safe to use, at some performance penalty. If
		your disks are battery-backed in one way or another,
		disabling barriers may safely improve performance.
		The mount options "barrier" and "nobarrier" can
		also be used to enable or disable barriers, for
		consistency with other ext4 mount options.

		inode_readahead=n This tuning parameter controls the maximum
		number of inode table blocks that ext4's inode
		@@ -310,6 +316,24 @@ journal_ioprio=prio The I/O priority (from 0 to 7, where 0 is the
		a slightly higher priority than the default I/O
		priority.

		auto_da_alloc(*) Many broken applications don't use fsync() when
		noauto_da_alloc replacing existing files via patterns such as
		fd = open("foo.new")/write(fd,..)/close(fd)/
		rename("foo.new", "foo"), or worse yet,
		fd = open("foo", O_TRUNC)/write(fd,..)/close(fd).
		If auto_da_alloc is enabled, ext4 will detect
		the replace-via-rename and replace-via-truncate
		patterns and force that any delayed allocation
		blocks are allocated such that at the next
		journal commit, in the default data=ordered
		mode, the data blocks of the new file are forced
		to disk before the rename() operation is
		commited. This provides roughly the same level
		of guarantees as ext3, and avoids the
		"zero-length" problem that can happen when a
		system crashes before the delayed allocation
		blocks are forced to disk.

		Data Mode
		=========
		There are 3 different data modes:

Documentation/filesystems/proc.txt

+0 −21

Original line number	Diff line number	Diff line
		@@ -940,27 +940,6 @@ Table 1-10: Files in /proc/fs/ext4/<devname>
		File Content
		mb_groups details of multiblock allocator buddy cache of free blocks
		mb_history multiblock allocation history
		stats controls whether the multiblock allocator should start
		collecting statistics, which are shown during the unmount
		group_prealloc the multiblock allocator will round up allocation
		requests to a multiple of this tuning parameter if the
		stripe size is not set in the ext4 superblock
		max_to_scan The maximum number of extents the multiblock allocator
		will search to find the best extent
		min_to_scan The minimum number of extents the multiblock allocator
		will search to find the best extent
		order2_req Tuning parameter which controls the minimum size for
		requests (as a power of 2) where the buddy cache is
		used
		stream_req Files which have fewer blocks than this tunable
		parameter will have their blocks allocated out of a
		block group specific preallocation pool, so that small
		files are packed closely together. Each large file
		will have its blocks allocated out of its own unique
		preallocation pool.
		inode_readahead Tuning parameter which controls the maximum number of
		inode table blocks that ext4's inode table readahead
		algorithm will pre-read into the buffer cache
		..............................................................................

fs/ext4/balloc.c

+5 −9

Original line number	Diff line number	Diff line
		@@ -55,7 +55,8 @@ static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block,
		}

		static int ext4_group_used_meta_blocks(struct super_block *sb,
		ext4_group_t block_group)
		ext4_group_t block_group,
		struct ext4_group_desc *gdp)
		{
		ext4_fsblk_t tmp;
		struct ext4_sb_info *sbi = EXT4_SB(sb);
		@@ -63,10 +64,6 @@ static int ext4_group_used_meta_blocks(struct super_block *sb,
		int used_blocks = sbi->s_itb_per_group + 2;

		if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
		struct ext4_group_desc *gdp;
		struct buffer_head *bh;

		gdp = ext4_get_group_desc(sb, block_group, &bh);
		if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp),
		block_group))
		used_blocks--;
		@@ -177,7 +174,7 @@ unsigned ext4_init_block_bitmap(struct super_block sb, struct buffer_head bh,
		*/
		mark_bitmap_end(group_blocks, sb->s_blocksize * 8, bh->b_data);
		}
		return free_blocks - ext4_group_used_meta_blocks(sb, block_group);
		return free_blocks - ext4_group_used_meta_blocks(sb, block_group, gdp);
		}


		@@ -473,9 +470,8 @@ void ext4_add_groupblocks(handle_t handle, struct super_block sb,

		if (sbi->s_log_groups_per_flex) {
		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
		spin_lock(sb_bgl_lock(sbi, flex_group));
		sbi->s_flex_groups[flex_group].free_blocks += blocks_freed;
		spin_unlock(sb_bgl_lock(sbi, flex_group));
		atomic_add(blocks_freed,
		&sbi->s_flex_groups[flex_group].free_blocks);
		}
		/*
		* request to reload the buddy with the

fs/ext4/dir.c

+10 −6

Original line number	Diff line number	Diff line
		@@ -67,7 +67,8 @@ int ext4_check_dir_entry(const char function, struct inode dir,
		unsigned int offset)
		{
		const char *error_msg = NULL;
		const int rlen = ext4_rec_len_from_disk(de->rec_len);
		const int rlen = ext4_rec_len_from_disk(de->rec_len,
		dir->i_sb->s_blocksize);

		if (rlen < EXT4_DIR_REC_LEN(1))
		error_msg = "rec_len is smaller than minimal";
		@@ -178,10 +179,11 @@ revalidate:
		* least that it is non-zero. A
		* failure will be detected in the
		* dirent test below. */
		if (ext4_rec_len_from_disk(de->rec_len)
		< EXT4_DIR_REC_LEN(1))
		if (ext4_rec_len_from_disk(de->rec_len,
		sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
		break;
		i += ext4_rec_len_from_disk(de->rec_len);
		i += ext4_rec_len_from_disk(de->rec_len,
		sb->s_blocksize);
		}
		offset = i;
		filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
		@@ -203,7 +205,8 @@ revalidate:
		ret = stored;
		goto out;
		}
		offset += ext4_rec_len_from_disk(de->rec_len);
		offset += ext4_rec_len_from_disk(de->rec_len,
		sb->s_blocksize);
		if (le32_to_cpu(de->inode)) {
		/* We might block in the next section
		* if the data destination is
		@@ -225,7 +228,8 @@ revalidate:
		goto revalidate;
		stored++;
		}
		filp->f_pos += ext4_rec_len_from_disk(de->rec_len);
		filp->f_pos += ext4_rec_len_from_disk(de->rec_len,
		sb->s_blocksize);
		}
		offset = 0;
		brelse(bh);

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