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-rw-r--r--fs/nilfs2/btnode.c298
1 files changed, 298 insertions, 0 deletions
diff --git a/fs/nilfs2/btnode.c b/fs/nilfs2/btnode.c
new file mode 100644
index 0000000000..5710833ac1
--- /dev/null
+++ b/fs/nilfs2/btnode.c
@@ -0,0 +1,298 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * 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, blk_opf_t opf,
+ 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 (opf & REQ_RAHEAD) {
+ if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
+ err = -EBUSY; /* internal code */
+ brelse(bh);
+ goto out_locked;
+ }
+ } else { /* opf == REQ_OP_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(opf, 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) {
+ struct page *opage = obh->b_page;
+ lock_page(opage);
+retry:
+ /* BUG_ON(oldkey != obh->b_folio->index); */
+ if (unlikely(oldkey != opage->index))
+ NILFS_PAGE_BUG(opage,
+ "invalid oldkey %lld (newkey=%lld)",
+ (unsigned long long)oldkey,
+ (unsigned long long)newkey);
+
+ xa_lock_irq(&btnc->i_pages);
+ err = __xa_insert(&btnc->i_pages, newkey, opage, GFP_NOFS);
+ 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.
+ */
+ if (!err)
+ return 0;
+ else if (err != -EBUSY)
+ goto failed_unlock;
+
+ err = invalidate_inode_pages2_range(btnc, newkey, newkey);
+ if (!err)
+ goto retry;
+ /* fallback to copy mode */
+ unlock_page(opage);
+ }
+
+ 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);
+ __xa_erase(&btnc->i_pages, oldkey);
+ __xa_set_mark(&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_erase_irq(&btnc->i_pages, newkey);
+ unlock_page(ctxt->bh->b_page);
+ } else {
+ /*
+ * When canceling a buffer that a prepare operation has
+ * allocated to copy a node block to another location, use
+ * nilfs_btnode_delete() to initialize and release the buffer
+ * so that the buffer flags will not be in an inconsistent
+ * state when it is reallocated.
+ */
+ nilfs_btnode_delete(nbh);
+ }
+}