| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * btnode.c - NILFS B-tree node cache |
| * |
| * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. |
| * |
| * Originally written by Seiji Kihara. |
| * Fully revised by Ryusuke Konishi for stabilization and simplification. |
| * |
| */ |
| |
| #include <linux/types.h> |
| #include <linux/buffer_head.h> |
| #include <linux/mm.h> |
| #include <linux/backing-dev.h> |
| #include <linux/gfp.h> |
| #include "nilfs.h" |
| #include "mdt.h" |
| #include "dat.h" |
| #include "page.h" |
| #include "btnode.h" |
| |
| |
| /** |
| * nilfs_init_btnc_inode - initialize B-tree node cache inode |
| * @btnc_inode: inode to be initialized |
| * |
| * nilfs_init_btnc_inode() sets up an inode for B-tree node cache. |
| */ |
| void nilfs_init_btnc_inode(struct inode *btnc_inode) |
| { |
| struct nilfs_inode_info *ii = NILFS_I(btnc_inode); |
| |
| btnc_inode->i_mode = S_IFREG; |
| ii->i_flags = 0; |
| memset(&ii->i_bmap_data, 0, sizeof(struct nilfs_bmap)); |
| mapping_set_gfp_mask(btnc_inode->i_mapping, GFP_NOFS); |
| } |
| |
| void nilfs_btnode_cache_clear(struct address_space *btnc) |
| { |
| invalidate_mapping_pages(btnc, 0, -1); |
| truncate_inode_pages(btnc, 0); |
| } |
| |
| struct buffer_head * |
| nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr) |
| { |
| struct inode *inode = btnc->host; |
| struct buffer_head *bh; |
| |
| bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node)); |
| if (unlikely(!bh)) |
| return NULL; |
| |
| if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) || |
| buffer_dirty(bh))) { |
| brelse(bh); |
| BUG(); |
| } |
| memset(bh->b_data, 0, i_blocksize(inode)); |
| bh->b_bdev = inode->i_sb->s_bdev; |
| bh->b_blocknr = blocknr; |
| set_buffer_mapped(bh); |
| set_buffer_uptodate(bh); |
| |
| unlock_page(bh->b_page); |
| put_page(bh->b_page); |
| return bh; |
| } |
| |
| int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr, |
| sector_t pblocknr, int mode, int mode_flags, |
| struct buffer_head **pbh, sector_t *submit_ptr) |
| { |
| struct buffer_head *bh; |
| struct inode *inode = btnc->host; |
| struct page *page; |
| int err; |
| |
| bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node)); |
| if (unlikely(!bh)) |
| return -ENOMEM; |
| |
| err = -EEXIST; /* internal code */ |
| page = bh->b_page; |
| |
| if (buffer_uptodate(bh) || buffer_dirty(bh)) |
| goto found; |
| |
| if (pblocknr == 0) { |
| pblocknr = blocknr; |
| if (inode->i_ino != NILFS_DAT_INO) { |
| struct the_nilfs *nilfs = inode->i_sb->s_fs_info; |
| |
| /* blocknr is a virtual block number */ |
| err = nilfs_dat_translate(nilfs->ns_dat, blocknr, |
| &pblocknr); |
| if (unlikely(err)) { |
| brelse(bh); |
| goto out_locked; |
| } |
| } |
| } |
| |
| if (mode_flags & REQ_RAHEAD) { |
| if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) { |
| err = -EBUSY; /* internal code */ |
| brelse(bh); |
| goto out_locked; |
| } |
| } else { /* mode == READ */ |
| lock_buffer(bh); |
| } |
| if (buffer_uptodate(bh)) { |
| unlock_buffer(bh); |
| err = -EEXIST; /* internal code */ |
| goto found; |
| } |
| set_buffer_mapped(bh); |
| bh->b_bdev = inode->i_sb->s_bdev; |
| bh->b_blocknr = pblocknr; /* set block address for read */ |
| bh->b_end_io = end_buffer_read_sync; |
| get_bh(bh); |
| submit_bh(mode, mode_flags, bh); |
| bh->b_blocknr = blocknr; /* set back to the given block address */ |
| *submit_ptr = pblocknr; |
| err = 0; |
| found: |
| *pbh = bh; |
| |
| out_locked: |
| unlock_page(page); |
| put_page(page); |
| return err; |
| } |
| |
| /** |
| * nilfs_btnode_delete - delete B-tree node buffer |
| * @bh: buffer to be deleted |
| * |
| * nilfs_btnode_delete() invalidates the specified buffer and delete the page |
| * including the buffer if the page gets unbusy. |
| */ |
| void nilfs_btnode_delete(struct buffer_head *bh) |
| { |
| struct address_space *mapping; |
| struct page *page = bh->b_page; |
| pgoff_t index = page_index(page); |
| int still_dirty; |
| |
| get_page(page); |
| lock_page(page); |
| wait_on_page_writeback(page); |
| |
| nilfs_forget_buffer(bh); |
| still_dirty = PageDirty(page); |
| mapping = page->mapping; |
| unlock_page(page); |
| put_page(page); |
| |
| if (!still_dirty && mapping) |
| invalidate_inode_pages2_range(mapping, index, index); |
| } |
| |
| /** |
| * nilfs_btnode_prepare_change_key |
| * prepare to move contents of the block for old key to one of new key. |
| * the old buffer will not be removed, but might be reused for new buffer. |
| * it might return -ENOMEM because of memory allocation errors, |
| * and might return -EIO because of disk read errors. |
| */ |
| int nilfs_btnode_prepare_change_key(struct address_space *btnc, |
| struct nilfs_btnode_chkey_ctxt *ctxt) |
| { |
| struct buffer_head *obh, *nbh; |
| struct inode *inode = btnc->host; |
| __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; |
| int err; |
| |
| if (oldkey == newkey) |
| return 0; |
| |
| obh = ctxt->bh; |
| ctxt->newbh = NULL; |
| |
| if (inode->i_blkbits == PAGE_SHIFT) { |
| lock_page(obh->b_page); |
| /* |
| * We cannot call radix_tree_preload for the kernels older |
| * than 2.6.23, because it is not exported for modules. |
| */ |
| retry: |
| err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM); |
| if (err) |
| goto failed_unlock; |
| /* BUG_ON(oldkey != obh->b_page->index); */ |
| if (unlikely(oldkey != obh->b_page->index)) |
| NILFS_PAGE_BUG(obh->b_page, |
| "invalid oldkey %lld (newkey=%lld)", |
| (unsigned long long)oldkey, |
| (unsigned long long)newkey); |
| |
| xa_lock_irq(&btnc->i_pages); |
| err = radix_tree_insert(&btnc->i_pages, newkey, obh->b_page); |
| xa_unlock_irq(&btnc->i_pages); |
| /* |
| * Note: page->index will not change to newkey until |
| * nilfs_btnode_commit_change_key() will be called. |
| * To protect the page in intermediate state, the page lock |
| * is held. |
| */ |
| radix_tree_preload_end(); |
| if (!err) |
| return 0; |
| else if (err != -EEXIST) |
| goto failed_unlock; |
| |
| err = invalidate_inode_pages2_range(btnc, newkey, newkey); |
| if (!err) |
| goto retry; |
| /* fallback to copy mode */ |
| unlock_page(obh->b_page); |
| } |
| |
| nbh = nilfs_btnode_create_block(btnc, newkey); |
| if (!nbh) |
| return -ENOMEM; |
| |
| BUG_ON(nbh == obh); |
| ctxt->newbh = nbh; |
| return 0; |
| |
| failed_unlock: |
| unlock_page(obh->b_page); |
| return err; |
| } |
| |
| /** |
| * nilfs_btnode_commit_change_key |
| * commit the change_key operation prepared by prepare_change_key(). |
| */ |
| void nilfs_btnode_commit_change_key(struct address_space *btnc, |
| struct nilfs_btnode_chkey_ctxt *ctxt) |
| { |
| struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh; |
| __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; |
| struct page *opage; |
| |
| if (oldkey == newkey) |
| return; |
| |
| if (nbh == NULL) { /* blocksize == pagesize */ |
| opage = obh->b_page; |
| if (unlikely(oldkey != opage->index)) |
| NILFS_PAGE_BUG(opage, |
| "invalid oldkey %lld (newkey=%lld)", |
| (unsigned long long)oldkey, |
| (unsigned long long)newkey); |
| mark_buffer_dirty(obh); |
| |
| xa_lock_irq(&btnc->i_pages); |
| radix_tree_delete(&btnc->i_pages, oldkey); |
| radix_tree_tag_set(&btnc->i_pages, newkey, |
| PAGECACHE_TAG_DIRTY); |
| xa_unlock_irq(&btnc->i_pages); |
| |
| opage->index = obh->b_blocknr = newkey; |
| unlock_page(opage); |
| } else { |
| nilfs_copy_buffer(nbh, obh); |
| mark_buffer_dirty(nbh); |
| |
| nbh->b_blocknr = newkey; |
| ctxt->bh = nbh; |
| nilfs_btnode_delete(obh); /* will decrement bh->b_count */ |
| } |
| } |
| |
| /** |
| * nilfs_btnode_abort_change_key |
| * abort the change_key operation prepared by prepare_change_key(). |
| */ |
| void nilfs_btnode_abort_change_key(struct address_space *btnc, |
| struct nilfs_btnode_chkey_ctxt *ctxt) |
| { |
| struct buffer_head *nbh = ctxt->newbh; |
| __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey; |
| |
| if (oldkey == newkey) |
| return; |
| |
| if (nbh == NULL) { /* blocksize == pagesize */ |
| xa_lock_irq(&btnc->i_pages); |
| radix_tree_delete(&btnc->i_pages, newkey); |
| xa_unlock_irq(&btnc->i_pages); |
| unlock_page(ctxt->bh->b_page); |
| } else |
| brelse(nbh); |
| } |