// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
#include <linux/mpage.h>
#include <linux/fs.h>
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/gfs2_ondisk.h>
#include <linux/backing-dev.h>
#include <linux/uio.h>
#include <trace/events/writeback.h>
#include <linux/sched/signal.h>
#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "inode.h"
#include "log.h"
#include "meta_io.h"
#include "quota.h"
#include "trans.h"
#include "rgrp.h"
#include "super.h"
#include "util.h"
#include "glops.h"
#include "aops.h"
void gfs2_trans_add_databufs(struct gfs2_inode *ip, struct folio *folio,
size_t from, size_t len)
{
struct buffer_head *head = folio_buffers(folio);
unsigned int bsize = head->b_size;
struct buffer_head *bh;
size_t to = from + len;
size_t start, end;
for (bh = head, start = 0; bh != head || !start;
bh = bh->b_this_page, start = end) {
end = start + bsize;
if (end <= from)
continue;
if (start >= to)
break;
set_buffer_uptodate(bh);
gfs2_trans_add_data(ip->i_gl, bh);
}
}
/**
* gfs2_get_block_noalloc - Fills in a buffer head with details about a block
* @inode: The inode
* @lblock: The block number to look up
* @bh_result: The buffer head to return the result in
* @create: Non-zero if we may add block to the file
*
* Returns: errno
*/
static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
struct buffer_head *bh_result, int create)
{
int error;
error = gfs2_block_map(inode, lblock, bh_result, 0);
if (error)
return error;
if (!buffer_mapped(bh_result))
return -ENODATA;
return 0;
}
/**
* gfs2_write_jdata_folio - gfs2 jdata-specific version of block_write_full_folio
* @folio: The folio to write
* @wbc: The writeback control
*
* This is the same as calling block_write_full_folio, but it also
* writes pages outside of i_size
*/
static int gfs2_write_jdata_folio(struct folio *folio,
struct writeback_control *wbc)
{
struct inode * const inode = folio->mapping->host;
loff_t i_size = i_size_read(inode);
/*
* The folio straddles i_size. It must be zeroed out on each and every
* writepage invocation because it may be mmapped. "A file is mapped
* in multiples of the page size. For a file that is not a multiple of
* the page size, the remaining memory is zeroed when mapped, and
* writes to that region are not written out to the file."
*/
if (folio_pos(folio) < i_size &&
i_size < folio_pos(folio) + folio_size(folio))
folio_zero_segment(folio, offset_in_folio(folio, i_size),
folio_size(folio));
return __block_write_full_folio(inode, folio, gfs2_get_block_noalloc,
wbc);
}
/**
* __gfs2_jdata_write_folio - The core of jdata writepage
* @folio: The folio to write
* @wbc: The writeback control
*
* Implements the core of write back. If a transaction is required then
* the checked flag will have been set and the transaction will have
* already been started before this is called.
*/
static int __gfs2_jdata_write_folio(struct folio *folio,
struct writeback_control *wbc)
{
struct inode *inode = folio->mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
if (folio_test_checked(folio)) {
folio_clear_checked(folio);
if (!folio_buffers(folio)) {
create_empty_buffers(folio,
inode->i_sb->s_blocksize,
BIT(BH_Dirty)|BIT(BH_Uptodate));
}
gfs2_trans_add_databufs(ip, folio, 0, folio_size(folio));
}
return gfs2_write_jdata_folio(folio, wbc);
}
/**
* gfs2_writepages - Write a bunch of dirty pages back to disk
* @mapping: The mapping to write
* @wbc: Write-back control
*
* Used for both ordered and writeback modes.
*/
static int gfs2_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
struct iomap_writepage_ctx wpc = { };
int ret;
/*
* Even if we didn't write enough pages here, we might still be holding
* dirty pages in the ail. We forcibly flush the ail because we don't
* want balance_dirty_pages() to loop indefinitely trying to write out
* pages held in the ail that it can't find.
*/
ret = iomap_writepages(mapping, wbc, &wpc, &gfs2_writeback_ops);
if (ret == 0 && wbc->nr_to_write > 0)
set_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags);
return ret;
}
/**
* gfs2_write_jdata_batch - Write back a folio batch's worth of folios
* @mapping: The mapping
* @wbc: The writeback control
* @fbatch: The batch of folios
* @done_index: Page index
*
* Returns: non-zero if loop should terminate, zero otherwise
*/
static int gfs2_write_jdata_batch(struct address_space *mapping,
struct writeback_control *wbc,
struct folio_batch *fbatch,
pgoff_t *done_index)
{
struct inode *inode = mapping->host;
struct gfs2_sbd *sdp = GFS2_SB(inode);
unsigned nrblocks;
int i;
int ret;
size_t size = 0;
int nr_folios = folio_batch_count(fbatch);
for (i = 0; i < nr_folios; i++)
size += folio_size(fbatch->folios[i]);
nrblocks = size >> inode->i_blkbits;
ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
if (ret < 0)
return ret;
for (i = 0; i < nr_folios; i++) {
struct folio *folio = fbatch->folios[i];
*done_index = folio->index;
folio_lock(folio);
if (unlikely(folio->mapping != mapping)) {
continue_unlock:
folio_unlock(folio);
continue;
}
if (!folio_test_dirty(folio)) {
/* someone wrote it for us */
goto continue_unlock;
}
if (folio_test_writeback(folio)) {
if (wbc->sync_mode != WB_SYNC_NONE)
folio_wait_writeback(folio);
else
goto continue_unlock;
}
BUG_ON(folio_test_writeback(folio));
if (!folio_clear_dirty_for_io(folio))
goto continue_unlock;
trace_wbc_writepage(wbc, inode_to_bdi(inode));
ret = __gfs2_jdata_write_folio(folio, wbc);
if (unlikely(ret)) {
if (ret == AOP_WRITEPAGE_ACTIVATE) {
folio_unlock(folio);
ret = 0;
} else {
/*
* done_index is set past this page,
* so media errors will not choke
* background writeout for the entire
* file. This has consequences for
* range_cyclic semantics (ie. it may
* not be suitable for data integrity
* writeout).
*/
*done_index = folio_next_index(folio);
ret = 1;
break;
}
}
/*
* We stop writing back only if we are not doing
* integrity sync. In case of integrity sync we have to
* keep going until we have written all the pages
* we tagged for writeback prior to entering this loop.
*/
if (--wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE) {
ret = 1;
break;
}
}
gfs2_trans_end(sdp);
return ret;
}
/**
* gfs2_write_cache_jdata - Like write_cache_pages but different
* @mapping: The mapping to write
* @wbc: The writeback control
*
* The reason that we use our own function here is that we need to
* start transactions before we grab page locks. This allows us
* to get the ordering right.
*/
static int gfs2_write_cache_jdata(struct address_space *mapping,
struct writeback_control *wbc)
{
int ret = 0;
int done = 0;
struct folio_batch fbatch;
int nr_folios;
pgoff_t writeback_index;
pgoff_t index;
pgoff_t end;
pgoff_t done_index;
int cycled;
int range_whole = 0;
xa_mark_t tag;
folio_batch_init(&fbatch);
if (wbc->range_cyclic) {
writeback_index = mapping->writeback_index; /* prev offset */
index = writeback_index;
if (index == 0)
cycled = 1;
else
cycled = 0;
end = -1;
} else {
index = wbc->range_start >> PAGE_SHIFT;
end = wbc->range_end >> PAGE_SHIFT;
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
cycled = 1; /* ignore range_cyclic tests */
}
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag = PAGECACHE_TAG_TOWRITE;
else
tag = PAGECACHE_TAG_DIRTY;
retry:
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag_pages_for_writeback(mapping, index, end);
done_index = index;
while (!done && (index <= end)) {
nr_folios = filemap_get_folios_tag(mapping, &index, end,
tag, &fbatch);
if (nr_folios == 0)
break;
ret = gfs2_write_jdata_batch(mapping, wbc, &fbatch,
&done_index);
if (ret)
done = 1;
if (ret > 0)
ret = 0;
folio_batch_release(&fbatch);
cond_resched();
}
if (!cycled && !done) {
/*
* range_cyclic:
* We hit the last page and there is more work to be done: wrap
* back to the start of the file
*/
cycled = 1;
index = 0;
end = writeback_index - 1;
goto retry;
}
if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
mapping->writeback_index = done_index;
return ret;
}
/**
* gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
* @mapping: The mapping to write
* @wbc: The writeback control
*
*/
static int gfs2_jdata_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct gfs2_inode *ip = GFS2_I(mapping->host);
struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
int ret;
ret = gfs2_write_cache_jdata(mapping, wbc);
if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
GFS2_LFC_JDATA_WPAGES);
ret = gfs2_write_cache_jdata(mapping, wbc);
}
return ret;
}
/**
* stuffed_read_folio - Fill in a Linux folio with stuffed file data
* @ip: the inode
* @folio: the folio
*
* Returns: errno
*/
static int stuffed_read_folio(struct gfs2_inode *ip, struct folio *folio)
{
struct buffer_head *dibh = NULL;
size_t dsize = i_size_read(&ip->i_inode);
void *from = NULL;
int error = 0;
/*
* Due to the order of unstuffing files and ->fault(), we can be
* asked for a zero folio in the case of a stuffed file being extended,
* so we need to supply one here. It doesn't happen often.
*/
if (unlikely(folio->index)) {
dsize = 0;
} else {
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
goto out;
from = dibh->b_data + sizeof(struct gfs2_dinode);
}
folio_fill_tail(folio, 0, from, dsize);
brelse(dibh);
out:
folio_end_read(folio, error == 0);
return error;
}
/**
* gfs2_read_folio - read a folio from a file
* @file: The file to read
* @folio: The folio in the file
*/
static int gfs2_read_folio(struct file *file, struct folio *folio)
{
struct inode *inode = folio->mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
int error;
if (!gfs2_is_jdata(ip) ||
(i_blocksize(inode) == PAGE_SIZE && !folio_buffers(folio))) {
error = iomap_read_folio(folio, &gfs2_iomap_ops);
} else if (gfs2_is_stuffed(ip)) {
error = stuffed_read_folio(ip, folio);
} else {
error = mpage_read_folio(folio, gfs2_block_map);
}
if (gfs2_withdrawing_or_withdrawn(sdp))
return -EIO;
return error;
}
/**
* gfs2_internal_read - read an internal file
* @ip: The gfs2 inode
* @buf: The buffer to fill
* @pos: The file position
* @size: The amount to read
*
*/
ssize_t gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
size_t size)
{
struct address_space *mapping = ip->i_inode.i_mapping;
unsigned long index = *pos >> PAGE_SHIFT;
size_t copied = 0;
do {
size_t offset, chunk;
struct folio *folio;
folio = read_cache_folio(mapping, index, gfs2_read_folio, NULL);
if (IS_ERR(folio)) {
if (PTR_ERR(folio) == -EINTR)
continue;
return PTR_ERR(folio);
}
offset = *pos + copied - folio_pos(folio);
chunk = min(size - copied, folio_size(folio) - offset);
memcpy_from_folio(buf + copied, folio, offset, chunk);
index = folio_next_index(folio);
folio_put(folio);
copied += chunk;
} while(copied < size);
(*pos) += size;
return size;
}
/**
* gfs2_readahead - Read a bunch of pages at once
* @rac: Read-ahead control structure
*
* Some notes:
* 1. This is only for readahead, so we can simply ignore any things
* which are slightly inconvenient (such as locking conflicts between
* the page lock and the glock) and return having done no I/O. Its
* obviously not something we'd want to do on too regular a basis.
* Any I/O we ignore at this time will be done via readpage later.
* 2. We don't handle stuffed files here we let readpage do the honours.
* 3. mpage_readahead() does most of the heavy lifting in the common case.
* 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
*/
static void gfs2_readahead(struct readahead_control *rac)
{
struct inode *inode = rac->mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
if (gfs2_is_stuffed(ip))
;
else if (gfs2_is_jdata(ip))
mpage_readahead(rac, gfs2_block_map);
else
iomap_readahead(rac, &gfs2_iomap_ops);
}
/**
* adjust_fs_space - Adjusts the free space available due to gfs2_grow
* @inode: the rindex inode
*/
void adjust_fs_space(struct inode *inode)
{
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
struct buffer_head *m_bh;
u64 fs_total, new_free;
if (gfs2_trans_begin(sdp, 2 * RES_STATFS, 0) != 0)
return;
/* Total up the file system space, according to the latest rindex. */
fs_total = gfs2_ri_total(sdp);
if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0)
goto out;
spin_lock(&sdp->sd_statfs_spin);
gfs2_statfs_change_in(m_sc, m_bh->b_data +
sizeof(struct gfs2_dinode));
if (fs_total > (m_sc->sc_total + l_sc->sc_total))
new_free = fs_total - (m_sc->sc_total + l_sc->sc_total);
else
new_free = 0;
spin_unlock(&sdp->sd_statfs_spin);
fs_warn(sdp, "File system extended by %llu blocks.\n",
(unsigned long long)new_free);
gfs2_statfs_change(sdp, new_free, new_free, 0);
update_statfs(sdp, m_bh);
brelse(m_bh);
out:
sdp->sd_rindex_uptodate = 0;
gfs2_trans_end(sdp);
}
static bool jdata_dirty_folio(struct address_space *mapping,
struct folio *folio)
{
if (current->journal_info)
folio_set_checked(folio);
return block_dirty_folio(mapping, folio);
}
/**
* gfs2_bmap - Block map function
* @mapping: Address space info
* @lblock: The block to map
*
* Returns: The disk address for the block or 0 on hole or error
*/
static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
{
struct gfs2_inode *ip = GFS2_I(mapping->host);
struct gfs2_holder i_gh;
sector_t dblock = 0;
int error;
error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
if (error)
return 0;
if (!gfs2_is_stuffed(ip))
dblock = iomap_bmap(mapping, lblock, &gfs2_iomap_ops);
gfs2_glock_dq_uninit(&i_gh);
return dblock;
}
static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
struct gfs2_bufdata *bd;
lock_buffer(bh);
gfs2_log_lock(sdp);
clear_buffer_dirty(bh);
bd = bh->b_private;
if (bd) {
if (!list_empty(&bd->bd_list) && !buffer_pinned(bh))
list_del_init(&bd->bd_list);
else {
spin_lock(&sdp->sd_ail_lock);
gfs2_remove_from_journal(bh, REMOVE_JDATA);
spin_unlock(&sdp->sd_ail_lock);
}
}
bh->b_bdev = NULL;
clear_buffer_mapped(bh);
clear_buffer_req(bh);
clear_buffer_new(bh);
gfs2_log_unlock(sdp);
unlock_buffer(bh);
}
static void gfs2_invalidate_folio(struct folio *folio, size_t offset,
size_t length)
{
struct gfs2_sbd *sdp = GFS2_SB(folio->mapping->host);
size_t stop = offset + length;
int partial_page = (offset || length < folio_size(folio));
struct buffer_head *bh, *head;
unsigned long pos = 0;
BUG_ON(!folio_test_locked(folio));
if (!partial_page)
folio_clear_checked(folio);
head = folio_buffers(folio);
if (!head)
goto out;
bh = head;
do {
if (pos + bh->b_size > stop)
return;
if (offset <= pos)
gfs2_discard(sdp, bh);
pos += bh->b_size;
bh = bh->b_this_page;
} while (bh != head);
out:
if (!partial_page)
filemap_release_folio(folio, 0);
}
/**
* gfs2_release_folio - free the metadata associated with a folio
* @folio: the folio that's being released
* @gfp_mask: passed from Linux VFS, ignored by us
*
* Calls try_to_free_buffers() to free the buffers and put the folio if the
* buffers can be released.
*
* Returns: true if the folio was put or else false
*/
bool gfs2_release_folio(struct folio *folio, gfp_t gfp_mask)
{
struct address_space *mapping = folio->mapping;
struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
struct buffer_head *bh, *head;
struct gfs2_bufdata *bd;
head = folio_buffers(folio);
if (!head)
return false;
/*
* mm accommodates an old ext3 case where clean folios might
* not have had the dirty bit cleared. Thus, it can send actual
* dirty folios to ->release_folio() via shrink_active_list().
*
* As a workaround, we skip folios that contain dirty buffers
* below. Once ->release_folio isn't called on dirty folios
* anymore, we can warn on dirty buffers like we used to here
* again.
*/
gfs2_log_lock(sdp);
bh = head;
do {
if (atomic_read(&bh->b_count))
goto cannot_release;
bd = bh->b_private;
if (bd && bd->bd_tr)
goto cannot_release;
if (buffer_dirty(bh) || WARN_ON(buffer_pinned(bh)))
goto cannot_release;
bh = bh->b_this_page;
} while (bh != head);
bh = head;
do {
bd = bh->b_private;
if (bd) {
gfs2_assert_warn(sdp, bd->bd_bh == bh);
bd->bd_bh = NULL;
bh->b_private = NULL;
/*
* The bd may still be queued as a revoke, in which
* case we must not dequeue nor free it.
*/
if (!bd->bd_blkno && !list_empty(&bd->bd_list))
list_del_init(&bd->bd_list);
if (list_empty(&bd->bd_list))
kmem_cache_free(gfs2_bufdata_cachep, bd);
}
bh = bh->b_this_page;
} while (bh != head);
gfs2_log_unlock(sdp);
return try_to_free_buffers(folio);
cannot_release:
gfs2_log_unlock(sdp);
return false;
}
static const struct address_space_operations gfs2_aops = {
.writepages = gfs2_writepages,
.read_folio = gfs2_read_folio,
.readahead = gfs2_readahead,
.dirty_folio = iomap_dirty_folio,
.release_folio = iomap_release_folio,
.invalidate_folio = iomap_invalidate_folio,
.bmap = gfs2_bmap,
.migrate_folio = filemap_migrate_folio,
.is_partially_uptodate = iomap_is_partially_uptodate,
.error_remove_folio = generic_error_remove_folio,
};
static const struct address_space_operations gfs2_jdata_aops = {
.writepages = gfs2_jdata_writepages,
.read_folio = gfs2_read_folio,
.readahead = gfs2_readahead,
.dirty_folio = jdata_dirty_folio,
.bmap = gfs2_bmap,
.migrate_folio = buffer_migrate_folio,
.invalidate_folio = gfs2_invalidate_folio,
.release_folio = gfs2_release_folio,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_folio = generic_error_remove_folio,
};
void gfs2_set_aops(struct inode *inode)
{
if (gfs2_is_jdata(GFS2_I(inode)))
inode->i_mapping->a_ops = &gfs2_jdata_aops;
else
inode->i_mapping->a_ops = &gfs2_aops;
}
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