Merge tag 'for-3.8-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull new F2FS filesystem from Jaegeuk Kim:
 "Introduce a new file system, Flash-Friendly File System (F2FS), to
  Linux 3.8.

  Highlights:
   - Add initial f2fs source codes
   - Fix an endian conversion bug
   - Fix build failures on random configs
   - Fix the power-off-recovery routine
   - Minor cleanup, coding style, and typos patches"

From the Kconfig help text:

  F2FS is based on Log-structured File System (LFS), which supports
  versatile "flash-friendly" features. The design has been focused on
  addressing the fundamental issues in LFS, which are snowball effect
  of wandering tree and high cleaning overhead.

  Since flash-based storages show different characteristics according to
  the internal geometry or flash memory management schemes aka FTL, F2FS
  and tools support various parameters not only for configuring on-disk
  layout, but also for selecting allocation and cleaning algorithms.

and there's an article by Neil Brown about it on lwn.net:

  http://lwn.net/Articles/518988/

* tag 'for-3.8-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (36 commits)
  f2fs: fix tracking parent inode number
  f2fs: cleanup the f2fs_bio_alloc routine
  f2fs: introduce accessor to retrieve number of dentry slots
  f2fs: remove redundant call to f2fs_put_page in delete entry
  f2fs: make use of GFP_F2FS_ZERO for setting gfp_mask
  f2fs: rewrite f2fs_bio_alloc to make it simpler
  f2fs: fix a typo in f2fs documentation
  f2fs: remove unused variable
  f2fs: move error condition for mkdir at proper place
  f2fs: remove unneeded initialization
  f2fs: check read only condition before beginning write out
  f2fs: remove unneeded memset from init_once
  f2fs: show error in case of invalid mount arguments
  f2fs: fix the compiler warning for uninitialized use of variable
  f2fs: resolve build failures
  f2fs: adjust kernel coding style
  f2fs: fix endian conversion bugs reported by sparse
  f2fs: remove unneeded version.h header file from f2fs.h
  f2fs: update the f2fs document
  f2fs: update Kconfig and Makefile
  ...

Documentation/filesystems/00-INDEX

@@ -50,6 +50,8 @@ ext4.txt
 	- info, mount options and specifications for the Ext4 filesystem.
 files.txt
 	- info on file management in the Linux kernel.
+f2fs.txt
+	- info and mount options for the F2FS filesystem.
 fuse.txt
 	- info on the Filesystem in User SpacE including mount options.
 gfs2.txt

Documentation/filesystems/f2fs.txt

+================================================================================
+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 file system formatting tool, "mkfs.f2fs", is available from the following
+git tree:
+>> 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_off      Turn off cleaning operations, namely garbage collection,
+		       triggered in background when I/O subsystem is idle.
+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.
+
+================================================================================
+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.
+
+================================================================================
+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
+
+Format options
+--------------
+-l [label]   : Give a volume label, up to 256 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"
+
+================================================================================
+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
+     _________________________________________________________________________
+    |            |            |    Node     |   Segment   |   Segment  |      |
+    | Superblock | Checkpoint |   Address   |    Info.    |   Summary  | Main |
+    |    (SB)    |   (CP)     | Table (NAT) | Table (SIT) | 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.
+
+- Node Address Table (NAT)
+ : It is composed of a block address table for all the node blocks stored in
+   Main area.
+
+- Segment Information Table (SIT)
+ : It contains segment information such as valid block count and bitmap for the
+   validity of all the blocks.
+
+- 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   |    NAT   |   SIT   |
+  +--------+----------+---------+
+  .         .          .          .
+  .            .              .              .
+  .               .                 .                 .
+  +-------+-------+--------+--------+--------+--------+
+  | CP #0 | CP #1 | NAT #0 | NAT #1 | SIT #0 | SIT #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, if n < MAX_DIR_HASH_DEPTH / 2,
+  # of buckets in level #n = |
+                             `- 2^((MAX_DIR_HASH_DEPTH / 2) - 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.

fs/Kconfig

@@ -220,6 +220,7 @@ source "fs/pstore/Kconfig"
 source "fs/sysv/Kconfig"
 source "fs/ufs/Kconfig"
 source "fs/exofs/Kconfig"
+source "fs/f2fs/Kconfig"
 
 endif # MISC_FILESYSTEMS
 

fs/Makefile

@@ -123,6 +123,7 @@ obj-$(CONFIG_DEBUG_FS)		+= debugfs/
 obj-$(CONFIG_OCFS2_FS)		+= ocfs2/
 obj-$(CONFIG_BTRFS_FS)		+= btrfs/
 obj-$(CONFIG_GFS2_FS)           += gfs2/
+obj-$(CONFIG_F2FS_FS)		+= f2fs/
 obj-y				+= exofs/ # Multiple modules
 obj-$(CONFIG_CEPH_FS)		+= ceph/
 obj-$(CONFIG_PSTORE)		+= pstore/

fs/f2fs/Kconfig

+config F2FS_FS
+	tristate "F2FS filesystem support (EXPERIMENTAL)"
+	depends on BLOCK
+	help
+	  F2FS is based on Log-structured File System (LFS), which supports
+	  versatile "flash-friendly" features. The design has been focused on
+	  addressing the fundamental issues in LFS, which are snowball effect
+	  of wandering tree and high cleaning overhead.
+
+	  Since flash-based storages show different characteristics according to
+	  the internal geometry or flash memory management schemes aka FTL, F2FS
+	  and tools support various parameters not only for configuring on-disk
+	  layout, but also for selecting allocation and cleaning algorithms.
+
+	  If unsure, say N.
+
+config F2FS_STAT_FS
+	bool "F2FS Status Information"
+	depends on F2FS_FS && DEBUG_FS
+	default y
+	help
+	  /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.
+
+config F2FS_FS_XATTR
+	bool "F2FS extended attributes"
+	depends on F2FS_FS
+	default y
+	help
+	  Extended attributes are name:value pairs associated with inodes by
+	  the kernel or by users (see the attr(5) manual page, or visit
+	  <http://acl.bestbits.at/> for details).
+
+	  If unsure, say N.
+
+config F2FS_FS_POSIX_ACL
+	bool "F2FS Access Control Lists"
+	depends on F2FS_FS_XATTR
+	select FS_POSIX_ACL
+	default y
+	help
+	  Posix Access Control Lists (ACLs) support permissions for users and
+	  gourps beyond the owner/group/world scheme.
+
+	  To learn more about Access Control Lists, visit the POSIX ACLs for
+	  Linux website <http://acl.bestbits.at/>.
+
+	  If you don't know what Access Control Lists are, say N

fs/f2fs/Makefile

+obj-$(CONFIG_F2FS_FS) += f2fs.o
+
+f2fs-y		:= dir.o file.o inode.o namei.o hash.o super.o
+f2fs-y		+= checkpoint.o gc.o data.o node.o segment.o recovery.o
+f2fs-$(CONFIG_F2FS_STAT_FS) += debug.o
+f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o
+f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o

fs/f2fs/acl.c

+/*
+ * fs/f2fs/acl.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * Portions of this code from linux/fs/ext2/acl.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/f2fs_fs.h>
+#include "f2fs.h"
+#include "xattr.h"
+#include "acl.h"
+
+#define get_inode_mode(i)	((is_inode_flag_set(F2FS_I(i), FI_ACL_MODE)) ? \
+					(F2FS_I(i)->i_acl_mode) : ((i)->i_mode))
+
+static inline size_t f2fs_acl_size(int count)
+{
+	if (count <= 4) {
+		return sizeof(struct f2fs_acl_header) +
+			count * sizeof(struct f2fs_acl_entry_short);
+	} else {
+		return sizeof(struct f2fs_acl_header) +
+			4 * sizeof(struct f2fs_acl_entry_short) +
+			(count - 4) * sizeof(struct f2fs_acl_entry);
+	}
+}
+
+static inline int f2fs_acl_count(size_t size)
+{
+	ssize_t s;
+	size -= sizeof(struct f2fs_acl_header);
+	s = size - 4 * sizeof(struct f2fs_acl_entry_short);
+	if (s < 0) {
+		if (size % sizeof(struct f2fs_acl_entry_short))
+			return -1;
+		return size / sizeof(struct f2fs_acl_entry_short);
+	} else {
+		if (s % sizeof(struct f2fs_acl_entry))
+			return -1;
+		return s / sizeof(struct f2fs_acl_entry) + 4;
+	}
+}
+
+static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size)
+{
+	int i, count;
+	struct posix_acl *acl;
+	struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value;
+	struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1);
+	const char *end = value + size;
+
+	if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION))
+		return ERR_PTR(-EINVAL);
+
+	count = f2fs_acl_count(size);
+	if (count < 0)
+		return ERR_PTR(-EINVAL);
+	if (count == 0)
+		return NULL;
+
+	acl = posix_acl_alloc(count, GFP_KERNEL);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < count; i++) {
+
+		if ((char *)entry > end)
+			goto fail;
+
+		acl->a_entries[i].e_tag  = le16_to_cpu(entry->e_tag);
+		acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm);
+
+		switch (acl->a_entries[i].e_tag) {
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			acl->a_entries[i].e_id = ACL_UNDEFINED_ID;
+			entry = (struct f2fs_acl_entry *)((char *)entry +
+					sizeof(struct f2fs_acl_entry_short));
+			break;
+
+		case ACL_USER:
+			acl->a_entries[i].e_uid =
+				make_kuid(&init_user_ns,
+						le32_to_cpu(entry->e_id));
+			entry = (struct f2fs_acl_entry *)((char *)entry +
+					sizeof(struct f2fs_acl_entry));
+			break;
+		case ACL_GROUP:
+			acl->a_entries[i].e_gid =
+				make_kgid(&init_user_ns,
+						le32_to_cpu(entry->e_id));
+			entry = (struct f2fs_acl_entry *)((char *)entry +
+					sizeof(struct f2fs_acl_entry));
+			break;
+		default:
+			goto fail;
+		}
+	}
+	if ((char *)entry != end)
+		goto fail;
+	return acl;
+fail:
+	posix_acl_release(acl);
+	return ERR_PTR(-EINVAL);
+}
+
+static void *f2fs_acl_to_disk(const struct posix_acl *acl, size_t *size)
+{
+	struct f2fs_acl_header *f2fs_acl;
+	struct f2fs_acl_entry *entry;
+	int i;
+
+	f2fs_acl = kmalloc(sizeof(struct f2fs_acl_header) + acl->a_count *
+			sizeof(struct f2fs_acl_entry), GFP_KERNEL);
+	if (!f2fs_acl)
+		return ERR_PTR(-ENOMEM);
+
+	f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION);
+	entry = (struct f2fs_acl_entry *)(f2fs_acl + 1);
+
+	for (i = 0; i < acl->a_count; i++) {
+
+		entry->e_tag  = cpu_to_le16(acl->a_entries[i].e_tag);
+		entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm);
+
+		switch (acl->a_entries[i].e_tag) {
+		case ACL_USER:
+			entry->e_id = cpu_to_le32(
+					from_kuid(&init_user_ns,
+						acl->a_entries[i].e_uid));
+			entry = (struct f2fs_acl_entry *)((char *)entry +
+					sizeof(struct f2fs_acl_entry));
+			break;
+		case ACL_GROUP:
+			entry->e_id = cpu_to_le32(
+					from_kgid(&init_user_ns,
+						acl->a_entries[i].e_gid));
+			entry = (struct f2fs_acl_entry *)((char *)entry +
+					sizeof(struct f2fs_acl_entry));
+			break;
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			entry = (struct f2fs_acl_entry *)((char *)entry +
+					sizeof(struct f2fs_acl_entry_short));
+			break;
+		default:
+			goto fail;
+		}
+	}
+	*size = f2fs_acl_size(acl->a_count);
+	return (void *)f2fs_acl;
+
+fail:
+	kfree(f2fs_acl);
+	return ERR_PTR(-EINVAL);
+}
+
+struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
+	void *value = NULL;
+	struct posix_acl *acl;
+	int retval;
+
+	if (!test_opt(sbi, POSIX_ACL))
+		return NULL;
+
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
+	if (type == ACL_TYPE_ACCESS)
+		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
+
+	retval = f2fs_getxattr(inode, name_index, "", NULL, 0);
+	if (retval > 0) {
+		value = kmalloc(retval, GFP_KERNEL);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		retval = f2fs_getxattr(inode, name_index, "", value, retval);
+	}
+
+	if (retval < 0) {
+		if (retval == -ENODATA)
+			acl = NULL;
+		else
+			acl = ERR_PTR(retval);
+	} else {
+		acl = f2fs_acl_from_disk(value, retval);
+	}
+	kfree(value);
+	if (!IS_ERR(acl))
+		set_cached_acl(inode, type, acl);
+
+	return acl;
+}
+
+static int f2fs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	int name_index;
+	void *value = NULL;
+	size_t size = 0;
+	int error;
+
+	if (!test_opt(sbi, POSIX_ACL))
+		return 0;
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
+		if (acl) {
+			error = posix_acl_equiv_mode(acl, &inode->i_mode);
+			if (error < 0)
+				return error;
+			set_acl_inode(fi, inode->i_mode);
+			if (error == 0)
+				acl = NULL;
+		}
+		break;
+
+	case ACL_TYPE_DEFAULT:
+		name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		if (!S_ISDIR(inode->i_mode))
+			return acl ? -EACCES : 0;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	if (acl) {
+		value = f2fs_acl_to_disk(acl, &size);
+		if (IS_ERR(value)) {
+			cond_clear_inode_flag(fi, FI_ACL_MODE);
+			return (int)PTR_ERR(value);
+		}
+	}
+
+	error = f2fs_setxattr(inode, name_index, "", value, size);
+
+	kfree(value);
+	if (!error)
+		set_cached_acl(inode, type, acl);
+
+	cond_clear_inode_flag(fi, FI_ACL_MODE);
+	return error;
+}
+
+int f2fs_init_acl(struct inode *inode, struct inode *dir)
+{
+	struct posix_acl *acl = NULL;
+	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
+	int error = 0;
+
+	if (!S_ISLNK(inode->i_mode)) {
+		if (test_opt(sbi, POSIX_ACL)) {
+			acl = f2fs_get_acl(dir, ACL_TYPE_DEFAULT);
+			if (IS_ERR(acl))
+				return PTR_ERR(acl);
+		}
+		if (!acl)
+			inode->i_mode &= ~current_umask();
+	}
+
+	if (test_opt(sbi, POSIX_ACL) && acl) {
+
+		if (S_ISDIR(inode->i_mode)) {
+			error = f2fs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
+			if (error)
+				goto cleanup;
+		}
+		error = posix_acl_create(&acl, GFP_KERNEL, &inode->i_mode);
+		if (error < 0)
+			return error;
+		if (error > 0)
+			error = f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl);
+	}
+cleanup:
+	posix_acl_release(acl);
+	return error;
+}
+
+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);
+
+	if (!test_opt(sbi, POSIX_ACL))
+		return 0;
+	if (S_ISLNK(mode))
+		return -EOPNOTSUPP;
+
+	acl = f2fs_get_acl(inode, ACL_TYPE_ACCESS);
+	if (IS_ERR(acl) || !acl)
+		return PTR_ERR(acl);
+
+	error = posix_acl_chmod(&acl, GFP_KERNEL, mode);
+	if (error)
+		return error;
+	error = f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl);
+	posix_acl_release(acl);
+	return error;
+}
+
+static size_t f2fs_xattr_list_acl(struct dentry *dentry, char *list,
+		size_t list_size, const char *name, size_t name_len, int type)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
+	const char *xname = POSIX_ACL_XATTR_DEFAULT;
+	size_t size;
+
+	if (!test_opt(sbi, POSIX_ACL))
+		return 0;
+
+	if (type == ACL_TYPE_ACCESS)
+		xname = POSIX_ACL_XATTR_ACCESS;
+
+	size = strlen(xname) + 1;
+	if (list && size <= list_size)
+		memcpy(list, xname, size);
+	return size;
+}
+
+static int f2fs_xattr_get_acl(struct dentry *dentry, const char *name,
+		void *buffer, size_t size, int type)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
+	struct posix_acl *acl;
+	int error;
+
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	if (!test_opt(sbi, POSIX_ACL))
+		return -EOPNOTSUPP;
+
+	acl = f2fs_get_acl(dentry->d_inode, type);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	if (!acl)
+		return -ENODATA;
+	error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
+	posix_acl_release(acl);
+
+	return error;
+}
+
+static int f2fs_xattr_set_acl(struct dentry *dentry, const char *name,
+		const void *value, size_t size, int flags, int type)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dentry->d_sb);
+	struct inode *inode = dentry->d_inode;
+	struct posix_acl *acl = NULL;
+	int error;
+
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	if (!test_opt(sbi, POSIX_ACL))
+		return -EOPNOTSUPP;
+	if (!inode_owner_or_capable(inode))
+		return -EPERM;
+
+	if (value) {
+		acl = posix_acl_from_xattr(&init_user_ns, value, size);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		if (acl) {
+			error = posix_acl_valid(acl);
+			if (error)
+				goto release_and_out;
+		}
+	} else {
+		acl = NULL;
+	}
+
+	error = f2fs_set_acl(inode, type, acl);
+
+release_and_out:
+	posix_acl_release(acl);
+	return error;
+}
+
+const struct xattr_handler f2fs_xattr_acl_default_handler = {
+	.prefix = POSIX_ACL_XATTR_DEFAULT,
+	.flags = ACL_TYPE_DEFAULT,
+	.list = f2fs_xattr_list_acl,
+	.get = f2fs_xattr_get_acl,
+	.set = f2fs_xattr_set_acl,
+};
+
+const struct xattr_handler f2fs_xattr_acl_access_handler = {
+	.prefix = POSIX_ACL_XATTR_ACCESS,
+	.flags = ACL_TYPE_ACCESS,
+	.list = f2fs_xattr_list_acl,
+	.get = f2fs_xattr_get_acl,
+	.set = f2fs_xattr_set_acl,
+};

fs/f2fs/acl.h

+/*
+ * fs/f2fs/acl.h
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * Portions of this code from linux/fs/ext2/acl.h
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __F2FS_ACL_H__
+#define __F2FS_ACL_H__
+
+#include <linux/posix_acl_xattr.h>
+
+#define F2FS_ACL_VERSION	0x0001
+
+struct f2fs_acl_entry {
+	__le16 e_tag;
+	__le16 e_perm;
+	__le32 e_id;
+};
+
+struct f2fs_acl_entry_short {
+	__le16 e_tag;
+	__le16 e_perm;
+};
+
+struct f2fs_acl_header {
+	__le32 a_version;
+};
+
+#ifdef CONFIG_F2FS_FS_POSIX_ACL
+
+extern struct posix_acl *f2fs_get_acl(struct inode *inode, int type);
+extern int f2fs_acl_chmod(struct inode *inode);
+extern int f2fs_init_acl(struct inode *inode, struct inode *dir);
+#else
+#define f2fs_check_acl	NULL
+#define f2fs_get_acl	NULL
+#define f2fs_set_acl	NULL
+
+static inline int f2fs_acl_chmod(struct inode *inode)
+{
+	return 0;
+}
+
+static inline int f2fs_init_acl(struct inode *inode, struct inode *dir)
+{
+	return 0;
+}
+#endif
+#endif /* __F2FS_ACL_H__ */

fs/f2fs/data.c

+/*
+ * fs/f2fs/data.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/fs.h>
+#include <linux/f2fs_fs.h>
+#include <linux/buffer_head.h>
+#include <linux/mpage.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+
+#include "f2fs.h"
+#include "node.h"
+#include "segment.h"
+
+/*
+ * Lock ordering for the change of data block address:
+ * ->data_page
+ *  ->node_page
+ *    update block addresses in the node page
+ */
+static void __set_data_blkaddr(struct dnode_of_data *dn, block_t new_addr)
+{
+	struct f2fs_node *rn;
+	__le32 *addr_array;
+	struct page *node_page = dn->node_page;
+	unsigned int ofs_in_node = dn->ofs_in_node;
+
+	wait_on_page_writeback(node_page);
+
+	rn = (struct f2fs_node *)page_address(node_page);
+
+	/* Get physical address of data block */
+	addr_array = blkaddr_in_node(rn);
+	addr_array[ofs_in_node] = cpu_to_le32(new_addr);
+	set_page_dirty(node_page);
+}
+
+int reserve_new_block(struct dnode_of_data *dn)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
+
+	if (is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC))
+		return -EPERM;
+	if (!inc_valid_block_count(sbi, dn->inode, 1))
+		return -ENOSPC;
+
+	__set_data_blkaddr(dn, NEW_ADDR);
+	dn->data_blkaddr = NEW_ADDR;
+	sync_inode_page(dn);
+	return 0;
+}
+
+static int check_extent_cache(struct inode *inode, pgoff_t pgofs,
+					struct buffer_head *bh_result)
+{
+	struct f2fs_inode_info *fi = F2FS_I(inode);
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	pgoff_t start_fofs, end_fofs;
+	block_t start_blkaddr;
+
+	read_lock(&fi->ext.ext_lock);
+	if (fi->ext.len == 0) {
+		read_unlock(&fi->ext.ext_lock);
+		return 0;
+	}
+
+	sbi->total_hit_ext++;
+	start_fofs = fi->ext.fofs;
+	end_fofs = fi->ext.fofs + fi->ext.len - 1;
+	start_blkaddr = fi->ext.blk_addr;
+
+	if (pgofs >= start_fofs && pgofs <= end_fofs) {
+		unsigned int blkbits = inode->i_sb->s_blocksize_bits;
+		size_t count;
+
+		clear_buffer_new(bh_result);
+		map_bh(bh_result, inode->i_sb,
+				start_blkaddr + pgofs - start_fofs);
+		count = end_fofs - pgofs + 1;
+		if (count < (UINT_MAX >> blkbits))
+			bh_result->b_size = (count << blkbits);
+		else
+			bh_result->b_size = UINT_MAX;
+
+		sbi->read_hit_ext++;
+		read_unlock(&fi->ext.ext_lock);
+		return 1;
+	}
+	read_unlock(&fi->ext.ext_lock);
+	return 0;
+}
+
+void update_extent_cache(block_t blk_addr, struct dnode_of_data *dn)
+{
+	struct f2fs_inode_info *fi = F2FS_I(dn->inode);
+	pgoff_t fofs, start_fofs, end_fofs;
+	block_t start_blkaddr, end_blkaddr;
+
+	BUG_ON(blk_addr == NEW_ADDR);
+	fofs = start_bidx_of_node(ofs_of_node(dn->node_page)) + dn->ofs_in_node;
+
+	/* Update the page address in the parent node */
+	__set_data_blkaddr(dn, blk_addr);
+
+	write_lock(&fi->ext.ext_lock);
+
+	start_fofs = fi->ext.fofs;
+	end_fofs = fi->ext.fofs + fi->ext.len - 1;
+	start_blkaddr = fi->ext.blk_addr;
+	end_blkaddr = fi->ext.blk_addr + fi->ext.len - 1;
+
+	/* Drop and initialize the matched extent */
+	if (fi->ext.len == 1 && fofs == start_fofs)
+		fi->ext.len = 0;
+
+	/* Initial extent */
+	if (fi->ext.len == 0) {
+		if (blk_addr != NULL_ADDR) {
+			fi->ext.fofs = fofs;
+			fi->ext.blk_addr = blk_addr;
+			fi->ext.len = 1;
+		}
+		goto end_update;
+	}
+
+	/* Frone merge */
+	if (fofs == start_fofs - 1 && blk_addr == start_blkaddr - 1) {
+		fi->ext.fofs--;
+		fi->ext.blk_addr--;
+		fi->ext.len++;
+		goto end_update;
+	}
+
+	/* Back merge */
+	if (fofs == end_fofs + 1 && blk_addr == end_blkaddr + 1) {
+		fi->ext.len++;
+		goto end_update;
+	}
+
+	/* Split the existing extent */
+	if (fi->ext.len > 1 &&
+		fofs >= start_fofs && fofs <= end_fofs) {
+		if ((end_fofs - fofs) < (fi->ext.len >> 1)) {
+			fi->ext.len = fofs - start_fofs;
+		} else {
+			fi->ext.fofs = fofs + 1;
+			fi->ext.blk_addr = start_blkaddr +
+					fofs - start_fofs + 1;
+			fi->ext.len -= fofs - start_fofs + 1;
+		}
+		goto end_update;
+	}
+	write_unlock(&fi->ext.ext_lock);
+	return;
+
+end_update:
+	write_unlock(&fi->ext.ext_lock);
+	sync_inode_page(dn);
+	return;
+}
+
+struct page *find_data_page(struct inode *inode, pgoff_t index)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	struct address_space *mapping = inode->i_mapping;
+	struct dnode_of_data dn;
+	struct page *page;
+	int err;
+
+	page = find_get_page(mapping, index);
+	if (page && PageUptodate(page))
+		return page;
+	f2fs_put_page(page, 0);
+
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	err = get_dnode_of_data(&dn, index, RDONLY_NODE);
+	if (err)
+		return ERR_PTR(err);
+	f2fs_put_dnode(&dn);
+
+	if (dn.data_blkaddr == NULL_ADDR)
+		return ERR_PTR(-ENOENT);
+
+	/* By fallocate(), there is no cached page, but with NEW_ADDR */
+	if (dn.data_blkaddr == NEW_ADDR)
+		return ERR_PTR(-EINVAL);
+
+	page = grab_cache_page(mapping, index);
+	if (!page)
+		return ERR_PTR(-ENOMEM);
+
+	err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
+	if (err) {
+		f2fs_put_page(page, 1);
+		return ERR_PTR(err);
+	}
+	unlock_page(page);
+	return page;
+}
+
+/*
+ * If it tries to access a hole, return an error.
+ * Because, the callers, functions in dir.c and GC, should be able to know
+ * whether this page exists or not.
+ */
+struct page *get_lock_data_page(struct inode *inode, pgoff_t index)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	struct address_space *mapping = inode->i_mapping;
+	struct dnode_of_data dn;
+	struct page *page;
+	int err;
+
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	err = get_dnode_of_data(&dn, index, RDONLY_NODE);
+	if (err)
+		return ERR_PTR(err);
+	f2fs_put_dnode(&dn);
+
+	if (dn.data_blkaddr == NULL_ADDR)
+		return ERR_PTR(-ENOENT);
+
+	page = grab_cache_page(mapping, index);
+	if (!page)
+		return ERR_PTR(-ENOMEM);
+
+	if (PageUptodate(page))
+		return page;
+
+	BUG_ON(dn.data_blkaddr == NEW_ADDR);
+	BUG_ON(dn.data_blkaddr == NULL_ADDR);
+
+	err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
+	if (err) {
+		f2fs_put_page(page, 1);
+		return ERR_PTR(err);
+	}
+	return page;
+}
+
+/*
+ * Caller ensures that this data page is never allocated.
+ * A new zero-filled data page is allocated in the page cache.
+ */
+struct page *get_new_data_page(struct inode *inode, pgoff_t index,
+						bool new_i_size)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	struct address_space *mapping = inode->i_mapping;
+	struct page *page;
+	struct dnode_of_data dn;
+	int err;
+
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	err = get_dnode_of_data(&dn, index, 0);
+	if (err)
+		return ERR_PTR(err);
+
+	if (dn.data_blkaddr == NULL_ADDR) {
+		if (reserve_new_block(&dn)) {
+			f2fs_put_dnode(&dn);
+			return ERR_PTR(-ENOSPC);
+		}
+	}
+	f2fs_put_dnode(&dn);
+
+	page = grab_cache_page(mapping, index);
+	if (!page)
+		return ERR_PTR(-ENOMEM);
+
+	if (PageUptodate(page))
+		return page;
+
+	if (dn.data_blkaddr == NEW_ADDR) {
+		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+	} else {
+		err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
+		if (err) {
+			f2fs_put_page(page, 1);
+			return ERR_PTR(err);
+		}
+	}
+	SetPageUptodate(page);
+
+	if (new_i_size &&
+		i_size_read(inode) < ((index + 1) << PAGE_CACHE_SHIFT)) {
+		i_size_write(inode, ((index + 1) << PAGE_CACHE_SHIFT));
+		mark_inode_dirty_sync(inode);
+	}
+	return page;
+}
+
+static void read_end_io(struct bio *bio, int err)
+{
+	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
+	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+
+	do {
+		struct page *page = bvec->bv_page;
+
+		if (--bvec >= bio->bi_io_vec)
+			prefetchw(&bvec->bv_page->flags);
+
+		if (uptodate) {
+			SetPageUptodate(page);
+		} else {
+			ClearPageUptodate(page);
+			SetPageError(page);
+		}
+		unlock_page(page);
+	} while (bvec >= bio->bi_io_vec);
+	kfree(bio->bi_private);
+	bio_put(bio);
+}
+
+/*
+ * Fill the locked page with data located in the block address.
+ * Read operation is synchronous, and caller must unlock the page.
+ */
+int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
+					block_t blk_addr, int type)
+{
+	struct block_device *bdev = sbi->sb->s_bdev;
+	bool sync = (type == READ_SYNC);
+	struct bio *bio;
+
+	/* This page can be already read by other threads */
+	if (PageUptodate(page)) {
+		if (!sync)
+			unlock_page(page);
+		return 0;
+	}
+
+	down_read(&sbi->bio_sem);
+
+	/* Allocate a new bio */
+	bio = f2fs_bio_alloc(bdev, 1);
+
+	/* Initialize the bio */
+	bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
+	bio->bi_end_io = read_end_io;
+
+	if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {
+		kfree(bio->bi_private);
+		bio_put(bio);
+		up_read(&sbi->bio_sem);
+		return -EFAULT;
+	}
+
+	submit_bio(type, bio);
+	up_read(&sbi->bio_sem);
+
+	/* wait for read completion if sync */
+	if (sync) {
+		lock_page(page);
+		if (PageError(page))
+			return -EIO;
+	}
+	return 0;
+}
+
+/*
+ * This function should be used by the data read flow only where it
+ * does not check the "create" flag that indicates block allocation.
+ * The reason for this special functionality is to exploit VFS readahead
+ * mechanism.
+ */
+static int get_data_block_ro(struct inode *inode, sector_t iblock,
+			struct buffer_head *bh_result, int create)
+{
+	unsigned int blkbits = inode->i_sb->s_blocksize_bits;
+	unsigned maxblocks = bh_result->b_size >> blkbits;
+	struct dnode_of_data dn;
+	pgoff_t pgofs;
+	int err;
+
+	/* Get the page offset from the block offset(iblock) */
+	pgofs =	(pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
+
+	if (check_extent_cache(inode, pgofs, bh_result))
+		return 0;
+
+	/* When reading holes, we need its node page */
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	err = get_dnode_of_data(&dn, pgofs, RDONLY_NODE);
+	if (err)
+		return (err == -ENOENT) ? 0 : err;
+
+	/* It does not support data allocation */
+	BUG_ON(create);
+
+	if (dn.data_blkaddr != NEW_ADDR && dn.data_blkaddr != NULL_ADDR) {
+		int i;
+		unsigned int end_offset;
+
+		end_offset = IS_INODE(dn.node_page) ?
+				ADDRS_PER_INODE :
+				ADDRS_PER_BLOCK;
+
+		clear_buffer_new(bh_result);
+
+		/* Give more consecutive addresses for the read ahead */
+		for (i = 0; i < end_offset - dn.ofs_in_node; i++)
+			if (((datablock_addr(dn.node_page,
+							dn.ofs_in_node + i))
+				!= (dn.data_blkaddr + i)) || maxblocks == i)
+				break;
+		map_bh(bh_result, inode->i_sb, dn.data_blkaddr);
+		bh_result->b_size = (i << blkbits);
+	}
+	f2fs_put_dnode(&dn);
+	return 0;
+}
+
+static int f2fs_read_data_page(struct file *file, struct page *page)
+{
+	return mpage_readpage(page, get_data_block_ro);
+}
+
+static int f2fs_read_data_pages(struct file *file,
+			struct address_space *mapping,
+			struct list_head *pages, unsigned nr_pages)
+{
+	return mpage_readpages(mapping, pages, nr_pages, get_data_block_ro);
+}
+
+int do_write_data_page(struct page *page)
+{
+	struct inode *inode = page->mapping->host;
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	block_t old_blk_addr, new_blk_addr;
+	struct dnode_of_data dn;
+	int err = 0;
+
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	err = get_dnode_of_data(&dn, page->index, RDONLY_NODE);
+	if (err)
+		return err;
+
+	old_blk_addr = dn.data_blkaddr;
+
+	/* This page is already truncated */
+	if (old_blk_addr == NULL_ADDR)
+		goto out_writepage;
+
+	set_page_writeback(page);
+
+	/*
+	 * If current allocation needs SSR,
+	 * it had better in-place writes for updated data.
+	 */
+	if (old_blk_addr != NEW_ADDR && !is_cold_data(page) &&
+				need_inplace_update(inode)) {
+		rewrite_data_page(F2FS_SB(inode->i_sb), page,
+						old_blk_addr);
+	} else {
+		write_data_page(inode, page, &dn,
+				old_blk_addr, &new_blk_addr);
+		update_extent_cache(new_blk_addr, &dn);
+		F2FS_I(inode)->data_version =
+			le64_to_cpu(F2FS_CKPT(sbi)->checkpoint_ver);
+	}
+out_writepage:
+	f2fs_put_dnode(&dn);
+	return err;
+}
+
+static int f2fs_write_data_page(struct page *page,
+					struct writeback_control *wbc)
+{
+	struct inode *inode = page->mapping->host;
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	loff_t i_size = i_size_read(inode);
+	const pgoff_t end_index = ((unsigned long long) i_size)
+							>> PAGE_CACHE_SHIFT;
+	unsigned offset;
+	int err = 0;
+
+	if (page->index < end_index)
+		goto out;
+
+	/*
+	 * If the offset is out-of-range of file size,
+	 * this page does not have to be written to disk.
+	 */
+	offset = i_size & (PAGE_CACHE_SIZE - 1);
+	if ((page->index >= end_index + 1) || !offset) {
+		if (S_ISDIR(inode->i_mode)) {
+			dec_page_count(sbi, F2FS_DIRTY_DENTS);
+			inode_dec_dirty_dents(inode);
+		}
+		goto unlock_out;
+	}
+
+	zero_user_segment(page, offset, PAGE_CACHE_SIZE);
+out:
+	if (sbi->por_doing)
+		goto redirty_out;
+
+	if (wbc->for_reclaim && !S_ISDIR(inode->i_mode) && !is_cold_data(page))
+		goto redirty_out;
+
+	mutex_lock_op(sbi, DATA_WRITE);
+	if (S_ISDIR(inode->i_mode)) {
+		dec_page_count(sbi, F2FS_DIRTY_DENTS);
+		inode_dec_dirty_dents(inode);
+	}
+	err = do_write_data_page(page);
+	if (err && err != -ENOENT) {
+		wbc->pages_skipped++;
+		set_page_dirty(page);
+	}
+	mutex_unlock_op(sbi, DATA_WRITE);
+
+	if (wbc->for_reclaim)
+		f2fs_submit_bio(sbi, DATA, true);
+
+	if (err == -ENOENT)
+		goto unlock_out;
+
+	clear_cold_data(page);
+	unlock_page(page);
+
+	if (!wbc->for_reclaim && !S_ISDIR(inode->i_mode))
+		f2fs_balance_fs(sbi);
+	return 0;
+
+unlock_out:
+	unlock_page(page);
+	return (err == -ENOENT) ? 0 : err;
+
+redirty_out:
+	wbc->pages_skipped++;
+	set_page_dirty(page);
+	return AOP_WRITEPAGE_ACTIVATE;
+}
+
+#define MAX_DESIRED_PAGES_WP	4096
+
+static int f2fs_write_data_pages(struct address_space *mapping,
+			    struct writeback_control *wbc)
+{
+	struct inode *inode = mapping->host;
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	int ret;
+	long excess_nrtw = 0, desired_nrtw;
+
+	if (wbc->nr_to_write < MAX_DESIRED_PAGES_WP) {
+		desired_nrtw = MAX_DESIRED_PAGES_WP;
+		excess_nrtw = desired_nrtw - wbc->nr_to_write;
+		wbc->nr_to_write = desired_nrtw;
+	}
+
+	if (!S_ISDIR(inode->i_mode))
+		mutex_lock(&sbi->writepages);
+	ret = generic_writepages(mapping, wbc);
+	if (!S_ISDIR(inode->i_mode))
+		mutex_unlock(&sbi->writepages);
+	f2fs_submit_bio(sbi, DATA, (wbc->sync_mode == WB_SYNC_ALL));
+
+	remove_dirty_dir_inode(inode);
+
+	wbc->nr_to_write -= excess_nrtw;
+	return ret;
+}
+
+static int f2fs_write_begin(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned len, unsigned flags,
+		struct page **pagep, void **fsdata)
+{
+	struct inode *inode = mapping->host;
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	struct page *page;
+	pgoff_t index = ((unsigned long long) pos) >> PAGE_CACHE_SHIFT;
+	struct dnode_of_data dn;
+	int err = 0;
+
+	/* for nobh_write_end */
+	*fsdata = NULL;
+
+	f2fs_balance_fs(sbi);
+
+	page = grab_cache_page_write_begin(mapping, index, flags);
+	if (!page)
+		return -ENOMEM;
+	*pagep = page;
+
+	mutex_lock_op(sbi, DATA_NEW);
+
+	set_new_dnode(&dn, inode, NULL, NULL, 0);
+	err = get_dnode_of_data(&dn, index, 0);
+	if (err) {
+		mutex_unlock_op(sbi, DATA_NEW);
+		f2fs_put_page(page, 1);
+		return err;
+	}
+
+	if (dn.data_blkaddr == NULL_ADDR) {
+		err = reserve_new_block(&dn);
+		if (err) {
+			f2fs_put_dnode(&dn);
+			mutex_unlock_op(sbi, DATA_NEW);
+			f2fs_put_page(page, 1);
+			return err;
+		}
+	}
+	f2fs_put_dnode(&dn);
+
+	mutex_unlock_op(sbi, DATA_NEW);
+
+	if ((len == PAGE_CACHE_SIZE) || PageUptodate(page))
+		return 0;
+
+	if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) {
+		unsigned start = pos & (PAGE_CACHE_SIZE - 1);
+		unsigned end = start + len;
+
+		/* Reading beyond i_size is simple: memset to zero */
+		zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE);
+		return 0;
+	}
+
+	if (dn.data_blkaddr == NEW_ADDR) {
+		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+	} else {
+		err = f2fs_readpage(sbi, page, dn.data_blkaddr, READ_SYNC);
+		if (err) {
+			f2fs_put_page(page, 1);
+			return err;
+		}
+	}
+	SetPageUptodate(page);
+	clear_cold_data(page);
+	return 0;
+}
+
+static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
+		const struct iovec *iov, loff_t offset, unsigned long nr_segs)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file->f_mapping->host;
+
+	if (rw == WRITE)
+		return 0;
+
+	/* Needs synchronization with the cleaner */
+	return blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
+						  get_data_block_ro);
+}
+
+static void f2fs_invalidate_data_page(struct page *page, unsigned long offset)
+{
+	struct inode *inode = page->mapping->host;
+	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
+	if (S_ISDIR(inode->i_mode) && PageDirty(page)) {
+		dec_page_count(sbi, F2FS_DIRTY_DENTS);
+		inode_dec_dirty_dents(inode);
+	}
+	ClearPagePrivate(page);
+}
+
+static int f2fs_release_data_page(struct page *page, gfp_t wait)
+{
+	ClearPagePrivate(page);
+	return 0;
+}
+
+static int f2fs_set_data_page_dirty(struct page *page)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *inode = mapping->host;
+
+	SetPageUptodate(page);
+	if (!PageDirty(page)) {
+		__set_page_dirty_nobuffers(page);
+		set_dirty_dir_page(inode, page);
+		return 1;
+	}
+	return 0;
+}
+
+const struct address_space_operations f2fs_dblock_aops = {
+	.readpage	= f2fs_read_data_page,
+	.readpages	= f2fs_read_data_pages,
+	.writepage	= f2fs_write_data_page,
+	.writepages	= f2fs_write_data_pages,
+	.write_begin	= f2fs_write_begin,
+	.write_end	= nobh_write_end,
+	.set_page_dirty	= f2fs_set_data_page_dirty,
+	.invalidatepage	= f2fs_invalidate_data_page,
+	.releasepage	= f2fs_release_data_page,
+	.direct_IO	= f2fs_direct_IO,
+};

fs/f2fs/debug.c

+/*
+ * f2fs debugging statistics
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ * Copyright (c) 2012 Linux Foundation
+ * Copyright (c) 2012 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/backing-dev.h>
+#include <linux/proc_fs.h>
+#include <linux/f2fs_fs.h>
+#include <linux/blkdev.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include "f2fs.h"
+#include "node.h"
+#include "segment.h"
+#include "gc.h"
+
+static LIST_HEAD(f2fs_stat_list);
+static struct dentry *debugfs_root;
+
+static void update_general_status(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_stat_info *si = sbi->stat_info;
+	int i;
+
+	/* valid check of the segment numbers */
+	si->hit_ext = sbi->read_hit_ext;
+	si->total_ext = sbi->total_hit_ext;
+	si->ndirty_node = get_pages(sbi, F2FS_DIRTY_NODES);
+	si->ndirty_dent = get_pages(sbi, F2FS_DIRTY_DENTS);
+	si->ndirty_dirs = sbi->n_dirty_dirs;
+	si->ndirty_meta = get_pages(sbi, F2FS_DIRTY_META);
+	si->total_count = (int)sbi->user_block_count / sbi->blocks_per_seg;
+	si->rsvd_segs = reserved_segments(sbi);
+	si->overp_segs = overprovision_segments(sbi);
+	si->valid_count = valid_user_blocks(sbi);
+	si->valid_node_count = valid_node_count(sbi);
+	si->valid_inode_count = valid_inode_count(sbi);
+	si->utilization = utilization(sbi);
+
+	si->free_segs = free_segments(sbi);
+	si->free_secs = free_sections(sbi);
+	si->prefree_count = prefree_segments(sbi);
+	si->dirty_count = dirty_segments(sbi);
+	si->node_pages = sbi->node_inode->i_mapping->nrpages;
+	si->meta_pages = sbi->meta_inode->i_mapping->nrpages;
+	si->nats = NM_I(sbi)->nat_cnt;
+	si->sits = SIT_I(sbi)->dirty_sentries;
+	si->fnids = NM_I(sbi)->fcnt;
+	si->bg_gc = sbi->bg_gc;
+	si->util_free = (int)(free_user_blocks(sbi) >> sbi->log_blocks_per_seg)
+		* 100 / (int)(sbi->user_block_count >> sbi->log_blocks_per_seg)
+		/ 2;
+	si->util_valid = (int)(written_block_count(sbi) >>
+						sbi->log_blocks_per_seg)
+		* 100 / (int)(sbi->user_block_count >> sbi->log_blocks_per_seg)
+		/ 2;
+	si->util_invalid = 50 - si->util_free - si->util_valid;
+	for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_NODE; i++) {
+		struct curseg_info *curseg = CURSEG_I(sbi, i);
+		si->curseg[i] = curseg->segno;
+		si->cursec[i] = curseg->segno / sbi->segs_per_sec;
+		si->curzone[i] = si->cursec[i] / sbi->secs_per_zone;
+	}
+
+	for (i = 0; i < 2; i++) {
+		si->segment_count[i] = sbi->segment_count[i];
+		si->block_count[i] = sbi->block_count[i];
+	}
+}
+
+/*
+ * This function calculates BDF of every segments
+ */
+static void update_sit_info(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_stat_info *si = sbi->stat_info;
+	unsigned int blks_per_sec, hblks_per_sec, total_vblocks, bimodal, dist;
+	struct sit_info *sit_i = SIT_I(sbi);
+	unsigned int segno, vblocks;
+	int ndirty = 0;
+
+	bimodal = 0;
+	total_vblocks = 0;
+	blks_per_sec = sbi->segs_per_sec * (1 << sbi->log_blocks_per_seg);
+	hblks_per_sec = blks_per_sec / 2;
+	mutex_lock(&sit_i->sentry_lock);
+	for (segno = 0; segno < TOTAL_SEGS(sbi); segno += sbi->segs_per_sec) {
+		vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
+		dist = abs(vblocks - hblks_per_sec);
+		bimodal += dist * dist;
+
+		if (vblocks > 0 && vblocks < blks_per_sec) {
+			total_vblocks += vblocks;
+			ndirty++;
+		}
+	}
+	mutex_unlock(&sit_i->sentry_lock);
+	dist = sbi->total_sections * hblks_per_sec * hblks_per_sec / 100;
+	si->bimodal = bimodal / dist;
+	if (si->dirty_count)
+		si->avg_vblocks = total_vblocks / ndirty;
+	else
+		si->avg_vblocks = 0;
+}
+
+/*
+ * This function calculates memory footprint.
+ */
+static void update_mem_info(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_stat_info *si = sbi->stat_info;
+	unsigned npages;
+
+	if (si->base_mem)
+		goto get_cache;
+
+	si->base_mem = sizeof(struct f2fs_sb_info) + sbi->sb->s_blocksize;
+	si->base_mem += 2 * sizeof(struct f2fs_inode_info);
+	si->base_mem += sizeof(*sbi->ckpt);
+
+	/* build sm */
+	si->base_mem += sizeof(struct f2fs_sm_info);
+
+	/* build sit */
+	si->base_mem += sizeof(struct sit_info);
+	si->base_mem += TOTAL_SEGS(sbi) * sizeof(struct seg_entry);
+	si->base_mem += f2fs_bitmap_size(TOTAL_SEGS(sbi));
+	si->base_mem += 2 * SIT_VBLOCK_MAP_SIZE * TOTAL_SEGS(sbi);
+	if (sbi->segs_per_sec > 1)
+		si->base_mem += sbi->total_sections *
+			sizeof(struct sec_entry);
+	si->base_mem += __bitmap_size(sbi, SIT_BITMAP);
+
+	/* build free segmap */
+	si->base_mem += sizeof(struct free_segmap_info);
+	si->base_mem += f2fs_bitmap_size(TOTAL_SEGS(sbi));
+	si->base_mem += f2fs_bitmap_size(sbi->total_sections);
+
+	/* build curseg */
+	si->base_mem += sizeof(struct curseg_info) * NR_CURSEG_TYPE;
+	si->base_mem += PAGE_CACHE_SIZE * NR_CURSEG_TYPE;
+
+	/* build dirty segmap */
+	si->base_mem += sizeof(struct dirty_seglist_info);
+	si->base_mem += NR_DIRTY_TYPE * f2fs_bitmap_size(TOTAL_SEGS(sbi));
+	si->base_mem += 2 * f2fs_bitmap_size(TOTAL_SEGS(sbi));
+
+	/* buld nm */
+	si->base_mem += sizeof(struct f2fs_nm_info);
+	si->base_mem += __bitmap_size(sbi, NAT_BITMAP);
+
+	/* build gc */
+	si->base_mem += sizeof(struct f2fs_gc_kthread);
+
+get_cache:
+	/* free nids */
+	si->cache_mem = NM_I(sbi)->fcnt;
+	si->cache_mem += NM_I(sbi)->nat_cnt;
+	npages = sbi->node_inode->i_mapping->nrpages;
+	si->cache_mem += npages << PAGE_CACHE_SHIFT;
+	npages = sbi->meta_inode->i_mapping->nrpages;
+	si->cache_mem += npages << PAGE_CACHE_SHIFT;
+	si->cache_mem += sbi->n_orphans * sizeof(struct orphan_inode_entry);
+	si->cache_mem += sbi->n_dirty_dirs * sizeof(struct dir_inode_entry);
+}
+
+static int stat_show(struct seq_file *s, void *v)
+{
+	struct f2fs_stat_info *si, *next;
+	int i = 0;
+	int j;
+
+	list_for_each_entry_safe(si, next, &f2fs_stat_list, stat_list) {
+
+		mutex_lock(&si->stat_lock);
+		if (!si->sbi) {
+			mutex_unlock(&si->stat_lock);
+			continue;
+		}
+		update_general_status(si->sbi);
+
+		seq_printf(s, "\n=====[ partition info. #%d ]=====\n", i++);
+		seq_printf(s, "[SB: 1] [CP: 2] [NAT: %d] [SIT: %d] ",
+			   si->nat_area_segs, si->sit_area_segs);
+		seq_printf(s, "[SSA: %d] [MAIN: %d",
+			   si->ssa_area_segs, si->main_area_segs);
+		seq_printf(s, "(OverProv:%d Resv:%d)]\n\n",
+			   si->overp_segs, si->rsvd_segs);
+		seq_printf(s, "Utilization: %d%% (%d valid blocks)\n",
+			   si->utilization, si->valid_count);
+		seq_printf(s, "  - Node: %u (Inode: %u, ",
+			   si->valid_node_count, si->valid_inode_count);
+		seq_printf(s, "Other: %u)\n  - Data: %u\n",
+			   si->valid_node_count - si->valid_inode_count,
+			   si->valid_count - si->valid_node_count);
+		seq_printf(s, "\nMain area: %d segs, %d secs %d zones\n",
+			   si->main_area_segs, si->main_area_sections,
+			   si->main_area_zones);
+		seq_printf(s, "  - COLD  data: %d, %d, %d\n",
+			   si->curseg[CURSEG_COLD_DATA],
+			   si->cursec[CURSEG_COLD_DATA],
+			   si->curzone[CURSEG_COLD_DATA]);
+		seq_printf(s, "  - WARM  data: %d, %d, %d\n",
+			   si->curseg[CURSEG_WARM_DATA],
+			   si->cursec[CURSEG_WARM_DATA],
+			   si->curzone[CURSEG_WARM_DATA]);
+		seq_printf(s, "  - HOT   data: %d, %d, %d\n",
+			   si->curseg[CURSEG_HOT_DATA],
+			   si->cursec[CURSEG_HOT_DATA],
+			   si->curzone[CURSEG_HOT_DATA]);
+		seq_printf(s, "  - Dir   dnode: %d, %d, %d\n",
+			   si->curseg[CURSEG_HOT_NODE],
+			   si->cursec[CURSEG_HOT_NODE],
+			   si->curzone[CURSEG_HOT_NODE]);
+		seq_printf(s, "  - File   dnode: %d, %d, %d\n",
+			   si->curseg[CURSEG_WARM_NODE],
+			   si->cursec[CURSEG_WARM_NODE],
+			   si->curzone[CURSEG_WARM_NODE]);
+		seq_printf(s, "  - Indir nodes: %d, %d, %d\n",
+			   si->curseg[CURSEG_COLD_NODE],
+			   si->cursec[CURSEG_COLD_NODE],
+			   si->curzone[CURSEG_COLD_NODE]);
+		seq_printf(s, "\n  - Valid: %d\n  - Dirty: %d\n",
+			   si->main_area_segs - si->dirty_count -
+			   si->prefree_count - si->free_segs,
+			   si->dirty_count);
+		seq_printf(s, "  - Prefree: %d\n  - Free: %d (%d)\n\n",
+			   si->prefree_count, si->free_segs, si->free_secs);
+		seq_printf(s, "GC calls: %d (BG: %d)\n",
+			   si->call_count, si->bg_gc);
+		seq_printf(s, "  - data segments : %d\n", si->data_segs);
+		seq_printf(s, "  - node segments : %d\n", si->node_segs);
+		seq_printf(s, "Try to move %d blocks\n", si->tot_blks);
+		seq_printf(s, "  - data blocks : %d\n", si->data_blks);
+		seq_printf(s, "  - node blocks : %d\n", si->node_blks);
+		seq_printf(s, "\nExtent Hit Ratio: %d / %d\n",
+			   si->hit_ext, si->total_ext);
+		seq_printf(s, "\nBalancing F2FS Async:\n");
+		seq_printf(s, "  - nodes %4d in %4d\n",
+			   si->ndirty_node, si->node_pages);
+		seq_printf(s, "  - dents %4d in dirs:%4d\n",
+			   si->ndirty_dent, si->ndirty_dirs);
+		seq_printf(s, "  - meta %4d in %4d\n",
+			   si->ndirty_meta, si->meta_pages);
+		seq_printf(s, "  - NATs %5d > %lu\n",
+			   si->nats, NM_WOUT_THRESHOLD);
+		seq_printf(s, "  - SITs: %5d\n  - free_nids: %5d\n",
+			   si->sits, si->fnids);
+		seq_printf(s, "\nDistribution of User Blocks:");
+		seq_printf(s, " [ valid | invalid | free ]\n");
+		seq_printf(s, "  [");
+
+		for (j = 0; j < si->util_valid; j++)
+			seq_printf(s, "-");
+		seq_printf(s, "|");
+
+		for (j = 0; j < si->util_invalid; j++)
+			seq_printf(s, "-");
+		seq_printf(s, "|");
+
+		for (j = 0; j < si->util_free; j++)
+			seq_printf(s, "-");
+		seq_printf(s, "]\n\n");
+		seq_printf(s, "SSR: %u blocks in %u segments\n",
+			   si->block_count[SSR], si->segment_count[SSR]);
+		seq_printf(s, "LFS: %u blocks in %u segments\n",
+			   si->block_count[LFS], si->segment_count[LFS]);
+
+		/* segment usage info */
+		update_sit_info(si->sbi);
+		seq_printf(s, "\nBDF: %u, avg. vblocks: %u\n",
+			   si->bimodal, si->avg_vblocks);
+
+		/* memory footprint */
+		update_mem_info(si->sbi);
+		seq_printf(s, "\nMemory: %u KB = static: %u + cached: %u\n",
+				(si->base_mem + si->cache_mem) >> 10,
+				si->base_mem >> 10, si->cache_mem >> 10);
+		mutex_unlock(&si->stat_lock);
+	}
+	return 0;
+}
+
+static int stat_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, stat_show, inode->i_private);
+}
+
+static const struct file_operations stat_fops = {
+	.open = stat_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static int init_stats(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
+	struct f2fs_stat_info *si;
+
+	sbi->stat_info = kzalloc(sizeof(struct f2fs_stat_info), GFP_KERNEL);
+	if (!sbi->stat_info)
+		return -ENOMEM;
+
+	si = sbi->stat_info;
+	mutex_init(&si->stat_lock);
+	list_add_tail(&si->stat_list, &f2fs_stat_list);
+
+	si->all_area_segs = le32_to_cpu(raw_super->segment_count);
+	si->sit_area_segs = le32_to_cpu(raw_super->segment_count_sit);
+	si->nat_area_segs = le32_to_cpu(raw_super->segment_count_nat);
+	si->ssa_area_segs = le32_to_cpu(raw_super->segment_count_ssa);
+	si->main_area_segs = le32_to_cpu(raw_super->segment_count_main);
+	si->main_area_sections = le32_to_cpu(raw_super->section_count);
+	si->main_area_zones = si->main_area_sections /
+				le32_to_cpu(raw_super->secs_per_zone);
+	si->sbi = sbi;
+	return 0;
+}
+
+int f2fs_build_stats(struct f2fs_sb_info *sbi)
+{
+	int retval;
+
+	retval = init_stats(sbi);
+	if (retval)
+		return retval;
+
+	if (!debugfs_root)
+		debugfs_root = debugfs_create_dir("f2fs", NULL);
+
+	debugfs_create_file("status", S_IRUGO, debugfs_root, NULL, &stat_fops);
+	return 0;
+}
+
+void f2fs_destroy_stats(struct f2fs_sb_info *sbi)
+{
+	struct f2fs_stat_info *si = sbi->stat_info;
+
+	list_del(&si->stat_list);
+	mutex_lock(&si->stat_lock);
+	si->sbi = NULL;
+	mutex_unlock(&si->stat_lock);
+	kfree(sbi->stat_info);
+}
+
+void destroy_root_stats(void)
+{
+	debugfs_remove_recursive(debugfs_root);
+	debugfs_root = NULL;
+}

fs/f2fs/dir.c

+/*
+ * fs/f2fs/dir.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/fs.h>
+#include <linux/f2fs_fs.h>
+#include "f2fs.h"
+#include "acl.h"
+
+static unsigned long dir_blocks(struct inode *inode)
+{
+	return ((unsigned long long) (i_size_read(inode) + PAGE_CACHE_SIZE - 1))
+							>> PAGE_CACHE_SHIFT;
+}
+
+static unsigned int dir_buckets(unsigned int level)
+{
+	if (level < MAX_DIR_HASH_DEPTH / 2)
+		return 1 << level;
+	else
+		return 1 << ((MAX_DIR_HASH_DEPTH / 2) - 1);
+}
+
+static unsigned int bucket_blocks(unsigned int level)
+{
+	if (level < MAX_DIR_HASH_DEPTH / 2)
+		return 2;
+	else
+		return 4;
+}
+
+static unsigned char f2fs_filetype_table[F2FS_FT_MAX] = {
+	[F2FS_FT_UNKNOWN]	= DT_UNKNOWN,
+	[F2FS_FT_REG_FILE]	= DT_REG,
+	[F2FS_FT_DIR]		= DT_DIR,
+	[F2FS_FT_CHRDEV]	= DT_CHR,
+	[F2FS_FT_BLKDEV]	= DT_BLK,
+	[F2FS_FT_FIFO]		= DT_FIFO,
+	[F2FS_FT_SOCK]		= DT_SOCK,
+	[F2FS_FT_SYMLINK]	= DT_LNK,
+};
+
+#define S_SHIFT 12
+static unsigned char f2fs_type_by_mode[S_IFMT >> S_SHIFT] = {
+	[S_IFREG >> S_SHIFT]	= F2FS_FT_REG_FILE,
+	[S_IFDIR >> S_SHIFT]	= F2FS_FT_DIR,
+	[S_IFCHR >> S_SHIFT]	= F2FS_FT_CHRDEV,
+	[S_IFBLK >> S_SHIFT]	= F2FS_FT_BLKDEV,
+	[S_IFIFO >> S_SHIFT]	= F2FS_FT_FIFO,
+	[S_IFSOCK >> S_SHIFT]	= F2FS_FT_SOCK,
+	[S_IFLNK >> S_SHIFT]	= F2FS_FT_SYMLINK,
+};
+
+static void set_de_type(struct f2fs_dir_entry *de, struct inode *inode)
+{
+	mode_t mode = inode->i_mode;
+	de->file_type = f2fs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
+}
+
+static unsigned long dir_block_index(unsigned int level, unsigned int idx)
+{
+	unsigned long i;
+	unsigned long bidx = 0;
+
+	for (i = 0; i < level; i++)
+		bidx += dir_buckets(i) * bucket_blocks(i);
+	bidx += idx * bucket_blocks(level);
+	return bidx;
+}
+
+static bool early_match_name(const char *name, int namelen,
+			f2fs_hash_t namehash, struct f2fs_dir_entry *de)
+{
+	if (le16_to_cpu(de->name_len) != namelen)
+		return false;
+
+	if (de->hash_code != namehash)
+		return false;
+
+	return true;
+}
+
+static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
+			const char *name, int namelen, int *max_slots,
+			f2fs_hash_t namehash, struct page **res_page)
+{
+	struct f2fs_dir_entry *de;
+	unsigned long bit_pos, end_pos, next_pos;
+	struct f2fs_dentry_block *dentry_blk = kmap(dentry_page);
+	int slots;
+
+	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
+					NR_DENTRY_IN_BLOCK, 0);
+	while (bit_pos < NR_DENTRY_IN_BLOCK) {
+		de = &dentry_blk->dentry[bit_pos];
+		slots = GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
+
+		if (early_match_name(name, namelen, namehash, de)) {
+			if (!memcmp(dentry_blk->filename[bit_pos],
+							name, namelen)) {
+				*res_page = dentry_page;
+				goto found;
+			}
+		}
+		next_pos = bit_pos + slots;
+		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
+				NR_DENTRY_IN_BLOCK, next_pos);
+		if (bit_pos >= NR_DENTRY_IN_BLOCK)
+			end_pos = NR_DENTRY_IN_BLOCK;
+		else
+			end_pos = bit_pos;
+		if (*max_slots < end_pos - next_pos)
+			*max_slots = end_pos - next_pos;
+	}
+
+	de = NULL;
+	kunmap(dentry_page);
+found:
+	return de;
+}
+
+static struct f2fs_dir_entry *find_in_level(struct inode *dir,
+		unsigned int level, const char *name, int namelen,
+			f2fs_hash_t namehash, struct page **res_page)
+{
+	int s = GET_DENTRY_SLOTS(namelen);
+	unsigned int nbucket, nblock;
+	unsigned int bidx, end_block;
+	struct page *dentry_page;
+	struct f2fs_dir_entry *de = NULL;
+	bool room = false;
+	int max_slots = 0;
+
+	BUG_ON(level > MAX_DIR_HASH_DEPTH);
+
+	nbucket = dir_buckets(level);
+	nblock = bucket_blocks(level);
+
+	bidx = dir_block_index(level, le32_to_cpu(namehash) % nbucket);
+	end_block = bidx + nblock;
+
+	for (; bidx < end_block; bidx++) {
+		/* no need to allocate new dentry pages to all the indices */
+		dentry_page = find_data_page(dir, bidx);
+		if (IS_ERR(dentry_page)) {
+			room = true;
+			continue;
+		}
+
+		de = find_in_block(dentry_page, name, namelen,
+					&max_slots, namehash, res_page);
+		if (de)
+			break;
+
+		if (max_slots >= s)
+			room = true;
+		f2fs_put_page(dentry_page, 0);
+	}
+
+	if (!de && room && F2FS_I(dir)->chash != namehash) {
+		F2FS_I(dir)->chash = namehash;
+		F2FS_I(dir)->clevel = level;
+	}
+
+	return de;
+}
+
+/*
+ * Find an entry in the specified directory with the wanted name.
+ * It returns the page where the entry was found (as a parameter - res_page),
+ * and the entry itself. Page is returned mapped and unlocked.
+ * Entry is guaranteed to be valid.
+ */
+struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
+			struct qstr *child, struct page **res_page)
+{
+	const char *name = child->name;
+	int namelen = child->len;
+	unsigned long npages = dir_blocks(dir);
+	struct f2fs_dir_entry *de = NULL;
+	f2fs_hash_t name_hash;
+	unsigned int max_depth;
+	unsigned int level;
+
+	if (npages == 0)
+		return NULL;
+
+	*res_page = NULL;
+
+	name_hash = f2fs_dentry_hash(name, namelen);
+	max_depth = F2FS_I(dir)->i_current_depth;
+
+	for (level = 0; level < max_depth; level++) {
+		de = find_in_level(dir, level, name,
+				namelen, name_hash, res_page);
+		if (de)
+			break;
+	}
+	if (!de && F2FS_I(dir)->chash != name_hash) {
+		F2FS_I(dir)->chash = name_hash;
+		F2FS_I(dir)->clevel = level - 1;
+	}
+	return de;
+}
+
+struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
+{
+	struct page *page = NULL;
+	struct f2fs_dir_entry *de = NULL;
+	struct f2fs_dentry_block *dentry_blk = NULL;
+
+	page = get_lock_data_page(dir, 0);
+	if (IS_ERR(page))
+		return NULL;
+
+	dentry_blk = kmap(page);
+	de = &dentry_blk->dentry[1];
+	*p = page;
+	unlock_page(page);
+	return de;
+}
+
+ino_t f2fs_inode_by_name(struct inode *dir, struct qstr *qstr)
+{
+	ino_t res = 0;
+	struct f2fs_dir_entry *de;
+	struct page *page;
+
+	de = f2fs_find_entry(dir, qstr, &page);
+	if (de) {
+		res = le32_to_cpu(de->ino);
+		kunmap(page);
+		f2fs_put_page(page, 0);
+	}
+
+	return res;
+}
+
+void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
+		struct page *page, struct inode *inode)
+{
+	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
+
+	mutex_lock_op(sbi, DENTRY_OPS);
+	lock_page(page);
+	wait_on_page_writeback(page);
+	de->ino = cpu_to_le32(inode->i_ino);
+	set_de_type(de, inode);
+	kunmap(page);
+	set_page_dirty(page);
+	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
+	mark_inode_dirty(dir);
+
+	/* update parent inode number before releasing dentry page */
+	F2FS_I(inode)->i_pino = dir->i_ino;
+
+	f2fs_put_page(page, 1);
+	mutex_unlock_op(sbi, DENTRY_OPS);
+}
+
+void init_dent_inode(struct dentry *dentry, struct page *ipage)
+{
+	struct f2fs_node *rn;
+
+	if (IS_ERR(ipage))
+		return;
+
+	wait_on_page_writeback(ipage);
+
+	/* copy dentry info. to this inode page */
+	rn = (struct f2fs_node *)page_address(ipage);
+	rn->i.i_namelen = cpu_to_le32(dentry->d_name.len);
+	memcpy(rn->i.i_name, dentry->d_name.name, dentry->d_name.len);
+	set_page_dirty(ipage);
+}
+
+static int init_inode_metadata(struct inode *inode, struct dentry *dentry)
+{
+	struct inode *dir = dentry->d_parent->d_inode;
+
+	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
+		int err;
+		err = new_inode_page(inode, dentry);
+		if (err)
+			return err;
+
+		if (S_ISDIR(inode->i_mode)) {
+			err = f2fs_make_empty(inode, dir);
+			if (err) {
+				remove_inode_page(inode);
+				return err;
+			}
+		}
+
+		err = f2fs_init_acl(inode, dir);
+		if (err) {
+			remove_inode_page(inode);
+			return err;
+		}
+	} else {
+		struct page *ipage;
+		ipage = get_node_page(F2FS_SB(dir->i_sb), inode->i_ino);
+		if (IS_ERR(ipage))
+			return PTR_ERR(ipage);
+		init_dent_inode(dentry, ipage);
+		f2fs_put_page(ipage, 1);
+	}
+	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK)) {
+		inc_nlink(inode);
+		f2fs_write_inode(inode, NULL);
+	}
+	return 0;
+}
+
+static void update_parent_metadata(struct inode *dir, struct inode *inode,
+						unsigned int current_depth)
+{
+	bool need_dir_update = false;
+
+	if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
+		if (S_ISDIR(inode->i_mode)) {
+			inc_nlink(dir);
+			need_dir_update = true;
+		}
+		clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);
+	}
+	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
+	if (F2FS_I(dir)->i_current_depth != current_depth) {
+		F2FS_I(dir)->i_current_depth = current_depth;
+		need_dir_update = true;
+	}
+
+	if (need_dir_update)
+		f2fs_write_inode(dir, NULL);
+	else
+		mark_inode_dirty(dir);
+
+	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))
+		clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
+}
+
+static int room_for_filename(struct f2fs_dentry_block *dentry_blk, int slots)
+{
+	int bit_start = 0;
+	int zero_start, zero_end;
+next:
+	zero_start = find_next_zero_bit_le(&dentry_blk->dentry_bitmap,
+						NR_DENTRY_IN_BLOCK,
+						bit_start);
+	if (zero_start >= NR_DENTRY_IN_BLOCK)
+		return NR_DENTRY_IN_BLOCK;
+
+	zero_end = find_next_bit_le(&dentry_blk->dentry_bitmap,
+						NR_DENTRY_IN_BLOCK,
+						zero_start);
+	if (zero_end - zero_start >= slots)
+		return zero_start;
+
+	bit_start = zero_end + 1;
+
+	if (zero_end + 1 >= NR_DENTRY_IN_BLOCK)
+		return NR_DENTRY_IN_BLOCK;
+	goto next;
+}
+
+int f2fs_add_link(struct dentry *dentry, struct inode *inode)
+{
+	unsigned int bit_pos;
+	unsigned int level;
+	unsigned int current_depth;
+	unsigned long bidx, block;
+	f2fs_hash_t dentry_hash;
+	struct f2fs_dir_entry *de;
+	unsigned int nbucket, nblock;
+	struct inode *dir = dentry->d_parent->d_inode;
+	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
+	const char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	struct page *dentry_page = NULL;
+	struct f2fs_dentry_block *dentry_blk = NULL;
+	int slots = GET_DENTRY_SLOTS(namelen);
+	int err = 0;
+	int i;
+
+	dentry_hash = f2fs_dentry_hash(name, dentry->d_name.len);
+	level = 0;
+	current_depth = F2FS_I(dir)->i_current_depth;
+	if (F2FS_I(dir)->chash == dentry_hash) {
+		level = F2FS_I(dir)->clevel;
+		F2FS_I(dir)->chash = 0;
+	}
+
+start:
+	if (current_depth == MAX_DIR_HASH_DEPTH)
+		return -ENOSPC;
+
+	/* Increase the depth, if required */
+	if (level == current_depth)
+		++current_depth;
+
+	nbucket = dir_buckets(level);
+	nblock = bucket_blocks(level);
+
+	bidx = dir_block_index(level, (le32_to_cpu(dentry_hash) % nbucket));
+
+	for (block = bidx; block <= (bidx + nblock - 1); block++) {
+		mutex_lock_op(sbi, DENTRY_OPS);
+		dentry_page = get_new_data_page(dir, block, true);
+		if (IS_ERR(dentry_page)) {
+			mutex_unlock_op(sbi, DENTRY_OPS);
+			return PTR_ERR(dentry_page);
+		}
+
+		dentry_blk = kmap(dentry_page);
+		bit_pos = room_for_filename(dentry_blk, slots);
+		if (bit_pos < NR_DENTRY_IN_BLOCK)
+			goto add_dentry;
+
+		kunmap(dentry_page);
+		f2fs_put_page(dentry_page, 1);
+		mutex_unlock_op(sbi, DENTRY_OPS);
+	}
+
+	/* Move to next level to find the empty slot for new dentry */
+	++level;
+	goto start;
+add_dentry:
+	err = init_inode_metadata(inode, dentry);
+	if (err)
+		goto fail;
+
+	wait_on_page_writeback(dentry_page);
+
+	de = &dentry_blk->dentry[bit_pos];
+	de->hash_code = dentry_hash;
+	de->name_len = cpu_to_le16(namelen);
+	memcpy(dentry_blk->filename[bit_pos], name, namelen);
+	de->ino = cpu_to_le32(inode->i_ino);
+	set_de_type(de, inode);
+	for (i = 0; i < slots; i++)
+		test_and_set_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
+	set_page_dirty(dentry_page);
+
+	update_parent_metadata(dir, inode, current_depth);
+
+	/* update parent inode number before releasing dentry page */
+	F2FS_I(inode)->i_pino = dir->i_ino;
+fail:
+	kunmap(dentry_page);
+	f2fs_put_page(dentry_page, 1);
+	mutex_unlock_op(sbi, DENTRY_OPS);
+	return err;
+}
+
+/*
+ * It only removes the dentry from the dentry page,corresponding name
+ * entry in name page does not need to be touched during deletion.
+ */
+void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
+						struct inode *inode)
+{
+	struct	f2fs_dentry_block *dentry_blk;
+	unsigned int bit_pos;
+	struct address_space *mapping = page->mapping;
+	struct inode *dir = mapping->host;
+	struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
+	int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
+	void *kaddr = page_address(page);
+	int i;
+
+	mutex_lock_op(sbi, DENTRY_OPS);
+
+	lock_page(page);
+	wait_on_page_writeback(page);
+
+	dentry_blk = (struct f2fs_dentry_block *)kaddr;
+	bit_pos = dentry - (struct f2fs_dir_entry *)dentry_blk->dentry;
+	for (i = 0; i < slots; i++)
+		test_and_clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
+
+	/* Let's check and deallocate this dentry page */
+	bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
+			NR_DENTRY_IN_BLOCK,
+			0);
+	kunmap(page); /* kunmap - pair of f2fs_find_entry */
+	set_page_dirty(page);
+
+	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+
+	if (inode && S_ISDIR(inode->i_mode)) {
+		drop_nlink(dir);
+		f2fs_write_inode(dir, NULL);
+	} else {
+		mark_inode_dirty(dir);
+	}
+
+	if (inode) {
+		inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+		drop_nlink(inode);
+		if (S_ISDIR(inode->i_mode)) {
+			drop_nlink(inode);
+			i_size_write(inode, 0);
+		}
+		f2fs_write_inode(inode, NULL);
+		if (inode->i_nlink == 0)
+			add_orphan_inode(sbi, inode->i_ino);
+	}
+
+	if (bit_pos == NR_DENTRY_IN_BLOCK) {
+		truncate_hole(dir, page->index, page->index + 1);
+		clear_page_dirty_for_io(page);
+		ClearPageUptodate(page);
+		dec_page_count(sbi, F2FS_DIRTY_DENTS);
+		inode_dec_dirty_dents(dir);
+	}
+	f2fs_put_page(page, 1);
+
+	mutex_unlock_op(sbi, DENTRY_OPS);
+}
+
+int f2fs_make_empty(struct inode *inode, struct inode *parent)
+{
+	struct page *dentry_page;
+	struct f2fs_dentry_block *dentry_blk;
+	struct f2fs_dir_entry *de;
+	void *kaddr;
+
+	dentry_page = get_new_data_page(inode, 0, true);
+	if (IS_ERR(dentry_page))
+		return PTR_ERR(dentry_page);
+
+	kaddr = kmap_atomic(dentry_page);
+	dentry_blk = (struct f2fs_dentry_block *)kaddr;
+
+	de = &dentry_blk->dentry[0];
+	de->name_len = cpu_to_le16(1);
+	de->hash_code = 0;
+	de->ino = cpu_to_le32(inode->i_ino);
+	memcpy(dentry_blk->filename[0], ".", 1);
+	set_de_type(de, inode);
+
+	de = &dentry_blk->dentry[1];
+	de->hash_code = 0;
+	de->name_len = cpu_to_le16(2);
+	de->ino = cpu_to_le32(parent->i_ino);
+	memcpy(dentry_blk->filename[1], "..", 2);
+	set_de_type(de, inode);
+
+	test_and_set_bit_le(0, &dentry_blk->dentry_bitmap);
+	test_and_set_bit_le(1, &dentry_blk->dentry_bitmap);
+	kunmap_atomic(kaddr);
+
+	set_page_dirty(dentry_page);
+	f2fs_put_page(dentry_page, 1);
+	return 0;
+}
+
+bool f2fs_empty_dir(struct inode *dir)
+{
+	unsigned long bidx;
+	struct page *dentry_page;
+	unsigned int bit_pos;
+	struct	f2fs_dentry_block *dentry_blk;
+	unsigned long nblock = dir_blocks(dir);
+
+	for (bidx = 0; bidx < nblock; bidx++) {
+		void *kaddr;
+		dentry_page = get_lock_data_page(dir, bidx);
+		if (IS_ERR(dentry_page)) {
+			if (PTR_ERR(dentry_page) == -ENOENT)
+				continue;
+			else
+				return false;
+		}
+
+		kaddr = kmap_atomic(dentry_page);
+		dentry_blk = (struct f2fs_dentry_block *)kaddr;
+		if (bidx == 0)
+			bit_pos = 2;
+		else
+			bit_pos = 0;
+		bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
+						NR_DENTRY_IN_BLOCK,
+						bit_pos);
+		kunmap_atomic(kaddr);
+
+		f2fs_put_page(dentry_page, 1);
+
+		if (bit_pos < NR_DENTRY_IN_BLOCK)
+			return false;
+	}
+	return true;
+}
+
+static int f2fs_readdir(struct file *file, void *dirent, filldir_t filldir)
+{
+	unsigned long pos = file->f_pos;
+	struct inode *inode = file->f_dentry->d_inode;
+	unsigned long npages = dir_blocks(inode);
+	unsigned char *types = NULL;
+	unsigned int bit_pos = 0, start_bit_pos = 0;
+	int over = 0;
+	struct f2fs_dentry_block *dentry_blk = NULL;
+	struct f2fs_dir_entry *de = NULL;
+	struct page *dentry_page = NULL;
+	unsigned int n = 0;
+	unsigned char d_type = DT_UNKNOWN;
+	int slots;
+
+	types = f2fs_filetype_table;
+	bit_pos = (pos % NR_DENTRY_IN_BLOCK);
+	n = (pos / NR_DENTRY_IN_BLOCK);
+
+	for ( ; n < npages; n++) {
+		dentry_page = get_lock_data_page(inode, n);
+		if (IS_ERR(dentry_page))
+			continue;
+
+		start_bit_pos = bit_pos;
+		dentry_blk = kmap(dentry_page);
+		while (bit_pos < NR_DENTRY_IN_BLOCK) {
+			d_type = DT_UNKNOWN;
+			bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
+							NR_DENTRY_IN_BLOCK,
+							bit_pos);
+			if (bit_pos >= NR_DENTRY_IN_BLOCK)
+				break;
+
+			de = &dentry_blk->dentry[bit_pos];
+			if (types && de->file_type < F2FS_FT_MAX)
+				d_type = types[de->file_type];
+
+			over = filldir(dirent,
+					dentry_blk->filename[bit_pos],
+					le16_to_cpu(de->name_len),
+					(n * NR_DENTRY_IN_BLOCK) + bit_pos,
+					le32_to_cpu(de->ino), d_type);
+			if (over) {
+				file->f_pos += bit_pos - start_bit_pos;
+				goto success;
+			}
+			slots = GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
+			bit_pos += slots;
+		}
+		bit_pos = 0;
+		file->f_pos = (n + 1) * NR_DENTRY_IN_BLOCK;
+		kunmap(dentry_page);
+		f2fs_put_page(dentry_page, 1);
+		dentry_page = NULL;
+	}
+success:
+	if (dentry_page && !IS_ERR(dentry_page)) {
+		kunmap(dentry_page);
+		f2fs_put_page(dentry_page, 1);
+	}
+
+	return 0;
+}
+
+const struct file_operations f2fs_dir_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.readdir	= f2fs_readdir,
+	.fsync		= f2fs_sync_file,
+	.unlocked_ioctl	= f2fs_ioctl,
+};

fs/f2fs/gc.h

+/*
+ * fs/f2fs/gc.h
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#define GC_THREAD_NAME	"f2fs_gc_task"
+#define GC_THREAD_MIN_WB_PAGES		1	/*
+						 * a threshold to determine
+						 * whether IO subsystem is idle
+						 * or not
+						 */
+#define GC_THREAD_MIN_SLEEP_TIME	10000 /* milliseconds */
+#define GC_THREAD_MAX_SLEEP_TIME	30000
+#define GC_THREAD_NOGC_SLEEP_TIME	10000
+#define LIMIT_INVALID_BLOCK	40 /* percentage over total user space */
+#define LIMIT_FREE_BLOCK	40 /* percentage over invalid + free space */
+
+/* Search max. number of dirty segments to select a victim segment */
+#define MAX_VICTIM_SEARCH	20
+
+enum {
+	GC_NONE = 0,
+	GC_ERROR,
+	GC_OK,
+	GC_NEXT,
+	GC_BLOCKED,
+	GC_DONE,
+};
+
+struct f2fs_gc_kthread {
+	struct task_struct *f2fs_gc_task;
+	wait_queue_head_t gc_wait_queue_head;
+};
+
+struct inode_entry {
+	struct list_head list;
+	struct inode *inode;
+};
+
+/*
+ * inline functions
+ */
+static inline block_t free_user_blocks(struct f2fs_sb_info *sbi)
+{
+	if (free_segments(sbi) < overprovision_segments(sbi))
+		return 0;
+	else
+		return (free_segments(sbi) - overprovision_segments(sbi))
+			<< sbi->log_blocks_per_seg;
+}
+
+static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi)
+{
+	return (long)(sbi->user_block_count * LIMIT_INVALID_BLOCK) / 100;
+}
+
+static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi)
+{
+	block_t reclaimable_user_blocks = sbi->user_block_count -
+		written_block_count(sbi);
+	return (long)(reclaimable_user_blocks * LIMIT_FREE_BLOCK) / 100;
+}
+
+static inline long increase_sleep_time(long wait)
+{
+	wait += GC_THREAD_MIN_SLEEP_TIME;
+	if (wait > GC_THREAD_MAX_SLEEP_TIME)
+		wait = GC_THREAD_MAX_SLEEP_TIME;
+	return wait;
+}
+
+static inline long decrease_sleep_time(long wait)
+{
+	wait -= GC_THREAD_MIN_SLEEP_TIME;
+	if (wait <= GC_THREAD_MIN_SLEEP_TIME)
+		wait = GC_THREAD_MIN_SLEEP_TIME;
+	return wait;
+}
+
+static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
+{
+	block_t invalid_user_blocks = sbi->user_block_count -
+					written_block_count(sbi);
+	/*
+	 * Background GC is triggered with the following condition.
+	 * 1. There are a number of invalid blocks.
+	 * 2. There is not enough free space.
+	 */
+	if (invalid_user_blocks > limit_invalid_user_blocks(sbi) &&
+			free_user_blocks(sbi) < limit_free_user_blocks(sbi))
+		return true;
+	return false;
+}
+
+static inline int is_idle(struct f2fs_sb_info *sbi)
+{
+	struct block_device *bdev = sbi->sb->s_bdev;
+	struct request_queue *q = bdev_get_queue(bdev);
+	struct request_list *rl = &q->root_rl;
+	return !(rl->count[BLK_RW_SYNC]) && !(rl->count[BLK_RW_ASYNC]);
+}
+
+static inline bool should_do_checkpoint(struct f2fs_sb_info *sbi)
+{
+	unsigned int pages_per_sec = sbi->segs_per_sec *
+					(1 << sbi->log_blocks_per_seg);
+	int node_secs = ((get_pages(sbi, F2FS_DIRTY_NODES) + pages_per_sec - 1)
+			>> sbi->log_blocks_per_seg) / sbi->segs_per_sec;
+	int dent_secs = ((get_pages(sbi, F2FS_DIRTY_DENTS) + pages_per_sec - 1)
+			>> sbi->log_blocks_per_seg) / sbi->segs_per_sec;
+	return free_sections(sbi) <= (node_secs + 2 * dent_secs + 2);
+}

fs/f2fs/hash.c

+/*
+ * fs/f2fs/hash.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * Portions of this code from linux/fs/ext3/hash.c
+ *
+ * Copyright (C) 2002 by Theodore Ts'o
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/f2fs_fs.h>
+#include <linux/cryptohash.h>
+#include <linux/pagemap.h>
+
+#include "f2fs.h"
+
+/*
+ * Hashing code copied from ext3
+ */
+#define DELTA 0x9E3779B9
+
+static void TEA_transform(unsigned int buf[4], unsigned int const in[])
+{
+	__u32 sum = 0;
+	__u32 b0 = buf[0], b1 = buf[1];
+	__u32 a = in[0], b = in[1], c = in[2], d = in[3];
+	int n = 16;
+
+	do {
+		sum += DELTA;
+		b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
+		b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
+	} while (--n);
+
+	buf[0] += b0;
+	buf[1] += b1;
+}
+
+static void str2hashbuf(const char *msg, int len, unsigned int *buf, int num)
+{
+	unsigned pad, val;
+	int i;
+
+	pad = (__u32)len | ((__u32)len << 8);
+	pad |= pad << 16;
+
+	val = pad;
+	if (len > num * 4)
+		len = num * 4;
+	for (i = 0; i < len; i++) {
+		if ((i % 4) == 0)
+			val = pad;
+		val = msg[i] + (val << 8);
+		if ((i % 4) == 3) {
+			*buf++ = val;
+			val = pad;
+			num--;
+		}
+	}
+	if (--num >= 0)
+		*buf++ = val;
+	while (--num >= 0)
+		*buf++ = pad;
+}
+
+f2fs_hash_t f2fs_dentry_hash(const char *name, int len)
+{
+	__u32 hash, minor_hash;
+	f2fs_hash_t f2fs_hash;
+	const char *p;
+	__u32 in[8], buf[4];
+
+	/* Initialize the default seed for the hash checksum functions */
+	buf[0] = 0x67452301;
+	buf[1] = 0xefcdab89;
+	buf[2] = 0x98badcfe;
+	buf[3] = 0x10325476;
+
+	p = name;
+	while (len > 0) {
+		str2hashbuf(p, len, in, 4);
+		TEA_transform(buf, in);
+		len -= 16;
+		p += 16;
+	}
+	hash = buf[0];
+	minor_hash = buf[1];
+
+	f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT);
+	return f2fs_hash;
+}

fs/f2fs/xattr.h

+/*
+ * fs/f2fs/xattr.h
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ *             http://www.samsung.com/
+ *
+ * Portions of this code from linux/fs/ext2/xattr.h
+ *
+ * On-disk format of extended attributes for the ext2 filesystem.
+ *
+ * (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __F2FS_XATTR_H__
+#define __F2FS_XATTR_H__
+
+#include <linux/init.h>
+#include <linux/xattr.h>
+
+/* Magic value in attribute blocks */
+#define F2FS_XATTR_MAGIC                0xF2F52011
+
+/* Maximum number of references to one attribute block */
+#define F2FS_XATTR_REFCOUNT_MAX         1024
+
+/* Name indexes */
+#define F2FS_SYSTEM_ADVISE_PREFIX		"system.advise"
+#define F2FS_XATTR_INDEX_USER			1
+#define F2FS_XATTR_INDEX_POSIX_ACL_ACCESS	2
+#define F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT	3
+#define F2FS_XATTR_INDEX_TRUSTED		4
+#define F2FS_XATTR_INDEX_LUSTRE			5
+#define F2FS_XATTR_INDEX_SECURITY		6
+#define F2FS_XATTR_INDEX_ADVISE			7
+
+struct f2fs_xattr_header {
+	__le32  h_magic;        /* magic number for identification */
+	__le32  h_refcount;     /* reference count */
+	__u32   h_reserved[4];  /* zero right now */
+};
+
+struct f2fs_xattr_entry {
+	__u8    e_name_index;
+	__u8    e_name_len;
+	__le16  e_value_size;   /* size of attribute value */
+	char    e_name[0];      /* attribute name */
+};
+
+#define XATTR_HDR(ptr)		((struct f2fs_xattr_header *)(ptr))
+#define XATTR_ENTRY(ptr)	((struct f2fs_xattr_entry *)(ptr))
+#define XATTR_FIRST_ENTRY(ptr)	(XATTR_ENTRY(XATTR_HDR(ptr)+1))
+#define XATTR_ROUND		(3)
+
+#define XATTR_ALIGN(size)	((size + XATTR_ROUND) & ~XATTR_ROUND)
+
+#define ENTRY_SIZE(entry) (XATTR_ALIGN(sizeof(struct f2fs_xattr_entry) + \
+			entry->e_name_len + le16_to_cpu(entry->e_value_size)))
+
+#define XATTR_NEXT_ENTRY(entry)	((struct f2fs_xattr_entry *)((char *)(entry) +\
+			ENTRY_SIZE(entry)))
+
+#define IS_XATTR_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
+
+#define list_for_each_xattr(entry, addr) \
+		for (entry = XATTR_FIRST_ENTRY(addr);\
+				!IS_XATTR_LAST_ENTRY(entry);\
+				entry = XATTR_NEXT_ENTRY(entry))
+
+
+#define MIN_OFFSET	XATTR_ALIGN(PAGE_SIZE - \
+			sizeof(struct node_footer) - \
+			sizeof(__u32))
+
+#define MAX_VALUE_LEN	(MIN_OFFSET - sizeof(struct f2fs_xattr_header) - \
+			sizeof(struct f2fs_xattr_entry))
+
+/*
+ * On-disk structure of f2fs_xattr
+ * We use only 1 block for xattr.
+ *
+ * +--------------------+
+ * | f2fs_xattr_header  |
+ * |                    |
+ * +--------------------+
+ * | f2fs_xattr_entry   |
+ * | .e_name_index = 1  |
+ * | .e_name_len = 3    |
+ * | .e_value_size = 14 |
+ * | .e_name = "foo"    |
+ * | "value_of_xattr"   |<- value_offs = e_name + e_name_len
+ * +--------------------+
+ * | f2fs_xattr_entry   |
+ * | .e_name_index = 4  |
+ * | .e_name = "bar"    |
+ * +--------------------+
+ * |                    |
+ * |        Free        |
+ * |                    |
+ * +--------------------+<- MIN_OFFSET
+ * |   node_footer      |
+ * | (nid, ino, offset) |
+ * +--------------------+
+ *
+ **/
+
+#ifdef CONFIG_F2FS_FS_XATTR
+extern const struct xattr_handler f2fs_xattr_user_handler;
+extern const struct xattr_handler f2fs_xattr_trusted_handler;
+extern const struct xattr_handler f2fs_xattr_acl_access_handler;
+extern const struct xattr_handler f2fs_xattr_acl_default_handler;
+extern const struct xattr_handler f2fs_xattr_advise_handler;
+
+extern const struct xattr_handler *f2fs_xattr_handlers[];
+
+extern int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
+		const void *value, size_t value_len);
+extern int f2fs_getxattr(struct inode *inode, int name_index, const char *name,
+		void *buffer, size_t buffer_size);
+extern ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
+		size_t buffer_size);
+
+#else
+
+#define f2fs_xattr_handlers	NULL
+static inline int f2fs_setxattr(struct inode *inode, int name_index,
+	const char *name, const void *value, size_t value_len)
+{
+	return -EOPNOTSUPP;
+}
+static inline int f2fs_getxattr(struct inode *inode, int name_index,
+		const char *name, void *buffer, size_t buffer_size)
+{
+	return -EOPNOTSUPP;
+}
+static inline ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer,
+		size_t buffer_size)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
+#endif /* __F2FS_XATTR_H__ */

include/uapi/linux/magic.h

@@ -23,6 +23,7 @@
 #define EXT4_SUPER_MAGIC	0xEF53
 #define BTRFS_SUPER_MAGIC	0x9123683E
 #define NILFS_SUPER_MAGIC	0x3434
+#define F2FS_SUPER_MAGIC	0xF2F52010
 #define HPFS_SUPER_MAGIC	0xf995e849
 #define ISOFS_SUPER_MAGIC	0x9660
 #define JFFS2_SUPER_MAGIC	0x72b6