// SPDX-License-Identifier: GPL-2.0+
/*
* Meta data file for NILFS
*
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
*
* Written by Ryusuke Konishi.
*/
#include <linux/buffer_head.h>
#include <linux/mpage.h>
#include <linux/mm.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include "nilfs.h"
#include "btnode.h"
#include "segment.h"
#include "page.h"
#include "mdt.h"
#include "alloc.h" /* nilfs_palloc_destroy_cache() */
#include <trace/events/nilfs2.h>
#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1)
static int
nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block,
struct buffer_head *bh,
void (*init_block)(struct inode *,
struct buffer_head *, void *))
{
struct nilfs_inode_info *ii = NILFS_I(inode);
void *kaddr;
int ret;
/* Caller exclude read accesses using page lock */
/* set_buffer_new(bh); */
bh->b_blocknr = 0;
ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh);
if (unlikely(ret))
return ret;
set_buffer_mapped(bh);
kaddr = kmap_local_page(bh->b_page);
memset(kaddr + bh_offset(bh), 0, i_blocksize(inode));
if (init_block)
init_block(inode, bh, kaddr);
flush_dcache_page(bh->b_page);
kunmap_local(kaddr);
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
nilfs_mdt_mark_dirty(inode);
trace_nilfs2_mdt_insert_new_block(inode, inode->i_ino, block);
return 0;
}
static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
struct buffer_head **out_bh,
void (*init_block)(struct inode *,
struct buffer_head *,
void *))
{
struct super_block *sb = inode->i_sb;
struct nilfs_transaction_info ti;
struct buffer_head *bh;
int err;
nilfs_transaction_begin(sb, &ti, 0);
err = -ENOMEM;
bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0);
if (unlikely(!bh))
goto failed_unlock;
err = -EEXIST;
if (buffer_uptodate(bh))
goto failed_bh;
wait_on_buffer(bh);
if (buffer_uptodate(bh))
goto failed_bh;
bh->b_bdev = sb->s_bdev;
err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
if (likely(!err)) {
get_bh(bh);
*out_bh = bh;
}
failed_bh:
folio_unlock(bh->b_folio);
folio_put(bh->b_folio);
brelse(bh);
failed_unlock:
if (likely(!err))
err = nilfs_transaction_commit(sb);
else
nilfs_transaction_abort(sb);
return err;
}
static int
nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff, blk_opf_t opf,
struct buffer_head **out_bh)
{
struct buffer_head *bh;
__u64 blknum = 0;
int ret = -ENOMEM;
bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
if (unlikely(!bh))
goto failed;
ret = -EEXIST; /* internal code */
if (buffer_uptodate(bh))
goto out;
if (opf & REQ_RAHEAD) {
if (!trylock_buffer(bh)) {
ret = -EBUSY;
goto failed_bh;
}
} else /* opf == REQ_OP_READ */
lock_buffer(bh);
if (buffer_uptodate(bh)) {
unlock_buffer(bh);
goto out;
}
ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
if (unlikely(ret)) {
unlock_buffer(bh);
goto failed_bh;
}
map_bh(bh, inode->i_sb, (sector_t)blknum);
bh->b_end_io = end_buffer_read_sync;
get_bh(bh);
submit_bh(opf, bh);
ret = 0;
trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff,
opf & REQ_OP_MASK);
out:
get_bh(bh);
*out_bh = bh;
failed_bh:
folio_unlock(bh->b_folio);
folio_put(bh->b_folio);
brelse(bh);
failed:
return ret;
}
static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
int readahead, struct buffer_head **out_bh)
{
struct buffer_head *first_bh, *bh;
unsigned long blkoff;
int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
int err;
err = nilfs_mdt_submit_block(inode, block, REQ_OP_READ, &first_bh);
if (err == -EEXIST) /* internal code */
goto out;
if (unlikely(err))
goto failed;
if (readahead) {
blkoff = block + 1;
for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
err = nilfs_mdt_submit_block(inode, blkoff,
REQ_OP_READ | REQ_RAHEAD, &bh);
if (likely(!err || err == -EEXIST))
brelse(bh);
else if (err != -EBUSY)
break;
/* abort readahead if bmap lookup failed */
if (!buffer_locked(first_bh))
goto out_no_wait;
}
}
wait_on_buffer(first_bh);
out_no_wait:
err = -EIO;
if (!buffer_uptodate(first_bh)) {
nilfs_err(inode->i_sb,
"I/O error reading meta-data file (ino=%lu, block-offset=%lu)",
inode->i_ino, block);
goto failed_bh;
}
out:
*out_bh = first_bh;
return 0;
failed_bh:
brelse(first_bh);
failed:
return err;
}
/**
* nilfs_mdt_get_block - read or create a buffer on meta data file.
* @inode: inode of the meta data file
* @blkoff: block offset
* @create: create flag
* @init_block: initializer used for newly allocated block
* @out_bh: output of a pointer to the buffer_head
*
* nilfs_mdt_get_block() looks up the specified buffer and tries to create
* a new buffer if @create is not zero. On success, the returned buffer is
* assured to be either existing or formatted using a buffer lock on success.
* @out_bh is substituted only when zero is returned.
*
* Return Value: On success, it returns 0. On error, the following negative
* error code is returned.
*
* %-ENOMEM - Insufficient memory available.
*
* %-EIO - I/O error
*
* %-ENOENT - the specified block does not exist (hole block)
*
* %-EROFS - Read only filesystem (for create mode)
*/
int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create,
void (*init_block)(struct inode *,
struct buffer_head *, void *),
struct buffer_head **out_bh)
{
int ret;
/* Should be rewritten with merging nilfs_mdt_read_block() */
retry:
ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh);
if (!create || ret != -ENOENT)
return ret;
ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block);
if (unlikely(ret == -EEXIST)) {
/* create = 0; */ /* limit read-create loop retries */
goto retry;
}
return ret;
}
/**
* nilfs_mdt_find_block - find and get a buffer on meta data file.
* @inode: inode of the meta data file
* @start: start block offset (inclusive)
* @end: end block offset (inclusive)
* @blkoff: block offset
* @out_bh: place to store a pointer to buffer_head struct
*
* nilfs_mdt_find_block() looks up an existing block in range of
* [@start, @end] and stores pointer to a buffer head of the block to
* @out_bh, and block offset to @blkoff, respectively. @out_bh and
* @blkoff are substituted only when zero is returned.
*
* Return Value: On success, it returns 0. On error, the following negative
* error code is returned.
*
* %-ENOMEM - Insufficient memory available.
*
* %-EIO - I/O error
*
* %-ENOENT - no block was found in the range
*/
int nilfs_mdt_find_block(struct inode *inode, unsigned long start,
unsigned long end, unsigned long *blkoff,
struct buffer_head **out_bh)
{
__u64 next;
int ret;
if (unlikely(start > end))
return -ENOENT;
ret = nilfs_mdt_read_block(inode, start, true, out_bh);
if (!ret) {
*blkoff = start;
goto out;
}
if (unlikely(ret != -ENOENT || start == ULONG_MAX))
goto out;
ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next);
if (!ret) {
if (next <= end) {
ret = nilfs_mdt_read_block(inode, next, true, out_bh);
if (!ret)
*blkoff = next;
} else {
ret = -ENOENT;
}
}
out:
return ret;
}
/**
* nilfs_mdt_delete_block - make a hole on the meta data file.
* @inode: inode of the meta data file
* @block: block offset
*
* Return Value: On success, zero is returned.
* On error, one of the following negative error code is returned.
*
* %-ENOMEM - Insufficient memory available.
*
* %-EIO - I/O error
*/
int nilfs_mdt_delete_block(struct inode *inode, unsigned long block)
{
struct nilfs_inode_info *ii = NILFS_I(inode);
int err;
err = nilfs_bmap_delete(ii->i_bmap, block);
if (!err || err == -ENOENT) {
nilfs_mdt_mark_dirty(inode);
nilfs_mdt_forget_block(inode, block);
}
return err;
}
/**
* nilfs_mdt_forget_block - discard dirty state and try to remove the page
* @inode: inode of the meta data file
* @block: block offset
*
* nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and
* tries to release the page including the buffer from a page cache.
*
* Return Value: On success, 0 is returned. On error, one of the following
* negative error code is returned.
*
* %-EBUSY - page has an active buffer.
*
* %-ENOENT - page cache has no page addressed by the offset.
*/
int nilfs_mdt_forget_block(struct inode *inode, unsigned long block)
{
pgoff_t index = block >> (PAGE_SHIFT - inode->i_blkbits);
struct folio *folio;
struct buffer_head *bh;
int ret = 0;
int still_dirty;
folio = filemap_lock_folio(inode->i_mapping, index);
if (IS_ERR(folio))
return -ENOENT;
folio_wait_writeback(folio);
bh = folio_buffers(folio);
if (bh) {
unsigned long first_block = index <<
(PAGE_SHIFT - inode->i_blkbits);
bh = get_nth_bh(bh, block - first_block);
nilfs_forget_buffer(bh);
}
still_dirty = folio_test_dirty(folio);
folio_unlock(folio);
folio_put(folio);
if (still_dirty ||
invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0)
ret = -EBUSY;
return ret;
}
int nilfs_mdt_fetch_dirty(struct inode *inode)
{
struct nilfs_inode_info *ii = NILFS_I(inode);
if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) {
set_bit(NILFS_I_DIRTY, &ii->i_state);
return 1;
}
return test_bit(NILFS_I_DIRTY, &ii->i_state);
}
static int
nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
{
struct folio *folio = page_folio(page);
struct inode *inode = folio->mapping->host;
struct super_block *sb;
int err = 0;
if (inode && sb_rdonly(inode->i_sb)) {
/*
* It means that filesystem was remounted in read-only
* mode because of error or metadata corruption. But we
* have dirty folios that try to be flushed in background.
* So, here we simply discard this dirty folio.
*/
nilfs_clear_folio_dirty(folio);
folio_unlock(folio);
return -EROFS;
}
folio_redirty_for_writepage(wbc, folio);
folio_unlock(folio);
if (!inode)
return 0;
sb = inode->i_sb;
if (wbc->sync_mode == WB_SYNC_ALL)
err = nilfs_construct_segment(sb);
else if (wbc->for_reclaim)
nilfs_flush_segment(sb, inode->i_ino);
return err;
}
static const struct address_space_operations def_mdt_aops = {
.dirty_folio = block_dirty_folio,
.invalidate_folio = block_invalidate_folio,
.writepage = nilfs_mdt_write_page,
};
static const struct inode_operations def_mdt_iops;
static const struct file_operations def_mdt_fops;
int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
{
struct nilfs_mdt_info *mi;
mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS);
if (!mi)
return -ENOMEM;
init_rwsem(&mi->mi_sem);
inode->i_private = mi;
inode->i_mode = S_IFREG;
mapping_set_gfp_mask(inode->i_mapping, gfp_mask);
inode->i_op = &def_mdt_iops;
inode->i_fop = &def_mdt_fops;
inode->i_mapping->a_ops = &def_mdt_aops;
return 0;
}
/**
* nilfs_mdt_clear - do cleanup for the metadata file
* @inode: inode of the metadata file
*/
void nilfs_mdt_clear(struct inode *inode)
{
struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
struct nilfs_shadow_map *shadow = mdi->mi_shadow;
if (mdi->mi_palloc_cache)
nilfs_palloc_destroy_cache(inode);
if (shadow) {
struct inode *s_inode = shadow->inode;
shadow->inode = NULL;
iput(s_inode);
mdi->mi_shadow = NULL;
}
}
/**
* nilfs_mdt_destroy - release resources used by the metadata file
* @inode: inode of the metadata file
*/
void nilfs_mdt_destroy(struct inode *inode)
{
struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
kfree(mdi->mi_bgl); /* kfree(NULL) is safe */
kfree(mdi);
}
void nilfs_mdt_set_entry_size(struct inode *inode, unsigned int entry_size,
unsigned int header_size)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
mi->mi_entry_size = entry_size;
mi->mi_entries_per_block = i_blocksize(inode) / entry_size;
mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size);
}
/**
* nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
* @inode: inode of the metadata file
* @shadow: shadow mapping
*/
int nilfs_mdt_setup_shadow_map(struct inode *inode,
struct nilfs_shadow_map *shadow)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
struct inode *s_inode;
INIT_LIST_HEAD(&shadow->frozen_buffers);
s_inode = nilfs_iget_for_shadow(inode);
if (IS_ERR(s_inode))
return PTR_ERR(s_inode);
shadow->inode = s_inode;
mi->mi_shadow = shadow;
return 0;
}
/**
* nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
* @inode: inode of the metadata file
*/
int nilfs_mdt_save_to_shadow_map(struct inode *inode)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
struct nilfs_inode_info *ii = NILFS_I(inode);
struct nilfs_shadow_map *shadow = mi->mi_shadow;
struct inode *s_inode = shadow->inode;
int ret;
ret = nilfs_copy_dirty_pages(s_inode->i_mapping, inode->i_mapping);
if (ret)
goto out;
ret = nilfs_copy_dirty_pages(NILFS_I(s_inode)->i_assoc_inode->i_mapping,
ii->i_assoc_inode->i_mapping);
if (ret)
goto out;
nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
out:
return ret;
}
int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
{
struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
struct buffer_head *bh_frozen;
struct folio *folio;
int blkbits = inode->i_blkbits;
folio = filemap_grab_folio(shadow->inode->i_mapping,
bh->b_folio->index);
if (IS_ERR(folio))
return PTR_ERR(folio);
bh_frozen = folio_buffers(folio);
if (!bh_frozen)
bh_frozen = create_empty_buffers(folio, 1 << blkbits, 0);
bh_frozen = get_nth_bh(bh_frozen, bh_offset(bh) >> blkbits);
if (!buffer_uptodate(bh_frozen))
nilfs_copy_buffer(bh_frozen, bh);
if (list_empty(&bh_frozen->b_assoc_buffers)) {
list_add_tail(&bh_frozen->b_assoc_buffers,
&shadow->frozen_buffers);
set_buffer_nilfs_redirected(bh);
} else {
brelse(bh_frozen); /* already frozen */
}
folio_unlock(folio);
folio_put(folio);
return 0;
}
struct buffer_head *
nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
{
struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow;
struct buffer_head *bh_frozen = NULL;
struct folio *folio;
int n;
folio = filemap_lock_folio(shadow->inode->i_mapping,
bh->b_folio->index);
if (!IS_ERR(folio)) {
bh_frozen = folio_buffers(folio);
if (bh_frozen) {
n = bh_offset(bh) >> inode->i_blkbits;
bh_frozen = get_nth_bh(bh_frozen, n);
}
folio_unlock(folio);
folio_put(folio);
}
return bh_frozen;
}
static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow)
{
struct list_head *head = &shadow->frozen_buffers;
struct buffer_head *bh;
while (!list_empty(head)) {
bh = list_first_entry(head, struct buffer_head,
b_assoc_buffers);
list_del_init(&bh->b_assoc_buffers);
brelse(bh); /* drop ref-count to make it releasable */
}
}
/**
* nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
* @inode: inode of the metadata file
*/
void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
struct nilfs_inode_info *ii = NILFS_I(inode);
struct nilfs_shadow_map *shadow = mi->mi_shadow;
down_write(&mi->mi_sem);
if (mi->mi_palloc_cache)
nilfs_palloc_clear_cache(inode);
nilfs_clear_dirty_pages(inode->i_mapping);
nilfs_copy_back_pages(inode->i_mapping, shadow->inode->i_mapping);
nilfs_clear_dirty_pages(ii->i_assoc_inode->i_mapping);
nilfs_copy_back_pages(ii->i_assoc_inode->i_mapping,
NILFS_I(shadow->inode)->i_assoc_inode->i_mapping);
nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
up_write(&mi->mi_sem);
}
/**
* nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
* @inode: inode of the metadata file
*/
void nilfs_mdt_clear_shadow_map(struct inode *inode)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
struct nilfs_shadow_map *shadow = mi->mi_shadow;
struct inode *shadow_btnc_inode = NILFS_I(shadow->inode)->i_assoc_inode;
down_write(&mi->mi_sem);
nilfs_release_frozen_buffers(shadow);
truncate_inode_pages(shadow->inode->i_mapping, 0);
truncate_inode_pages(shadow_btnc_inode->i_mapping, 0);
up_write(&mi->mi_sem);
}
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