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authorDavid Sterba <dsterba@suse.com>2021-10-27 11:44:21 +0300
committerDavid Sterba <dsterba@suse.com>2021-10-29 14:25:43 +0300
commitccaa66c8dd277ac02f96914168bb7177f7ea8117 (patch)
tree3731205a362c6bd3103e67bec62c03e0ca03e234 /fs
parent55276e14df4324ade34583adef110e11d249fb7b (diff)
downloadlinux-ccaa66c8dd277ac02f96914168bb7177f7ea8117.tar.xz
Revert "btrfs: compression: drop kmap/kunmap from lzo"
This reverts commit 8c945d32e60427cbc0859cf7045bbe6196bb03d8. 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 a6e66e6f8c1b ("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>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/lzo.c36
1 files changed, 25 insertions, 11 deletions
diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
index c25dfd1a8a54..3dbe6eb5fda7 100644
--- a/fs/btrfs/lzo.c
+++ b/fs/btrfs/lzo.c
@@ -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;
}