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inode.c
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// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/ext4/inode.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card ([email protected])
* 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
*
* Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
*/
#include <linux/fs.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>
#define MPAGE_DA_EXTENT_TAIL 0x01
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;
}
static 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 void ext4_invalidatepage(struct page *page, unsigned int offset,
unsigned int length);
static int __ext4_journalled_writepage(struct page *page, unsigned int len);
static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
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;
trace_ext4_evict_inode(inode);
if (inode->i_nlink) {
/*
* When journalling data dirty buffers are tracked only in the
* journal. So although mm thinks everything is clean and
* ready for reaping the inode might still have some pages to
* write in the running transaction or waiting to be
* checkpointed. Thus calling jbd2_journal_invalidatepage()
* (via truncate_inode_pages()) to discard these buffers can
* cause data loss. Also even if we did not discard these
* buffers, we would have no way to find them after the inode
* is reaped and thus user could see stale data if he tries to
* read them before the transaction is checkpointed. So be
* careful and force everything to disk here... We use
* ei->i_datasync_tid to store the newest transaction
* containing inode's data.
*
* Note that directories do not have this problem because they
* don't use page cache.
*/
if (inode->i_ino != EXT4_JOURNAL_INO &&
ext4_should_journal_data(inode) &&
(S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
inode->i_data.nrpages) {
journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
tid_t commit_tid = EXT4_I(inode)->i_datasync_tid;
jbd2_complete_transaction(journal, commit_tid);
filemap_write_and_wait(&inode->i_data);
}
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);
/*
* Protect us against freezing - iput() caller didn't have to have any
* protection against it
*/
sb_start_intwrite(inode->i_sb);
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);
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(inode->i_sb,
"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);
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);
sb_end_intwrite(inode->i_sb);
ext4_xattr_inode_array_free(ea_inode_array);
return;
no_delete:
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(&EXT4_I(inode)->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_data_block_valid(EXT4_SB(inode->i_sb), 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))
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, flags &
EXT4_GET_BLOCKS_KEEP_SIZE);
} else {
retval = ext4_ind_map_blocks(handle, inode, map, flags &
EXT4_GET_BLOCKS_KEEP_SIZE);
}
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 */
/*
* 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
* create==0 and the blocks are pre-allocated and unwritten, the resulting @map
* is marked as unwritten. If the create == 1, 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("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u,"
"logical block %lu\n", inode->i_ino, 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_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;
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();
}
#ifdef ES_AGGRESSIVE_TEST
ext4_map_blocks_es_recheck(handle, inode, map,
&orig_map, flags);
#endif
goto found;
}
/*
* 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, flags &
EXT4_GET_BLOCKS_KEEP_SIZE);
} else {
retval = ext4_ind_map_blocks(handle, inode, map, flags &
EXT4_GET_BLOCKS_KEEP_SIZE);
}
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;
ret = ext4_es_insert_extent(inode, map->m_lblk,
map->m_len, map->m_pblk, status);
if (ret < 0)
retval = ret;
}
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_get_block() returns the create = 0
* 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);
}
/*
* Update reserved blocks/metadata blocks after successful
* block allocation which had been deferred till now. We don't
* support fallocate for non extent files. So we can update
* reserve space here.
*/
if ((retval > 0) &&
(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE))
ext4_da_update_reserve_space(inode, retval, 1);
}
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;
ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
map->m_pblk, status);
if (ret < 0) {
retval = ret;
goto out_sem;
}
}
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;
}
}
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.
*/
do {
old_state = READ_ONCE(bh->b_state);
new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
} while (unlikely(
cmpxchg(&bh->b_state, old_state, new_state) != old_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)
{
ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
inode->i_ino, create);
return _ext4_get_block(inode, iblock, bh_result,
EXT4_GET_BLOCKS_IO_CREATE_EXT);
}
/* 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;
int err;
J_ASSERT(handle != NULL || create == 0);
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);
bh = sb_getblk(inode->i_sb, map.m_pblk);
if (unlikely(!bh))
return ERR_PTR(-ENOMEM);
if (map.m_flags & EXT4_MAP_NEW) {
J_ASSERT(create != 0);
J_ASSERT(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, bh);
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;
bh = ext4_getblk(handle, inode, block, map_flags);
if (IS_ERR(bh))
return bh;
if (!bh || ext4_buffer_uptodate(bh))
return bh;
ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1, &bh);
wait_on_buffer(bh);
if (buffer_uptodate(bh))
return bh;
put_bh(bh);
return ERR_PTR(-EIO);
}
/* 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]))
ll_rw_block(REQ_OP_READ, REQ_META | REQ_PRIO, 1,
&bhs[i]);
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 buffer_head *head,
unsigned from,
unsigned to,
int *partial,
int (*fn)(handle_t *handle,
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, bh);
if (!ret)
ret = err;
}
return ret;
}
/*
* 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 commit_write(). So doing the jbd2_journal_start at the start of
* prepare_write() is the right place.
*
* Also, this function can nest inside ext4_writepage(). In that case, we
* *know* that ext4_writepage() has generated enough buffer credits to do the
* whole page. So we won't block on the journal in that case, which is good,
* because the caller may be PF_MEMALLOC.
*
* By accident, ext4 can be reentered when a transaction is open via
* quota file writes. If we were to commit the transaction while thus
* reentered, there can be a deadlock - we would be holding a quota
* lock, and the commit would never complete if another thread had a
* transaction open and was blocking on the quota lock - a ranking
* violation.
*
* So what we do is to rely on the fact that jbd2_journal_stop/journal_start
* will _not_ run commit under these circumstances because handle->h_ref
* is elevated. We'll still have enough credits for the tiny quotafile
* write.
*/
int do_journal_get_write_access(handle_t *handle,
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