aboutsummaryrefslogtreecommitdiff
path: root/fs/hfsplus/wrapper.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/hfsplus/wrapper.c')
-rw-r--r--fs/hfsplus/wrapper.c83
1 files changed, 63 insertions, 20 deletions
diff --git a/fs/hfsplus/wrapper.c b/fs/hfsplus/wrapper.c
index 2f933e83f5c..10e515a0d45 100644
--- a/fs/hfsplus/wrapper.c
+++ b/fs/hfsplus/wrapper.c
@@ -31,25 +31,67 @@ static void hfsplus_end_io_sync(struct bio *bio, int err)
complete(bio->bi_private);
}
-int hfsplus_submit_bio(struct block_device *bdev, sector_t sector,
- void *data, int rw)
+/*
+ * hfsplus_submit_bio - Perfrom block I/O
+ * @sb: super block of volume for I/O
+ * @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes
+ * @buf: buffer for I/O
+ * @data: output pointer for location of requested data
+ * @rw: direction of I/O
+ *
+ * The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than
+ * HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads
+ * @data will return a pointer to the start of the requested sector,
+ * which may not be the same location as @buf.
+ *
+ * If @sector is not aligned to the bdev logical block size it will
+ * be rounded down. For writes this means that @buf should contain data
+ * that starts at the rounded-down address. As long as the data was
+ * read using hfsplus_submit_bio() and the same buffer is used things
+ * will work correctly.
+ */
+int hfsplus_submit_bio(struct super_block *sb, sector_t sector,
+ void *buf, void **data, int rw)
{
DECLARE_COMPLETION_ONSTACK(wait);
struct bio *bio;
int ret = 0;
+ unsigned int io_size;
+ loff_t start;
+ int offset;
+
+ /*
+ * Align sector to hardware sector size and find offset. We
+ * assume that io_size is a power of two, which _should_
+ * be true.
+ */
+ io_size = hfsplus_min_io_size(sb);
+ start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT;
+ offset = start & (io_size - 1);
+ sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1);
bio = bio_alloc(GFP_NOIO, 1);
bio->bi_sector = sector;
- bio->bi_bdev = bdev;
+ bio->bi_bdev = sb->s_bdev;
bio->bi_end_io = hfsplus_end_io_sync;
bio->bi_private = &wait;
- /*
- * We always submit one sector at a time, so bio_add_page must not fail.
- */
- if (bio_add_page(bio, virt_to_page(data), HFSPLUS_SECTOR_SIZE,
- offset_in_page(data)) != HFSPLUS_SECTOR_SIZE)
- BUG();
+ if (!(rw & WRITE) && data)
+ *data = (u8 *)buf + offset;
+
+ while (io_size > 0) {
+ unsigned int page_offset = offset_in_page(buf);
+ unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset,
+ io_size);
+
+ ret = bio_add_page(bio, virt_to_page(buf), len, page_offset);
+ if (ret != len) {
+ ret = -EIO;
+ goto out;
+ }
+ io_size -= len;
+ buf = (u8 *)buf + len;
+ }
submit_bio(rw, bio);
wait_for_completion(&wait);
@@ -57,8 +99,9 @@ int hfsplus_submit_bio(struct block_device *bdev, sector_t sector,
if (!bio_flagged(bio, BIO_UPTODATE))
ret = -EIO;
+out:
bio_put(bio);
- return ret;
+ return ret < 0 ? ret : 0;
}
static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd)
@@ -143,17 +186,17 @@ int hfsplus_read_wrapper(struct super_block *sb)
goto out;
error = -ENOMEM;
- sbi->s_vhdr = kmalloc(HFSPLUS_SECTOR_SIZE, GFP_KERNEL);
- if (!sbi->s_vhdr)
+ sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
+ if (!sbi->s_vhdr_buf)
goto out;
- sbi->s_backup_vhdr = kmalloc(HFSPLUS_SECTOR_SIZE, GFP_KERNEL);
- if (!sbi->s_backup_vhdr)
+ sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
+ if (!sbi->s_backup_vhdr_buf)
goto out_free_vhdr;
reread:
- error = hfsplus_submit_bio(sb->s_bdev,
- part_start + HFSPLUS_VOLHEAD_SECTOR,
- sbi->s_vhdr, READ);
+ error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR,
+ sbi->s_vhdr_buf, (void **)&sbi->s_vhdr,
+ READ);
if (error)
goto out_free_backup_vhdr;
@@ -183,9 +226,9 @@ reread:
goto reread;
}
- error = hfsplus_submit_bio(sb->s_bdev,
- part_start + part_size - 2,
- sbi->s_backup_vhdr, READ);
+ error = hfsplus_submit_bio(sb, part_start + part_size - 2,
+ sbi->s_backup_vhdr_buf,
+ (void **)&sbi->s_backup_vhdr, READ);
if (error)
goto out_free_backup_vhdr;