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jbd2: Remove page size assumptions

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jbd2_alloc() allocates a buffer from slab when the block size is smaller
than PAGE_SIZE, and slab may be using a compound page.  Before commit
8147c4c454, we set b_page to the precise page containing the buffer
and this code worked well.  Now we set b_page to the head page of the
allocation, so we can no longer use offset_in_page().  While we could
do a 1:1 replacement with offset_in_folio(), use the more idiomatic
bh_offset() and the folio APIs to map the buffer.

This isn't enough to support a b_size larger than PAGE_SIZE on HIGHMEM
machines, but this is good enough to fix the actual bug we're seeing.

Fixes: 8147c4c454 ("jbd2: use a folio in jbd2_journal_write_metadata_buffer()")
Reported-by: Zorro Lang <zlang@kernel.org>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
[converted to be more folio]
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
This commit is contained in:
Ritesh Harjani (IBM)
2023-09-07 09:47:32 -04:00
committed by Theodore Ts'o
parent f94cf2206b
commit 147d4a092e
2 changed files with 10 additions and 18 deletions
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16
fs/jbd2/commit.c
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@@ -298,14 +298,12 @@ static int journal_finish_inode_data_buffers(journal_t *journal,
static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
{
struct page *page = bh->b_page;
char *addr;
__u32 checksum;
addr = kmap_atomic(page);
checksum = crc32_be(crc32_sum,
(void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
kunmap_atomic(addr);
addr = kmap_local_folio(bh->b_folio, bh_offset(bh));
checksum = crc32_be(crc32_sum, addr, bh->b_size);
kunmap_local(addr);
return checksum;
}
@@ -322,7 +320,6 @@ static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
struct buffer_head *bh, __u32 sequence)
{
journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
struct page *page = bh->b_page;
__u8 *addr;
__u32 csum32;
__be32 seq;
@@ -331,11 +328,10 @@ static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
return;
seq = cpu_to_be32(sequence);
addr = kmap_atomic(page);
addr = kmap_local_folio(bh->b_folio, bh_offset(bh));
csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
bh->b_size);
kunmap_atomic(addr);
csum32 = jbd2_chksum(j, csum32, addr, bh->b_size);
kunmap_local(addr);
if (jbd2_has_feature_csum3(j))
tag3->t_checksum = cpu_to_be32(csum32);