On Thu 23-03-23 10:32:59, Jiapeng Chong wrote: > Variable 'err' set but not used. > > fs/buffer.c:2613:2: warning: Value stored to 'err' is never read. > > Reported-by: Abaci Robot <abaci@xxxxxxxxxxxxxxxxx> > Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4589 > Signed-off-by: Jiapeng Chong <jiapeng.chong@xxxxxxxxxxxxxxxxx> I don't think the patch is quite correct (Christian, please drop it if I'm correct). See below: > diff --git a/fs/buffer.c b/fs/buffer.c > index d759b105c1e7..b3eb905f87d6 100644 > --- a/fs/buffer.c > +++ b/fs/buffer.c > @@ -2580,7 +2580,7 @@ int block_truncate_page(struct address_space *mapping, > struct inode *inode = mapping->host; > struct page *page; > struct buffer_head *bh; > - int err; > + int err = 0; > > blocksize = i_blocksize(inode); > length = offset & (blocksize - 1); > @@ -2593,9 +2593,8 @@ int block_truncate_page(struct address_space *mapping, > iblock = (sector_t)index << (PAGE_SHIFT - inode->i_blkbits); > > page = grab_cache_page(mapping, index); > - err = -ENOMEM; > if (!page) > - goto out; > + return -ENOMEM; > > if (!page_has_buffers(page)) > create_empty_buffers(page, blocksize, 0); > @@ -2609,7 +2608,6 @@ int block_truncate_page(struct address_space *mapping, > pos += blocksize; > } > > - err = 0; > if (!buffer_mapped(bh)) { > WARN_ON(bh->b_size != blocksize); > err = get_block(inode, iblock, bh, 0); > @@ -2633,12 +2631,11 @@ int block_truncate_page(struct address_space *mapping, > > zero_user(page, offset, length); > mark_buffer_dirty(bh); > - err = 0; There is: if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) err = -EIO; above this assignment. So now we'll be returning -EIO if block_truncate_page() needs to read the block AFAICT. Did this pass fstests with some filesystem exercising this code (ext2 driver comes to mind)? Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
