Google Git
Sign in
android-kvm / linux / 6cd90e5ea72f35fa40f971c419e16142cd8272bf / . / fs / ext4 / inode.c
blob: 941c1c0d5c6ed93f5ce3ba7b6cbdeb98e3167c75 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/ext4/inode.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/inode.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 64-bit file support on 64-bit platforms by Jakub Jelinek
* (jj@sunsite.ms.mff.cuni.cz)
*
* Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
*/
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/time.h>
#include <linux/highuid.h>
#include <linux/pagemap.h>
#include <linux/dax.h>
#include <linux/quotaops.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/pagevec.h>
#include <linux/mpage.h>
#include <linux/namei.h>
#include <linux/uio.h>
#include <linux/bio.h>
#include <linux/workqueue.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/iomap.h>
#include <linux/iversion.h>
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
#include "truncate.h"
#include <trace/events/ext4.h>
static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
struct ext4_inode_info *ei)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
__u32 csum;
__u16 dummy_csum = 0;
int offset = offsetof(struct ext4_inode, i_checksum_lo);
unsigned int csum_size = sizeof(dummy_csum);
csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, offset);
csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, csum_size);
offset += csum_size;
csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
EXT4_GOOD_OLD_INODE_SIZE - offset);
if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
offset = offsetof(struct ext4_inode, i_checksum_hi);
csum = ext4_chksum(sbi, csum, (__u8 *)raw +
EXT4_GOOD_OLD_INODE_SIZE,
offset - EXT4_GOOD_OLD_INODE_SIZE);
if (EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum,
csum_size);
offset += csum_size;
}
csum = ext4_chksum(sbi, csum, (__u8 *)raw + offset,
EXT4_INODE_SIZE(inode->i_sb) - offset);
}
return csum;
}
static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
struct ext4_inode_info *ei)
{
__u32 provided, calculated;
if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
cpu_to_le32(EXT4_OS_LINUX) ||
!ext4_has_metadata_csum(inode->i_sb))
return 1;
provided = le16_to_cpu(raw->i_checksum_lo);
calculated = ext4_inode_csum(inode, raw, ei);
if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
else
calculated &= 0xFFFF;
return provided == calculated;
}
void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
struct ext4_inode_info *ei)
{
__u32 csum;
if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
cpu_to_le32(EXT4_OS_LINUX) ||
!ext4_has_metadata_csum(inode->i_sb))
return;
csum = ext4_inode_csum(inode, raw, ei);
raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
raw->i_checksum_hi = cpu_to_le16(csum >> 16);
}
static inline int ext4_begin_ordered_truncate(struct inode *inode,
loff_t new_size)
{
trace_ext4_begin_ordered_truncate(inode, new_size);
/*
* If jinode is zero, then we never opened the file for
* writing, so there's no need to call
* jbd2_journal_begin_ordered_truncate() since there's no
* outstanding writes we need to flush.
*/
if (!EXT4_I(inode)->jinode)
return 0;
return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
EXT4_I(inode)->jinode,
new_size);
}
static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
int pextents);
/*
* Test whether an inode is a fast symlink.
* A fast symlink has its symlink data stored in ext4_inode_info->i_data.
*/
int ext4_inode_is_fast_symlink(struct inode *inode)
{
if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
int ea_blocks = EXT4_I(inode)->i_file_acl ?
EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;
if (ext4_has_inline_data(inode))
return 0;
return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
}
return S_ISLNK(inode->i_mode) && inode->i_size &&
(inode->i_size < EXT4_N_BLOCKS * 4);
}
/*
* Called at the last iput() if i_nlink is zero.
*/
void ext4_evict_inode(struct inode *inode)
{
handle_t *handle;
int err;
/*
* Credits for final inode cleanup and freeing:
* sb + inode (ext4_orphan_del()), block bitmap, group descriptor
* (xattr block freeing), bitmap, group descriptor (inode freeing)
*/
int extra_credits = 6;
struct ext4_xattr_inode_array *ea_inode_array = NULL;
bool freeze_protected = false;
trace_ext4_evict_inode(inode);
if (EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)
ext4_evict_ea_inode(inode);
if (inode->i_nlink) {
truncate_inode_pages_final(&inode->i_data);
goto no_delete;
}
if (is_bad_inode(inode))
goto no_delete;
dquot_initialize(inode);
if (ext4_should_order_data(inode))
ext4_begin_ordered_truncate(inode, 0);
truncate_inode_pages_final(&inode->i_data);
/*
* For inodes with journalled data, transaction commit could have
* dirtied the inode. And for inodes with dioread_nolock, unwritten
* extents converting worker could merge extents and also have dirtied
* the inode. Flush worker is ignoring it because of I_FREEING flag but
* we still need to remove the inode from the writeback lists.
*/
if (!list_empty_careful(&inode->i_io_list))
inode_io_list_del(inode);
/*
* Protect us against freezing - iput() caller didn't have to have any
* protection against it. When we are in a running transaction though,
* we are already protected against freezing and we cannot grab further
* protection due to lock ordering constraints.
*/
if (!ext4_journal_current_handle()) {
sb_start_intwrite(inode->i_sb);
freeze_protected = true;
}
if (!IS_NOQUOTA(inode))
extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
/*
* Block bitmap, group descriptor, and inode are accounted in both
* ext4_blocks_for_truncate() and extra_credits. So subtract 3.
*/
handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
ext4_blocks_for_truncate(inode) + extra_credits - 3);
if (IS_ERR(handle)) {
ext4_std_error(inode->i_sb, PTR_ERR(handle));
/*
* If we're going to skip the normal cleanup, we still need to
* make sure that the in-core orphan linked list is properly
* cleaned up.
*/
ext4_orphan_del(NULL, inode);
if (freeze_protected)
sb_end_intwrite(inode->i_sb);
goto no_delete;
}
if (IS_SYNC(inode))
ext4_handle_sync(handle);
/*
* Set inode->i_size to 0 before calling ext4_truncate(). We need
* special handling of symlinks here because i_size is used to
* determine whether ext4_inode_info->i_data contains symlink data or
* block mappings. Setting i_size to 0 will remove its fast symlink
* status. Erase i_data so that it becomes a valid empty block map.
*/
if (ext4_inode_is_fast_symlink(inode))
memset(EXT4_I(inode)->i_data, 0, sizeof(EXT4_I(inode)->i_data));
inode->i_size = 0;
err = ext4_mark_inode_dirty(handle, inode);
if (err) {
ext4_warning(inode->i_sb,
"couldn't mark inode dirty (err %d)", err);
goto stop_handle;
}
if (inode->i_blocks) {
err = ext4_truncate(inode);
if (err) {
ext4_error_err(inode->i_sb, -err,
"couldn't truncate inode %lu (err %d)",
inode->i_ino, err);
goto stop_handle;
}
}
/* Remove xattr references. */
err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
extra_credits);
if (err) {
ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
stop_handle:
ext4_journal_stop(handle);
ext4_orphan_del(NULL, inode);
if (freeze_protected)
sb_end_intwrite(inode->i_sb);
ext4_xattr_inode_array_free(ea_inode_array);
goto no_delete;
}
/*
* Kill off the orphan record which ext4_truncate created.
* AKPM: I think this can be inside the above `if'.
* Note that ext4_orphan_del() has to be able to cope with the
* deletion of a non-existent orphan - this is because we don't
* know if ext4_truncate() actually created an orphan record.
* (Well, we could do this if we need to, but heck - it works)
*/
ext4_orphan_del(handle, inode);
EXT4_I(inode)->i_dtime = (__u32)ktime_get_real_seconds();
/*
* One subtle ordering requirement: if anything has gone wrong
* (transaction abort, IO errors, whatever), then we can still
* do these next steps (the fs will already have been marked as
* having errors), but we can't free the inode if the mark_dirty
* fails.
*/
if (ext4_mark_inode_dirty(handle, inode))
/* If that failed, just do the required in-core inode clear. */
ext4_clear_inode(inode);
else
ext4_free_inode(handle, inode);
ext4_journal_stop(handle);
if (freeze_protected)
sb_end_intwrite(inode->i_sb);
ext4_xattr_inode_array_free(ea_inode_array);
return;
no_delete:
/*
* Check out some where else accidentally dirty the evicting inode,
* which may probably cause inode use-after-free issues later.
*/
WARN_ON_ONCE(!list_empty_careful(&inode->i_io_list));
if (!list_empty(&EXT4_I(inode)->i_fc_list))
ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_NOMEM, NULL);
ext4_clear_inode(inode); /* We must guarantee clearing of inode... */
}
#ifdef CONFIG_QUOTA
qsize_t *ext4_get_reserved_space(struct inode *inode)
{
return &EXT4_I(inode)->i_reserved_quota;
}
#endif
/*
* Called with i_data_sem down, which is important since we can call
* ext4_discard_preallocations() from here.
*/
void ext4_da_update_reserve_space(struct inode *inode,
int used, int quota_claim)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct ext4_inode_info *ei = EXT4_I(inode);
spin_lock(&ei->i_block_reservation_lock);
trace_ext4_da_update_reserve_space(inode, used, quota_claim);
if (unlikely(used > ei->i_reserved_data_blocks)) {
ext4_warning(inode->i_sb, "%s: ino %lu, used %d "
"with only %d reserved data blocks",
__func__, inode->i_ino, used,
ei->i_reserved_data_blocks);
WARN_ON(1);
used = ei->i_reserved_data_blocks;
}
/* Update per-inode reservations */
ei->i_reserved_data_blocks -= used;
percpu_counter_sub(&sbi->s_dirtyclusters_counter, used);
spin_unlock(&ei->i_block_reservation_lock);
/* Update quota subsystem for data blocks */
if (quota_claim)
dquot_claim_block(inode, EXT4_C2B(sbi, used));
else {
/*
* We did fallocate with an offset that is already delayed
* allocated. So on delayed allocated writeback we should
* not re-claim the quota for fallocated blocks.
*/
dquot_release_reservation_block(inode, EXT4_C2B(sbi, used));
}
/*
* If we have done all the pending block allocations and if
* there aren't any writers on the inode, we can discard the
* inode's preallocations.
*/
if ((ei->i_reserved_data_blocks == 0) &&
!inode_is_open_for_write(inode))
ext4_discard_preallocations(inode);
}
static int __check_block_validity(struct inode *inode, const char *func,
unsigned int line,
struct ext4_map_blocks *map)
{
if (ext4_has_feature_journal(inode->i_sb) &&
(inode->i_ino ==
le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
return 0;
if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
ext4_error_inode(inode, func, line, map->m_pblk,
"lblock %lu mapped to illegal pblock %llu "
"(length %d)", (unsigned long) map->m_lblk,
map->m_pblk, map->m_len);
return -EFSCORRUPTED;
}
return 0;
}
int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk, ext4_fsblk_t pblk,
ext4_lblk_t len)
{
int ret;
if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode))
return fscrypt_zeroout_range(inode, lblk, pblk, len);
ret = sb_issue_zeroout(inode->i_sb, pblk, len, GFP_NOFS);
if (ret > 0)
ret = 0;
return ret;
}
#define check_block_validity(inode, map) \
__check_block_validity((inode), __func__, __LINE__, (map))
#ifdef ES_AGGRESSIVE_TEST
static void ext4_map_blocks_es_recheck(handle_t *handle,
struct inode *inode,
struct ext4_map_blocks *es_map,
struct ext4_map_blocks *map,
int flags)
{
int retval;
map->m_flags = 0;
/*
* There is a race window that the result is not the same.
* e.g. xfstests #223 when dioread_nolock enables. The reason
* is that we lookup a block mapping in extent status tree with
* out taking i_data_sem. So at the time the unwritten extent
* could be converted.
*/
down_read(&EXT4_I(inode)->i_data_sem);
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
retval = ext4_ext_map_blocks(handle, inode, map, 0);
} else {
retval = ext4_ind_map_blocks(handle, inode, map, 0);
}
up_read((&EXT4_I(inode)->i_data_sem));
/*
* We don't check m_len because extent will be collpased in status
* tree. So the m_len might not equal.
*/
if (es_map->m_lblk != map->m_lblk ||
es_map->m_flags != map->m_flags ||
es_map->m_pblk != map->m_pblk) {
printk("ES cache assertion failed for inode: %lu "
"es_cached ex [%d/%d/%llu/%x] != "
"found ex [%d/%d/%llu/%x] retval %d flags %x\n",
inode->i_ino, es_map->m_lblk, es_map->m_len,
es_map->m_pblk, es_map->m_flags, map->m_lblk,
map->m_len, map->m_pblk, map->m_flags,
retval, flags);
}
}
#endif /* ES_AGGRESSIVE_TEST */
static int ext4_map_query_blocks(handle_t *handle, struct inode *inode,
struct ext4_map_blocks *map)
{
unsigned int status;
int retval;
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
retval = ext4_ext_map_blocks(handle, inode, map, 0);
else
retval = ext4_ind_map_blocks(handle, inode, map, 0);
if (retval <= 0)
return retval;
if (unlikely(retval != map->m_len)) {
ext4_warning(inode->i_sb,
"ES len assertion failed for inode "
"%lu: retval %d != map->m_len %d",
inode->i_ino, retval, map->m_len);
WARN_ON(1);
}
status = map->m_flags & EXT4_MAP_UNWRITTEN ?
EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
map->m_pblk, status);
return retval;
}
/*
* The ext4_map_blocks() function tries to look up the requested blocks,
* and returns if the blocks are already mapped.
*
* Otherwise it takes the write lock of the i_data_sem and allocate blocks
* and store the allocated blocks in the result buffer head and mark it
* mapped.
*
* If file type is extents based, it will call ext4_ext_map_blocks(),
* Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping
* based files
*
* On success, it returns the number of blocks being mapped or allocated.
* If flags doesn't contain EXT4_GET_BLOCKS_CREATE the blocks are
* pre-allocated and unwritten, the resulting @map is marked as unwritten.
* If the flags contain EXT4_GET_BLOCKS_CREATE, it will mark @map as mapped.
*
* It returns 0 if plain look up failed (blocks have not been allocated), in
* that case, @map is returned as unmapped but we still do fill map->m_len to
* indicate the length of a hole starting at map->m_lblk.
*
* It returns the error in case of allocation failure.
*/
int ext4_map_blocks(handle_t *handle, struct inode *inode,
struct ext4_map_blocks *map, int flags)
{
struct extent_status es;
int retval;
int ret = 0;
#ifdef ES_AGGRESSIVE_TEST
struct ext4_map_blocks orig_map;
memcpy(&orig_map, map, sizeof(*map));
#endif
map->m_flags = 0;
ext_debug(inode, "flag 0x%x, max_blocks %u, logical block %lu\n",
flags, map->m_len, (unsigned long) map->m_lblk);
/*
* ext4_map_blocks returns an int, and m_len is an unsigned int
*/
if (unlikely(map->m_len > INT_MAX))
map->m_len = INT_MAX;
/* We can handle the block number less than EXT_MAX_BLOCKS */
if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
return -EFSCORRUPTED;
/* Lookup extent status tree firstly */
if (!(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) &&
ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
if (ext4_es_is_written(&es) || ext4_es_is_unwritten(&es)) {
map->m_pblk = ext4_es_pblock(&es) +
map->m_lblk - es.es_lblk;
map->m_flags |= ext4_es_is_written(&es) ?
EXT4_MAP_MAPPED : EXT4_MAP_UNWRITTEN;
retval = es.es_len - (map->m_lblk - es.es_lblk);
if (retval > map->m_len)
retval = map->m_len;
map->m_len = retval;
} else if (ext4_es_is_delayed(&es) || ext4_es_is_hole(&es)) {
map->m_pblk = 0;
map->m_flags |= ext4_es_is_delayed(&es) ?
EXT4_MAP_DELAYED : 0;
retval = es.es_len - (map->m_lblk - es.es_lblk);
if (retval > map->m_len)
retval = map->m_len;
map->m_len = retval;
retval = 0;
} else {
BUG();
}
if (flags & EXT4_GET_BLOCKS_CACHED_NOWAIT)
return retval;
#ifdef ES_AGGRESSIVE_TEST
ext4_map_blocks_es_recheck(handle, inode, map,
&orig_map, flags);
#endif
goto found;
}
/*
* In the query cache no-wait mode, nothing we can do more if we
* cannot find extent in the cache.
*/
if (flags & EXT4_GET_BLOCKS_CACHED_NOWAIT)
return 0;
/*
* Try to see if we can get the block without requesting a new
* file system block.
*/
down_read(&EXT4_I(inode)->i_data_sem);
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
retval = ext4_ext_map_blocks(handle, inode, map, 0);
} else {
retval = ext4_ind_map_blocks(handle, inode, map, 0);
}
if (retval > 0) {
unsigned int status;
if (unlikely(retval != map->m_len)) {
ext4_warning(inode->i_sb,
"ES len assertion failed for inode "
"%lu: retval %d != map->m_len %d",
inode->i_ino, retval, map->m_len);
WARN_ON(1);
}
status = map->m_flags & EXT4_MAP_UNWRITTEN ?
EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
!(status & EXTENT_STATUS_WRITTEN) &&
ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
map->m_lblk + map->m_len - 1))
status |= EXTENT_STATUS_DELAYED;
ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
map->m_pblk, status);
}
up_read((&EXT4_I(inode)->i_data_sem));
found:
if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
ret = check_block_validity(inode, map);
if (ret != 0)
return ret;
}
/* If it is only a block(s) look up */
if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
return retval;
/*
* Returns if the blocks have already allocated
*
* Note that if blocks have been preallocated
* ext4_ext_map_blocks() returns with buffer head unmapped
*/
if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
/*
* If we need to convert extent to unwritten
* we continue and do the actual work in
* ext4_ext_map_blocks()
*/
if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
return retval;
/*
* Here we clear m_flags because after allocating an new extent,
* it will be set again.
*/
map->m_flags &= ~EXT4_MAP_FLAGS;
/*
* New blocks allocate and/or writing to unwritten extent
* will possibly result in updating i_data, so we take
* the write lock of i_data_sem, and call get_block()
* with create == 1 flag.
*/
down_write(&EXT4_I(inode)->i_data_sem);
/*
* We need to check for EXT4 here because migrate
* could have changed the inode type in between
*/
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
retval = ext4_ext_map_blocks(handle, inode, map, flags);
} else {
retval = ext4_ind_map_blocks(handle, inode, map, flags);
if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
/*
* We allocated new blocks which will result in
* i_data's format changing. Force the migrate
* to fail by clearing migrate flags
*/
ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
}
}
if (retval > 0) {
unsigned int status;
if (unlikely(retval != map->m_len)) {
ext4_warning(inode->i_sb,
"ES len assertion failed for inode "
"%lu: retval %d != map->m_len %d",
inode->i_ino, retval, map->m_len);
WARN_ON(1);
}
/*
* We have to zeroout blocks before inserting them into extent
* status tree. Otherwise someone could look them up there and
* use them before they are really zeroed. We also have to
* unmap metadata before zeroing as otherwise writeback can
* overwrite zeros with stale data from block device.
*/
if (flags & EXT4_GET_BLOCKS_ZERO &&
map->m_flags & EXT4_MAP_MAPPED &&
map->m_flags & EXT4_MAP_NEW) {
ret = ext4_issue_zeroout(inode, map->m_lblk,
map->m_pblk, map->m_len);
if (ret) {
retval = ret;
goto out_sem;
}
}
/*
* If the extent has been zeroed out, we don't need to update
* extent status tree.
*/
if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
if (ext4_es_is_written(&es))
goto out_sem;
}
status = map->m_flags & EXT4_MAP_UNWRITTEN ?
EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
!(status & EXTENT_STATUS_WRITTEN) &&
ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
map->m_lblk + map->m_len - 1))
status |= EXTENT_STATUS_DELAYED;
ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
map->m_pblk, status);
}
out_sem:
up_write((&EXT4_I(inode)->i_data_sem));
if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
ret = check_block_validity(inode, map);
if (ret != 0)
return ret;
/*
* Inodes with freshly allocated blocks where contents will be
* visible after transaction commit must be on transaction's
* ordered data list.
*/
if (map->m_flags & EXT4_MAP_NEW &&
!(map->m_flags & EXT4_MAP_UNWRITTEN) &&
!(flags & EXT4_GET_BLOCKS_ZERO) &&
!ext4_is_quota_file(inode) &&
ext4_should_order_data(inode)) {
loff_t start_byte =
(loff_t)map->m_lblk << inode->i_blkbits;
loff_t length = (loff_t)map->m_len << inode->i_blkbits;
if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
ret = ext4_jbd2_inode_add_wait(handle, inode,
start_byte, length);
else
ret = ext4_jbd2_inode_add_write(handle, inode,
start_byte, length);
if (ret)
return ret;
}
}
if (retval > 0 && (map->m_flags & EXT4_MAP_UNWRITTEN ||
map->m_flags & EXT4_MAP_MAPPED))
ext4_fc_track_range(handle, inode, map->m_lblk,
map->m_lblk + map->m_len - 1);
if (retval < 0)
ext_debug(inode, "failed with err %d\n", retval);
return retval;
}
/*
* Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
* we have to be careful as someone else may be manipulating b_state as well.
*/
static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
{
unsigned long old_state;
unsigned long new_state;
flags &= EXT4_MAP_FLAGS;
/* Dummy buffer_head? Set non-atomically. */
if (!bh->b_page) {
bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
return;
}
/*
* Someone else may be modifying b_state. Be careful! This is ugly but
* once we get rid of using bh as a container for mapping information
* to pass to / from get_block functions, this can go away.
*/
old_state = READ_ONCE(bh->b_state);
do {
new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
} while (unlikely(!try_cmpxchg(&bh->b_state, &old_state, new_state)));
}
static int _ext4_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh, int flags)
{
struct ext4_map_blocks map;
int ret = 0;
if (ext4_has_inline_data(inode))
return -ERANGE;
map.m_lblk = iblock;
map.m_len = bh->b_size >> inode->i_blkbits;
ret = ext4_map_blocks(ext4_journal_current_handle(), inode, &map,
flags);
if (ret > 0) {
map_bh(bh, inode->i_sb, map.m_pblk);
ext4_update_bh_state(bh, map.m_flags);
bh->b_size = inode->i_sb->s_blocksize * map.m_len;
ret = 0;
} else if (ret == 0) {
/* hole case, need to fill in bh->b_size */
bh->b_size = inode->i_sb->s_blocksize * map.m_len;
}
return ret;
}
int ext4_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh, int create)
{
return _ext4_get_block(inode, iblock, bh,
create ? EXT4_GET_BLOCKS_CREATE : 0);
}
/*
* Get block function used when preparing for buffered write if we require
* creating an unwritten extent if blocks haven't been allocated. The extent
* will be converted to written after the IO is complete.
*/
int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
int ret = 0;
ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
inode->i_ino, create);
ret = _ext4_get_block(inode, iblock, bh_result,
EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT);
/*
* If the buffer is marked unwritten, mark it as new to make sure it is
* zeroed out correctly in case of partial writes. Otherwise, there is
* a chance of stale data getting exposed.
*/
if (ret == 0 && buffer_unwritten(bh_result))
set_buffer_new(bh_result);
return ret;
}
/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096
/*
* `handle' can be NULL if create is zero
*/
struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
ext4_lblk_t block, int map_flags)
{
struct ext4_map_blocks map;
struct buffer_head *bh;
int create = map_flags & EXT4_GET_BLOCKS_CREATE;
bool nowait = map_flags & EXT4_GET_BLOCKS_CACHED_NOWAIT;
int err;
ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
|| handle != NULL || create == 0);
ASSERT(create == 0 || !nowait);
map.m_lblk = block;
map.m_len = 1;
err = ext4_map_blocks(handle, inode, &map, map_flags);
if (err == 0)
return create ? ERR_PTR(-ENOSPC) : NULL;
if (err < 0)
return ERR_PTR(err);
if (nowait)
return sb_find_get_block(inode->i_sb, map.m_pblk);
bh = sb_getblk(inode->i_sb, map.m_pblk);
if (unlikely(!bh))
return ERR_PTR(-ENOMEM);
if (map.m_flags & EXT4_MAP_NEW) {
ASSERT(create != 0);
ASSERT((EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
|| (handle != NULL));
/*
* Now that we do not always journal data, we should
* keep in mind whether this should always journal the
* new buffer as metadata. For now, regular file
* writes use ext4_get_block instead, so it's not a
* problem.
*/
lock_buffer(bh);
BUFFER_TRACE(bh, "call get_create_access");
err = ext4_journal_get_create_access(handle, inode->i_sb, bh,
EXT4_JTR_NONE);
if (unlikely(err)) {
unlock_buffer(bh);
goto errout;
}
if (!buffer_uptodate(bh)) {
memset(bh->b_data, 0, inode->i_sb->s_blocksize);
set_buffer_uptodate(bh);
}
unlock_buffer(bh);
BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
err = ext4_handle_dirty_metadata(handle, inode, bh);
if (unlikely(err))
goto errout;
} else
BUFFER_TRACE(bh, "not a new buffer");
return bh;
errout:
brelse(bh);
return ERR_PTR(err);
}
struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
ext4_lblk_t block, int map_flags)
{
struct buffer_head *bh;
int ret;
bh = ext4_getblk(handle, inode, block, map_flags);
if (IS_ERR(bh))
return bh;
if (!bh || ext4_buffer_uptodate(bh))
return bh;
ret = ext4_read_bh_lock(bh, REQ_META | REQ_PRIO, true);
if (ret) {
put_bh(bh);
return ERR_PTR(ret);
}
return bh;
}
/* Read a contiguous batch of blocks. */
int ext4_bread_batch(struct inode *inode, ext4_lblk_t block, int bh_count,
bool wait, struct buffer_head **bhs)
{
int i, err;
for (i = 0; i < bh_count; i++) {
bhs[i] = ext4_getblk(NULL, inode, block + i, 0 /* map_flags */);
if (IS_ERR(bhs[i])) {
err = PTR_ERR(bhs[i]);
bh_count = i;
goto out_brelse;
}
}
for (i = 0; i < bh_count; i++)
/* Note that NULL bhs[i] is valid because of holes. */
if (bhs[i] && !ext4_buffer_uptodate(bhs[i]))
ext4_read_bh_lock(bhs[i], REQ_META | REQ_PRIO, false);
if (!wait)
return 0;
for (i = 0; i < bh_count; i++)
if (bhs[i])
wait_on_buffer(bhs[i]);
for (i = 0; i < bh_count; i++) {
if (bhs[i] && !buffer_uptodate(bhs[i])) {
err = -EIO;
goto out_brelse;
}
}
return 0;
out_brelse:
for (i = 0; i < bh_count; i++) {
brelse(bhs[i]);
bhs[i] = NULL;
}
return err;
}
int ext4_walk_page_buffers(handle_t *handle, struct inode *inode,
struct buffer_head *head,
unsigned from,
unsigned to,
int *partial,
int (*fn)(handle_t *handle, struct inode *inode,
struct buffer_head *bh))
{
struct buffer_head *bh;
unsigned block_start, block_end;
unsigned blocksize = head->b_size;
int err, ret = 0;
struct buffer_head *next;
for (bh = head, block_start = 0;
ret == 0 && (bh != head || !block_start);
block_start = block_end, bh = next) {
next = bh->b_this_page;
block_end = block_start + blocksize;
if (block_end <= from || block_start >= to) {
if (partial && !buffer_uptodate(bh))
*partial = 1;
continue;
}
err = (*fn)(handle, inode, bh);
if (!ret)
ret = err;
}
return ret;
}
/*
* Helper for handling dirtying of journalled data. We also mark the folio as
* dirty so that writeback code knows about this page (and inode) contains
* dirty data. ext4_writepages() then commits appropriate transaction to
* make data stable.
*/
static int ext4_dirty_journalled_data(handle_t *handle, struct buffer_head *bh)
{
folio_mark_dirty(bh->b_folio);
return ext4_handle_dirty_metadata(handle, NULL, bh);
}
int do_journal_get_write_access(handle_t *handle, struct inode *inode,
struct buffer_head *bh)
{
int dirty = buffer_dirty(bh);
int ret;
if (!buffer_mapped(bh) || buffer_freed(bh))
return 0;
/*
* __block_write_begin() could have dirtied some buffers. Clean
* the dirty bit as jbd2_journal_get_write_access() could complain
* otherwise about fs integrity issues. Setting of the dirty bit
* by __block_write_begin() isn't a real problem here as we clear
* the bit before releasing a page lock and thus writeback cannot
* ever write the buffer.
*/
if (dirty)
clear_buffer_dirty(bh);
BUFFER_TRACE(bh, "get write access");
ret = ext4_journal_get_write_access(handle, inode->i_sb, bh,
EXT4_JTR_NONE);
if (!ret && dirty)
ret = ext4_dirty_journalled_data(handle, bh);
return ret;
}
#ifdef CONFIG_FS_ENCRYPTION
static int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
get_block_t *get_block)
{
unsigned from = pos & (PAGE_SIZE - 1);
unsigned to = from + len;
struct inode *inode = folio->mapping->host;
unsigned block_start, block_end;
sector_t block;
int err = 0;
unsigned blocksize = inode->i_sb->s_blocksize;
unsigned bbits;
struct buffer_head *bh, *head, *wait[2];
int nr_wait = 0;
int i;
BUG_ON(!folio_test_locked(folio));
BUG_ON(from > PAGE_SIZE);
BUG_ON(to > PAGE_SIZE);
BUG_ON(from > to);
head = folio_buffers(folio);
if (!head)
head = create_empty_buffers(folio, blocksize, 0);
bbits = ilog2(blocksize);
block = (sector_t)folio->index << (PAGE_SHIFT - bbits);
for (bh = head, block_start = 0; bh != head || !block_start;
block++, block_start = block_end, bh = bh->b_this_page) {
block_end = block_start + blocksize;
if (block_end <= from || block_start >= to) {
if (folio_test_uptodate(folio)) {
set_buffer_uptodate(bh);
}
continue;
}
if (buffer_new(bh))
clear_buffer_new(bh);
if (!buffer_mapped(bh)) {
WARN_ON(bh->b_size != blocksize);
err = get_block(inode, block, bh, 1);
if (err)
break;
if (buffer_new(bh)) {
if (folio_test_uptodate(folio)) {
clear_buffer_new(bh);
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
continue;
}
if (block_end > to || block_start < from)
folio_zero_segments(folio, to,
block_end,
block_start, from);
continue;
}
}
if (folio_test_uptodate(folio)) {
set_buffer_uptodate(bh);
continue;
}
if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
!buffer_unwritten(bh) &&
(block_start < from || block_end > to)) {
ext4_read_bh_lock(bh, 0, false);
wait[nr_wait++] = bh;
}
}
/*
* If we issued read requests, let them complete.
*/
for (i = 0; i < nr_wait; i++) {
wait_on_buffer(wait[i]);
if (!buffer_uptodate(wait[i]))
err = -EIO;
}
if (unlikely(err)) {
folio_zero_new_buffers(folio, from, to);
} else if (fscrypt_inode_uses_fs_layer_crypto(inode)) {
for (i = 0; i < nr_wait; i++) {
int err2;
err2 = fscrypt_decrypt_pagecache_blocks(folio,
blocksize, bh_offset(wait[i]));
if (err2) {
clear_buffer_uptodate(wait[i]);
err = err2;
}
}
}
return err;
}
#endif
/*
* To preserve ordering, it is essential that the hole instantiation and
* the data write be encapsulated in a single transaction. We cannot
* close off a transaction and start a new one between the ext4_get_block()
* and the ext4_write_end(). So doing the jbd2_journal_start at the start of
* ext4_write_begin() is the right place.
*/
static int ext4_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len,
struct page **pagep, void **fsdata)
{
struct inode *inode = mapping->host;
int ret, needed_blocks;
handle_t *handle;
int retries = 0;
struct folio *folio;
pgoff_t index;
unsigned from, to;
if (unlikely(ext4_forced_shutdown(inode->i_sb)))
return -EIO;
trace_ext4_write_begin(inode, pos, len);
/*
* Reserve one block more for addition to orphan list in case
* we allocate blocks but write fails for some reason
*/
needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
index = pos >> PAGE_SHIFT;
from = pos & (PAGE_SIZE - 1);
to = from + len;
if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
pagep);
if (ret < 0)
return ret;
if (ret == 1)
return 0;
}
/*
* __filemap_get_folio() can take a long time if the
* system is thrashing due to memory pressure, or if the folio
* is being written back. So grab it first before we start
* the transaction handle. This also allows us to allocate
* the folio (if needed) without using GFP_NOFS.
*/
retry_grab:
folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
mapping_gfp_mask(mapping));
if (IS_ERR(folio))
return PTR_ERR(folio);
/*
* The same as page allocation, we prealloc buffer heads before
* starting the handle.
*/
if (!folio_buffers(folio))
create_empty_buffers(folio, inode->i_sb->s_blocksize, 0);
folio_unlock(folio);
retry_journal:
handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks);
if (IS_ERR(handle)) {
folio_put(folio);
return PTR_ERR(handle);
}
folio_lock(folio);
if (folio->mapping != mapping) {
/* The folio got truncated from under us */
folio_unlock(folio);
folio_put(folio);
ext4_journal_stop(handle);
goto retry_grab;
}
/* In case writeback began while the folio was unlocked */
folio_wait_stable(folio);
#ifdef CONFIG_FS_ENCRYPTION
if (ext4_should_dioread_nolock(inode))
ret = ext4_block_write_begin(folio, pos, len,
ext4_get_block_unwritten);
else
ret = ext4_block_write_begin(folio, pos, len, ext4_get_block);
#else
if (ext4_should_dioread_nolock(inode))
ret = __block_write_begin(&folio->page, pos, len,
ext4_get_block_unwritten);
else
ret = __block_write_begin(&folio->page, pos, len, ext4_get_block);
#endif
if (!ret && ext4_should_journal_data(inode)) {
ret = ext4_walk_page_buffers(handle, inode,
folio_buffers(folio), from, to,
NULL, do_journal_get_write_access);
}
if (ret) {
bool extended = (pos + len > inode->i_size) &&
!ext4_verity_in_progress(inode);
folio_unlock(folio);
/*
* __block_write_begin may have instantiated a few blocks
* outside i_size. Trim these off again. Don't need
* i_size_read because we hold i_rwsem.
*
* Add inode to orphan list in case we crash before
* truncate finishes
*/
if (extended && ext4_can_truncate(inode))
ext4_orphan_add(handle, inode);
ext4_journal_stop(handle);
if (extended) {
ext4_truncate_failed_write(inode);
/*
* If truncate failed early the inode might
* still be on the orphan list; we need to
* make sure the inode is removed from the
* orphan list in that case.
*/
if (inode->i_nlink)
ext4_orphan_del(NULL, inode);
}
if (ret == -ENOSPC &&
ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry_journal;
folio_put(folio);
return ret;
}
*pagep = &folio->page;
return ret;
}
/* For write_end() in data=journal mode */
static int write_end_fn(handle_t *handle, struct inode *inode,
struct buffer_head *bh)
{
int ret;
if (!buffer_mapped(bh) || buffer_freed(bh))
return 0;
set_buffer_uptodate(bh);
ret = ext4_dirty_journalled_data(handle, bh);
clear_buffer_meta(bh);
clear_buffer_prio(bh);
return ret;
}
/*
* We need to pick up the new inode size which generic_commit_write gave us
* `file' can be NULL - eg, when called from page_symlink().
*
* ext4 never places buffers on inode->i_mapping->i_private_list. metadata
* buffers are managed internally.
*/
static int ext4_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct folio *folio = page_folio(page);
handle_t *handle = ext4_journal_current_handle();
struct inode *inode = mapping->host;
loff_t old_size = inode->i_size;
int ret = 0, ret2;
int i_size_changed = 0;
bool verity = ext4_verity_in_progress(inode);
trace_ext4_write_end(inode, pos, len, copied);
if (ext4_has_inline_data(inode) &&
ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))
return ext4_write_inline_data_end(inode, pos, len, copied,
folio);
copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
/*
* it's important to update i_size while still holding folio lock:
* page writeout could otherwise come in and zero beyond i_size.
*
* If FS_IOC_ENABLE_VERITY is running on this inode, then Merkle tree
* blocks are being written past EOF, so skip the i_size update.
*/
if (!verity)
i_size_changed = ext4_update_inode_size(inode, pos + copied);
folio_unlock(folio);
folio_put(folio);
if (old_size < pos && !verity)
pagecache_isize_extended(inode, old_size, pos);
/*
* Don't mark the inode dirty under folio lock. First, it unnecessarily
* makes the holding time of folio lock longer. Second, it forces lock
* ordering of folio lock and transaction start for journaling
* filesystems.
*/
if (i_size_changed)
ret = ext4_mark_inode_dirty(handle, inode);
if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
/* if we have allocated more blocks and copied
* less. We will have blocks allocated outside
* inode->i_size. So truncate them
*/
ext4_orphan_add(handle, inode);
ret2 = ext4_journal_stop(handle);
if (!ret)
ret = ret2;
if (pos + len > inode->i_size && !verity) {
ext4_truncate_failed_write(inode);
/*
* If truncate failed early the inode might still be
* on the orphan list; we need to make sure the inode
* is removed from the orphan list in that case.
*/
if (inode->i_nlink)
ext4_orphan_del(NULL, inode);
}
return ret ? ret : copied;
}
/*
* This is a private version of folio_zero_new_buffers() which doesn't
* set the buffer to be dirty, since in data=journalled mode we need
* to call ext4_dirty_journalled_data() instead.
*/
static void ext4_journalled_zero_new_buffers(handle_t *handle,
struct inode *inode,
struct folio *folio,
unsigned from, unsigned to)
{
unsigned int block_start = 0, block_end;
struct buffer_head *head, *bh;
bh = head = folio_buffers(folio);
do {
block_end = block_start + bh->b_size;
if (buffer_new(bh)) {
if (block_end > from && block_start < to) {
if (!folio_test_uptodate(folio)) {
unsigned start, size;
start = max(from, block_start);
size = min(to, block_end) - start;
folio_zero_range(folio, start, size);
write_end_fn(handle, inode, bh);
}
clear_buffer_new(bh);
}
}
block_start = block_end;
bh = bh->b_this_page;
} while (bh != head);
}
static int ext4_journalled_write_end(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct folio *folio = page_folio(page);
handle_t *handle = ext4_journal_current_handle();
struct inode *inode = mapping->host;
loff_t old_size = inode->i_size;
int ret = 0, ret2;
int partial = 0;
unsigned from, to;
int size_changed = 0;
bool verity = ext4_verity_in_progress(inode);
trace_ext4_journalled_write_end(inode, pos, len, copied);
from = pos & (PAGE_SIZE - 1);
to = from + len;
BUG_ON(!ext4_handle_valid(handle));
if (ext4_has_inline_data(inode))
return ext4_write_inline_data_end(inode, pos, len, copied,
folio);
if (unlikely(copied < len) && !folio_test_uptodate(folio)) {
copied = 0;
ext4_journalled_zero_new_buffers(handle, inode, folio,
from, to);
} else {
if (unlikely(copied < len))
ext4_journalled_zero_new_buffers(handle, inode, folio,
from + copied, to);
ret = ext4_walk_page_buffers(handle, inode,
folio_buffers(folio),
from, from + copied, &partial,
write_end_fn);
if (!partial)
folio_mark_uptodate(folio);
}
if (!verity)
size_changed = ext4_update_inode_size(inode, pos + copied);
EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
folio_unlock(folio);
folio_put(folio);
if (old_size < pos && !verity)
pagecache_isize_extended(inode, old_size, pos);
if (size_changed) {
ret2 = ext4_mark_inode_dirty(handle, inode);
if (!ret)
ret = ret2;
}
if (pos + len > inode->i_size && !verity && ext4_can_truncate(inode))
/* if we have allocated more blocks and copied
* less. We will have blocks allocated outside
* inode->i_size. So truncate them
*/
ext4_orphan_add(handle, inode);
ret2 = ext4_journal_stop(handle);
if (!ret)
ret = ret2;
if (pos + len > inode->i_size && !verity) {
ext4_truncate_failed_write(inode);
/*
* If truncate failed early the inode might still be
* on the orphan list; we need to make sure the inode
* is removed from the orphan list in that case.
*/
if (inode->i_nlink)
ext4_orphan_del(NULL, inode);
}
return ret ? ret : copied;
}
/*
* Reserve space for 'nr_resv' clusters
*/
static int ext4_da_reserve_space(struct inode *inode, int nr_resv)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct ext4_inode_info *ei = EXT4_I(inode);
int ret;
/*
* We will charge metadata quota at writeout time; this saves
* us from metadata over-estimation, though we may go over by
* a small amount in the end. Here we just reserve for data.
*/
ret = dquot_reserve_block(inode, EXT4_C2B(sbi, nr_resv));
if (ret)
return ret;
spin_lock(&ei->i_block_reservation_lock);
if (ext4_claim_free_clusters(sbi, nr_resv, 0)) {
spin_unlock(&ei->i_block_reservation_lock);
dquot_release_reservation_block(inode, EXT4_C2B(sbi, nr_resv));
return -ENOSPC;
}
ei->i_reserved_data_blocks += nr_resv;
trace_ext4_da_reserve_space(inode, nr_resv);
spin_unlock(&ei->i_block_reservation_lock);
return 0; /* success */
}
void ext4_da_release_space(struct inode *inode, int to_free)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct ext4_inode_info *ei = EXT4_I(inode);
if (!to_free)
return; /* Nothing to release, exit */
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
trace_ext4_da_release_space(inode, to_free);
if (unlikely(to_free > ei->i_reserved_data_blocks)) {
/*
* if there aren't enough reserved blocks, then the
* counter is messed up somewhere. Since this
* function is called from invalidate page, it's
* harmless to return without any action.
*/
ext4_warning(inode->i_sb, "ext4_da_release_space: "
"ino %lu, to_free %d with only %d reserved "
"data blocks", inode->i_ino, to_free,
ei->i_reserved_data_blocks);
WARN_ON(1);
to_free = ei->i_reserved_data_blocks;
}
ei->i_reserved_data_blocks -= to_free;
/* update fs dirty data blocks counter */
percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
}
/*
* Delayed allocation stuff
*/
struct mpage_da_data {
/* These are input fields for ext4_do_writepages() */
struct inode *inode;
struct writeback_control *wbc;
unsigned int can_map:1; /* Can writepages call map blocks? */
/* These are internal state of ext4_do_writepages() */
pgoff_t first_page; /* The first page to write */
pgoff_t next_page; /* Current page to examine */
pgoff_t last_page; /* Last page to examine */
/*
* Extent to map - this can be after first_page because that can be
* fully mapped. We somewhat abuse m_flags to store whether the extent
* is delalloc or unwritten.
*/
struct ext4_map_blocks map;
struct ext4_io_submit io_submit; /* IO submission data */
unsigned int do_map:1;
unsigned int scanned_until_end:1;
unsigned int journalled_more_data:1;
};
static void mpage_release_unused_pages(struct mpage_da_data *mpd,
bool invalidate)
{
unsigned nr, i;
pgoff_t index, end;
struct folio_batch fbatch;
struct inode *inode = mpd->inode;
struct address_space *mapping = inode->i_mapping;
/* This is necessary when next_page == 0. */
if (mpd->first_page >= mpd->next_page)
return;
mpd->scanned_until_end = 0;
index = mpd->first_page;
end = mpd->next_page - 1;
if (invalidate) {
ext4_lblk_t start, last;
start = index << (PAGE_SHIFT - inode->i_blkbits);
last = end << (PAGE_SHIFT - inode->i_blkbits);
/*
* avoid racing with extent status tree scans made by
* ext4_insert_delayed_block()
*/
down_write(&EXT4_I(inode)->i_data_sem);
ext4_es_remove_extent(inode, start, last - start + 1);
up_write(&EXT4_I(inode)->i_data_sem);
}
folio_batch_init(&fbatch);
while (index <= end) {
nr = filemap_get_folios(mapping, &index, end, &fbatch);
if (nr == 0)
break;
for (i = 0; i < nr; i++) {
struct folio *folio = fbatch.folios[i];
if (folio->index < mpd->first_page)
continue;
if (folio_next_index(folio) - 1 > end)
continue;
BUG_ON(!folio_test_locked(folio));
BUG_ON(folio_test_writeback(folio));
if (invalidate) {
if (folio_mapped(folio))
folio_clear_dirty_for_io(folio);
block_invalidate_folio(folio, 0,
folio_size(folio));
folio_clear_uptodate(folio);
}
folio_unlock(folio);
}
folio_batch_release(&fbatch);
}
}
static void ext4_print_free_blocks(struct inode *inode)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct super_block *sb = inode->i_sb;
struct ext4_inode_info *ei = EXT4_I(inode);
ext4_msg(sb, KERN_CRIT, "Total free blocks count %lld",
EXT4_C2B(EXT4_SB(inode->i_sb),
ext4_count_free_clusters(sb)));
ext4_msg(sb, KERN_CRIT, "Free/Dirty block details");
ext4_msg(sb, KERN_CRIT, "free_blocks=%lld",
(long long) EXT4_C2B(EXT4_SB(sb),
percpu_counter_sum(&sbi->s_freeclusters_counter)));
ext4_msg(sb, KERN_CRIT, "dirty_blocks=%lld",
(long long) EXT4_C2B(EXT4_SB(sb),
percpu_counter_sum(&sbi->s_dirtyclusters_counter)));
ext4_msg(sb, KERN_CRIT, "Block reservation details");
ext4_msg(sb, KERN_CRIT, "i_reserved_data_blocks=%u",
ei->i_reserved_data_blocks);
return;
}
/*
* Check whether the cluster containing lblk has been allocated or has
* delalloc reservation.
*
* Returns 0 if the cluster doesn't have either, 1 if it has delalloc
* reservation, 2 if it's already been allocated, negative error code on
* failure.
*/
static int ext4_clu_alloc_state(struct inode *inode, ext4_lblk_t lblk)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
int ret;
/* Has delalloc reservation? */
if (ext4_es_scan_clu(inode, &ext4_es_is_delonly, lblk))
return 1;
/* Already been allocated? */
if (ext4_es_scan_clu(inode, &ext4_es_is_mapped, lblk))
return 2;
ret = ext4_clu_mapped(inode, EXT4_B2C(sbi, lblk));
if (ret < 0)
return ret;
if (ret > 0)
return 2;
return 0;
}
/*
* ext4_insert_delayed_blocks - adds a multiple delayed blocks to the extents
* status tree, incrementing the reserved
* cluster/block count or making pending
* reservations where needed
*
* @inode - file containing the newly added block
* @lblk - start logical block to be added
* @len - length of blocks to be added
*
* Returns 0 on success, negative error code on failure.
*/
static int ext4_insert_delayed_blocks(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
int ret;
bool lclu_allocated = false;
bool end_allocated = false;
ext4_lblk_t resv_clu;
ext4_lblk_t end = lblk + len - 1;
/*
* If the cluster containing lblk or end is shared with a delayed,
* written, or unwritten extent in a bigalloc file system, it's
* already been accounted for and does not need to be reserved.
* A pending reservation must be made for the cluster if it's
* shared with a written or unwritten extent and doesn't already
* have one. Written and unwritten extents can be purged from the
* extents status tree if the system is under memory pressure, so
* it's necessary to examine the extent tree if a search of the
* extents status tree doesn't get a match.
*/
if (sbi->s_cluster_ratio == 1) {
ret = ext4_da_reserve_space(inode, len);
if (ret != 0) /* ENOSPC */
return ret;
} else { /* bigalloc */
resv_clu = EXT4_B2C(sbi, end) - EXT4_B2C(sbi, lblk) + 1;
ret = ext4_clu_alloc_state(inode, lblk);
if (ret < 0)
return ret;
if (ret > 0) {
resv_clu--;
lclu_allocated = (ret == 2);
}
if (EXT4_B2C(sbi, lblk) != EXT4_B2C(sbi, end)) {
ret = ext4_clu_alloc_state(inode, end);
if (ret < 0)
return ret;
if (ret > 0) {
resv_clu--;
end_allocated = (ret == 2);
}
}
if (resv_clu) {
ret = ext4_da_reserve_space(inode, resv_clu);
if (ret != 0) /* ENOSPC */
return ret;
}
}
ext4_es_insert_delayed_extent(inode, lblk, len, lclu_allocated,
end_allocated);
return 0;
}
/*
* Looks up the requested blocks and sets the delalloc extent map.
* First try to look up for the extent entry that contains the requested
* blocks in the extent status tree without i_data_sem, then try to look
* up for the ondisk extent mapping with i_data_sem in read mode,
* finally hold i_data_sem in write mode, looks up again and add a
* delalloc extent entry if it still couldn't find any extent. Pass out
* the mapped extent through @map and return 0 on success.
*/
static int ext4_da_map_blocks(struct inode *inode, struct ext4_map_blocks *map)
{
struct extent_status es;
int retval;
#ifdef ES_AGGRESSIVE_TEST
struct ext4_map_blocks orig_map;
memcpy(&orig_map, map, sizeof(*map));
#endif
map->m_flags = 0;
ext_debug(inode, "max_blocks %u, logical block %lu\n", map->m_len,
(unsigned long) map->m_lblk);
/* Lookup extent status tree firstly */
if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
map->m_len = min_t(unsigned int, map->m_len,
es.es_len - (map->m_lblk - es.es_lblk));
if (ext4_es_is_hole(&es))
goto add_delayed;
found:
/*
* Delayed extent could be allocated by fallocate.
* So we need to check it.
*/
if (ext4_es_is_delonly(&es)) {
map->m_flags |= EXT4_MAP_DELAYED;
return 0;
}
map->m_pblk = ext4_es_pblock(&es) + map->m_lblk - es.es_lblk;
if (ext4_es_is_written(&es))
map->m_flags |= EXT4_MAP_MAPPED;
else if (ext4_es_is_unwritten(&es))
map->m_flags |= EXT4_MAP_UNWRITTEN;
else
BUG();
#ifdef ES_AGGRESSIVE_TEST
ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
#endif
return 0;
}
/*
* Try to see if we can get the block without requesting a new
* file system block.
*/
down_read(&EXT4_I(inode)->i_data_sem);
if (ext4_has_inline_data(inode))
retval = 0;
else
retval = ext4_map_query_blocks(NULL, inode, map);
up_read(&EXT4_I(inode)->i_data_sem);
if (retval)
return retval < 0 ? retval : 0;
add_delayed:
down_write(&EXT4_I(inode)->i_data_sem);
/*
* Page fault path (ext4_page_mkwrite does not take i_rwsem)
* and fallocate path (no folio lock) can race. Make sure we
* lookup the extent status tree here again while i_data_sem
* is held in write mode, before inserting a new da entry in
* the extent status tree.
*/
if (ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
map->m_len = min_t(unsigned int, map->m_len,
es.es_len - (map->m_lblk - es.es_lblk));
if (!ext4_es_is_hole(&es)) {
up_write(&EXT4_I(inode)->i_data_sem);
goto found;
}
} else if (!ext4_has_inline_data(inode)) {
retval = ext4_map_query_blocks(NULL, inode, map);
if (retval) {
up_write(&EXT4_I(inode)->i_data_sem);
return retval < 0 ? retval : 0;
}
}
map->m_flags |= EXT4_MAP_DELAYED;
retval = ext4_insert_delayed_blocks(inode, map->m_lblk, map->m_len);
up_write(&EXT4_I(inode)->i_data_sem);
return retval;
}
/*
* This is a special get_block_t callback which is used by
* ext4_da_write_begin(). It will either return mapped block or
* reserve space for a single block.
*
* For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
* We also have b_blocknr = -1 and b_bdev initialized properly
*
* For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
* We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
* initialized properly.
*/
int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
struct buffer_head *bh, int create)
{
struct ext4_map_blocks map;
sector_t invalid_block = ~((sector_t) 0xffff);
int ret = 0;
BUG_ON(create == 0);
BUG_ON(bh->b_size != inode->i_sb->s_blocksize);
if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
invalid_block = ~0;
map.m_lblk = iblock;
map.m_len = 1;
/*
* first, we need to know whether the block is allocated already
* preallocated blocks are unmapped but should treated
* the same as allocated blocks.
*/
ret = ext4_da_map_blocks(inode, &map);
if (ret < 0)
return ret;
if (map.m_flags & EXT4_MAP_DELAYED) {
map_bh(bh, inode->i_sb, invalid_block);
set_buffer_new(bh);
set_buffer_delay(bh);
return 0;
}
map_bh(bh, inode->i_sb, map.m_pblk);
ext4_update_bh_state(bh, map.m_flags);
if (buffer_unwritten(bh)) {
/* A delayed write to unwritten bh should be marked
* new and mapped. Mapped ensures that we don't do
* get_block multiple times when we write to the same
* offset and new ensures that we do proper zero out
* for partial write.
*/
set_buffer_new(bh);
set_buffer_mapped(bh);
}
return 0;
}
static void mpage_folio_done(struct mpage_da_data *mpd, struct folio *folio)
{
mpd->first_page += folio_nr_pages(folio);
folio_unlock(folio);
}
static int mpage_submit_folio(struct mpage_da_data *mpd, struct folio *folio)
{
size_t len;
loff_t size;
int err;
BUG_ON(folio->index != mpd->first_page);
folio_clear_dirty_for_io(folio);
/*
* We have to be very careful here! Nothing protects writeback path
* against i_size changes and the page can be writeably mapped into
* page tables. So an application can be growing i_size and writing
* data through mmap while writeback runs. folio_clear_dirty_for_io()
* write-protects our page in page tables and the page cannot get
* written to again until we release folio lock. So only after
* folio_clear_dirty_for_io() we are safe to sample i_size for
* ext4_bio_write_folio() to zero-out tail of the written page. We rely
* on the barrier provided by folio_test_clear_dirty() in
* folio_clear_dirty_for_io() to make sure i_size is really sampled only
* after page tables are updated.
*/
size = i_size_read(mpd->inode);
len = folio_size(folio);
if (folio_pos(folio) + len > size &&
!ext4_verity_in_progress(mpd->inode))
len = size & (len - 1);
err = ext4_bio_write_folio(&mpd->io_submit, folio, len);
if (!err)
mpd->wbc->nr_to_write--;
return err;
}
#define BH_FLAGS (BIT(BH_Unwritten) | BIT(BH_Delay))
/*
* mballoc gives us at most this number of blocks...
* XXX: That seems to be only a limitation of ext4_mb_normalize_request().
* The rest of mballoc seems to handle chunks up to full group size.
*/
#define MAX_WRITEPAGES_EXTENT_LEN 2048
/*
* mpage_add_bh_to_extent - try to add bh to extent of blocks to map
*
* @mpd - extent of blocks
* @lblk - logical number of the block in the file
* @bh - buffer head we want to add to the extent
*
* The function is used to collect contig. blocks in the same state. If the
* buffer doesn't require mapping for writeback and we haven't started the
* extent of buffers to map yet, the function returns 'true' immediately - the
* caller can write the buffer right away. Otherwise the function returns true
* if the block has been added to the extent, false if the block couldn't be
* added.
*/
static bool mpage_add_bh_to_extent(struct mpage_da_data *mpd, ext4_lblk_t lblk,
struct buffer_head *bh)
{
struct ext4_map_blocks *map = &mpd->map;
/* Buffer that doesn't need mapping for writeback? */
if (!buffer_dirty(bh) || !buffer_mapped(bh) ||
(!buffer_delay(bh) && !buffer_unwritten(bh))) {
/* So far no extent to map => we write the buffer right away */
if (map->m_len == 0)
return true;
return false;
}
/* First block in the extent? */
if (map->m_len == 0) {
/* We cannot map unless handle is started... */
if (!mpd->do_map)
return false;
map->m_lblk = lblk;
map->m_len = 1;
map->m_flags = bh->b_state & BH_FLAGS;
return true;
}
/* Don't go larger than mballoc is willing to allocate */
if (map->m_len >= MAX_WRITEPAGES_EXTENT_LEN)
return false;
/* Can we merge the block to our big extent? */
if (lblk == map->m_lblk + map->m_len &&
(bh->b_state & BH_FLAGS) == map->m_flags) {
map->m_len++;
return true;
}
return false;
}
/*
* mpage_process_page_bufs - submit page buffers for IO or add them to extent
*
* @mpd - extent of blocks for mapping
* @head - the first buffer in the page
* @bh - buffer we should start processing from
* @lblk - logical number of the block in the file corresponding to @bh
*
* Walk through page buffers from @bh upto @head (exclusive) and either submit
* the page for IO if all buffers in this page were mapped and there's no
* accumulated extent of buffers to map or add buffers in the page to the
* extent of buffers to map. The function returns 1 if the caller can continue
* by processing the next page, 0 if it should stop adding buffers to the
* extent to map because we cannot extend it anymore. It can also return value
* < 0 in case of error during IO submission.
*/
static int mpage_process_page_bufs(struct mpage_da_data *mpd,
struct buffer_head *head,
struct buffer_head *bh,
ext4_lblk_t lblk)
{
struct inode *inode = mpd->inode;
int err;
ext4_lblk_t blocks = (i_size_read(inode) + i_blocksize(inode) - 1)
>> inode->i_blkbits;
if (ext4_verity_in_progress(inode))
blocks = EXT_MAX_BLOCKS;
do {
BUG_ON(buffer_locked(bh));
if (lblk >= blocks || !mpage_add_bh_to_extent(mpd, lblk, bh)) {
/* Found extent to map? */
if (mpd->map.m_len)
return 0;
/* Buffer needs mapping and handle is not started? */
if (!mpd->do_map)
return 0;
/* Everything mapped so far and we hit EOF */
break;
}
} while (lblk++, (bh = bh->b_this_page) != head);
/* So far everything mapped? Submit the page for IO. */
if (mpd->map.m_len == 0) {
err = mpage_submit_folio(mpd, head->b_folio);
if (err < 0)
return err;
mpage_folio_done(mpd, head->b_folio);
}
if (lblk >= blocks) {
mpd->scanned_until_end = 1;
return 0;
}
return 1;
}
/*
* mpage_process_folio - update folio buffers corresponding to changed extent
* and may submit fully mapped page for IO
* @mpd: description of extent to map, on return next extent to map
* @folio: Contains these buffers.
* @m_lblk: logical block mapping.
* @m_pblk: corresponding physical mapping.
* @map_bh: determines on return whether this page requires any further
* mapping or not.
*
* Scan given folio buffers corresponding to changed extent and update buffer
* state according to new extent state.
* We map delalloc buffers to their physical location, clear unwritten bits.
* If the given folio is not fully mapped, we update @mpd to the next extent in
* the given folio that needs mapping & return @map_bh as true.
*/
static int mpage_process_folio(struct mpage_da_data *mpd, struct folio *folio,
ext4_lblk_t *m_lblk, ext4_fsblk_t *m_pblk,
bool *map_bh)
{
struct buffer_head *head, *bh;
ext4_io_end_t *io_end = mpd->io_submit.io_end;
ext4_lblk_t lblk = *m_lblk;
ext4_fsblk_t pblock = *m_pblk;
int err = 0;
int blkbits = mpd->inode->i_blkbits;
ssize_t io_end_size = 0;
struct ext4_io_end_vec *io_end_vec = ext4_last_io_end_vec(io_end);
bh = head = folio_buffers(folio);
do {
if (lblk < mpd->map.m_lblk)
continue;
if (lblk >= mpd->map.m_lblk + mpd->map.m_len) {
/*
* Buffer after end of mapped extent.
* Find next buffer in the folio to map.
*/
mpd->map.m_len = 0;
mpd->map.m_flags = 0;
io_end_vec->size += io_end_size;
err = mpage_process_page_bufs(mpd, head, bh, lblk);
if (err > 0)
err = 0;
if (!err && mpd->map.m_len && mpd->map.m_lblk > lblk) {
io_end_vec = ext4_alloc_io_end_vec(io_end);
if (IS_ERR(io_end_vec)) {
err = PTR_ERR(io_end_vec);
goto out;
}
io_end_vec->offset = (loff_t)mpd->map.m_lblk << blkbits;
}
*map_bh = true;
goto out;
}
if (buffer_delay(bh)) {
clear_buffer_delay(bh);
bh->b_blocknr = pblock++;
}
clear_buffer_unwritten(bh);
io_end_size += (1 << blkbits);
} while (lblk++, (bh = bh->b_this_page) != head);
io_end_vec->size += io_end_size;
*map_bh = false;
out:
*m_lblk = lblk;
*m_pblk = pblock;
return err;
}
/*
* mpage_map_buffers - update buffers corresponding to changed extent and
* submit fully mapped pages for IO
*
* @mpd - description of extent to map, on return next extent to map
*
* Scan buffers corresponding to changed extent (we expect corresponding pages
* to be already locked) and update buffer state according to new extent state.
* We map delalloc buffers to their physical location, clear unwritten bits,
* and mark buffers as uninit when we perform writes to unwritten extents
* and do extent conversion after IO is finished. If the last page is not fully
* mapped, we update @map to the next extent in the last page that needs
* mapping. Otherwise we submit the page for IO.
*/
static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd)
{
struct folio_batch fbatch;
unsigned nr, i;
struct inode *inode = mpd->inode;
int bpp_bits = PAGE_SHIFT - inode->i_blkbits;
pgoff_t start, end;
ext4_lblk_t lblk;
ext4_fsblk_t pblock;
int err;
bool map_bh = false;
start = mpd->map.m_lblk >> bpp_bits;
end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits;
lblk = start << bpp_bits;
pblock = mpd->map.m_pblk;
folio_batch_init(&fbatch);
while (start <= end) {
nr = filemap_get_folios(inode->i_mapping, &start, end, &fbatch);
if (nr == 0)
break;
for (i = 0; i < nr; i++) {
struct folio *folio = fbatch.folios[i];
err = mpage_process_folio(mpd, folio, &lblk, &pblock,
&map_bh);
/*
* If map_bh is true, means page may require further bh
* mapping, or maybe the page was submitted for IO.
* So we return to call further extent mapping.
*/
if (err < 0 || map_bh)
goto out;
/* Page fully mapped - let IO run! */
err = mpage_submit_folio(mpd, folio);
if (err < 0)
goto out;
mpage_folio_done(mpd, folio);
}
folio_batch_release(&fbatch);
}
/* Extent fully mapped and matches with page boundary. We are done. */
mpd->map.m_len = 0;
mpd->map.m_flags = 0;
return 0;
out:
folio_batch_release(&fbatch);
return err;
}
static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd)
{
struct inode *inode = mpd->inode;
struct ext4_map_blocks *map = &mpd->map;
int get_blocks_flags;
int err, dioread_nolock;
trace_ext4_da_write_pages_extent(inode, map);
/*
* Call ext4_map_blocks() to allocate any delayed allocation blocks, or
* to convert an unwritten extent to be initialized (in the case
* where we have written into one or more preallocated blocks). It is
* possible that we're going to need more metadata blocks than
* previously reserved. However we must not fail because we're in
* writeback and there is nothing we can do about it so it might result
* in data loss. So use reserved blocks to allocate metadata if
* possible.
*
* We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE if
* the blocks in question are delalloc blocks. This indicates
* that the blocks and quotas has already been checked when
* the data was copied into the page cache.
*/
get_blocks_flags = EXT4_GET_BLOCKS_CREATE |
EXT4_GET_BLOCKS_METADATA_NOFAIL |
EXT4_GET_BLOCKS_IO_SUBMIT;
dioread_nolock = ext4_should_dioread_nolock(inode);
if (dioread_nolock)
get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT;
if (map->m_flags & BIT(BH_Delay))
get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE;
err = ext4_map_blocks(handle, inode, map, get_blocks_flags);
if (err < 0)
return err;
if (dioread_nolock && (map->m_flags & EXT4_MAP_UNWRITTEN)) {
if (!mpd->io_submit.io_end->handle &&
ext4_handle_valid(handle)) {
mpd->io_submit.io_end->handle = handle->h_rsv_handle;
handle->h_rsv_handle = NULL;
}
ext4_set_io_unwritten_flag(inode, mpd->io_submit.io_end);
}
BUG_ON(map->m_len == 0);
return 0;
}
/*
* mpage_map_and_submit_extent - map extent starting at mpd->lblk of length
* mpd->len and submit pages underlying it for IO
*
* @handle - handle for journal operations
* @mpd - extent to map
* @give_up_on_write - we set this to true iff there is a fatal error and there
* is no hope of writing the data. The caller should discard
* dirty pages to avoid infinite loops.
*
* The function maps extent starting at mpd->lblk of length mpd->len. If it is
* delayed, blocks are allocated, if it is unwritten, we may need to convert
* them to initialized or split the described range from larger unwritten
* extent. Note that we need not map all the described range since allocation
* can return less blocks or the range is covered by more unwritten extents. We
* cannot map more because we are limited by reserved transaction credits. On
* the other hand we always make sure that the last touched page is fully
* mapped so that it can be written out (and thus forward progress is
* guaranteed). After mapping we submit all mapped pages for IO.
*/
static int mpage_map_and_submit_extent(handle_t *handle,
struct mpage_da_data *mpd,
bool *give_up_on_write)
{
struct inode *inode = mpd->inode;
struct ext4_map_blocks *map = &mpd->map;
int err;
loff_t disksize;
int progress = 0;
ext4_io_end_t *io_end = mpd->io_submit.io_end;
struct ext4_io_end_vec *io_end_vec;
io_end_vec = ext4_alloc_io_end_vec(io_end);
if (IS_ERR(io_end_vec))
return PTR_ERR(io_end_vec);
io_end_vec->offset = ((loff_t)map->m_lblk) << inode->i_blkbits;
do {
err = mpage_map_one_extent(handle, mpd);
if (err < 0) {
struct super_block *sb = inode->i_sb;
if (ext4_forced_shutdown(sb))
goto invalidate_dirty_pages;
/*
* Let the uper layers retry transient errors.
* In the case of ENOSPC, if ext4_count_free_blocks()
* is non-zero, a commit should free up blocks.
*/
if ((err == -ENOMEM) ||
(err == -ENOSPC && ext4_count_free_clusters(sb))) {
if (progress)
goto update_disksize;
return err;
}
ext4_msg(sb, KERN_CRIT,
"Delayed block allocation failed for "
"inode %lu at logical offset %llu with"
" max blocks %u with error %d",
inode->i_ino,
(unsigned long long)map->m_lblk,
(unsigned)map->m_len, -err);
ext4_msg(sb, KERN_CRIT,
"This should not happen!! Data will "
"be lost\n");
if (err == -ENOSPC)
ext4_print_free_blocks(inode);
invalidate_dirty_pages:
*give_up_on_write = true;
return err;
}
progress = 1;
/*
* Update buffer state, submit mapped pages, and get us new
* extent to map
*/
err = mpage_map_and_submit_buffers(mpd);
if (err < 0)
goto update_disksize;
} while (map->m_len);
update_disksize:
/*
* Update on-disk size after IO is submitted. Races with
* truncate are avoided by checking i_size under i_data_sem.
*/
disksize = ((loff_t)mpd->first_page) << PAGE_SHIFT;
if (disksize > READ_ONCE(EXT4_I(inode)->i_disksize)) {
int err2;
loff_t i_size;
down_write(&EXT4_I(inode)->i_data_sem);
i_size = i_size_read(inode);
if (disksize > i_size)
disksize = i_size;
if (disksize > EXT4_I(inode)->i_disksize)
EXT4_I(inode)->i_disksize = disksize;
up_write(&EXT4_I(inode)->i_data_sem);
err2 = ext4_mark_inode_dirty(handle, inode);
if (err2) {
ext4_error_err(inode->i_sb, -err2,
"Failed to mark inode %lu dirty",
inode->i_ino);
}
if (!err)
err = err2;
}
return err;
}
/*
* Calculate the total number of credits to reserve for one writepages
* iteration. This is called from ext4_writepages(). We map an extent of
* up to MAX_WRITEPAGES_EXTENT_LEN blocks and then we go on and finish mapping
* the last partial page. So in total we can map MAX_WRITEPAGES_EXTENT_LEN +
* bpp - 1 blocks in bpp different extents.
*/
static int ext4_da_writepages_trans_blocks(struct inode *inode)
{
int bpp = ext4_journal_blocks_per_page(inode);
return ext4_meta_trans_blocks(inode,
MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
}
static int ext4_journal_folio_buffers(handle_t *handle, struct folio *folio,
size_t len)
{
struct buffer_head *page_bufs = folio_buffers(folio);
struct inode *inode = folio->mapping->host;
int ret, err;
ret = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
NULL, do_journal_get_write_access);
err = ext4_walk_page_buffers(handle, inode, page_bufs, 0, len,
NULL, write_end_fn);
if (ret == 0)
ret = err;
err = ext4_jbd2_inode_add_write(handle, inode, folio_pos(folio), len);
if (ret == 0)
ret = err;
EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
return ret;
}
static int mpage_journal_page_buffers(handle_t *handle,
struct mpage_da_data *mpd,
struct folio *folio)
{
struct inode *inode = mpd->inode;
loff_t size = i_size_read(inode);
size_t len = folio_size(folio);
folio_clear_checked(folio);
mpd->wbc->nr_to_write--;
if (folio_pos(folio) + len > size &&
!ext4_verity_in_progress(inode))
len = size & (len - 1);
return ext4_journal_folio_buffers(handle, folio, len);
}
/*
* mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages
* needing mapping, submit mapped pages
*
* @mpd - where to look for pages
*
* Walk dirty pages in the mapping. If they are fully mapped, submit them for
* IO immediately. If we cannot map blocks, we submit just already mapped
* buffers in the page for IO and keep page dirty. When we can map blocks and
* we find a page which isn't mapped we start accumulating extent of buffers
* underlying these pages that needs mapping (formed by either delayed or
* unwritten buffers). We also lock the pages containing these buffers. The
* extent found is returned in @mpd structure (starting at mpd->lblk with
* length mpd->len blocks).
*
* Note that this function can attach bios to one io_end structure which are
* neither logically nor physically contiguous. Although it may seem as an
* unnecessary complication, it is actually inevitable in blocksize < pagesize
* case as we need to track IO to all buffers underlying a page in one io_end.
*/
static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
{
struct address_space *mapping = mpd->inode->i_mapping;
struct folio_batch fbatch;
unsigned int nr_folios;
pgoff_t index = mpd->first_page;
pgoff_t end = mpd->last_page;
xa_mark_t tag;
int i, err = 0;
int blkbits = mpd->inode->i_blkbits;
ext4_lblk_t lblk;
struct buffer_head *head;
handle_t *handle = NULL;
int bpp = ext4_journal_blocks_per_page(mpd->inode);
if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages)
tag = PAGECACHE_TAG_TOWRITE;
else
tag = PAGECACHE_TAG_DIRTY;
mpd->map.m_len = 0;
mpd->next_page = index;
if (ext4_should_journal_data(mpd->inode)) {
handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,
bpp);
if (IS_ERR(handle))
return PTR_ERR(handle);
}
folio_batch_init(&fbatch);
while (index <= end) {
nr_folios = filemap_get_folios_tag(mapping, &index, end,
tag, &fbatch);
if (nr_folios == 0)
break;
for (i = 0; i < nr_folios; i++) {
struct folio *folio = fbatch.folios[i];
/*
* Accumulated enough dirty pages? This doesn't apply
* to WB_SYNC_ALL mode. For integrity sync we have to
* keep going because someone may be concurrently
* dirtying pages, and we might have synced a lot of
* newly appeared dirty pages, but have not synced all
* of the old dirty pages.
*/
if (mpd->wbc->sync_mode == WB_SYNC_NONE &&
mpd->wbc->nr_to_write <=
mpd->map.m_len >> (PAGE_SHIFT - blkbits))
goto out;
/* If we can't merge this page, we are done. */
if (mpd->map.m_len > 0 && mpd->next_page != folio->index)
goto out;
if (handle) {
err = ext4_journal_ensure_credits(handle, bpp,
0);
if (err < 0)
goto out;
}
folio_lock(folio);
/*
* If the page is no longer dirty, or its mapping no
* longer corresponds to inode we are writing (which
* means it has been truncated or invalidated), or the
* page is already under writeback and we are not doing
* a data integrity writeback, skip the page
*/
if (!folio_test_dirty(folio) ||
(folio_test_writeback(folio) &&
(mpd->wbc->sync_mode == WB_SYNC_NONE)) ||
unlikely(folio->mapping != mapping)) {
folio_unlock(folio);
continue;
}
folio_wait_writeback(folio);
BUG_ON(folio_test_writeback(folio));
/*
* Should never happen but for buggy code in
* other subsystems that call
* set_page_dirty() without properly warning
* the file system first. See [1] for more
* information.
*
* [1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz
*/
if (!folio_buffers(folio)) {
ext4_warning_inode(mpd->inode, "page %lu does not have buffers attached", folio->index);
folio_clear_dirty(folio);
folio_unlock(folio);
continue;
}
if (mpd->map.m_len == 0)
mpd->first_page = folio->index;
mpd->next_page = folio_next_index(folio);
/*
* Writeout when we cannot modify metadata is simple.
* Just submit the page. For data=journal mode we
* first handle writeout of the page for checkpoint and
* only after that handle delayed page dirtying. This
* makes sure current data is checkpointed to the final
* location before possibly journalling it again which
* is desirable when the page is frequently dirtied
* through a pin.
*/
if (!mpd->can_map) {
err = mpage_submit_folio(mpd, folio);
if (err < 0)
goto out;
/* Pending dirtying of journalled data? */
if (folio_test_checked(folio)) {
err = mpage_journal_page_buffers(handle,
mpd, folio);
if (err < 0)
goto out;
mpd->journalled_more_data = 1;
}
mpage_folio_done(mpd, folio);
} else {
/* Add all dirty buffers to mpd */
lblk = ((ext4_lblk_t)folio->index) <<
(PAGE_SHIFT - blkbits);
head = folio_buffers(folio);
err = mpage_process_page_bufs(mpd, head, head,
lblk);
if (err <= 0)
goto out;
err = 0;
}
}
folio_batch_release(&fbatch);
cond_resched();
}
mpd->scanned_until_end = 1;
if (handle)
ext4_journal_stop(handle);
return 0;
out:
folio_batch_release(&fbatch);
if (handle)
ext4_journal_stop(handle);
return err;
}
static int ext4_do_writepages(struct mpage_da_data *mpd)
{
struct writeback_control *wbc = mpd->wbc;
pgoff_t writeback_index = 0;
long nr_to_write = wbc->nr_to_write;
int range_whole = 0;
int cycled = 1;
handle_t *handle = NULL;
struct inode *inode = mpd->inode;
struct address_space *mapping = inode->i_mapping;
int needed_blocks, rsv_blocks = 0, ret = 0;
struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
struct blk_plug plug;
bool give_up_on_write = false;
trace_ext4_writepages(inode, wbc);
/*
* No pages to write? This is mainly a kludge to avoid starting
* a transaction for special inodes like journal inode on last iput()
* because that could violate lock ordering on umount
*/
if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
goto out_writepages;
/*
* If the filesystem has aborted, it is read-only, so return
* right away instead of dumping stack traces later on that
* will obscure the real source of the problem. We test
* fs shutdown state instead of sb->s_flag's SB_RDONLY because
* the latter could be true if the filesystem is mounted
* read-only, and in that case, ext4_writepages should
* *never* be called, so if that ever happens, we would want
* the stack trace.
*/
if (unlikely(ext4_forced_shutdown(mapping->host->i_sb))) {
ret = -EROFS;
goto out_writepages;
}
/*
* If we have inline data and arrive here, it means that
* we will soon create the block for the 1st page, so
* we'd better clear the inline data here.
*/
if (ext4_has_inline_data(inode)) {
/* Just inode will be modified... */
handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out_writepages;
}
BUG_ON(ext4_test_inode_state(inode,
EXT4_STATE_MAY_INLINE_DATA));
ext4_destroy_inline_data(handle, inode);
ext4_journal_stop(handle);
}
/*
* data=journal mode does not do delalloc so we just need to writeout /
* journal already mapped buffers. On the other hand we need to commit
* transaction to make data stable. We expect all the data to be
* already in the journal (the only exception are DMA pinned pages
* dirtied behind our back) so we commit transaction here and run the
* writeback loop to checkpoint them. The checkpointing is not actually
* necessary to make data persistent *but* quite a few places (extent
* shifting operations, fsverity, ...) depend on being able to drop
* pagecache pages after calling filemap_write_and_wait() and for that
* checkpointing needs to happen.
*/
if (ext4_should_journal_data(inode)) {
mpd->can_map = 0;
if (wbc->sync_mode == WB_SYNC_ALL)
ext4_fc_commit(sbi->s_journal,
EXT4_I(inode)->i_datasync_tid);
}
mpd->journalled_more_data = 0;
if (ext4_should_dioread_nolock(inode)) {
/*
* We may need to convert up to one extent per block in
* the page and we may dirty the inode.
*/
rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
PAGE_SIZE >> inode->i_blkbits);
}
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
if (wbc->range_cyclic) {
writeback_index = mapping->writeback_index;
if (writeback_index)
cycled = 0;
mpd->first_page = writeback_index;
mpd->last_page = -1;
} else {
mpd->first_page = wbc->range_start >> PAGE_SHIFT;
mpd->last_page = wbc->range_end >> PAGE_SHIFT;
}
ext4_io_submit_init(&mpd->io_submit, wbc);
retry:
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag_pages_for_writeback(mapping, mpd->first_page,
mpd->last_page);
blk_start_plug(&plug);
/*
* First writeback pages that don't need mapping - we can avoid
* starting a transaction unnecessarily and also avoid being blocked
* in the block layer on device congestion while having transaction
* started.
*/
mpd->do_map = 0;
mpd->scanned_until_end = 0;
mpd->io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
if (!mpd->io_submit.io_end) {
ret = -ENOMEM;
goto unplug;
}
ret = mpage_prepare_extent_to_map(mpd);
/* Unlock pages we didn't use */
mpage_release_unused_pages(mpd, false);
/* Submit prepared bio */
ext4_io_submit(&mpd->io_submit);
ext4_put_io_end_defer(mpd->io_submit.io_end);
mpd->io_submit.io_end = NULL;
if (ret < 0)
goto unplug;
while (!mpd->scanned_until_end && wbc->nr_to_write > 0) {
/* For each extent of pages we use new io_end */
mpd->io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
if (!mpd->io_submit.io_end) {
ret = -ENOMEM;
break;
}
WARN_ON_ONCE(!mpd->can_map);
/*
* We have two constraints: We find one extent to map and we
* must always write out whole page (makes a difference when
* blocksize < pagesize) so that we don't block on IO when we
* try to write out the rest of the page. Journalled mode is
* not supported by delalloc.
*/
BUG_ON(ext4_should_journal_data(inode));
needed_blocks = ext4_da_writepages_trans_blocks(inode);
/* start a new transaction */
handle = ext4_journal_start_with_reserve(inode,
EXT4_HT_WRITE_PAGE, needed_blocks, rsv_blocks);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
"%ld pages, ino %lu; err %d", __func__,
wbc->nr_to_write, inode->i_ino, ret);
/* Release allocated io_end */
ext4_put_io_end(mpd->io_submit.io_end);
mpd->io_submit.io_end = NULL;
break;
}
mpd->do_map = 1;
trace_ext4_da_write_pages(inode, mpd->first_page, wbc);
ret = mpage_prepare_extent_to_map(mpd);
if (!ret && mpd->map.m_len)
ret = mpage_map_and_submit_extent(handle, mpd,
&give_up_on_write);
/*
* Caution: If the handle is synchronous,
* ext4_journal_stop() can wait for transaction commit
* to finish which may depend on writeback of pages to
* complete or on page lock to be released. In that
* case, we have to wait until after we have
* submitted all the IO, released page locks we hold,
* and dropped io_end reference (for extent conversion
* to be able to complete) before stopping the handle.
*/
if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
ext4_journal_stop(handle);
handle = NULL;
mpd->do_map = 0;
}
/* Unlock pages we didn't use */
mpage_release_unused_pages(mpd, give_up_on_write);
/* Submit prepared bio */
ext4_io_submit(&mpd->io_submit);
/*
* Drop our io_end reference we got from init. We have
* to be careful and use deferred io_end finishing if
* we are still holding the transaction as we can
* release the last reference to io_end which may end
* up doing unwritten extent conversion.
*/
if (handle) {
ext4_put_io_end_defer(mpd->io_submit.io_end);
ext4_journal_stop(handle);
} else
ext4_put_io_end(mpd->io_submit.io_end);
mpd->io_submit.io_end = NULL;
if (ret == -ENOSPC && sbi->s_journal) {
/*
* Commit the transaction which would
* free blocks released in the transaction
* and try again
*/
jbd2_journal_force_commit_nested(sbi->s_journal);
ret = 0;
continue;
}
/* Fatal error - ENOMEM, EIO... */
if (ret)
break;
}
unplug:
blk_finish_plug(&plug);
if (!ret && !cycled && wbc->nr_to_write > 0) {
cycled = 1;
mpd->last_page = writeback_index - 1;
mpd->first_page = 0;
goto retry;
}
/* Update index */
if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
/*
* Set the writeback_index so that range_cyclic
* mode will write it back later
*/
mapping->writeback_index = mpd->first_page;
out_writepages:
trace_ext4_writepages_result(inode, wbc, ret,
nr_to_write - wbc->nr_to_write);
return ret;
}
static int ext4_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct super_block *sb = mapping->host->i_sb;
struct mpage_da_data mpd = {
.inode = mapping->host,
.wbc = wbc,
.can_map = 1,
};
int ret;
int alloc_ctx;
if (unlikely(ext4_forced_shutdown(sb)))
return -EIO;
alloc_ctx = ext4_writepages_down_read(sb);
ret = ext4_do_writepages(&mpd);
/*
* For data=journal writeback we could have come across pages marked
* for delayed dirtying (PageChecked) which were just added to the
* running transaction. Try once more to get them to stable storage.
*/
if (!ret && mpd.journalled_more_data)
ret = ext4_do_writepages(&mpd);
ext4_writepages_up_read(sb, alloc_ctx);
return ret;
}
int ext4_normal_submit_inode_data_buffers(struct jbd2_inode *jinode)
{
struct writeback_control wbc = {
.sync_mode = WB_SYNC_ALL,
.nr_to_write = LONG_MAX,
.range_start = jinode->i_dirty_start,
.range_end = jinode->i_dirty_end,
};
struct mpage_da_data mpd = {
.inode = jinode->i_vfs_inode,
.wbc = &wbc,
.can_map = 0,
};
return ext4_do_writepages(&mpd);
}
static int ext4_dax_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
int ret;
long nr_to_write = wbc->nr_to_write;
struct inode *inode = mapping->host;
int alloc_ctx;
if (unlikely(ext4_forced_shutdown(inode->i_sb)))
return -EIO;
alloc_ctx = ext4_writepages_down_read(inode->i_sb);
trace_ext4_writepages(inode, wbc);
ret = dax_writeback_mapping_range(mapping,
EXT4_SB(inode->i_sb)->s_daxdev, wbc);
trace_ext4_writepages_result(inode, wbc, ret,
nr_to_write - wbc->nr_to_write);
ext4_writepages_up_read(inode->i_sb, alloc_ctx);
return ret;
}
static int ext4_nonda_switch(struct super_block *sb)
{
s64 free_clusters, dirty_clusters;
struct ext4_sb_info *sbi = EXT4_SB(sb);
/*
* switch to non delalloc mode if we are running low
* on free block. The free block accounting via percpu
* counters can get slightly wrong with percpu_counter_batch getting
* accumulated on each CPU without updating global counters
* Delalloc need an accurate free block accounting. So switch
* to non delalloc when we are near to error range.
*/
free_clusters =
percpu_counter_read_positive(&sbi->s_freeclusters_counter);
dirty_clusters =
percpu_counter_read_positive(&sbi->s_dirtyclusters_counter);
/*
* Start pushing delalloc when 1/2 of free blocks are dirty.
*/
if (dirty_clusters && (free_clusters < 2 * dirty_clusters))
try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
if (2 * free_clusters < 3 * dirty_clusters ||
free_clusters < (dirty_clusters + EXT4_FREECLUSTERS_WATERMARK)) {
/*
* free block count is less than 150% of dirty blocks
* or free blocks is less than watermark
*/
return 1;
}
return 0;
}
static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len,
struct page **pagep, void **fsdata)
{
int ret, retries = 0;
struct folio *folio;
pgoff_t index;
struct inode *inode = mapping->host;
if (unlikely(ext4_forced_shutdown(inode->i_sb)))
return -EIO;
index = pos >> PAGE_SHIFT;
if (ext4_nonda_switch(inode->i_sb) || ext4_verity_in_progress(inode)) {
*fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
return ext4_write_begin(file, mapping, pos,
len, pagep, fsdata);
}
*fsdata = (void *)0;
trace_ext4_da_write_begin(inode, pos, len);
if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
ret = ext4_da_write_inline_data_begin(mapping, inode, pos, len,
pagep, fsdata);
if (ret < 0)
return ret;
if (ret == 1)
return 0;
}
retry:
folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
mapping_gfp_mask(mapping));
if (IS_ERR(folio))
return PTR_ERR(folio);
#ifdef CONFIG_FS_ENCRYPTION
ret = ext4_block_write_begin(folio, pos, len, ext4_da_get_block_prep);
#else
ret = __block_write_begin(&folio->page, pos, len, ext4_da_get_block_prep);
#endif
if (ret < 0) {
folio_unlock(folio);
folio_put(folio);
/*
* block_write_begin may have instantiated a few blocks
* outside i_size. Trim these off again. Don't need
* i_size_read because we hold inode lock.
*/
if (pos + len > inode->i_size)
ext4_truncate_failed_write(inode);
if (ret == -ENOSPC &&
ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry;
return ret;
}
*pagep = &folio->page;
return ret;
}
/*
* Check if we should update i_disksize
* when write to the end of file but not require block allocation
*/
static int ext4_da_should_update_i_disksize(struct folio *folio,
unsigned long offset)
{
struct buffer_head *bh;
struct inode *inode = folio->mapping->host;
unsigned int idx;
int i;
bh = folio_buffers(folio);
idx = offset >> inode->i_blkbits;
for (i = 0; i < idx; i++)
bh = bh->b_this_page;
if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
return 0;
return 1;
}
static int ext4_da_do_write_end(struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct folio *folio)
{
struct inode *inode = mapping->host;
loff_t old_size = inode->i_size;
bool disksize_changed = false;
loff_t new_i_size;
if (unlikely(!folio_buffers(folio))) {
folio_unlock(folio);
folio_put(folio);
return -EIO;
}
/*
* block_write_end() will mark the inode as dirty with I_DIRTY_PAGES
* flag, which all that's needed to trigger page writeback.
*/
copied = block_write_end(NULL, mapping, pos, len, copied,
&folio->page, NULL);
new_i_size = pos + copied;
/*
* It's important to update i_size while still holding folio lock,
* because folio writeout could otherwise come in and zero beyond
* i_size.
*
* Since we are holding inode lock, we are sure i_disksize <=
* i_size. We also know that if i_disksize < i_size, there are
* delalloc writes pending in the range up to i_size. If the end of
* the current write is <= i_size, there's no need to touch
* i_disksize since writeback will push i_disksize up to i_size
* eventually. If the end of the current write is > i_size and
* inside an allocated block which ext4_da_should_update_i_disksize()
* checked, we need to update i_disksize here as certain
* ext4_writepages() paths not allocating blocks and update i_disksize.
*/
if (new_i_size > inode->i_size) {
unsigned long end;
i_size_write(inode, new_i_size);
end = (new_i_size - 1) & (PAGE_SIZE - 1);
if (copied && ext4_da_should_update_i_disksize(folio, end)) {
ext4_update_i_disksize(inode, new_i_size);
disksize_changed = true;
}
}
folio_unlock(folio);
folio_put(folio);
if (old_size < pos)
pagecache_isize_extended(inode, old_size, pos);
if (disksize_changed) {
handle_t *handle;
handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle))
return PTR_ERR(handle);
ext4_mark_inode_dirty(handle, inode);
ext4_journal_stop(handle);
}
return copied;
}
static int ext4_da_write_end(struct file *file,
struct address_space *mapping,