fs: Enable bmap() function to properly return errors
By now, bmap() will either return the physical block number related to
the requested file offset or 0 in case of error or the requested offset
maps into a hole.
This patch makes the needed changes to enable bmap() to proper return
errors, using the return value as an error return, and now, a pointer
must be passed to bmap() to be filled with the mapped physical block.
It will change the behavior of bmap() on return:
- negative value in case of error
- zero on success or map fell into a hole
In case of a hole, the *block will be zero too
Since this is a prep patch, by now, the only error return is -EINVAL if
->bmap doesn't exist.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 3ad1824..92d3b51 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -364,7 +364,7 @@ static int read_page(struct file *file, unsigned long index,
int ret = 0;
struct inode *inode = file_inode(file);
struct buffer_head *bh;
- sector_t block;
+ sector_t block, blk_cur;
pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
(unsigned long long)index << PAGE_SHIFT);
@@ -375,17 +375,21 @@ static int read_page(struct file *file, unsigned long index,
goto out;
}
attach_page_buffers(page, bh);
- block = index << (PAGE_SHIFT - inode->i_blkbits);
+ blk_cur = index << (PAGE_SHIFT - inode->i_blkbits);
while (bh) {
+ block = blk_cur;
+
if (count == 0)
bh->b_blocknr = 0;
else {
- bh->b_blocknr = bmap(inode, block);
- if (bh->b_blocknr == 0) {
- /* Cannot use this file! */
+ ret = bmap(inode, &block);
+ if (ret || !block) {
ret = -EINVAL;
+ bh->b_blocknr = 0;
goto out;
}
+
+ bh->b_blocknr = block;
bh->b_bdev = inode->i_sb->s_bdev;
if (count < (1<<inode->i_blkbits))
count = 0;
@@ -399,7 +403,7 @@ static int read_page(struct file *file, unsigned long index,
set_buffer_mapped(bh);
submit_bh(REQ_OP_READ, 0, bh);
}
- block++;
+ blk_cur++;
bh = bh->b_this_page;
}
page->index = index;
