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Revert "btrfs: compression: drop kmap/kunmap from lzo"

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This reverts commit 8c945d32e6.

The kmaps in compression code are still needed and cause crashes on
32bit machines (ARM, x86). Reproducible eg. by running fstest btrfs/004
with enabled LZO or ZSTD compression.

The revert does not apply cleanly due to changes in a6e66e6f8c
("btrfs: rework lzo_decompress_bio() to make it subpage compatible")
that reworked the page iteration so the revert is done to be equivalent
to the original code.

Link: https://lore.kernel.org/all/CAJCQCtT+OuemovPO7GZk8Y8=qtOObr0XTDp8jh4OHD6y84AFxw@mail.gmail.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214839
Tested-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2021-10-27 10:44:21 +02:00
parent 55276e14df
commit ccaa66c8dd
1 changed files with 25 additions and 11 deletions
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36
fs/btrfs/lzo.c
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@ -141,7 +141,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
*total_in = 0;
in_page = find_get_page(mapping, start >> PAGE_SHIFT);
data_in = page_address(in_page);
data_in = kmap(in_page);
/*
* store the size of all chunks of compressed data in
@ -152,7 +152,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
ret = -ENOMEM;
goto out;
}
cpage_out = page_address(out_page);
cpage_out = kmap(out_page);
out_offset = LZO_LEN;
tot_out = LZO_LEN;
pages[0] = out_page;
@ -210,6 +210,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
if (out_len == 0 && tot_in >= len)
break;
kunmap(out_page);
if (nr_pages == nr_dest_pages) {
out_page = NULL;
ret = -E2BIG;
@ -221,7 +222,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
ret = -ENOMEM;
goto out;
}
cpage_out = page_address(out_page);
cpage_out = kmap(out_page);
pages[nr_pages++] = out_page;
pg_bytes_left = PAGE_SIZE;
@ -243,11 +244,12 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
break;
bytes_left = len - tot_in;
kunmap(in_page);
put_page(in_page);
start += PAGE_SIZE;
in_page = find_get_page(mapping, start >> PAGE_SHIFT);
data_in = page_address(in_page);
data_in = kmap(in_page);
in_len = min(bytes_left, PAGE_SIZE);
}
@ -257,17 +259,22 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
}
/* store the size of all chunks of compressed data */
sizes_ptr = page_address(pages[0]);
sizes_ptr = kmap_local_page(pages[0]);
write_compress_length(sizes_ptr, tot_out);
kunmap_local(sizes_ptr);
ret = 0;
*total_out = tot_out;
*total_in = tot_in;
out:
*out_pages = nr_pages;
if (out_page)
kunmap(out_page);
if (in_page)
if (in_page) {
kunmap(in_page);
put_page(in_page);
}
return ret;
}
@ -283,6 +290,7 @@ static void copy_compressed_segment(struct compressed_bio *cb,
u32 orig_in = *cur_in;
while (*cur_in < orig_in + len) {
char *kaddr;
struct page *cur_page;
u32 copy_len = min_t(u32, PAGE_SIZE - offset_in_page(*cur_in),
orig_in + len - *cur_in);
@ -290,9 +298,11 @@ static void copy_compressed_segment(struct compressed_bio *cb,
ASSERT(copy_len);
cur_page = cb->compressed_pages[*cur_in / PAGE_SIZE];
kaddr = kmap(cur_page);
memcpy(dest + *cur_in - orig_in,
page_address(cur_page) + offset_in_page(*cur_in),
kaddr + offset_in_page(*cur_in),
copy_len);
kunmap(cur_page);
*cur_in += copy_len;
}
@ -303,6 +313,7 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
struct workspace *workspace = list_entry(ws, struct workspace, list);
const struct btrfs_fs_info *fs_info = btrfs_sb(cb->inode->i_sb);
const u32 sectorsize = fs_info->sectorsize;
char *kaddr;
int ret;
/* Compressed data length, can be unaligned */
u32 len_in;
@ -311,7 +322,9 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
/* Bytes decompressed so far */
u32 cur_out = 0;
len_in = read_compress_length(page_address(cb->compressed_pages[0]));
kaddr = kmap(cb->compressed_pages[0]);
len_in = read_compress_length(kaddr);
kunmap(cb->compressed_pages[0]);
cur_in += LZO_LEN;
/*
@ -344,9 +357,9 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
ASSERT(cur_in / sectorsize ==
(cur_in + LZO_LEN - 1) / sectorsize);
cur_page = cb->compressed_pages[cur_in / PAGE_SIZE];
kaddr = kmap(cur_page);
ASSERT(cur_page);
seg_len = read_compress_length(page_address(cur_page) +
offset_in_page(cur_in));
seg_len = read_compress_length(kaddr + offset_in_page(cur_in));
cur_in += LZO_LEN;
/* Copy the compressed segment payload into workspace */
@ -431,7 +444,7 @@ int lzo_decompress(struct list_head *ws, unsigned char *data_in,
destlen = min_t(unsigned long, destlen, PAGE_SIZE);
bytes = min_t(unsigned long, destlen, out_len - start_byte);
kaddr = page_address(dest_page);
kaddr = kmap_local_page(dest_page);
memcpy(kaddr, workspace->buf + start_byte, bytes);
/*
@ -441,6 +454,7 @@ int lzo_decompress(struct list_head *ws, unsigned char *data_in,
*/
if (bytes < destlen)
memset(kaddr+bytes, 0, destlen-bytes);
kunmap_local(kaddr);
out:
return ret;
}