This patch supports to store chksum value with compressed
data, and verify the integrality of compressed data while
reading the data.
The feature can be enabled through specifying mount option
'compress_chksum'.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Add two slab caches: "f2fs_cic_entry" and "f2fs_dic_entry" for memory
allocation of compress_io_ctx and decompress_io_ctx structure.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
As 5kft <5kft@5kft.org> reported:
kworker/u9:3: page allocation failure: order:9, mode:0x40c40(GFP_NOFS|__GFP_COMP), nodemask=(null),cpuset=/,mems_allowed=0
CPU: 3 PID: 8168 Comm: kworker/u9:3 Tainted: G C 5.8.3-sunxi #trunk
Hardware name: Allwinner sun8i Family
Workqueue: f2fs_post_read_wq f2fs_post_read_work
[<c010d6d5>] (unwind_backtrace) from [<c0109a55>] (show_stack+0x11/0x14)
[<c0109a55>] (show_stack) from [<c056d489>] (dump_stack+0x75/0x84)
[<c056d489>] (dump_stack) from [<c0243b53>] (warn_alloc+0xa3/0x104)
[<c0243b53>] (warn_alloc) from [<c024473b>] (__alloc_pages_nodemask+0xb87/0xc40)
[<c024473b>] (__alloc_pages_nodemask) from [<c02267c5>] (kmalloc_order+0x19/0x38)
[<c02267c5>] (kmalloc_order) from [<c02267fd>] (kmalloc_order_trace+0x19/0x90)
[<c02267fd>] (kmalloc_order_trace) from [<c047c665>] (zstd_init_decompress_ctx+0x21/0x88)
[<c047c665>] (zstd_init_decompress_ctx) from [<c047e9cf>] (f2fs_decompress_pages+0x97/0x228)
[<c047e9cf>] (f2fs_decompress_pages) from [<c045d0ab>] (__read_end_io+0xfb/0x130)
[<c045d0ab>] (__read_end_io) from [<c045d141>] (f2fs_post_read_work+0x61/0x84)
[<c045d141>] (f2fs_post_read_work) from [<c0130b2f>] (process_one_work+0x15f/0x3b0)
[<c0130b2f>] (process_one_work) from [<c0130e7b>] (worker_thread+0xfb/0x3e0)
[<c0130e7b>] (worker_thread) from [<c0135c3b>] (kthread+0xeb/0x10c)
[<c0135c3b>] (kthread) from [<c0100159>]
zstd may allocate large size memory for {,de}compression, it may cause
file copy failure on low-end device which has very few memory.
For decompression, let's just allocate proper size memory based on current
file's cluster size instead of max cluster size.
Reported-by: 5kft <5kft@5kft.org>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
refcount_t type variable should never be less than one, so it's a
little bit hard to understand when we use it to indicate pending
compressed page count, let's change to use atomic_t for better
readability.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
In this round, we've added two small interfaces, 1) GC_URGENT_LOW mode for
performance, and 2) F2FS_IOC_SEC_TRIM_FILE ioctl for security. The new GC
mode allows Android to run some lower priority GCs in background, while new
ioctl discards user information without race condition when the account is
removed. In addition, some patches were merged to address latency-related
issues. We've fixed some compression-related bug fixes as well as edge race
conditions.
Enhancement:
- add GC_URGENT_LOW mode in gc_urgent
- introduce F2FS_IOC_SEC_TRIM_FILE ioctl
- bypass racy readahead to improve read latencies
- shrink node_write lock coverage to avoid long latency
Bug fix:
- fix missing compression flag control, i_size, and mount option
- fix deadlock between quota writes and checkpoint
- remove inode eviction path in synchronous path to avoid deadlock
- fix to wait GCed compressed page writeback
- fix a kernel panic in f2fs_is_compressed_page
- check page dirty status before writeback
- wait page writeback before update in node page write flow
- fix a race condition between f2fs_write_end_io and f2fs_del_fsync_node_entry
We've added some minor sanity checks and refactored trivial code blocks for
better readability and debugging information.
-----BEGIN PGP SIGNATURE-----
iQIzBAABCgAdFiEE00UqedjCtOrGVvQiQBSofoJIUNIFAl8xhqMACgkQQBSofoJI
UNLYgA//WMoOqBACDuOWwYmgQ8oq4vrH2LOwssZF9/77vEfaHKc+TSq1il54lcUl
MPEx7FK54CnfT8VLLR5ByobZFyH9FFeAw4FN4LBhcfE8jh8ysAGjeoZjwfcmJF6R
cVKtn8ltUpgH3IEUuPjTiKkVNHfVJxuuL3zHbg1CEl+AkR6NJ/U9kNLwf7ZgPWq2
I0qwyXRlUIEChhyPZB+Y6RsdGjkeievKld56DMCgG73f4yHRO/yBcrfsN875sGdM
ALL+mYiunMT6aXcfoiQiAjeImoNajuflI6Zso2Sk8Vl6sBj0QwAuEBF5x1Z5e1mt
YVYNuC4ucqsDBKpOqtsPP0MFTC2T5Rr9wWXjqv+9TjN7zvJ8xx+zDWtQxvI2bpqB
4ZRxaJP45aThLYh/SEYDmj+ppyPtfLDeG0HzUkwMmuopf9eg+kxGPjBsZewgkCKg
kmMKU0P7deGlkrWLUcz2vm0Lso+ieGm0IeLOQl9/rOLu3IQQFia0Vla7dLDgqF0P
sz+udIiBztC3JPEmEZhfayA6P6e1TyWQUdquL08jp+DZD17gPqcaZDhHr62U5rmK
7zoiZqkR03SbNaFhBhhoVOaAVcAnF0pSIgqzkCa3dVXxp1QV+JfD9CGR9NFyiIqB
HK5RPFskIUCg0K2LSaAKbyoFWa/fJ8ZD8/CbFWcnXfWzoaaSkmc=
=PjaF
-----END PGP SIGNATURE-----
Merge tag 'f2fs-for-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim:
"In this round, we've added two small interfaces: (a) GC_URGENT_LOW
mode for performance and (b) F2FS_IOC_SEC_TRIM_FILE ioctl for
security.
The new GC mode allows Android to run some lower priority GCs in
background, while new ioctl discards user information without race
condition when the account is removed.
In addition, some patches were merged to address latency-related
issues. We've fixed some compression-related bug fixes as well as edge
race conditions.
Enhancements:
- add GC_URGENT_LOW mode in gc_urgent
- introduce F2FS_IOC_SEC_TRIM_FILE ioctl
- bypass racy readahead to improve read latencies
- shrink node_write lock coverage to avoid long latency
Bug fixes:
- fix missing compression flag control, i_size, and mount option
- fix deadlock between quota writes and checkpoint
- remove inode eviction path in synchronous path to avoid deadlock
- fix to wait GCed compressed page writeback
- fix a kernel panic in f2fs_is_compressed_page
- check page dirty status before writeback
- wait page writeback before update in node page write flow
- fix a race condition between f2fs_write_end_io and f2fs_del_fsync_node_entry
We've added some minor sanity checks and refactored trivial code
blocks for better readability and debugging information"
* tag 'f2fs-for-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (52 commits)
f2fs: prepare a waiter before entering io_schedule
f2fs: update_sit_entry: Make the judgment condition of f2fs_bug_on more intuitive
f2fs: replace test_and_set/clear_bit() with set/clear_bit()
f2fs: make file immutable even if releasing zero compression block
f2fs: compress: disable compression mount option if compression is off
f2fs: compress: add sanity check during compressed cluster read
f2fs: use macro instead of f2fs verity version
f2fs: fix deadlock between quota writes and checkpoint
f2fs: correct comment of f2fs_exist_written_data
f2fs: compress: delay temp page allocation
f2fs: compress: fix to update isize when overwriting compressed file
f2fs: space related cleanup
f2fs: fix use-after-free issue
f2fs: Change the type of f2fs_flush_inline_data() to void
f2fs: add F2FS_IOC_SEC_TRIM_FILE ioctl
f2fs: should avoid inode eviction in synchronous path
f2fs: segment.h: delete a duplicated word
f2fs: compress: fix to avoid memory leak on cc->cpages
f2fs: use generic names for generic ioctls
f2fs: don't keep meta inode pages used for compressed block migration
...
Currently, we allocate temp pages which is used to pad hole in
cluster during read IO submission, it may take long time before
releasing them in f2fs_decompress_pages(), since they are only
used as temp output buffer in decompression context, so let's
just do the allocation in that context to reduce time of memory
pool resource occupation.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Memory allocated for storing compressed pages' poitner should be
released after f2fs_write_compressed_pages(), otherwise it will
cause memory leak issue.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Fixes: 4c8ff7095b ("f2fs: support data compression")
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Wire up f2fs to support inline encryption via the helper functions which
fs/crypto/ now provides. This includes:
- Adding a mount option 'inlinecrypt' which enables inline encryption
on encrypted files where it can be used.
- Setting the bio_crypt_ctx on bios that will be submitted to an
inline-encrypted file.
- Not adding logically discontiguous data to bios that will be submitted
to an inline-encrypted file.
- Not doing filesystem-layer crypto on inline-encrypted files.
This patch includes a fix for a race during IPU by
Sahitya Tummala <stummala@codeaurora.org>
Signed-off-by: Satya Tangirala <satyat@google.com>
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20200702015607.1215430-4-satyat@google.com
Co-developed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
In f2fs_write_raw_pages(), we need to check page dirty status before
writeback, because there could be a racer (e.g. reclaimer) helps
writebacking the dirty page.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
The parameter compr is unused in the f2fs_cluster_blocks function
so we no longer need to pass it as a parameter.
Signed-off-by: Wang Xiaojun <wangxiaojun11@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
- to avoid race between checkpoint and quota file writeback, it
just needs to hold read lock of node_write in writeback path.
- node_write lock has covered all LFS data write paths, it's not
necessary, we only need to hold node_write lock at write path of
quota file.
This refactors commit ca7f76e680 ("f2fs: fix wrong discard space").
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
While compressed data writeback, we need to drop dirty pages like we did
for non-compressed pages if cp stops, however it's not needed to compress
any data in such case, so let's detect cp stop condition in
cluster_may_compress() to avoid redundant compressing and let following
f2fs_write_raw_pages() drops dirty pages correctly.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
During zstd compression, ZSTD_endStream() may return non-zero value
because distination buffer is full, but there is still compressed data
remained in intermediate buffer, it means that zstd algorithm can not
save at last one block space, let's just writeback raw data instead of
compressed one, this can fix data corruption when decompressing
incomplete stored compression data.
Fixes: 50cfa66f0d ("f2fs: compress: support zstd compress algorithm")
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Commonly, in order to handle lz4 worst compress case, caller should
allocate buffer with size of LZ4_compressBound(inputsize) for target
compressed data storing, however in this case, if caller didn't
allocate enough space, lz4 compressor still can handle output buffer
budget properly, and end up compressing when left space in output
buffer is not enough.
So we don't have to allocate buffer with size for worst case, then
we can avoid 2 * 4KB size intermediate buffer allocation when
log_cluster_size is 2, and avoid unnecessary compressing work of
compressor if we can not save at least 4KB space.
Suggested-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
LZO-RLE extension (run length encoding) was introduced to improve
performance of LZO algorithm in scenario of data contains many zeros,
zram has changed to use this extended algorithm by default, this
patch adds to support this algorithm extension, to enable this
extension, it needs to enable F2FS_FS_LZO and F2FS_FS_LZORLE config,
and specifies "compress_algorithm=lzo-rle" mountoption.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
If compression feature is on, in scenario of no enough free memory,
page refault ratio is higher than before, the root cause is:
- {,de}compression flow needs to allocate intermediate pages to store
compressed data in cluster, so during their allocation, vm may reclaim
mmaped pages.
- if above reclaimed pages belong to compressed cluster, during its
refault, it may cause more intermediate pages allocation, result in
reclaiming more mmaped pages.
So this patch introduces a mempool for intermediate page allocation,
in order to avoid high refault ratio, by default, number of
preallocated page in pool is 512, user can change the number by
assigning 'num_compress_pages' parameter during module initialization.
Ma Feng found warnings in the original patch and fixed like below.
Fix the following sparse warning:
fs/f2fs/compress.c:501:5: warning: symbol 'num_compress_pages' was not declared.
Should it be static?
fs/f2fs/compress.c:530:6: warning: symbol 'f2fs_compress_free_page' was not
declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Ma Feng <mafeng.ma@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs_quota_sync() uses f2fs_lock_op() before flushing dirty pages, but
f2fs_write_data_page() returns EAGAIN.
Likewise dentry blocks, we can just bypass getting the lock, since quota
blocks are also maintained by checkpoint.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
In below error path, tpages[i] could be NULL, fix to check it before
releasing it.
- f2fs_read_multi_pages
- f2fs_alloc_dic
- f2fs_free_dic
Fixes: 61fbae2b2b ("f2fs: fix to avoid NULL pointer dereference")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Add zstd compress algorithm support, use "compress_algorithm=zstd"
mountoption to enable it.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Add below two callback interfaces in struct f2fs_compress_ops:
int (*init_decompress_ctx)(struct decompress_io_ctx *dic);
void (*destroy_decompress_ctx)(struct decompress_io_ctx *dic);
Which will be used by zstd compress algorithm later.
In addition, this patch adds callback function pointer check, so that
specified algorithm can avoid defining unneeded functions.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
{cic,dic}.ref should be initialized to number of compressed pages,
let's initialize it directly rather than doing w/
f2fs_set_compressed_page().
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
If both compression and fsverity feature is on, generic/572 will
report below NULL pointer dereference bug.
BUG: kernel NULL pointer dereference, address: 0000000000000018
RIP: 0010:f2fs_verity_work+0x60/0x90 [f2fs]
#PF: supervisor read access in kernel mode
Workqueue: fsverity_read_queue f2fs_verity_work [f2fs]
RIP: 0010:f2fs_verity_work+0x60/0x90 [f2fs]
Call Trace:
process_one_work+0x16c/0x3f0
worker_thread+0x4c/0x440
? rescuer_thread+0x350/0x350
kthread+0xf8/0x130
? kthread_unpark+0x70/0x70
ret_from_fork+0x35/0x40
There are two issue in f2fs_verity_work():
- it needs to traverse and verify all pages in bio.
- if pages in bio belong to non-compressed cluster, accessing
decompress IO context stored in page private will cause NULL
pointer dereference.
Fix them.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
In f2fs_decompress_end_io(), we should clear PG_error flag before page
unlock, otherwise reread will fail due to the flag as described in
commit fb7d70db30 ("f2fs: clear PageError on the read path").
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
por_fsstress reports inconsistent status in orphan inode, the root cause
of this is in f2fs_write_raw_pages() we decrease i_compr_blocks incorrectly
due to wrong calculation in f2fs_compressed_blocks().
So this patch exposes below two functions based on __f2fs_cluster_blocks:
- f2fs_compressed_blocks: get count of compressed blocks in compressed cluster
- f2fs_cluster_blocks: get count of valid blocks (including reserved blocks)
in compressed cluster.
Then use f2fs_compress_blocks() to get correct compressed blocks count in
f2fs_write_raw_pages().
sanity_check_inode: inode (ino=ad80) hash inconsistent i_compr_blocks:2, i_blocks:1, run fsck to fix
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
If we are in write IO path, we need to avoid using GFP_KERNEL.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
As Geert Uytterhoeven reported:
for parameter HZ/50 in congestion_wait(BLK_RW_ASYNC, HZ/50);
On some platforms, HZ can be less than 50, then unexpected 0 timeout
jiffies will be set in congestion_wait().
This patch introduces a macro DEFAULT_IO_TIMEOUT to wrap a determinate
value with msecs_to_jiffies(20) to instead HZ/50 to avoid such issue.
Quoted from Geert Uytterhoeven:
"A timeout of HZ means 1 second.
HZ/50 means 20 ms, but has the risk of being zero, if HZ < 50.
If you want to use a timeout of 20 ms, you best use msecs_to_jiffies(20),
as that takes care of the special cases, and never returns 0."
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
- rename datablock_addr() to data_blkaddr().
- wrap data_blkaddr() with f2fs_data_blkaddr() to clean up
parameters.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This change solves below hangtask issue:
INFO: task kworker/u16:1:58 blocked for more than 122 seconds.
Not tainted 5.6.0-rc2-00590-g9983bdae4974e #11
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u16:1 D 0 58 2 0x00000000
Workqueue: writeback wb_workfn (flush-179:0)
Backtrace:
(__schedule) from [<c0913234>] (schedule+0x78/0xf4)
(schedule) from [<c017ec74>] (rwsem_down_write_slowpath+0x24c/0x4c0)
(rwsem_down_write_slowpath) from [<c0915f2c>] (down_write+0x6c/0x70)
(down_write) from [<c0435b80>] (f2fs_write_single_data_page+0x608/0x7ac)
(f2fs_write_single_data_page) from [<c0435fd8>] (f2fs_write_cache_pages+0x2b4/0x7c4)
(f2fs_write_cache_pages) from [<c043682c>] (f2fs_write_data_pages+0x344/0x35c)
(f2fs_write_data_pages) from [<c0267ee8>] (do_writepages+0x3c/0xd4)
(do_writepages) from [<c0310cbc>] (__writeback_single_inode+0x44/0x454)
(__writeback_single_inode) from [<c03112d0>] (writeback_sb_inodes+0x204/0x4b0)
(writeback_sb_inodes) from [<c03115cc>] (__writeback_inodes_wb+0x50/0xe4)
(__writeback_inodes_wb) from [<c03118f4>] (wb_writeback+0x294/0x338)
(wb_writeback) from [<c0312dac>] (wb_workfn+0x35c/0x54c)
(wb_workfn) from [<c014f2b8>] (process_one_work+0x214/0x544)
(process_one_work) from [<c014f634>] (worker_thread+0x4c/0x574)
(worker_thread) from [<c01564fc>] (kthread+0x144/0x170)
(kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
Reported-and-tested-by: Ondřej Jirman <megi@xff.cz>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Using f2fs_trylock_op() in f2fs_write_compressed_pages() to avoid potential
deadlock like we did in f2fs_write_single_data_page().
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
In Struct compress_data, chksum field was never used, remove it.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Unable to handle kernel NULL pointer dereference at virtual address 00000000
PC is at f2fs_free_dic+0x60/0x2c8
LR is at f2fs_decompress_pages+0x3c4/0x3e8
f2fs_free_dic+0x60/0x2c8
f2fs_decompress_pages+0x3c4/0x3e8
__read_end_io+0x78/0x19c
f2fs_post_read_work+0x6c/0x94
process_one_work+0x210/0x48c
worker_thread+0x2e8/0x44c
kthread+0x110/0x120
ret_from_fork+0x10/0x18
In f2fs_free_dic(), we can not use f2fs_put_page(,1) to release dic->tpages[i],
as the page's mapping is NULL.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
When the compressed data of a cluster doesn't end on a page boundary,
the remainder of the last page must be zeroed in order to avoid leaking
uninitialized memory to disk.
Fixes: 4c8ff7095b ("f2fs: support data compression")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This patch tries to support compression in f2fs.
- New term named cluster is defined as basic unit of compression, file can
be divided into multiple clusters logically. One cluster includes 4 << n
(n >= 0) logical pages, compression size is also cluster size, each of
cluster can be compressed or not.
- In cluster metadata layout, one special flag is used to indicate cluster
is compressed one or normal one, for compressed cluster, following metadata
maps cluster to [1, 4 << n - 1] physical blocks, in where f2fs stores
data including compress header and compressed data.
- In order to eliminate write amplification during overwrite, F2FS only
support compression on write-once file, data can be compressed only when
all logical blocks in file are valid and cluster compress ratio is lower
than specified threshold.
- To enable compression on regular inode, there are three ways:
* chattr +c file
* chattr +c dir; touch dir/file
* mount w/ -o compress_extension=ext; touch file.ext
Compress metadata layout:
[Dnode Structure]
+-----------------------------------------------+
| cluster 1 | cluster 2 | ......... | cluster N |
+-----------------------------------------------+
. . . .
. . . .
. Compressed Cluster . . Normal Cluster .
+----------+---------+---------+---------+ +---------+---------+---------+---------+
|compr flag| block 1 | block 2 | block 3 | | block 1 | block 2 | block 3 | block 4 |
+----------+---------+---------+---------+ +---------+---------+---------+---------+
. .
. .
. .
+-------------+-------------+----------+----------------------------+
| data length | data chksum | reserved | compressed data |
+-------------+-------------+----------+----------------------------+
Changelog:
20190326:
- fix error handling of read_end_io().
- remove unneeded comments in f2fs_encrypt_one_page().
20190327:
- fix wrong use of f2fs_cluster_is_full() in f2fs_mpage_readpages().
- don't jump into loop directly to avoid uninitialized variables.
- add TODO tag in error path of f2fs_write_cache_pages().
20190328:
- fix wrong merge condition in f2fs_read_multi_pages().
- check compressed file in f2fs_post_read_required().
20190401
- allow overwrite on non-compressed cluster.
- check cluster meta before writing compressed data.
20190402
- don't preallocate blocks for compressed file.
- add lz4 compress algorithm
- process multiple post read works in one workqueue
Now f2fs supports processing post read work in multiple workqueue,
it shows low performance due to schedule overhead of multiple
workqueue executing orderly.
20190921
- compress: support buffered overwrite
C: compress cluster flag
V: valid block address
N: NEW_ADDR
One cluster contain 4 blocks
before overwrite after overwrite
- VVVV -> CVNN
- CVNN -> VVVV
- CVNN -> CVNN
- CVNN -> CVVV
- CVVV -> CVNN
- CVVV -> CVVV
20191029
- add kconfig F2FS_FS_COMPRESSION to isolate compression related
codes, add kconfig F2FS_FS_{LZO,LZ4} to cover backend algorithm.
note that: will remove lzo backend if Jaegeuk agreed that too.
- update codes according to Eric's comments.
20191101
- apply fixes from Jaegeuk
20191113
- apply fixes from Jaegeuk
- split workqueue for fsverity
20191216
- apply fixes from Jaegeuk
20200117
- fix to avoid NULL pointer dereference
[Jaegeuk Kim]
- add tracepoint for f2fs_{,de}compress_pages()
- fix many bugs and add some compression stats
- fix overwrite/mmap bugs
- address 32bit build error, reported by Geert.
- bug fixes when handling errors and i_compressed_blocks
Reported-by: <noreply@ellerman.id.au>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Chao Yu