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Jaegeuk Kim 763bfe1bc5 f2fs: remove reusing any prefree segments 
This patch removes check_prefree_segments initially designed to enhance the
performance by narrowing the range of LBA usage across the whole block device.

When allocating a new segment, previous f2fs tries to find proper prefree
segments, and then, if finds a segment, it reuses the segment for further
data or node block allocation.

However, I found that this was totally wrong approach since the prefree segments
have several data or node blocks that will be used by the roll-forward mechanism
operated after sudden-power-off.

Let's assume the following scenario.

/* write 8MB with fsync */
for (i = 0; i < 2048; i++) {
	offset = i * 4096;
	write(fd, offset, 4KB);
	fsync(fd);
}

In this case, naive segment allocation sequence will be like:
 data segment: x, x+1, x+2, x+3
 node segment: y, y+1, y+2, y+3.

But, if we can reuse prefree segments, the sequence can be like:
 data segment: x, x+1, y, y+1
 node segment: y, y+1, y+2, y+3.
Because, y, y+1, and y+2 became prefree segments one by one, and those are
reused by data allocation.

After conducting this workload, we should consider how to recover the latest
inode with its data.
If we reuse the prefree segments such as y or y+1, we lost the old node blocks
so that f2fs even cannot start roll-forward recovery.

Therefore, I suggest that we should remove reusing prefree segments.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
2013-07-02 08:48:15 +09:00
..
9p aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
adfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
affs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
afs aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
autofs4 autofs - remove autofs dentry mount check 2013-05-06 13:06:59 -07:00
befs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-04-30 09:36:50 -07:00
bfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2013-05-18 11:35:28 -07:00
cachefiles lift sb_start_write() out of ->write() 2013-04-09 14:12:56 -04:00
ceph aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
cifs cifs: only set ops for inodes in I_NEW state 2013-05-08 17:12:47 -05:00
coda lift sb_start_write() out of ->write() 2013-04-09 14:12:56 -04:00
configfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
cramfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
debugfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
devpts fs: Limit sys_mount to only request filesystem modules (Part 2). 2013-03-07 01:08:55 -08:00
dlm Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-05-01 14:08:52 -07:00
ecryptfs Improve performance when AES-NI (and most likely other crypto accelerators) is 2013-05-10 09:20:01 -07:00
efivarfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
efs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
exofs block: Add bio_for_each_segment_all() 2013-03-23 14:26:28 -07:00
exportfs hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
ext2 aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
ext3 Merge branch 'akpm' (incoming from Andrew) 2013-05-07 20:49:51 -07:00
ext4 Fixed regressions (two stability regressions and a performance 2013-05-14 09:30:54 -07:00
f2fs f2fs: remove reusing any prefree segments 2013-07-02 08:48:15 +09:00
fat fat: fix possible overflow for fat_clusters 2013-05-24 16:22:50 -07:00
freevxfs fs: Readd the fs module aliases. 2013-03-12 18:55:21 -07:00
fscache fs/fscache/stats.c: fix memory leak 2013-04-29 15:54:27 -07:00
fuse Merge branch 'akpm' (incoming from Andrew) 2013-05-07 20:49:51 -07:00
gfs2 GFS2: Fix typo in gfs2_log_end_write loop 2013-05-24 13:48:09 +01:00
hfs hfs: avoid crash in hfs_bnode_create 2013-05-24 16:22:51 -07:00
hfsplus aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
hostfs hostfs: use kmalloc instead of kzalloc 2013-05-04 15:48:45 -04:00
hpfs hpfs: move setting hpfs-private i_dirty to ->write_end() 2013-04-09 14:12:55 -04:00
hppfs hppfs: get rid of ->fsync() 2013-04-29 15:41:42 -04:00
hugetlbfs hugetlbfs: fix mmap failure in unaligned size request 2013-05-07 18:38:27 -07:00
isofs fs: Readd the fs module aliases. 2013-03-12 18:55:21 -07:00
jbd Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2013-05-03 09:56:25 -07:00
jbd2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
jffs2 fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
jfs Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
lockd LOCKD: Ensure that nlmclnt_block resets block->b_status after a server reboot 2013-04-21 18:08:42 -04:00
logfs block: Remove bi_idx references 2013-03-23 14:15:31 -07:00
minix fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
ncpfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
nfs NFS: Fix SETCLIENTID fallback if GSS is not available 2013-05-23 18:50:40 -04:00
nfs_common nfs_common: Update the translation between nfsv3 acls linux posix acls 2013-02-13 06:15:14 -08:00
nfsd Merge branch 'for-3.10' of git://linux-nfs.org/~bfields/linux 2013-05-10 09:28:55 -07:00
nilfs2 nilfs2: fix issue of nilfs_set_page_dirty() for page at EOF boundary 2013-05-24 16:22:52 -07:00
nls
notify unify compat fanotify_mark(2), switch to COMPAT_SYSCALL_DEFINE 2013-05-09 13:46:38 -04:00
ntfs aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
ocfs2 ocfs2: goto out_unlock if ocfs2_get_clusters_nocache() failed in ocfs2_fiemap() 2013-05-24 16:22:52 -07:00
omfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
openpromfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
proc Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 2013-05-07 08:42:20 -07:00
pstore Couple of pstore cleanups 2013-05-09 16:42:10 -07:00
qnx4 fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
qnx6 fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
quota quota: add missing use of dq_data_lock in __dquot_initialize 2013-03-11 22:05:56 +01:00
ramfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
reiserfs Merge branch 'akpm' (incoming from Andrew) 2013-05-07 20:49:51 -07:00
romfs romfs: fix nommu map length to keep inside filesystem 2013-04-29 09:17:57 +10:00
squashfs fs: Limit sys_mount to only request filesystem modules. (Part 3) 2013-03-11 07:09:48 -07:00
sysfs sysfs: check if one entry has been removed before freeing 2013-04-05 15:35:52 -07:00
sysv fs: Readd the fs module aliases. 2013-03-12 18:55:21 -07:00
ubifs aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
udf aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
ufs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-04-30 09:36:50 -07:00
xfs xfs: remote attribute lookups require the value length 2013-05-24 16:31:20 -05:00
aio.c aio: fix kioctx not being freed after cancellation at exit time 2013-05-24 16:22:53 -07:00
anon_inodes.c get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero 2013-02-26 02:46:11 -05:00
attr.c
bad_inode.c lseek: the "whence" argument is called "whence" 2012-12-17 17:15:12 -08:00
binfmt_aout.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
binfmt_elf_fdpic.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2013-05-02 10:16:16 -07:00
binfmt_elf.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2013-05-02 10:16:16 -07:00
binfmt_em86.c exec: use -ELOOP for max recursion depth 2012-12-17 17:15:23 -08:00
binfmt_flat.c new helper: read_code() 2013-04-29 15:40:23 -04:00
binfmt_misc.c binfmt_misc: reuse string_unescape_inplace() 2013-04-30 17:04:03 -07:00
binfmt_script.c exec: do not leave bprm->interp on stack 2012-12-20 17:40:19 -08:00
binfmt_som.c
bio-integrity.c bio-integrity: Add explicit field for owner of bip_buf 2013-03-23 14:26:34 -07:00
bio.c Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
block_dev.c Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
buffer.c Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
char_dev.c
compat_binfmt_elf.c
compat_ioctl.c Removed unused typedef to avoid "unused local typedef" warnings. 2013-05-04 15:03:05 -04:00
compat.c aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
coredump.c do_coredump(): don't wait for thaw if coredump has already been interrupted 2013-05-04 14:45:54 -04:00
coredump.h
dcache.c vfs: use list_move instead of list_del/list_add 2013-05-04 15:43:02 -04:00
dcookies.c consolidate compat lookup_dcookie() 2013-03-03 23:00:23 -05:00
direct-io.c Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
drop_caches.c
eventfd.c fs, eventfd: add procfs fdinfo helper 2012-12-17 17:15:27 -08:00
eventpoll.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2013-05-01 07:21:43 -07:00
exec.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
fcntl.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
fhandle.c Merge branch 'for-3.8' of git://linux-nfs.org/~bfields/linux 2012-12-20 14:04:11 -08:00
file_table.c cache the value of file_inode() in struct file 2013-03-01 19:48:30 -05:00
file.c don't bother with deferred freeing of fdtables 2013-05-01 17:31:42 -04:00
filesystems.c fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
fs_struct.c constify path_get/path_put and fs_struct.c stuff 2013-03-01 23:51:07 -05:00
fs-writeback.c Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block 2013-05-08 10:13:35 -07:00
generic_acl.c
inode.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
internal.h pipe: fold file_operations instances in one 2013-04-09 14:12:58 -04:00
ioctl.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
ioprio.c
Kconfig efivarfs: Move to fs/efivarfs 2013-04-17 13:25:09 +01:00
Kconfig.binfmt fs: make binfmt support for #! scripts modular and removable 2013-04-30 17:04:04 -07:00
libfs.c vfs: drop vmtruncate 2012-12-20 18:46:29 -05:00
locks.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
Makefile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
mbcache.c
mount.h get rid of full-hash scan on detaching vfsmounts 2013-04-09 14:12:52 -04:00
mpage.c
namei.c Merge git://git.infradead.org/users/eparis/audit 2013-05-11 14:29:11 -07:00
namespace.c create_mnt_ns: unidiomatic use of list_add() 2013-05-04 15:18:53 -04:00
no-block.c
open.c make SYSCALL_DEFINE<n>-generated wrappers do asmlinkage_protect 2013-03-03 22:58:33 -05:00
pipe.c aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
pnode.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
pnode.h Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
posix_acl.c
proc_namespace.c
read_write.c aio: don't include aio.h in sched.h 2013-05-07 20:16:25 -07:00
readdir.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
select.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
seq_file.c new helper: single_open_size() 2013-04-09 14:13:29 -04:00
signalfd.c switch signalfd{,4}() to COMPAT_SYSCALL_DEFINE 2013-03-03 22:58:46 -05:00
splice.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
stack.c
stat.c switch vfs_getattr() to struct path 2013-02-26 02:46:08 -05:00
statfs.c vfs: fix user_statfs to retry once on ESTALE errors 2012-12-20 18:50:07 -05:00
super.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
sync.c teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long 2013-03-03 22:46:22 -05:00
timerfd.c compat: restore timerfd settime and gettime compat syscalls 2013-03-02 09:35:13 -05:00
utimes.c vfs: allow utimensat() calls to retry once on an ESTALE error 2012-12-20 18:50:08 -05:00
xattr_acl.c
xattr.c vfs: make lremovexattr retry once on ESTALE error 2012-12-20 18:50:11 -05:00