linux.git/fs/erofs, branch v5.7

erofs: handle corrupted images whose decompressed size less than it'd be

2020-03-03T15:40:52+00:00

As Lasse pointed out, "Looking at fs/erofs/decompress.c,
the return value from LZ4_decompress_safe_partial is only
checked for negative value to catch errors. ... So if
I understood it correctly, if there is bad data whose
uncompressed size is much less than it should be, it can
leave part of the output buffer untouched and expose the
previous data as the file content. "

Let's fix it now.

Cc: Lasse Collin 
Fixes: 7fc45dbc938a ("staging: erofs: introduce generic decompression backend")
[ Gao Xiang: v5.3+, I will manually backport this to stable later. ]
Link: https://lore.kernel.org/r/20200226081008.86348-3-gaoxiang25@huawei.com
Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang

erofs: use LZ4_decompress_safe() for full decoding

2020-03-03T15:40:16+00:00

As Lasse pointed out, "EROFS uses LZ4_decompress_safe_partial
for both partial and full blocks. Thus when it is decoding a
full block, it doesn't know if the LZ4 decoder actually decoded
all the input. The real uncompressed size could be bigger than
the value stored in the file system metadata.

Using LZ4_decompress_safe instead of _safe_partial when
decompressing a full block would help to detect errors."

So it's reasonable to use _safe in case of potential corrupted
images and it might have some speed gain as well although
I didn't observe much difference.

Note that legacy compressor (< 5.3, no LZ4_0PADDING) could
encode extra data in a pcluster, which is excluded as well.

Cc: Lasse Collin 
Fixes: 0ffd71bcc3a0 ("staging: erofs: introduce LZ4 decompression inplace")
[ Gao Xiang: v5.3+, I will manually backport this to stable later. ]
Link: https://lore.kernel.org/r/20200226081008.86348-2-gaoxiang25@huawei.com
Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang

erofs: correct the remaining shrink objects

2020-03-03T15:39:29+00:00

The remaining count should not include successful
shrink attempts.

Fixes: e7e9a307be9d ("staging: erofs: introduce workstation for decompression")
Cc:  # 4.19+
Link: https://lore.kernel.org/r/20200226081008.86348-1-gaoxiang25@huawei.com
Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang

erofs: convert workstn to XArray

2020-03-03T15:27:25+00:00

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 
Link: https://lore.kernel.org/r/20200220024642.91529-1-gaoxiang25@huawei.com
Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang

erofs: clean up z_erofs_submit_queue()

2020-01-21T08:46:23+00:00

A label and extra variables will be eliminated,
which is more cleaner.

Link: https://lore.kernel.org/r/20200121064819.139469-1-gaoxiang25@huawei.com
Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang

erofs: fold in postsubmit_is_all_bypassed()

2020-01-21T08:46:17+00:00

No need to introduce such separated helper since
cache strategy compile configs were changed into
runtime options instead in v5.4. No logic changes.

Link: https://lore.kernel.org/r/20200121064747.138987-1-gaoxiang25@huawei.com
Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang

erofs: fix out-of-bound read for shifted uncompressed block

2020-01-11T10:29:19+00:00

rq->out[1] should be valid before accessing. Otherwise,
in very rare cases, out-of-bound dirty onstack rq->out[1]
can equal to *in and lead to unintended memmove behavior.

Link: https://lore.kernel.org/r/20200107022546.19432-1-gaoxiang25@huawei.com
Fixes: 7fc45dbc938a ("staging: erofs: introduce generic decompression backend")
Cc:  # 5.3+
Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang

erofs: remove void tagging/untagging of workgroup pointers

2020-01-07T02:09:21+00:00

Because workgroup pointers inserted to a radix tree are always tagged with
a single value of 0, it is possible to remove tagging and untagging of the
pointers completely.

Signed-off-by: Vladimir Zapolskiy 
Link: https://lore.kernel.org/r/20200102120118.14979-4-vladimir@tuxera.com
Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang

erofs: remove unused tag argument while registering a workgroup

2020-01-07T02:08:45+00:00

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 
Link: https://lore.kernel.org/r/20200102120118.14979-3-vladimir@tuxera.com
Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang

erofs: remove unused tag argument while finding a workgroup

2020-01-07T02:08:38+00:00

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 
Link: https://lore.kernel.org/r/20200102120118.14979-2-vladimir@tuxera.com
Reviewed-by: Chao Yu 
Signed-off-by: Gao Xiang