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-rw-r--r--fs/nilfs2/page.c579
1 files changed, 579 insertions, 0 deletions
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
new file mode 100644
index 000000000..cf4f1c679
--- /dev/null
+++ b/fs/nilfs2/page.c
@@ -0,0 +1,579 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Buffer/page management specific to NILFS
+ *
+ * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
+ *
+ * Written by Ryusuke Konishi and Seiji Kihara.
+ */
+
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/swap.h>
+#include <linux/bitops.h>
+#include <linux/page-flags.h>
+#include <linux/list.h>
+#include <linux/highmem.h>
+#include <linux/folio_batch.h>
+#include <linux/gfp.h>
+#include "nilfs.h"
+#include "page.h"
+#include "mdt.h"
+
+
+#define NILFS_BUFFER_INHERENT_BITS \
+ (BIT(BH_Uptodate) | BIT(BH_Mapped) | BIT(BH_NILFS_Node) | \
+ BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Checked))
+
+static struct buffer_head *__nilfs_get_folio_block(struct folio *folio,
+ unsigned long block, pgoff_t index, int blkbits,
+ unsigned long b_state)
+
+{
+ unsigned long first_block;
+ struct buffer_head *bh = folio_buffers(folio);
+
+ if (!bh)
+ bh = create_empty_buffers(folio, 1 << blkbits, b_state);
+
+ first_block = (unsigned long)index << (PAGE_SHIFT - blkbits);
+ bh = get_nth_bh(bh, block - first_block);
+
+ wait_on_buffer(bh);
+ return bh;
+}
+
+struct buffer_head *nilfs_grab_buffer(struct inode *inode,
+ struct address_space *mapping,
+ unsigned long blkoff,
+ unsigned long b_state)
+{
+ int blkbits = inode->i_blkbits;
+ pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits);
+ struct folio *folio;
+ struct buffer_head *bh;
+
+ folio = filemap_grab_folio(mapping, index);
+ if (IS_ERR(folio))
+ return NULL;
+
+ bh = __nilfs_get_folio_block(folio, blkoff, index, blkbits, b_state);
+ if (unlikely(!bh)) {
+ folio_unlock(folio);
+ folio_put(folio);
+ return NULL;
+ }
+ bh->b_bdev = inode->i_sb->s_bdev;
+ return bh;
+}
+
+/**
+ * nilfs_forget_buffer - discard dirty state
+ * @bh: buffer head of the buffer to be discarded
+ */
+void nilfs_forget_buffer(struct buffer_head *bh)
+{
+ struct folio *folio = bh->b_folio;
+ const unsigned long clear_bits =
+ (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
+ BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
+ BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected) |
+ BIT(BH_Delay));
+
+ lock_buffer(bh);
+ set_mask_bits(&bh->b_state, clear_bits, 0);
+ if (nilfs_folio_buffers_clean(folio))
+ __nilfs_clear_folio_dirty(folio);
+
+ bh->b_blocknr = -1;
+ folio_clear_uptodate(folio);
+ folio_clear_mappedtodisk(folio);
+ unlock_buffer(bh);
+ brelse(bh);
+}
+
+/**
+ * nilfs_copy_buffer -- copy buffer data and flags
+ * @dbh: destination buffer
+ * @sbh: source buffer
+ */
+void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
+{
+ void *saddr, *daddr;
+ unsigned long bits;
+ struct folio *sfolio = sbh->b_folio, *dfolio = dbh->b_folio;
+ struct buffer_head *bh;
+
+ saddr = kmap_local_folio(sfolio, bh_offset(sbh));
+ daddr = kmap_local_folio(dfolio, bh_offset(dbh));
+ memcpy(daddr, saddr, sbh->b_size);
+ kunmap_local(daddr);
+ kunmap_local(saddr);
+
+ dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
+ dbh->b_blocknr = sbh->b_blocknr;
+ dbh->b_bdev = sbh->b_bdev;
+
+ bh = dbh;
+ bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped));
+ while ((bh = bh->b_this_page) != dbh) {
+ lock_buffer(bh);
+ bits &= bh->b_state;
+ unlock_buffer(bh);
+ }
+ if (bits & BIT(BH_Uptodate))
+ folio_mark_uptodate(dfolio);
+ else
+ folio_clear_uptodate(dfolio);
+ if (bits & BIT(BH_Mapped))
+ folio_set_mappedtodisk(dfolio);
+ else
+ folio_clear_mappedtodisk(dfolio);
+}
+
+/**
+ * nilfs_folio_buffers_clean - Check if a folio has dirty buffers or not.
+ * @folio: Folio to be checked.
+ *
+ * Return: false if the folio has dirty buffers, true otherwise.
+ */
+bool nilfs_folio_buffers_clean(struct folio *folio)
+{
+ struct buffer_head *bh, *head;
+
+ bh = head = folio_buffers(folio);
+ do {
+ if (buffer_dirty(bh))
+ return false;
+ bh = bh->b_this_page;
+ } while (bh != head);
+ return true;
+}
+
+void nilfs_folio_bug(struct folio *folio)
+{
+ struct buffer_head *bh, *head;
+ struct address_space *m;
+ u64 ino;
+
+ if (unlikely(!folio)) {
+ printk(KERN_CRIT "NILFS_FOLIO_BUG(NULL)\n");
+ return;
+ }
+
+ m = folio->mapping;
+ ino = m ? m->host->i_ino : 0;
+
+ printk(KERN_CRIT "NILFS_FOLIO_BUG(%p): cnt=%d index#=%lu flags=0x%lx mapping=%p ino=%llu\n",
+ folio, folio_ref_count(folio), folio->index, folio->flags.f,
+ m, ino);
+
+ head = folio_buffers(folio);
+ if (head) {
+ int i = 0;
+
+ bh = head;
+ do {
+ printk(KERN_CRIT
+ " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
+ i++, bh, atomic_read(&bh->b_count),
+ (unsigned long long)bh->b_blocknr, bh->b_state);
+ bh = bh->b_this_page;
+ } while (bh != head);
+ }
+}
+
+/**
+ * nilfs_copy_folio -- copy the folio with buffers
+ * @dst: destination folio
+ * @src: source folio
+ * @copy_dirty: flag whether to copy dirty states on the folio's buffer heads.
+ *
+ * This function is for both data folios and btnode folios. The dirty flag
+ * should be treated by caller. The folio must not be under i/o.
+ * Both src and dst folio must be locked
+ */
+static void nilfs_copy_folio(struct folio *dst, struct folio *src,
+ bool copy_dirty)
+{
+ struct buffer_head *dbh, *dbufs, *sbh;
+ unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
+
+ BUG_ON(folio_test_writeback(dst));
+
+ sbh = folio_buffers(src);
+ dbh = folio_buffers(dst);
+ if (!dbh)
+ dbh = create_empty_buffers(dst, sbh->b_size, 0);
+
+ if (copy_dirty)
+ mask |= BIT(BH_Dirty);
+
+ dbufs = dbh;
+ do {
+ lock_buffer(sbh);
+ lock_buffer(dbh);
+ dbh->b_state = sbh->b_state & mask;
+ dbh->b_blocknr = sbh->b_blocknr;
+ dbh->b_bdev = sbh->b_bdev;
+ sbh = sbh->b_this_page;
+ dbh = dbh->b_this_page;
+ } while (dbh != dbufs);
+
+ folio_copy(dst, src);
+
+ if (folio_test_uptodate(src) && !folio_test_uptodate(dst))
+ folio_mark_uptodate(dst);
+ else if (!folio_test_uptodate(src) && folio_test_uptodate(dst))
+ folio_clear_uptodate(dst);
+ if (folio_test_mappedtodisk(src) && !folio_test_mappedtodisk(dst))
+ folio_set_mappedtodisk(dst);
+ else if (!folio_test_mappedtodisk(src) && folio_test_mappedtodisk(dst))
+ folio_clear_mappedtodisk(dst);
+
+ do {
+ unlock_buffer(sbh);
+ unlock_buffer(dbh);
+ sbh = sbh->b_this_page;
+ dbh = dbh->b_this_page;
+ } while (dbh != dbufs);
+}
+
+int nilfs_copy_dirty_pages(struct address_space *dmap,
+ struct address_space *smap)
+{
+ struct inode *smap_inode = smap->host;
+ struct folio_batch fbatch;
+ unsigned int i;
+ pgoff_t index = 0;
+ int err = 0;
+
+ folio_batch_init(&fbatch);
+repeat:
+ if (!filemap_get_folios_tag(smap, &index, (pgoff_t)-1,
+ PAGECACHE_TAG_DIRTY, &fbatch))
+ return 0;
+
+ for (i = 0; i < folio_batch_count(&fbatch); i++) {
+ struct folio *folio = fbatch.folios[i], *dfolio;
+
+ folio_lock(folio);
+ if (unlikely(!folio_test_dirty(folio))) {
+ if (WARN_ONCE(!sb_rdonly(smap_inode->i_sb),
+ "inconsistent dirty state\n"))
+ goto unlock_folio;
+
+ /*
+ * If the filesystem has been forced to read-only
+ * due to metadata corruption.
+ */
+ folio_unlock(folio);
+ err = -EROFS;
+ break;
+ }
+
+ dfolio = filemap_grab_folio(dmap, folio->index);
+ if (IS_ERR(dfolio)) {
+ /* No empty page is added to the page cache */
+ folio_unlock(folio);
+ err = PTR_ERR(dfolio);
+ break;
+ }
+ if (unlikely(!folio_buffers(folio)))
+ NILFS_FOLIO_BUG(folio,
+ "found empty page in dat page cache");
+
+ nilfs_copy_folio(dfolio, folio, true);
+ filemap_dirty_folio(folio_mapping(dfolio), dfolio);
+
+ folio_unlock(dfolio);
+ folio_put(dfolio);
+unlock_folio:
+ folio_unlock(folio);
+ }
+ folio_batch_release(&fbatch);
+ cond_resched();
+
+ if (likely(!err))
+ goto repeat;
+ return err;
+}
+
+/**
+ * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
+ * @dmap: destination page cache
+ * @smap: source page cache
+ *
+ * No pages must be added to the cache during this process.
+ * This must be ensured by the caller.
+ */
+void nilfs_copy_back_pages(struct address_space *dmap,
+ struct address_space *smap)
+{
+ struct folio_batch fbatch;
+ unsigned int i, n;
+ pgoff_t start = 0;
+
+ folio_batch_init(&fbatch);
+repeat:
+ n = filemap_get_folios(smap, &start, ~0UL, &fbatch);
+ if (!n)
+ return;
+
+ for (i = 0; i < folio_batch_count(&fbatch); i++) {
+ struct folio *folio = fbatch.folios[i], *dfolio;
+ pgoff_t index = folio->index;
+
+ folio_lock(folio);
+ dfolio = filemap_lock_folio(dmap, index);
+ if (!IS_ERR(dfolio)) {
+ /* overwrite existing folio in the destination cache */
+ WARN_ON(folio_test_dirty(dfolio));
+ nilfs_copy_folio(dfolio, folio, false);
+ folio_unlock(dfolio);
+ folio_put(dfolio);
+ /* Do we not need to remove folio from smap here? */
+ } else {
+ struct folio *f;
+
+ /* move the folio to the destination cache */
+ xa_lock_irq(&smap->i_pages);
+ f = __xa_erase(&smap->i_pages, index);
+ WARN_ON(folio != f);
+ smap->nrpages--;
+ xa_unlock_irq(&smap->i_pages);
+
+ xa_lock_irq(&dmap->i_pages);
+ f = __xa_store(&dmap->i_pages, index, folio, GFP_NOFS);
+ if (unlikely(f)) {
+ /* Probably -ENOMEM */
+ folio->mapping = NULL;
+ folio_put(folio);
+ } else {
+ folio->mapping = dmap;
+ dmap->nrpages++;
+ if (folio_test_dirty(folio))
+ __xa_set_mark(&dmap->i_pages, index,
+ PAGECACHE_TAG_DIRTY);
+ }
+ xa_unlock_irq(&dmap->i_pages);
+ }
+ folio_unlock(folio);
+ }
+ folio_batch_release(&fbatch);
+ cond_resched();
+
+ goto repeat;
+}
+
+/**
+ * nilfs_clear_dirty_pages - discard dirty pages in address space
+ * @mapping: address space with dirty pages for discarding
+ */
+void nilfs_clear_dirty_pages(struct address_space *mapping)
+{
+ struct folio_batch fbatch;
+ unsigned int i;
+ pgoff_t index = 0;
+
+ folio_batch_init(&fbatch);
+
+ while (filemap_get_folios_tag(mapping, &index, (pgoff_t)-1,
+ PAGECACHE_TAG_DIRTY, &fbatch)) {
+ for (i = 0; i < folio_batch_count(&fbatch); i++) {
+ struct folio *folio = fbatch.folios[i];
+
+ folio_lock(folio);
+
+ /*
+ * This folio may have been removed from the address
+ * space by truncation or invalidation when the lock
+ * was acquired. Skip processing in that case.
+ */
+ if (likely(folio->mapping == mapping))
+ nilfs_clear_folio_dirty(folio);
+
+ folio_unlock(folio);
+ }
+ folio_batch_release(&fbatch);
+ cond_resched();
+ }
+}
+
+/**
+ * nilfs_clear_folio_dirty - discard dirty folio
+ * @folio: dirty folio that will be discarded
+ *
+ * nilfs_clear_folio_dirty() clears working states including dirty state for
+ * the folio and its buffers. If the folio has buffers, clear only if it is
+ * confirmed that none of the buffer heads are busy (none have valid
+ * references and none are locked).
+ */
+void nilfs_clear_folio_dirty(struct folio *folio)
+{
+ struct buffer_head *bh, *head;
+
+ BUG_ON(!folio_test_locked(folio));
+
+ head = folio_buffers(folio);
+ if (head) {
+ const unsigned long clear_bits =
+ (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
+ BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
+ BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected) |
+ BIT(BH_Delay));
+ bool busy, invalidated = false;
+
+recheck_buffers:
+ busy = false;
+ bh = head;
+ do {
+ if (atomic_read(&bh->b_count) | buffer_locked(bh)) {
+ busy = true;
+ break;
+ }
+ } while (bh = bh->b_this_page, bh != head);
+
+ if (busy) {
+ if (invalidated)
+ return;
+ invalidate_bh_lrus();
+ invalidated = true;
+ goto recheck_buffers;
+ }
+
+ bh = head;
+ do {
+ lock_buffer(bh);
+ set_mask_bits(&bh->b_state, clear_bits, 0);
+ unlock_buffer(bh);
+ } while (bh = bh->b_this_page, bh != head);
+ }
+
+ folio_clear_uptodate(folio);
+ folio_clear_mappedtodisk(folio);
+ folio_clear_checked(folio);
+ __nilfs_clear_folio_dirty(folio);
+}
+
+unsigned int nilfs_page_count_clean_buffers(struct folio *folio,
+ unsigned int from, unsigned int to)
+{
+ unsigned int block_start, block_end;
+ struct buffer_head *bh, *head;
+ unsigned int nc = 0;
+
+ for (bh = head = folio_buffers(folio), block_start = 0;
+ bh != head || !block_start;
+ block_start = block_end, bh = bh->b_this_page) {
+ block_end = block_start + bh->b_size;
+ if (block_end > from && block_start < to && !buffer_dirty(bh))
+ nc++;
+ }
+ return nc;
+}
+
+/*
+ * NILFS2 needs clear_page_dirty() in the following two cases:
+ *
+ * 1) For B-tree node pages and data pages of DAT file, NILFS2 clears dirty
+ * flag of pages when it copies back pages from shadow cache to the
+ * original cache.
+ *
+ * 2) Some B-tree operations like insertion or deletion may dispose buffers
+ * in dirty state, and this needs to cancel the dirty state of their pages.
+ */
+void __nilfs_clear_folio_dirty(struct folio *folio)
+{
+ struct address_space *mapping = folio->mapping;
+
+ if (mapping) {
+ xa_lock_irq(&mapping->i_pages);
+ if (folio_test_dirty(folio)) {
+ __xa_clear_mark(&mapping->i_pages, folio->index,
+ PAGECACHE_TAG_DIRTY);
+ xa_unlock_irq(&mapping->i_pages);
+ folio_clear_dirty_for_io(folio);
+ return;
+ }
+ xa_unlock_irq(&mapping->i_pages);
+ return;
+ }
+ folio_clear_dirty(folio);
+}
+
+/**
+ * nilfs_find_uncommitted_extent - find extent of uncommitted data
+ * @inode: inode
+ * @start_blk: start block offset (in)
+ * @blkoff: start offset of the found extent (out)
+ *
+ * This function searches an extent of buffers marked "delayed" which
+ * starts from a block offset equal to or larger than @start_blk. If
+ * such an extent was found, this will store the start offset in
+ * @blkoff and return its length in blocks.
+ *
+ * Return: Length in blocks of found extent, 0 otherwise.
+ */
+unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
+ sector_t start_blk,
+ sector_t *blkoff)
+{
+ unsigned int i, nr_folios;
+ pgoff_t index;
+ unsigned long length = 0;
+ struct folio_batch fbatch;
+ struct folio *folio;
+
+ if (inode->i_mapping->nrpages == 0)
+ return 0;
+
+ index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
+
+ folio_batch_init(&fbatch);
+
+repeat:
+ nr_folios = filemap_get_folios_contig(inode->i_mapping, &index, ULONG_MAX,
+ &fbatch);
+ if (nr_folios == 0)
+ return length;
+
+ i = 0;
+ do {
+ folio = fbatch.folios[i];
+
+ folio_lock(folio);
+ if (folio_buffers(folio)) {
+ struct buffer_head *bh, *head;
+ sector_t b;
+
+ b = folio->index << (PAGE_SHIFT - inode->i_blkbits);
+ bh = head = folio_buffers(folio);
+ do {
+ if (b < start_blk)
+ continue;
+ if (buffer_delay(bh)) {
+ if (length == 0)
+ *blkoff = b;
+ length++;
+ } else if (length > 0) {
+ goto out_locked;
+ }
+ } while (++b, bh = bh->b_this_page, bh != head);
+ } else {
+ if (length > 0)
+ goto out_locked;
+ }
+ folio_unlock(folio);
+
+ } while (++i < nr_folios);
+
+ folio_batch_release(&fbatch);
+ cond_resched();
+ goto repeat;
+
+out_locked:
+ folio_unlock(folio);
+ folio_batch_release(&fbatch);
+ return length;
+}
generated by cgit v1.3.1 (git 2.54.0) at 2026-10-12 10:43:52 +0000