Prior to big pcluster, there was only one compressed page so it'd
easy to map this. However, when big pcluster is enabled, more work
needs to be done to handle multiple compressed pages. In detail,
- (maptype 0) if there is only one compressed page + no need
to copy inplace I/O, just map it directly what we did before;
- (maptype 1) if there are more compressed pages + no need to
copy inplace I/O, vmap such compressed pages instead;
- (maptype 2) if inplace I/O needs to be copied, use per-CPU
buffers for decompression then.
Another thing is how to detect inplace decompression is feasable or
not (it's still quite easy for non big pclusters), apart from the
inplace margin calculation, inplace I/O page reusing order is also
needed to be considered for each compressed page. Currently, if the
compressed page is the xth page, it shouldn't be reused as [0 ...
nrpages_out - nrpages_in + x], otherwise a full copy will be triggered.
Although there are some extra optimization ideas for this, I'd like
to make big pcluster work correctly first and obviously it can be
further optimized later since it has nothing with the on-disk format
at all.
Link: https://lore.kernel.org/r/20210407043927.10623-10-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Adjust per-CPU buffers on demand since big pcluster definition is
available. Also, bail out unsupported pcluster size according to
Z_EROFS_PCLUSTER_MAX_SIZE.
Link: https://lore.kernel.org/r/20210407043927.10623-7-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Big pcluster indicates the size of compressed data for each physical
pcluster is no longer fixed as block size, but could be more than 1
block (more accurately, 1 logical pcluster)
When big pcluster feature is enabled for head0/1, delta0 of the 1st
non-head lcluster index will keep block count of this pcluster in
lcluster size instead of 1. Or, the compressed size of pcluster
should be 1 lcluster if pcluster has no non-head lcluster index.
Also note that BIG_PCLUSTER feature reuses COMPR_CFGS feature since
it depends on COMPR_CFGS and will be released together.
Link: https://lore.kernel.org/r/20210407043927.10623-6-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Since multiple pcluster sizes could be used at once, the number of
compressed pages will become a variable factor. It's necessary to
introduce slab pools rather than a single slab cache now.
This limits the pclustersize to 1M (Z_EROFS_PCLUSTER_MAX_SIZE), and
get rid of the obsolete EROFS_FS_CLUSTER_PAGE_LIMIT, which has no
use now.
Link: https://lore.kernel.org/r/20210407043927.10623-4-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
To deal the with the cases which inplace decompression is infeasible
for some inplace I/O. Per-CPU buffers was introduced to get rid of page
allocation latency and thrash for low-latency decompression algorithms
such as lz4.
For the big pcluster feature, introduce multipage per-CPU buffers to
keep such inplace I/O pclusters temporarily as well but note that
per-CPU pages are just consecutive virtually.
When a new big pcluster fs is mounted, its max pclustersize will be
read and per-CPU buffers can be growed if needed. Shrinking adjustable
per-CPU buffers is more complex (because we don't know if such size
is still be used), so currently just release them all when unloading.
Link: https://lore.kernel.org/r/20210409190630.19569-1-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Formal big pcluster design is actually more powerful / flexable than
the previous thought whose pclustersize was fixed as power-of-2 blocks,
which was obviously inefficient and space-wasting. Instead, pclustersize
can now be set independently for each pcluster, so various pcluster
sizes can also be used together in one file if mkfs wants (for example,
according to data type and/or compression ratio).
Let's get rid of previous physical_clusterbits[] setting (also notice
that corresponding on-disk fields are still 0 for now). Therefore,
head1/2 can be used for at most 2 different algorithms in one file and
again pclustersize is now independent of these.
Link: https://lore.kernel.org/r/20210407043927.10623-2-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Add a bitmap for available compression algorithms and a variable-sized
on-disk table for compression options in preparation for upcoming big
pcluster and LZMA algorithm, which follows the end of super block.
To parse the compression options, the bitmap is scanned one by one.
For each available algorithm, there is data followed by 2-byte `length'
correspondingly (it's enough for most cases, or entire fs blocks should
be used.)
With such available algorithm bitmap, kernel itself can also refuse to
mount such filesystem if any unsupported compression algorithm exists.
Note that COMPR_CFGS feature will be enabled with BIG_PCLUSTER.
Link: https://lore.kernel.org/r/20210329100012.12980-1-hsiangkao@aol.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Introduce z_erofs_lz4_cfgs to store all lz4 configurations.
Currently it's only max_distance, but will be used for new
features later.
Link: https://lore.kernel.org/r/20210329012308.28743-4-hsiangkao@aol.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
lz4 uses LZ4_DISTANCE_MAX to record history preservation. When
using rolling decompression, a block with a higher compression
ratio will cause a larger memory allocation (up to 64k). It may
cause a large resource burden in extreme cases on devices with
small memory and a large number of concurrent IOs. So appropriately
reducing this value can improve performance.
Decreasing this value will reduce the compression ratio (except
when input_size <LZ4_DISTANCE_MAX). But considering that erofs
currently only supports 4k output, reducing this value will not
significantly reduce the compression benefits.
The maximum value of LZ4_DISTANCE_MAX defined by lz4 is 64k, and
we can only reduce this value. For the old kernel, it just can't
reduce the memory allocation during rolling decompression without
affecting the decompression result.
Link: https://lore.kernel.org/r/20210329012308.28743-3-hsiangkao@aol.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Signed-off-by: Guo Weichao <guoweichao@oppo.com>
[ Gao Xiang: introduce struct erofs_sb_lz4_info for configurations. ]
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Introduce erofs_sb_has_xxx() to make long checks short, especially
for later big pcluster & LZMA features.
Link: https://lore.kernel.org/r/20210329012308.28743-2-hsiangkao@aol.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Currently, erofs_map_blocks() will be called only from
erofs_{bmap, read_raw_page} which are all for uncompressed files.
So, the compression branch in erofs_map_blocks() is pointless. Let's
remove it and use erofs_map_blocks_flatmode() directly. Also update
related comments.
Link: https://lore.kernel.org/r/20210325071008.573-1-zbestahu@gmail.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Sync decompression was introduced to get rid of additional kworker
scheduling overhead. But there is no such overhead in non-atomic
contexts. Therefore, it should be better to turn off sync decompression
to avoid the current thread waiting in z_erofs_runqueue.
Link: https://lore.kernel.org/r/20210317035448.13921-3-huangjianan@oppo.com
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Signed-off-by: Guo Weichao <guoweichao@oppo.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.
As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.
Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.
Deterministic algorithm:
For each file:
If not .svg:
For each line:
If doesn't contain `\bxmlns\b`:
For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`:
If both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/20200713130944.34419-1-grandmaster@al2klimov.de
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Convert the erofs to use new internal mount API as the old one will
be obsoleted and removed. This allows greater flexibility in
communication of mount parameters between userspace, the VFS and the
filesystem.
See Documentation/filesystems/mount_api.txt for more information.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20200529104836.17843-1-hsiangkao@redhat.com
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
XArray has friendly APIs and it will replace the old radix
tree in the near future.
This convert makes use of __xa_cmpxchg when inserting on
a just inserted item by other thread. In detail, instead
of totally looking up again as what we did for the old
radix tree, it will try to legitimize the current in-tree
item in the XArray therefore more effective.
In addition, naming is rather a challenge for non-English
speaker like me. The basic idea of workstn is to provide
a runtime sparse array with items arranged in the physical
block number order. Such items (was called workgroup) can be
used to record compress clusters or for later new features.
However, both workgroup and workstn seem not good names from
whatever point of view, so I'd like to rename them as pslot
and managed_pslots to stand for physical slots. This patch
handles the second as a part of the radix tree convert.
Cc: Matthew Wilcox <willy@infradead.org>
Link: https://lore.kernel.org/r/20200220024642.91529-1-gaoxiang25@huawei.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
All workgroups are registered with tag value set to 0, to simplify
erofs_register_workgroup() interface the tag argument can be removed,
if its only value is sent down to the function body.
Signed-off-by: Vladimir Zapolskiy <vladimir@tuxera.com>
Link: https://lore.kernel.org/r/20200102120118.14979-3-vladimir@tuxera.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
It is feasible to simplify erofs_find_workgroup() interface by removing
an unused function argument. While formally the argument is used in the
function itself, its assigned value is ignored on the caller side.
Signed-off-by: Vladimir Zapolskiy <vladimir@tuxera.com>
Link: https://lore.kernel.org/r/20200102120118.14979-2-vladimir@tuxera.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
VLE was an old informal name of fixed-sized output
compression which came from published ATC'19 paper [1].
Drop those old annotations since erofs can handle
all encoded clusters in block-aligned basis, which
is wider than fixed-sized output compression after
larger clustersize feature is fully implemented.
Unaligned encoding won't be considered in EROFS
since it's not friendly to inplace I/O and perhaps
decompression inplace.
a) Fixed-sized output compression with 16KB pcluster:
___________________________________
|xxxxxxxx|xxxxxxxx|xxxxxxxx|xxxxxxxx|
|___ 0___|___ 1___|___ 2___|___ 3___| physical blocks
b) Block-aligned fixed-sized input compression with
16KB pcluster:
___________________________________
|xxxxxxxx|xxxxxxxx|xxxxxxxx|xxx00000|
|___ 0___|___ 1___|___ 2___|___ 3___| physical blocks
c) Block-unaligned fixed-sized input compression with
16KB compression unit:
____________________________________________
|..xxxxxx|xxxxxxxx|xxxxxxxx|xxxxxxxx|x.......|
|___ 0___|___ 1___|___ 2___|___ 3___|___ 4___| physical blocks
Refine better names for those as well.
[1] https://www.usenix.org/conference/atc19/presentation/gao
Link: https://lore.kernel.org/r/20191108033733.63919-1-gaoxiang25@huawei.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Introduce superblock checksum feature in order to
check at mounting time.
Note that the first 1024 bytes are ignore for x86
boot sectors and other oddities.
Link: https://lore.kernel.org/r/20191104024937.113939-1-gaoxiang25@huawei.com
Signed-off-by: Pratik Shinde <pratikshinde320@gmail.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Add prefix "erofs_" to these functions and print
sb->s_id as a prefix to erofs_{err, info} so that
the user knows which file system is affected.
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190904020912.63925-23-gaoxiang25@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As Christoph pointed out [1], "
Why is there __submit_bio which really just obsfucates
what is going on? Also why is __submit_bio using
bio_set_op_attrs instead of opencode it as the comment
right next to it asks you to? "
Let's use submit_bio directly instead.
[1] https://lore.kernel.org/r/20190830162812.GA10694@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190904020912.63925-18-gaoxiang25@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As Christoph pointed out [1],
"Why is there __erofs_get_meta_page with the two weird
booleans instead of a single erofs_get_meta_page that
gets and gfp_t for additional flags and an unsigned int
for additional bio op flags."
And since all callers can handle errors, let's kill
prio and nofail and erofs_get_inline_page() now.
[1] https://lore.kernel.org/r/20190830162812.GA10694@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190904020912.63925-17-gaoxiang25@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
EROFS filesystem has been merged into linux-staging for a year.
EROFS is designed to be a better solution of saving extra storage
space with guaranteed end-to-end performance for read-only files
with the help of reduced metadata, fixed-sized output compression
and decompression inplace technologies.
In the past year, EROFS was greatly improved by many people as
a staging driver, self-tested, betaed by a large number of our
internal users, successfully applied to almost all in-service
HUAWEI smartphones as the part of EMUI 9.1 and proven to be stable
enough to be moved out of staging.
EROFS is a self-contained filesystem driver. Although there are
still some TODOs to be more generic, we have a dedicated team
actively keeping on working on EROFS in order to make it better
with the evolution of Linux kernel as the other in-kernel filesystems.
As Pavel suggested, it's better to do as one commit since git
can do moves and all histories will be saved in this way.
Let's promote it from staging and enhance it more actively as
a "real" part of kernel for more wider scenarios!
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Pavel Machek <pavel@denx.de>
Cc: David Sterba <dsterba@suse.cz>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J . Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Richard Weinberger <richard@nod.at>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Miao Xie <miaoxie@huawei.com>
Cc: Li Guifu <bluce.liguifu@huawei.com>
Cc: Fang Wei <fangwei1@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190822213659.5501-1-hsiangkao@aol.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Gao Xiang
Huang Jianan
Yue Hu
Christian Brauner
Alexander A. Klimov
Chao Yu
Gao Xiang
Vladimir Zapolskiy
Pratik Shinde
Gao Xiang