/
fs: f2fs: update to latest F2FS version .patch
4863 lines (4495 loc) · 155 KB
/
fs: f2fs: update to latest F2FS version .patch
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From 8ba88b5539096c55784140ef4e16600d6127ab3a Mon Sep 17 00:00:00 2001
From: barome <romain.semanaz@gmail.com>
Date: Tue, 6 May 2014 08:49:24 +0200
Subject: [PATCH] fs: f2fs: update to latest F2FS version
Signed-off-by: Lens-F <tnoah12@gmail.com>
---
Documentation/ABI/testing/sysfs-fs-f2fs | 69 ++++
Documentation/filesystems/00-INDEX | 2 +
Documentation/filesystems/f2fs.txt | 541 ++++++++++++++++++++++++++++++++
fs/f2fs/Kconfig | 1 +
fs/f2fs/acl.c | 4 +-
fs/f2fs/checkpoint.c | 230 +++++++++-----
fs/f2fs/data.c | 138 ++++----
fs/f2fs/debug.c | 12 +-
fs/f2fs/dir.c | 118 ++++---
fs/f2fs/f2fs.h | 138 +++++---
fs/f2fs/file.c | 64 ++--
fs/f2fs/gc.c | 21 +-
fs/f2fs/inline.c | 4 +-
fs/f2fs/inode.c | 31 +-
fs/f2fs/namei.c | 30 +-
fs/f2fs/node.c | 378 ++++++++++++----------
fs/f2fs/node.h | 25 +-
fs/f2fs/recovery.c | 109 ++-----
fs/f2fs/segment.c | 293 ++++++++++-------
fs/f2fs/segment.h | 75 +++--
fs/f2fs/super.c | 137 ++++----
fs/f2fs/xattr.c | 16 +-
include/linux/f2fs_fs.h | 2 +-
23 files changed, 1644 insertions(+), 794 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-fs-f2fs
create mode 100644 Documentation/filesystems/f2fs.txt
diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
new file mode 100644
index 0000000..62dd725
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -0,0 +1,69 @@
+What: /sys/fs/f2fs/<disk>/gc_max_sleep_time
+Date: July 2013
+Contact: "Namjae Jeon" <namjae.jeon@samsung.com>
+Description:
+ Controls the maximun sleep time for gc_thread. Time
+ is in milliseconds.
+
+What: /sys/fs/f2fs/<disk>/gc_min_sleep_time
+Date: July 2013
+Contact: "Namjae Jeon" <namjae.jeon@samsung.com>
+Description:
+ Controls the minimum sleep time for gc_thread. Time
+ is in milliseconds.
+
+What: /sys/fs/f2fs/<disk>/gc_no_gc_sleep_time
+Date: July 2013
+Contact: "Namjae Jeon" <namjae.jeon@samsung.com>
+Description:
+ Controls the default sleep time for gc_thread. Time
+ is in milliseconds.
+
+What: /sys/fs/f2fs/<disk>/gc_idle
+Date: July 2013
+Contact: "Namjae Jeon" <namjae.jeon@samsung.com>
+Description:
+ Controls the victim selection policy for garbage collection.
+
+What: /sys/fs/f2fs/<disk>/reclaim_segments
+Date: October 2013
+Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
+Description:
+ Controls the issue rate of segment discard commands.
+
+What: /sys/fs/f2fs/<disk>/ipu_policy
+Date: November 2013
+Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
+Description:
+ Controls the in-place-update policy.
+
+What: /sys/fs/f2fs/<disk>/min_ipu_util
+Date: November 2013
+Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
+Description:
+ Controls the FS utilization condition for the in-place-update
+ policies.
+
+What: /sys/fs/f2fs/<disk>/max_small_discards
+Date: November 2013
+Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
+Description:
+ Controls the issue rate of small discard commands.
+
+What: /sys/fs/f2fs/<disk>/max_victim_search
+Date: January 2014
+Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
+Description:
+ Controls the number of trials to find a victim segment.
+
+What: /sys/fs/f2fs/<disk>/dir_level
+Date: March 2014
+Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
+Description:
+ Controls the directory level for large directory.
+
+What: /sys/fs/f2fs/<disk>/ram_thresh
+Date: March 2014
+Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
+Description:
+ Controls the memory footprint used by f2fs.
diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX
index 8c624a1..a328432 100644
--- a/Documentation/filesystems/00-INDEX
+++ b/Documentation/filesystems/00-INDEX
@@ -46,6 +46,8 @@ ext3.txt
- info, mount options and specifications for the Ext3 filesystem.
ext4.txt
- info, mount options and specifications for the Ext4 filesystem.
+f2fs.txt
+ - info and mount options for the F2FS filesystem.
files.txt
- info on file management in the Linux kernel.
fuse.txt
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
new file mode 100644
index 0000000..2f6d021
--- /dev/null
+++ b/Documentation/filesystems/f2fs.txt
@@ -0,0 +1,541 @@
+================================================================================
+WHAT IS Flash-Friendly File System (F2FS)?
+================================================================================
+
+NAND flash memory-based storage devices, such as SSD, eMMC, and SD cards, have
+been equipped on a variety systems ranging from mobile to server systems. Since
+they are known to have different characteristics from the conventional rotating
+disks, a file system, an upper layer to the storage device, should adapt to the
+changes from the sketch in the design level.
+
+F2FS is a file system exploiting NAND flash memory-based storage devices, which
+is based on Log-structured File System (LFS). The design has been focused on
+addressing the fundamental issues in LFS, which are snowball effect of wandering
+tree and high cleaning overhead.
+
+Since a NAND flash memory-based storage device shows different characteristic
+according to its internal geometry or flash memory management scheme, namely FTL,
+F2FS and its tools support various parameters not only for configuring on-disk
+layout, but also for selecting allocation and cleaning algorithms.
+
+The following git tree provides the file system formatting tool (mkfs.f2fs),
+a consistency checking tool (fsck.f2fs), and a debugging tool (dump.f2fs).
+>> git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs-tools.git
+
+For reporting bugs and sending patches, please use the following mailing list:
+>> linux-f2fs-devel@lists.sourceforge.net
+
+================================================================================
+BACKGROUND AND DESIGN ISSUES
+================================================================================
+
+Log-structured File System (LFS)
+--------------------------------
+"A log-structured file system writes all modifications to disk sequentially in
+a log-like structure, thereby speeding up both file writing and crash recovery.
+The log is the only structure on disk; it contains indexing information so that
+files can be read back from the log efficiently. In order to maintain large free
+areas on disk for fast writing, we divide the log into segments and use a
+segment cleaner to compress the live information from heavily fragmented
+segments." from Rosenblum, M. and Ousterhout, J. K., 1992, "The design and
+implementation of a log-structured file system", ACM Trans. Computer Systems
+10, 1, 26–52.
+
+Wandering Tree Problem
+----------------------
+In LFS, when a file data is updated and written to the end of log, its direct
+pointer block is updated due to the changed location. Then the indirect pointer
+block is also updated due to the direct pointer block update. In this manner,
+the upper index structures such as inode, inode map, and checkpoint block are
+also updated recursively. This problem is called as wandering tree problem [1],
+and in order to enhance the performance, it should eliminate or relax the update
+propagation as much as possible.
+
+[1] Bityutskiy, A. 2005. JFFS3 design issues. http://www.linux-mtd.infradead.org/
+
+Cleaning Overhead
+-----------------
+Since LFS is based on out-of-place writes, it produces so many obsolete blocks
+scattered across the whole storage. In order to serve new empty log space, it
+needs to reclaim these obsolete blocks seamlessly to users. This job is called
+as a cleaning process.
+
+The process consists of three operations as follows.
+1. A victim segment is selected through referencing segment usage table.
+2. It loads parent index structures of all the data in the victim identified by
+ segment summary blocks.
+3. It checks the cross-reference between the data and its parent index structure.
+4. It moves valid data selectively.
+
+This cleaning job may cause unexpected long delays, so the most important goal
+is to hide the latencies to users. And also definitely, it should reduce the
+amount of valid data to be moved, and move them quickly as well.
+
+================================================================================
+KEY FEATURES
+================================================================================
+
+Flash Awareness
+---------------
+- Enlarge the random write area for better performance, but provide the high
+ spatial locality
+- Align FS data structures to the operational units in FTL as best efforts
+
+Wandering Tree Problem
+----------------------
+- Use a term, “node”, that represents inodes as well as various pointer blocks
+- Introduce Node Address Table (NAT) containing the locations of all the “node”
+ blocks; this will cut off the update propagation.
+
+Cleaning Overhead
+-----------------
+- Support a background cleaning process
+- Support greedy and cost-benefit algorithms for victim selection policies
+- Support multi-head logs for static/dynamic hot and cold data separation
+- Introduce adaptive logging for efficient block allocation
+
+================================================================================
+MOUNT OPTIONS
+================================================================================
+
+background_gc=%s Turn on/off cleaning operations, namely garbage
+ collection, triggered in background when I/O subsystem is
+ idle. If background_gc=on, it will turn on the garbage
+ collection and if background_gc=off, garbage collection
+ will be truned off.
+ Default value for this option is on. So garbage
+ collection is on by default.
+disable_roll_forward Disable the roll-forward recovery routine
+discard Issue discard/TRIM commands when a segment is cleaned.
+no_heap Disable heap-style segment allocation which finds free
+ segments for data from the beginning of main area, while
+ for node from the end of main area.
+nouser_xattr Disable Extended User Attributes. Note: xattr is enabled
+ by default if CONFIG_F2FS_FS_XATTR is selected.
+noacl Disable POSIX Access Control List. Note: acl is enabled
+ by default if CONFIG_F2FS_FS_POSIX_ACL is selected.
+active_logs=%u Support configuring the number of active logs. In the
+ current design, f2fs supports only 2, 4, and 6 logs.
+ Default number is 6.
+disable_ext_identify Disable the extension list configured by mkfs, so f2fs
+ does not aware of cold files such as media files.
+inline_xattr Enable the inline xattrs feature.
+inline_data Enable the inline data feature: New created small(<~3.4k)
+ files can be written into inode block.
+
+================================================================================
+DEBUGFS ENTRIES
+================================================================================
+
+/sys/kernel/debug/f2fs/ contains information about all the partitions mounted as
+f2fs. Each file shows the whole f2fs information.
+
+/sys/kernel/debug/f2fs/status includes:
+ - major file system information managed by f2fs currently
+ - average SIT information about whole segments
+ - current memory footprint consumed by f2fs.
+
+================================================================================
+SYSFS ENTRIES
+================================================================================
+
+Information about mounted f2f2 file systems can be found in
+/sys/fs/f2fs. Each mounted filesystem will have a directory in
+/sys/fs/f2fs based on its device name (i.e., /sys/fs/f2fs/sda).
+The files in each per-device directory are shown in table below.
+
+Files in /sys/fs/f2fs/<devname>
+(see also Documentation/ABI/testing/sysfs-fs-f2fs)
+..............................................................................
+ File Content
+
+ gc_max_sleep_time This tuning parameter controls the maximum sleep
+ time for the garbage collection thread. Time is
+ in milliseconds.
+
+ gc_min_sleep_time This tuning parameter controls the minimum sleep
+ time for the garbage collection thread. Time is
+ in milliseconds.
+
+ gc_no_gc_sleep_time This tuning parameter controls the default sleep
+ time for the garbage collection thread. Time is
+ in milliseconds.
+
+ gc_idle This parameter controls the selection of victim
+ policy for garbage collection. Setting gc_idle = 0
+ (default) will disable this option. Setting
+ gc_idle = 1 will select the Cost Benefit approach
+ & setting gc_idle = 2 will select the greedy aproach.
+
+ reclaim_segments This parameter controls the number of prefree
+ segments to be reclaimed. If the number of prefree
+ segments is larger than the number of segments
+ in the proportion to the percentage over total
+ volume size, f2fs tries to conduct checkpoint to
+ reclaim the prefree segments to free segments.
+ By default, 5% over total # of segments.
+
+ max_small_discards This parameter controls the number of discard
+ commands that consist small blocks less than 2MB.
+ The candidates to be discarded are cached until
+ checkpoint is triggered, and issued during the
+ checkpoint. By default, it is disabled with 0.
+
+ ipu_policy This parameter controls the policy of in-place
+ updates in f2fs. There are five policies:
+ 0: F2FS_IPU_FORCE, 1: F2FS_IPU_SSR,
+ 2: F2FS_IPU_UTIL, 3: F2FS_IPU_SSR_UTIL,
+ 4: F2FS_IPU_DISABLE.
+
+ min_ipu_util This parameter controls the threshold to trigger
+ in-place-updates. The number indicates percentage
+ of the filesystem utilization, and used by
+ F2FS_IPU_UTIL and F2FS_IPU_SSR_UTIL policies.
+
+ max_victim_search This parameter controls the number of trials to
+ find a victim segment when conducting SSR and
+ cleaning operations. The default value is 4096
+ which covers 8GB block address range.
+
+ dir_level This parameter controls the directory level to
+ support large directory. If a directory has a
+ number of files, it can reduce the file lookup
+ latency by increasing this dir_level value.
+ Otherwise, it needs to decrease this value to
+ reduce the space overhead. The default value is 0.
+
+ ram_thresh This parameter controls the memory footprint used
+ by free nids and cached nat entries. By default,
+ 10 is set, which indicates 10 MB / 1 GB RAM.
+
+================================================================================
+USAGE
+================================================================================
+
+1. Download userland tools and compile them.
+
+2. Skip, if f2fs was compiled statically inside kernel.
+ Otherwise, insert the f2fs.ko module.
+ # insmod f2fs.ko
+
+3. Create a directory trying to mount
+ # mkdir /mnt/f2fs
+
+4. Format the block device, and then mount as f2fs
+ # mkfs.f2fs -l label /dev/block_device
+ # mount -t f2fs /dev/block_device /mnt/f2fs
+
+mkfs.f2fs
+---------
+The mkfs.f2fs is for the use of formatting a partition as the f2fs filesystem,
+which builds a basic on-disk layout.
+
+The options consist of:
+-l [label] : Give a volume label, up to 512 unicode name.
+-a [0 or 1] : Split start location of each area for heap-based allocation.
+ 1 is set by default, which performs this.
+-o [int] : Set overprovision ratio in percent over volume size.
+ 5 is set by default.
+-s [int] : Set the number of segments per section.
+ 1 is set by default.
+-z [int] : Set the number of sections per zone.
+ 1 is set by default.
+-e [str] : Set basic extension list. e.g. "mp3,gif,mov"
+-t [0 or 1] : Disable discard command or not.
+ 1 is set by default, which conducts discard.
+
+fsck.f2fs
+---------
+The fsck.f2fs is a tool to check the consistency of an f2fs-formatted
+partition, which examines whether the filesystem metadata and user-made data
+are cross-referenced correctly or not.
+Note that, initial version of the tool does not fix any inconsistency.
+
+The options consist of:
+ -d debug level [default:0]
+
+dump.f2fs
+---------
+The dump.f2fs shows the information of specific inode and dumps SSA and SIT to
+file. Each file is dump_ssa and dump_sit.
+
+The dump.f2fs is used to debug on-disk data structures of the f2fs filesystem.
+It shows on-disk inode information reconized by a given inode number, and is
+able to dump all the SSA and SIT entries into predefined files, ./dump_ssa and
+./dump_sit respectively.
+
+The options consist of:
+ -d debug level [default:0]
+ -i inode no (hex)
+ -s [SIT dump segno from #1~#2 (decimal), for all 0~-1]
+ -a [SSA dump segno from #1~#2 (decimal), for all 0~-1]
+
+Examples:
+# dump.f2fs -i [ino] /dev/sdx
+# dump.f2fs -s 0~-1 /dev/sdx (SIT dump)
+# dump.f2fs -a 0~-1 /dev/sdx (SSA dump)
+
+================================================================================
+DESIGN
+================================================================================
+
+On-disk Layout
+--------------
+
+F2FS divides the whole volume into a number of segments, each of which is fixed
+to 2MB in size. A section is composed of consecutive segments, and a zone
+consists of a set of sections. By default, section and zone sizes are set to one
+segment size identically, but users can easily modify the sizes by mkfs.
+
+F2FS splits the entire volume into six areas, and all the areas except superblock
+consists of multiple segments as described below.
+
+ align with the zone size <-|
+ |-> align with the segment size
+ _________________________________________________________________________
+ | | | Segment | Node | Segment | |
+ | Superblock | Checkpoint | Info. | Address | Summary | Main |
+ | (SB) | (CP) | Table (SIT) | Table (NAT) | Area (SSA) | |
+ |____________|_____2______|______N______|______N______|______N_____|__N___|
+ . .
+ . .
+ . .
+ ._________________________________________.
+ |_Segment_|_..._|_Segment_|_..._|_Segment_|
+ . .
+ ._________._________
+ |_section_|__...__|_
+ . .
+ .________.
+ |__zone__|
+
+- Superblock (SB)
+ : It is located at the beginning of the partition, and there exist two copies
+ to avoid file system crash. It contains basic partition information and some
+ default parameters of f2fs.
+
+- Checkpoint (CP)
+ : It contains file system information, bitmaps for valid NAT/SIT sets, orphan
+ inode lists, and summary entries of current active segments.
+
+- Segment Information Table (SIT)
+ : It contains segment information such as valid block count and bitmap for the
+ validity of all the blocks.
+
+- Node Address Table (NAT)
+ : It is composed of a block address table for all the node blocks stored in
+ Main area.
+
+- Segment Summary Area (SSA)
+ : It contains summary entries which contains the owner information of all the
+ data and node blocks stored in Main area.
+
+- Main Area
+ : It contains file and directory data including their indices.
+
+In order to avoid misalignment between file system and flash-based storage, F2FS
+aligns the start block address of CP with the segment size. Also, it aligns the
+start block address of Main area with the zone size by reserving some segments
+in SSA area.
+
+Reference the following survey for additional technical details.
+https://wiki.linaro.org/WorkingGroups/Kernel/Projects/FlashCardSurvey
+
+File System Metadata Structure
+------------------------------
+
+F2FS adopts the checkpointing scheme to maintain file system consistency. At
+mount time, F2FS first tries to find the last valid checkpoint data by scanning
+CP area. In order to reduce the scanning time, F2FS uses only two copies of CP.
+One of them always indicates the last valid data, which is called as shadow copy
+mechanism. In addition to CP, NAT and SIT also adopt the shadow copy mechanism.
+
+For file system consistency, each CP points to which NAT and SIT copies are
+valid, as shown as below.
+
+ +--------+----------+---------+
+ | CP | SIT | NAT |
+ +--------+----------+---------+
+ . . . .
+ . . . .
+ . . . .
+ +-------+-------+--------+--------+--------+--------+
+ | CP #0 | CP #1 | SIT #0 | SIT #1 | NAT #0 | NAT #1 |
+ +-------+-------+--------+--------+--------+--------+
+ | ^ ^
+ | | |
+ `----------------------------------------'
+
+Index Structure
+---------------
+
+The key data structure to manage the data locations is a "node". Similar to
+traditional file structures, F2FS has three types of node: inode, direct node,
+indirect node. F2FS assigns 4KB to an inode block which contains 923 data block
+indices, two direct node pointers, two indirect node pointers, and one double
+indirect node pointer as described below. One direct node block contains 1018
+data blocks, and one indirect node block contains also 1018 node blocks. Thus,
+one inode block (i.e., a file) covers:
+
+ 4KB * (923 + 2 * 1018 + 2 * 1018 * 1018 + 1018 * 1018 * 1018) := 3.94TB.
+
+ Inode block (4KB)
+ |- data (923)
+ |- direct node (2)
+ | `- data (1018)
+ |- indirect node (2)
+ | `- direct node (1018)
+ | `- data (1018)
+ `- double indirect node (1)
+ `- indirect node (1018)
+ `- direct node (1018)
+ `- data (1018)
+
+Note that, all the node blocks are mapped by NAT which means the location of
+each node is translated by the NAT table. In the consideration of the wandering
+tree problem, F2FS is able to cut off the propagation of node updates caused by
+leaf data writes.
+
+Directory Structure
+-------------------
+
+A directory entry occupies 11 bytes, which consists of the following attributes.
+
+- hash hash value of the file name
+- ino inode number
+- len the length of file name
+- type file type such as directory, symlink, etc
+
+A dentry block consists of 214 dentry slots and file names. Therein a bitmap is
+used to represent whether each dentry is valid or not. A dentry block occupies
+4KB with the following composition.
+
+ Dentry Block(4 K) = bitmap (27 bytes) + reserved (3 bytes) +
+ dentries(11 * 214 bytes) + file name (8 * 214 bytes)
+
+ [Bucket]
+ +--------------------------------+
+ |dentry block 1 | dentry block 2 |
+ +--------------------------------+
+ . .
+ . .
+ . [Dentry Block Structure: 4KB] .
+ +--------+----------+----------+------------+
+ | bitmap | reserved | dentries | file names |
+ +--------+----------+----------+------------+
+ [Dentry Block: 4KB] . .
+ . .
+ . .
+ +------+------+-----+------+
+ | hash | ino | len | type |
+ +------+------+-----+------+
+ [Dentry Structure: 11 bytes]
+
+F2FS implements multi-level hash tables for directory structure. Each level has
+a hash table with dedicated number of hash buckets as shown below. Note that
+"A(2B)" means a bucket includes 2 data blocks.
+
+----------------------
+A : bucket
+B : block
+N : MAX_DIR_HASH_DEPTH
+----------------------
+
+level #0 | A(2B)
+ |
+level #1 | A(2B) - A(2B)
+ |
+level #2 | A(2B) - A(2B) - A(2B) - A(2B)
+ . | . . . .
+level #N/2 | A(2B) - A(2B) - A(2B) - A(2B) - A(2B) - ... - A(2B)
+ . | . . . .
+level #N | A(4B) - A(4B) - A(4B) - A(4B) - A(4B) - ... - A(4B)
+
+The number of blocks and buckets are determined by,
+
+ ,- 2, if n < MAX_DIR_HASH_DEPTH / 2,
+ # of blocks in level #n = |
+ `- 4, Otherwise
+
+ ,- 2^ (n + dir_level),
+ | if n < MAX_DIR_HASH_DEPTH / 2,
+ # of buckets in level #n = |
+ `- 2^((MAX_DIR_HASH_DEPTH / 2 + dir_level) - 1),
+ Otherwise
+
+When F2FS finds a file name in a directory, at first a hash value of the file
+name is calculated. Then, F2FS scans the hash table in level #0 to find the
+dentry consisting of the file name and its inode number. If not found, F2FS
+scans the next hash table in level #1. In this way, F2FS scans hash tables in
+each levels incrementally from 1 to N. In each levels F2FS needs to scan only
+one bucket determined by the following equation, which shows O(log(# of files))
+complexity.
+
+ bucket number to scan in level #n = (hash value) % (# of buckets in level #n)
+
+In the case of file creation, F2FS finds empty consecutive slots that cover the
+file name. F2FS searches the empty slots in the hash tables of whole levels from
+1 to N in the same way as the lookup operation.
+
+The following figure shows an example of two cases holding children.
+ --------------> Dir <--------------
+ | |
+ child child
+
+ child - child [hole] - child
+
+ child - child - child [hole] - [hole] - child
+
+ Case 1: Case 2:
+ Number of children = 6, Number of children = 3,
+ File size = 7 File size = 7
+
+Default Block Allocation
+------------------------
+
+At runtime, F2FS manages six active logs inside "Main" area: Hot/Warm/Cold node
+and Hot/Warm/Cold data.
+
+- Hot node contains direct node blocks of directories.
+- Warm node contains direct node blocks except hot node blocks.
+- Cold node contains indirect node blocks
+- Hot data contains dentry blocks
+- Warm data contains data blocks except hot and cold data blocks
+- Cold data contains multimedia data or migrated data blocks
+
+LFS has two schemes for free space management: threaded log and copy-and-compac-
+tion. The copy-and-compaction scheme which is known as cleaning, is well-suited
+for devices showing very good sequential write performance, since free segments
+are served all the time for writing new data. However, it suffers from cleaning
+overhead under high utilization. Contrarily, the threaded log scheme suffers
+from random writes, but no cleaning process is needed. F2FS adopts a hybrid
+scheme where the copy-and-compaction scheme is adopted by default, but the
+policy is dynamically changed to the threaded log scheme according to the file
+system status.
+
+In order to align F2FS with underlying flash-based storage, F2FS allocates a
+segment in a unit of section. F2FS expects that the section size would be the
+same as the unit size of garbage collection in FTL. Furthermore, with respect
+to the mapping granularity in FTL, F2FS allocates each section of the active
+logs from different zones as much as possible, since FTL can write the data in
+the active logs into one allocation unit according to its mapping granularity.
+
+Cleaning process
+----------------
+
+F2FS does cleaning both on demand and in the background. On-demand cleaning is
+triggered when there are not enough free segments to serve VFS calls. Background
+cleaner is operated by a kernel thread, and triggers the cleaning job when the
+system is idle.
+
+F2FS supports two victim selection policies: greedy and cost-benefit algorithms.
+In the greedy algorithm, F2FS selects a victim segment having the smallest number
+of valid blocks. In the cost-benefit algorithm, F2FS selects a victim segment
+according to the segment age and the number of valid blocks in order to address
+log block thrashing problem in the greedy algorithm. F2FS adopts the greedy
+algorithm for on-demand cleaner, while background cleaner adopts cost-benefit
+algorithm.
+
+In order to identify whether the data in the victim segment are valid or not,
+F2FS manages a bitmap. Each bit represents the validity of a block, and the
+bitmap is composed of a bit stream covering whole blocks in main area.
diff --git a/fs/f2fs/Kconfig b/fs/f2fs/Kconfig
index 214fe10..5ee046b 100644
--- a/fs/f2fs/Kconfig
+++ b/fs/f2fs/Kconfig
@@ -71,3 +71,4 @@ config F2FS_CHECK_FS
Enables BUG_ONs which check the file system consistency in runtime.
If you want to improve the performance, say N.
+
diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index afc979d..cdcbd28 100644
--- a/fs/f2fs/acl.c
+++ b/fs/f2fs/acl.c
@@ -169,7 +169,7 @@ struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
retval = f2fs_getxattr(inode, name_index, "", NULL, 0);
if (retval > 0) {
- value = kmalloc(retval, GFP_KERNEL);
+ value = kmalloc(retval, GFP_F2FS_ZERO);
if (!value)
return ERR_PTR(-ENOMEM);
retval = f2fs_getxattr(inode, name_index, "", value, retval);
@@ -285,7 +285,7 @@ int f2fs_acl_chmod(struct inode *inode)
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct posix_acl *acl;
int error;
- mode_t mode = get_inode_mode(inode);
+ umode_t mode = get_inode_mode(inode);
if (!test_opt(sbi, POSIX_ACL))
return 0;
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 677b23b..4aa521a 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -33,14 +33,12 @@ struct page *grab_meta_page(struct f2fs_sb_info *sbi, pgoff_t index)
struct address_space *mapping = META_MAPPING(sbi);
struct page *page = NULL;
repeat:
- page = grab_cache_page(mapping, index);
+ page = grab_cache_page_write_begin(mapping, index, AOP_FLAG_NOFS);
if (!page) {
cond_resched();
goto repeat;
}
- /* We wait writeback only inside grab_meta_page() */
- wait_on_page_writeback(page);
SetPageUptodate(page);
return page;
}
@@ -75,23 +73,102 @@ struct page *get_meta_page(struct f2fs_sb_info *sbi, pgoff_t index)
return page;
}
+inline int get_max_meta_blks(struct f2fs_sb_info *sbi, int type)
+{
+ switch (type) {
+ case META_NAT:
+ return NM_I(sbi)->max_nid / NAT_ENTRY_PER_BLOCK;
+ case META_SIT:
+ return SIT_BLK_CNT(sbi);
+ case META_SSA:
+ case META_CP:
+ return 0;
+ default:
+ BUG();
+ }
+}
+
+/*
+ * Readahead CP/NAT/SIT/SSA pages
+ */
+int ra_meta_pages(struct f2fs_sb_info *sbi, int start, int nrpages, int type)
+{
+ block_t prev_blk_addr = 0;
+ struct page *page;
+ int blkno = start;
+ int max_blks = get_max_meta_blks(sbi, type);
+
+ struct f2fs_io_info fio = {
+ .type = META,
+ .rw = READ_SYNC | REQ_META | REQ_PRIO
+ };
+
+ for (; nrpages-- > 0; blkno++) {
+ block_t blk_addr;
+
+ switch (type) {
+ case META_NAT:
+ /* get nat block addr */
+ if (unlikely(blkno >= max_blks))
+ blkno = 0;
+ blk_addr = current_nat_addr(sbi,
+ blkno * NAT_ENTRY_PER_BLOCK);
+ break;
+ case META_SIT:
+ /* get sit block addr */
+ if (unlikely(blkno >= max_blks))
+ goto out;
+ blk_addr = current_sit_addr(sbi,
+ blkno * SIT_ENTRY_PER_BLOCK);
+ if (blkno != start && prev_blk_addr + 1 != blk_addr)
+ goto out;
+ prev_blk_addr = blk_addr;
+ break;
+ case META_SSA:
+ case META_CP:
+ /* get ssa/cp block addr */
+ blk_addr = blkno;
+ break;
+ default:
+ BUG();
+ }
+
+ page = grab_cache_page(META_MAPPING(sbi), blk_addr);
+ if (!page)
+ continue;
+ if (PageUptodate(page)) {
+ mark_page_accessed(page);
+ f2fs_put_page(page, 1);
+ continue;
+ }
+
+ f2fs_submit_page_mbio(sbi, page, blk_addr, &fio);
+ mark_page_accessed(page);
+ f2fs_put_page(page, 0);
+ }
+out:
+ f2fs_submit_merged_bio(sbi, META, READ);
+ return blkno - start;
+}
+
static int f2fs_write_meta_page(struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
- /* Should not write any meta pages, if any IO error was occurred */
- if (unlikely(sbi->por_doing ||
- is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)))
+ if (unlikely(sbi->por_doing))
goto redirty_out;
-
if (wbc->for_reclaim)
goto redirty_out;
- wait_on_page_writeback(page);
+ /* Should not write any meta pages, if any IO error was occurred */
+ if (unlikely(is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)))
+ goto no_write;
+ f2fs_wait_on_page_writeback(page, META);
write_meta_page(sbi, page);
+no_write:
dec_page_count(sbi, F2FS_DIRTY_META);
unlock_page(page);
return 0;
@@ -99,6 +176,7 @@ static int f2fs_write_meta_page(struct page *page,
redirty_out:
dec_page_count(sbi, F2FS_DIRTY_META);
wbc->pages_skipped++;
+ account_page_redirty(page);
set_page_dirty(page);
return AOP_WRITEPAGE_ACTIVATE;
}
@@ -107,21 +185,23 @@ static int f2fs_write_meta_pages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
- int nrpages = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
- long written;
-
- if (wbc->for_kupdate)
- return 0;
+ long diff, written;
/* collect a number of dirty meta pages and write together */
- if (get_pages(sbi, F2FS_DIRTY_META) < nrpages)
- return 0;
+ if (wbc->for_kupdate ||
+ get_pages(sbi, F2FS_DIRTY_META) < nr_pages_to_skip(sbi, META))
+ goto skip_write;
/* if mounting is failed, skip writing node pages */
mutex_lock(&sbi->cp_mutex);
- written = sync_meta_pages(sbi, META, nrpages);
+ diff = nr_pages_to_write(sbi, META, wbc);
+ written = sync_meta_pages(sbi, META, wbc->nr_to_write);
mutex_unlock(&sbi->cp_mutex);
- wbc->nr_to_write -= written;
+ wbc->nr_to_write = max((long)0, wbc->nr_to_write - written - diff);
+ return 0;
+
+skip_write:
+ wbc->pages_skipped += get_pages(sbi, F2FS_DIRTY_META);
return 0;
}
@@ -148,10 +228,22 @@ long sync_meta_pages(struct f2fs_sb_info *sbi, enum page_type type,
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
+
lock_page(page);
- f2fs_bug_on(page->mapping != mapping);
- f2fs_bug_on(!PageDirty(page));
- clear_page_dirty_for_io(page);
+
+ if (unlikely(page->mapping != mapping)) {
+continue_unlock:
+ unlock_page(page);
+ continue;
+ }
+ if (!PageDirty(page)) {
+ /* someone wrote it for us */
+ goto continue_unlock;
+ }
+
+ if (!clear_page_dirty_for_io(page))
+ goto continue_unlock;
+
if (f2fs_write_meta_page(page, &wbc)) {
unlock_page(page);
break;
@@ -209,27 +301,22 @@ int acquire_orphan_inode(struct f2fs_sb_info *sbi)
void release_orphan_inode(struct f2fs_sb_info *sbi)
{
spin_lock(&sbi->orphan_inode_lock);
- if (sbi->n_orphans == 0) {
- f2fs_msg(sbi->sb, KERN_ERR, "releasing "
- "unacquired orphan inode");
- f2fs_handle_error(sbi);
- } else
- sbi->n_orphans--;
+ f2fs_bug_on(sbi->n_orphans == 0);
+ sbi->n_orphans--;
spin_unlock(&sbi->orphan_inode_lock);
}
void add_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
{
- struct list_head *head, *this;
- struct orphan_inode_entry *new = NULL, *orphan = NULL;
+ struct list_head *head;
+ struct orphan_inode_entry *new, *orphan;
new = f2fs_kmem_cache_alloc(orphan_entry_slab, GFP_ATOMIC);
new->ino = ino;
spin_lock(&sbi->orphan_inode_lock);
head = &sbi->orphan_inode_list;
- list_for_each(this, head) {
- orphan = list_entry(this, struct orphan_inode_entry, list);
+ list_for_each_entry(orphan, head, list) {
if (orphan->ino == ino) {
spin_unlock(&sbi->orphan_inode_lock);
kmem_cache_free(orphan_entry_slab, new);
@@ -238,14 +325,10 @@ void add_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
if (orphan->ino > ino)
break;
- orphan = NULL;
}
- /* add new_oentry into list which is sorted by inode number */
- if (orphan)
- list_add(&new->list, this->prev);
- else
- list_add_tail(&new->list, head);
+ /* add new orphan entry into list which is sorted by inode number */
+ list_add_tail(&new->list, &orphan->list);
spin_unlock(&sbi->orphan_inode_lock);
}
@@ -259,15 +342,11 @@ void remove_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
list_for_each_entry(orphan, head, list) {
if (orphan->ino == ino) {
list_del(&orphan->list);
+ f2fs_bug_on(sbi->n_orphans == 0);
+ sbi->n_orphans--;
+ spin_unlock(&sbi->orphan_inode_lock);
kmem_cache_free(orphan_entry_slab, orphan);
- if (sbi->n_orphans == 0) {
- f2fs_msg(sbi->sb, KERN_ERR, "removing "
- "unacquired orphan inode %d",
- ino);
- f2fs_handle_error(sbi);
- } else
- sbi->n_orphans--;
- break;
+ return;
}
}
spin_unlock(&sbi->orphan_inode_lock);
@@ -276,12 +355,7 @@ void remove_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
static void recover_orphan_inode(struct f2fs_sb_info *sbi, nid_t ino)
{
struct inode *inode = f2fs_iget(sbi->sb, ino);
- if (IS_ERR(inode)) {
- f2fs_msg(sbi->sb, KERN_ERR, "unable to recover orphan inode %d",
- ino);
- f2fs_handle_error(sbi);
- return;
- }
+ f2fs_bug_on(IS_ERR(inode));
clear_nlink(inode);
/* truncate all the data during iput */
@@ -299,6 +373,8 @@ void recover_orphan_inodes(struct f2fs_sb_info *sbi)
start_blk = __start_cp_addr(sbi) + 1;
orphan_blkaddr = __start_sum_addr(sbi) - 1;
+ ra_meta_pages(sbi, start_blk, orphan_blkaddr, META_CP);
+
for (i = 0; i < orphan_blkaddr; i++) {
struct page *page = get_meta_page(sbi, start_blk + i);
struct f2fs_orphan_block *orphan_blk;
@@ -480,14 +556,12 @@ static int __add_dirty_inode(struct inode *inode, struct dir_inode_entry *new)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct list_head *head = &sbi->dir_inode_list;
- struct list_head *this;
+ struct dir_inode_entry *entry;
- list_for_each(this, head) {
- struct dir_inode_entry *entry;
- entry = list_entry(this, struct dir_inode_entry, list);
+ list_for_each_entry(entry, head, list)
if (unlikely(entry->inode == inode))