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Btrfs: While doing checksums on bios, cache the extent_buffer mapping

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Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2008-02-20 12:07:25 -05:00
parent 065631f6dc
commit 6e92f5e651
1 changed files with 33 additions and 3 deletions
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36
fs/btrfs/file-item.c
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@ -156,6 +156,11 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
int bio_index = 0;
struct bio_vec *bvec = bio->bi_io_vec;
char *data;
char *eb_map;
char *eb_token;
unsigned long map_len;
unsigned long map_start;
path = btrfs_alloc_path();
BUG_ON(!path);
@ -272,6 +277,7 @@ found:
item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
item_end = (struct btrfs_csum_item *)((unsigned char *)item_end +
btrfs_item_size_nr(leaf, path->slots[0]));
eb_token = NULL;
next_bvec:
data = kmap_atomic(bvec->bv_page, KM_IRQ0);
csum_result = ~(u32)0;
@ -283,15 +289,39 @@ next_bvec:
printk("csum result is 0 for inode %lu offset %Lu\n", inode->i_ino, offset);
}
write_extent_buffer(leaf, &csum_result, (unsigned long)item,
BTRFS_CRC32_SIZE);
if (!eb_token ||
(unsigned long)item + BTRFS_CRC32_SIZE >= map_start + map_len) {
int err;
if (eb_token)
unmap_extent_buffer(leaf, eb_token, KM_IRQ1);
eb_token = NULL;
err = map_private_extent_buffer(leaf, (unsigned long)item,
BTRFS_CRC32_SIZE,
&eb_token, &eb_map,
&map_start, &map_len, KM_IRQ1);
if (err)
eb_token = NULL;
}
if (eb_token) {
memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)),
&csum_result, BTRFS_CRC32_SIZE);
} else {
write_extent_buffer(leaf, &csum_result, (unsigned long)item,
BTRFS_CRC32_SIZE);
}
bio_index++;
bvec++;
if (bio_index < bio->bi_vcnt) {
item = (struct btrfs_csum_item *)((char *)item + BTRFS_CRC32_SIZE);
item = (struct btrfs_csum_item *)((char *)item +
BTRFS_CRC32_SIZE);
if (item < item_end)
goto next_bvec;
}
if (eb_token) {
unmap_extent_buffer(leaf, eb_token, KM_IRQ1);
eb_token = NULL;
}
btrfs_mark_buffer_dirty(path->nodes[0]);
if (bio_index < bio->bi_vcnt) {
btrfs_release_path(root, path);