v4.19.13 snapshot.
diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
new file mode 100644
index 0000000..fa2c682
--- /dev/null
+++ b/fs/jfs/jfs_metapage.c
@@ -0,0 +1,831 @@
+/*
+ * Copyright (C) International Business Machines Corp., 2000-2005
+ * Portions Copyright (C) Christoph Hellwig, 2001-2002
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/buffer_head.h>
+#include <linux/mempool.h>
+#include <linux/seq_file.h>
+#include "jfs_incore.h"
+#include "jfs_superblock.h"
+#include "jfs_filsys.h"
+#include "jfs_metapage.h"
+#include "jfs_txnmgr.h"
+#include "jfs_debug.h"
+
+#ifdef CONFIG_JFS_STATISTICS
+static struct {
+ uint pagealloc; /* # of page allocations */
+ uint pagefree; /* # of page frees */
+ uint lockwait; /* # of sleeping lock_metapage() calls */
+} mpStat;
+#endif
+
+#define metapage_locked(mp) test_bit(META_locked, &(mp)->flag)
+#define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag)
+
+static inline void unlock_metapage(struct metapage *mp)
+{
+ clear_bit_unlock(META_locked, &mp->flag);
+ wake_up(&mp->wait);
+}
+
+static inline void __lock_metapage(struct metapage *mp)
+{
+ DECLARE_WAITQUEUE(wait, current);
+ INCREMENT(mpStat.lockwait);
+ add_wait_queue_exclusive(&mp->wait, &wait);
+ do {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (metapage_locked(mp)) {
+ unlock_page(mp->page);
+ io_schedule();
+ lock_page(mp->page);
+ }
+ } while (trylock_metapage(mp));
+ __set_current_state(TASK_RUNNING);
+ remove_wait_queue(&mp->wait, &wait);
+}
+
+/*
+ * Must have mp->page locked
+ */
+static inline void lock_metapage(struct metapage *mp)
+{
+ if (trylock_metapage(mp))
+ __lock_metapage(mp);
+}
+
+#define METAPOOL_MIN_PAGES 32
+static struct kmem_cache *metapage_cache;
+static mempool_t *metapage_mempool;
+
+#define MPS_PER_PAGE (PAGE_SIZE >> L2PSIZE)
+
+#if MPS_PER_PAGE > 1
+
+struct meta_anchor {
+ int mp_count;
+ atomic_t io_count;
+ struct metapage *mp[MPS_PER_PAGE];
+};
+#define mp_anchor(page) ((struct meta_anchor *)page_private(page))
+
+static inline struct metapage *page_to_mp(struct page *page, int offset)
+{
+ if (!PagePrivate(page))
+ return NULL;
+ return mp_anchor(page)->mp[offset >> L2PSIZE];
+}
+
+static inline int insert_metapage(struct page *page, struct metapage *mp)
+{
+ struct meta_anchor *a;
+ int index;
+ int l2mp_blocks; /* log2 blocks per metapage */
+
+ if (PagePrivate(page))
+ a = mp_anchor(page);
+ else {
+ a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS);
+ if (!a)
+ return -ENOMEM;
+ set_page_private(page, (unsigned long)a);
+ SetPagePrivate(page);
+ kmap(page);
+ }
+
+ if (mp) {
+ l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
+ index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
+ a->mp_count++;
+ a->mp[index] = mp;
+ }
+
+ return 0;
+}
+
+static inline void remove_metapage(struct page *page, struct metapage *mp)
+{
+ struct meta_anchor *a = mp_anchor(page);
+ int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
+ int index;
+
+ index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
+
+ BUG_ON(a->mp[index] != mp);
+
+ a->mp[index] = NULL;
+ if (--a->mp_count == 0) {
+ kfree(a);
+ set_page_private(page, 0);
+ ClearPagePrivate(page);
+ kunmap(page);
+ }
+}
+
+static inline void inc_io(struct page *page)
+{
+ atomic_inc(&mp_anchor(page)->io_count);
+}
+
+static inline void dec_io(struct page *page, void (*handler) (struct page *))
+{
+ if (atomic_dec_and_test(&mp_anchor(page)->io_count))
+ handler(page);
+}
+
+#else
+static inline struct metapage *page_to_mp(struct page *page, int offset)
+{
+ return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL;
+}
+
+static inline int insert_metapage(struct page *page, struct metapage *mp)
+{
+ if (mp) {
+ set_page_private(page, (unsigned long)mp);
+ SetPagePrivate(page);
+ kmap(page);
+ }
+ return 0;
+}
+
+static inline void remove_metapage(struct page *page, struct metapage *mp)
+{
+ set_page_private(page, 0);
+ ClearPagePrivate(page);
+ kunmap(page);
+}
+
+#define inc_io(page) do {} while(0)
+#define dec_io(page, handler) handler(page)
+
+#endif
+
+static inline struct metapage *alloc_metapage(gfp_t gfp_mask)
+{
+ struct metapage *mp = mempool_alloc(metapage_mempool, gfp_mask);
+
+ if (mp) {
+ mp->lid = 0;
+ mp->lsn = 0;
+ mp->data = NULL;
+ mp->clsn = 0;
+ mp->log = NULL;
+ init_waitqueue_head(&mp->wait);
+ }
+ return mp;
+}
+
+static inline void free_metapage(struct metapage *mp)
+{
+ mempool_free(mp, metapage_mempool);
+}
+
+int __init metapage_init(void)
+{
+ /*
+ * Allocate the metapage structures
+ */
+ metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage),
+ 0, 0, NULL);
+ if (metapage_cache == NULL)
+ return -ENOMEM;
+
+ metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES,
+ metapage_cache);
+
+ if (metapage_mempool == NULL) {
+ kmem_cache_destroy(metapage_cache);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+void metapage_exit(void)
+{
+ mempool_destroy(metapage_mempool);
+ kmem_cache_destroy(metapage_cache);
+}
+
+static inline void drop_metapage(struct page *page, struct metapage *mp)
+{
+ if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) ||
+ test_bit(META_io, &mp->flag))
+ return;
+ remove_metapage(page, mp);
+ INCREMENT(mpStat.pagefree);
+ free_metapage(mp);
+}
+
+/*
+ * Metapage address space operations
+ */
+
+static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
+ int *len)
+{
+ int rc = 0;
+ int xflag;
+ s64 xaddr;
+ sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
+ inode->i_blkbits;
+
+ if (lblock >= file_blocks)
+ return 0;
+ if (lblock + *len > file_blocks)
+ *len = file_blocks - lblock;
+
+ if (inode->i_ino) {
+ rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0);
+ if ((rc == 0) && *len)
+ lblock = (sector_t)xaddr;
+ else
+ lblock = 0;
+ } /* else no mapping */
+
+ return lblock;
+}
+
+static void last_read_complete(struct page *page)
+{
+ if (!PageError(page))
+ SetPageUptodate(page);
+ unlock_page(page);
+}
+
+static void metapage_read_end_io(struct bio *bio)
+{
+ struct page *page = bio->bi_private;
+
+ if (bio->bi_status) {
+ printk(KERN_ERR "metapage_read_end_io: I/O error\n");
+ SetPageError(page);
+ }
+
+ dec_io(page, last_read_complete);
+ bio_put(bio);
+}
+
+static void remove_from_logsync(struct metapage *mp)
+{
+ struct jfs_log *log = mp->log;
+ unsigned long flags;
+/*
+ * This can race. Recheck that log hasn't been set to null, and after
+ * acquiring logsync lock, recheck lsn
+ */
+ if (!log)
+ return;
+
+ LOGSYNC_LOCK(log, flags);
+ if (mp->lsn) {
+ mp->log = NULL;
+ mp->lsn = 0;
+ mp->clsn = 0;
+ log->count--;
+ list_del(&mp->synclist);
+ }
+ LOGSYNC_UNLOCK(log, flags);
+}
+
+static void last_write_complete(struct page *page)
+{
+ struct metapage *mp;
+ unsigned int offset;
+
+ for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
+ mp = page_to_mp(page, offset);
+ if (mp && test_bit(META_io, &mp->flag)) {
+ if (mp->lsn)
+ remove_from_logsync(mp);
+ clear_bit(META_io, &mp->flag);
+ }
+ /*
+ * I'd like to call drop_metapage here, but I don't think it's
+ * safe unless I have the page locked
+ */
+ }
+ end_page_writeback(page);
+}
+
+static void metapage_write_end_io(struct bio *bio)
+{
+ struct page *page = bio->bi_private;
+
+ BUG_ON(!PagePrivate(page));
+
+ if (bio->bi_status) {
+ printk(KERN_ERR "metapage_write_end_io: I/O error\n");
+ SetPageError(page);
+ }
+ dec_io(page, last_write_complete);
+ bio_put(bio);
+}
+
+static int metapage_writepage(struct page *page, struct writeback_control *wbc)
+{
+ struct bio *bio = NULL;
+ int block_offset; /* block offset of mp within page */
+ struct inode *inode = page->mapping->host;
+ int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
+ int len;
+ int xlen;
+ struct metapage *mp;
+ int redirty = 0;
+ sector_t lblock;
+ int nr_underway = 0;
+ sector_t pblock;
+ sector_t next_block = 0;
+ sector_t page_start;
+ unsigned long bio_bytes = 0;
+ unsigned long bio_offset = 0;
+ int offset;
+ int bad_blocks = 0;
+
+ page_start = (sector_t)page->index <<
+ (PAGE_SHIFT - inode->i_blkbits);
+ BUG_ON(!PageLocked(page));
+ BUG_ON(PageWriteback(page));
+ set_page_writeback(page);
+
+ for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
+ mp = page_to_mp(page, offset);
+
+ if (!mp || !test_bit(META_dirty, &mp->flag))
+ continue;
+
+ if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) {
+ redirty = 1;
+ /*
+ * Make sure this page isn't blocked indefinitely.
+ * If the journal isn't undergoing I/O, push it
+ */
+ if (mp->log && !(mp->log->cflag & logGC_PAGEOUT))
+ jfs_flush_journal(mp->log, 0);
+ continue;
+ }
+
+ clear_bit(META_dirty, &mp->flag);
+ set_bit(META_io, &mp->flag);
+ block_offset = offset >> inode->i_blkbits;
+ lblock = page_start + block_offset;
+ if (bio) {
+ if (xlen && lblock == next_block) {
+ /* Contiguous, in memory & on disk */
+ len = min(xlen, blocks_per_mp);
+ xlen -= len;
+ bio_bytes += len << inode->i_blkbits;
+ continue;
+ }
+ /* Not contiguous */
+ if (bio_add_page(bio, page, bio_bytes, bio_offset) <
+ bio_bytes)
+ goto add_failed;
+ /*
+ * Increment counter before submitting i/o to keep
+ * count from hitting zero before we're through
+ */
+ inc_io(page);
+ if (!bio->bi_iter.bi_size)
+ goto dump_bio;
+ submit_bio(bio);
+ nr_underway++;
+ bio = NULL;
+ } else
+ inc_io(page);
+ xlen = (PAGE_SIZE - offset) >> inode->i_blkbits;
+ pblock = metapage_get_blocks(inode, lblock, &xlen);
+ if (!pblock) {
+ printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
+ /*
+ * We already called inc_io(), but can't cancel it
+ * with dec_io() until we're done with the page
+ */
+ bad_blocks++;
+ continue;
+ }
+ len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage);
+
+ bio = bio_alloc(GFP_NOFS, 1);
+ bio_set_dev(bio, inode->i_sb->s_bdev);
+ bio->bi_iter.bi_sector = pblock << (inode->i_blkbits - 9);
+ bio->bi_end_io = metapage_write_end_io;
+ bio->bi_private = page;
+ bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+
+ /* Don't call bio_add_page yet, we may add to this vec */
+ bio_offset = offset;
+ bio_bytes = len << inode->i_blkbits;
+
+ xlen -= len;
+ next_block = lblock + len;
+ }
+ if (bio) {
+ if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
+ goto add_failed;
+ if (!bio->bi_iter.bi_size)
+ goto dump_bio;
+
+ submit_bio(bio);
+ nr_underway++;
+ }
+ if (redirty)
+ redirty_page_for_writepage(wbc, page);
+
+ unlock_page(page);
+
+ if (bad_blocks)
+ goto err_out;
+
+ if (nr_underway == 0)
+ end_page_writeback(page);
+
+ return 0;
+add_failed:
+ /* We should never reach here, since we're only adding one vec */
+ printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
+ goto skip;
+dump_bio:
+ print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16,
+ 4, bio, sizeof(*bio), 0);
+skip:
+ bio_put(bio);
+ unlock_page(page);
+ dec_io(page, last_write_complete);
+err_out:
+ while (bad_blocks--)
+ dec_io(page, last_write_complete);
+ return -EIO;
+}
+
+static int metapage_readpage(struct file *fp, struct page *page)
+{
+ struct inode *inode = page->mapping->host;
+ struct bio *bio = NULL;
+ int block_offset;
+ int blocks_per_page = PAGE_SIZE >> inode->i_blkbits;
+ sector_t page_start; /* address of page in fs blocks */
+ sector_t pblock;
+ int xlen;
+ unsigned int len;
+ int offset;
+
+ BUG_ON(!PageLocked(page));
+ page_start = (sector_t)page->index <<
+ (PAGE_SHIFT - inode->i_blkbits);
+
+ block_offset = 0;
+ while (block_offset < blocks_per_page) {
+ xlen = blocks_per_page - block_offset;
+ pblock = metapage_get_blocks(inode, page_start + block_offset,
+ &xlen);
+ if (pblock) {
+ if (!PagePrivate(page))
+ insert_metapage(page, NULL);
+ inc_io(page);
+ if (bio)
+ submit_bio(bio);
+
+ bio = bio_alloc(GFP_NOFS, 1);
+ bio_set_dev(bio, inode->i_sb->s_bdev);
+ bio->bi_iter.bi_sector =
+ pblock << (inode->i_blkbits - 9);
+ bio->bi_end_io = metapage_read_end_io;
+ bio->bi_private = page;
+ bio_set_op_attrs(bio, REQ_OP_READ, 0);
+ len = xlen << inode->i_blkbits;
+ offset = block_offset << inode->i_blkbits;
+ if (bio_add_page(bio, page, len, offset) < len)
+ goto add_failed;
+ block_offset += xlen;
+ } else
+ block_offset++;
+ }
+ if (bio)
+ submit_bio(bio);
+ else
+ unlock_page(page);
+
+ return 0;
+
+add_failed:
+ printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
+ bio_put(bio);
+ dec_io(page, last_read_complete);
+ return -EIO;
+}
+
+static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
+{
+ struct metapage *mp;
+ int ret = 1;
+ int offset;
+
+ for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
+ mp = page_to_mp(page, offset);
+
+ if (!mp)
+ continue;
+
+ jfs_info("metapage_releasepage: mp = 0x%p", mp);
+ if (mp->count || mp->nohomeok ||
+ test_bit(META_dirty, &mp->flag)) {
+ jfs_info("count = %ld, nohomeok = %d", mp->count,
+ mp->nohomeok);
+ ret = 0;
+ continue;
+ }
+ if (mp->lsn)
+ remove_from_logsync(mp);
+ remove_metapage(page, mp);
+ INCREMENT(mpStat.pagefree);
+ free_metapage(mp);
+ }
+ return ret;
+}
+
+static void metapage_invalidatepage(struct page *page, unsigned int offset,
+ unsigned int length)
+{
+ BUG_ON(offset || length < PAGE_SIZE);
+
+ BUG_ON(PageWriteback(page));
+
+ metapage_releasepage(page, 0);
+}
+
+const struct address_space_operations jfs_metapage_aops = {
+ .readpage = metapage_readpage,
+ .writepage = metapage_writepage,
+ .releasepage = metapage_releasepage,
+ .invalidatepage = metapage_invalidatepage,
+ .set_page_dirty = __set_page_dirty_nobuffers,
+};
+
+struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
+ unsigned int size, int absolute,
+ unsigned long new)
+{
+ int l2BlocksPerPage;
+ int l2bsize;
+ struct address_space *mapping;
+ struct metapage *mp = NULL;
+ struct page *page;
+ unsigned long page_index;
+ unsigned long page_offset;
+
+ jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
+ inode->i_ino, lblock, absolute);
+
+ l2bsize = inode->i_blkbits;
+ l2BlocksPerPage = PAGE_SHIFT - l2bsize;
+ page_index = lblock >> l2BlocksPerPage;
+ page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
+ if ((page_offset + size) > PAGE_SIZE) {
+ jfs_err("MetaData crosses page boundary!!");
+ jfs_err("lblock = %lx, size = %d", lblock, size);
+ dump_stack();
+ return NULL;
+ }
+ if (absolute)
+ mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
+ else {
+ /*
+ * If an nfs client tries to read an inode that is larger
+ * than any existing inodes, we may try to read past the
+ * end of the inode map
+ */
+ if ((lblock << inode->i_blkbits) >= inode->i_size)
+ return NULL;
+ mapping = inode->i_mapping;
+ }
+
+ if (new && (PSIZE == PAGE_SIZE)) {
+ page = grab_cache_page(mapping, page_index);
+ if (!page) {
+ jfs_err("grab_cache_page failed!");
+ return NULL;
+ }
+ SetPageUptodate(page);
+ } else {
+ page = read_mapping_page(mapping, page_index, NULL);
+ if (IS_ERR(page) || !PageUptodate(page)) {
+ jfs_err("read_mapping_page failed!");
+ return NULL;
+ }
+ lock_page(page);
+ }
+
+ mp = page_to_mp(page, page_offset);
+ if (mp) {
+ if (mp->logical_size != size) {
+ jfs_error(inode->i_sb,
+ "get_mp->logical_size != size\n");
+ jfs_err("logical_size = %d, size = %d",
+ mp->logical_size, size);
+ dump_stack();
+ goto unlock;
+ }
+ mp->count++;
+ lock_metapage(mp);
+ if (test_bit(META_discard, &mp->flag)) {
+ if (!new) {
+ jfs_error(inode->i_sb,
+ "using a discarded metapage\n");
+ discard_metapage(mp);
+ goto unlock;
+ }
+ clear_bit(META_discard, &mp->flag);
+ }
+ } else {
+ INCREMENT(mpStat.pagealloc);
+ mp = alloc_metapage(GFP_NOFS);
+ if (!mp)
+ goto unlock;
+ mp->page = page;
+ mp->sb = inode->i_sb;
+ mp->flag = 0;
+ mp->xflag = COMMIT_PAGE;
+ mp->count = 1;
+ mp->nohomeok = 0;
+ mp->logical_size = size;
+ mp->data = page_address(page) + page_offset;
+ mp->index = lblock;
+ if (unlikely(insert_metapage(page, mp))) {
+ free_metapage(mp);
+ goto unlock;
+ }
+ lock_metapage(mp);
+ }
+
+ if (new) {
+ jfs_info("zeroing mp = 0x%p", mp);
+ memset(mp->data, 0, PSIZE);
+ }
+
+ unlock_page(page);
+ jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
+ return mp;
+
+unlock:
+ unlock_page(page);
+ return NULL;
+}
+
+void grab_metapage(struct metapage * mp)
+{
+ jfs_info("grab_metapage: mp = 0x%p", mp);
+ get_page(mp->page);
+ lock_page(mp->page);
+ mp->count++;
+ lock_metapage(mp);
+ unlock_page(mp->page);
+}
+
+void force_metapage(struct metapage *mp)
+{
+ struct page *page = mp->page;
+ jfs_info("force_metapage: mp = 0x%p", mp);
+ set_bit(META_forcewrite, &mp->flag);
+ clear_bit(META_sync, &mp->flag);
+ get_page(page);
+ lock_page(page);
+ set_page_dirty(page);
+ if (write_one_page(page))
+ jfs_error(mp->sb, "write_one_page() failed\n");
+ clear_bit(META_forcewrite, &mp->flag);
+ put_page(page);
+}
+
+void hold_metapage(struct metapage *mp)
+{
+ lock_page(mp->page);
+}
+
+void put_metapage(struct metapage *mp)
+{
+ if (mp->count || mp->nohomeok) {
+ /* Someone else will release this */
+ unlock_page(mp->page);
+ return;
+ }
+ get_page(mp->page);
+ mp->count++;
+ lock_metapage(mp);
+ unlock_page(mp->page);
+ release_metapage(mp);
+}
+
+void release_metapage(struct metapage * mp)
+{
+ struct page *page = mp->page;
+ jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
+
+ BUG_ON(!page);
+
+ lock_page(page);
+ unlock_metapage(mp);
+
+ assert(mp->count);
+ if (--mp->count || mp->nohomeok) {
+ unlock_page(page);
+ put_page(page);
+ return;
+ }
+
+ if (test_bit(META_dirty, &mp->flag)) {
+ set_page_dirty(page);
+ if (test_bit(META_sync, &mp->flag)) {
+ clear_bit(META_sync, &mp->flag);
+ if (write_one_page(page))
+ jfs_error(mp->sb, "write_one_page() failed\n");
+ lock_page(page); /* write_one_page unlocks the page */
+ }
+ } else if (mp->lsn) /* discard_metapage doesn't remove it */
+ remove_from_logsync(mp);
+
+ /* Try to keep metapages from using up too much memory */
+ drop_metapage(page, mp);
+
+ unlock_page(page);
+ put_page(page);
+}
+
+void __invalidate_metapages(struct inode *ip, s64 addr, int len)
+{
+ sector_t lblock;
+ int l2BlocksPerPage = PAGE_SHIFT - ip->i_blkbits;
+ int BlocksPerPage = 1 << l2BlocksPerPage;
+ /* All callers are interested in block device's mapping */
+ struct address_space *mapping =
+ JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
+ struct metapage *mp;
+ struct page *page;
+ unsigned int offset;
+
+ /*
+ * Mark metapages to discard. They will eventually be
+ * released, but should not be written.
+ */
+ for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
+ lblock += BlocksPerPage) {
+ page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
+ if (!page)
+ continue;
+ for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
+ mp = page_to_mp(page, offset);
+ if (!mp)
+ continue;
+ if (mp->index < addr)
+ continue;
+ if (mp->index >= addr + len)
+ break;
+
+ clear_bit(META_dirty, &mp->flag);
+ set_bit(META_discard, &mp->flag);
+ if (mp->lsn)
+ remove_from_logsync(mp);
+ }
+ unlock_page(page);
+ put_page(page);
+ }
+}
+
+#ifdef CONFIG_JFS_STATISTICS
+int jfs_mpstat_proc_show(struct seq_file *m, void *v)
+{
+ seq_printf(m,
+ "JFS Metapage statistics\n"
+ "=======================\n"
+ "page allocations = %d\n"
+ "page frees = %d\n"
+ "lock waits = %d\n",
+ mpStat.pagealloc,
+ mpStat.pagefree,
+ mpStat.lockwait);
+ return 0;
+}
+#endif