| /* |
| * 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/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 "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); |
| __u16 csum_lo; |
| __u16 csum_hi = 0; |
| __u32 csum; |
| |
| csum_lo = le16_to_cpu(raw->i_checksum_lo); |
| raw->i_checksum_lo = 0; |
| if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE && |
| EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) { |
| csum_hi = le16_to_cpu(raw->i_checksum_hi); |
| raw->i_checksum_hi = 0; |
| } |
| |
| csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw, |
| EXT4_INODE_SIZE(inode->i_sb)); |
| |
| raw->i_checksum_lo = cpu_to_le16(csum_lo); |
| 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_hi); |
| |
| 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. |
| */ |
| int ext4_inode_is_fast_symlink(struct inode *inode) |
| { |
| 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); |
| } |
| |
| /* |
| * Restart the transaction associated with *handle. This does a commit, |
| * so before we call here everything must be consistently dirtied against |
| * this transaction. |
| */ |
| int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode, |
| int nblocks) |
| { |
| int ret; |
| |
| /* |
| * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this |
| * moment, get_block can be called only for blocks inside i_size since |
| * page cache has been already dropped and writes are blocked by |
| * i_mutex. So we can safely drop the i_data_sem here. |
| */ |
| BUG_ON(EXT4_JOURNAL(inode) == NULL); |
| jbd_debug(2, "restarting handle %p\n", handle); |
| up_write(&EXT4_I(inode)->i_data_sem); |
| ret = ext4_journal_restart(handle, nblocks); |
| down_write(&EXT4_I(inode)->i_data_sem); |
| ext4_discard_preallocations(inode); |
| |
| return ret; |
| } |
| |
| /* |
| * Called at the last iput() if i_nlink is zero. |
| */ |
| void ext4_evict_inode(struct inode *inode) |
| { |
| handle_t *handle; |
| int err; |
| |
| 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 (ext4_should_journal_data(inode) && |
| (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) && |
| inode->i_ino != EXT4_JOURNAL_INO) { |
| 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); |
| handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, |
| ext4_blocks_for_truncate(inode)+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); |
| 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) |
| ext4_truncate(inode); |
| |
| /* |
| * ext4_ext_truncate() doesn't reserve any slop when it |
| * restarts journal transactions; therefore there may not be |
| * enough credits left in the handle to remove the inode from |
| * the orphan list and set the dtime field. |
| */ |
| if (!ext4_handle_has_enough_credits(handle, 3)) { |
| err = ext4_journal_extend(handle, 3); |
| if (err > 0) |
| err = ext4_journal_restart(handle, 3); |
| if (err != 0) { |
| ext4_warning(inode->i_sb, |
| "couldn't extend journal (err %d)", err); |
| stop_handle: |
| ext4_journal_stop(handle); |
| ext4_orphan_del(NULL, inode); |
| sb_end_intwrite(inode->i_sb); |
| 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 = get_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); |
| 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) && |
| (atomic_read(&inode->i_writecount) == 0)) |
| 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_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 " |
| "(length %d)", (unsigned long) map->m_lblk, |
| 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 (ext4_encrypted_inode(inode)) |
| return ext4_encrypted_zeroout(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, &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_ON(1); |
| } |
| #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_find_delalloc_range(inode, 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. |
| */ |
| 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, &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_find_delalloc_range(inode, 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) && |
| !IS_NOQUOTA(inode) && |
| ext4_should_order_data(inode)) { |
| if (flags & EXT4_GET_BLOCKS_IO_SUBMIT) |
| ret = ext4_jbd2_inode_add_wait(handle, inode); |
| else |
| ret = ext4_jbd2_inode_add_write(handle, inode); |
| 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; |
| } |
| 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 |
| |
| /* |
| * Get blocks function for the cases that need to start a transaction - |
| * generally difference cases of direct IO and DAX IO. It also handles retries |
| * in case of ENOSPC. |
| */ |
| static int ext4_get_block_trans(struct inode *inode, sector_t iblock, |
| struct buffer_head *bh_result, int flags) |
| { |
| int dio_credits; |
| handle_t *handle; |
| int retries = 0; |
| int ret; |
| |
| /* Trim mapping request to maximum we can map at once for DIO */ |
| if (bh_result->b_size >> inode->i_blkbits > DIO_MAX_BLOCKS) |
| bh_result->b_size = DIO_MAX_BLOCKS << inode->i_blkbits; |
| dio_credits = ext4_chunk_trans_blocks(inode, |
| bh_result->b_size >> inode->i_blkbits); |
| retry: |
| handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits); |
| if (IS_ERR(handle)) |
| return PTR_ERR(handle); |
| |
| ret = _ext4_get_block(inode, iblock, bh_result, flags); |
| ext4_journal_stop(handle); |
| |
| if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) |
| goto retry; |
| return ret; |
| } |
| |
| /* Get block function for DIO reads and writes to inodes without extents */ |
| int ext4_dio_get_block(struct inode *inode, sector_t iblock, |
| struct buffer_head *bh, int create) |
| { |
| /* We don't expect handle for direct IO */ |
| WARN_ON_ONCE(ext4_journal_current_handle()); |
| |
| if (!create) |
| return _ext4_get_block(inode, iblock, bh, 0); |
| return ext4_get_block_trans(inode, iblock, bh, EXT4_GET_BLOCKS_CREATE); |
| } |
| |
| /* |
| * Get block function for AIO DIO writes when we create unwritten extent if |
| * blocks are not allocated yet. The extent will be converted to written |
| * after IO is complete. |
| */ |
| static int ext4_dio_get_block_unwritten_async(struct inode *inode, |
| sector_t iblock, struct buffer_head *bh_result, int create) |
| { |
| int ret; |
| |
| /* We don't expect handle for direct IO */ |
| WARN_ON_ONCE(ext4_journal_current_handle()); |
| |
| ret = ext4_get_block_trans(inode, iblock, bh_result, |
| EXT4_GET_BLOCKS_IO_CREATE_EXT); |
| |
| /* |
| * When doing DIO using unwritten extents, we need io_end to convert |
| * unwritten extents to written on IO completion. We allocate io_end |
| * once we spot unwritten extent and store it in b_private. Generic |
| * DIO code keeps b_private set and furthermore passes the value to |
| * our completion callback in 'private' argument. |
| */ |
| if (!ret && buffer_unwritten(bh_result)) { |
| if (!bh_result->b_private) { |
| ext4_io_end_t *io_end; |
| |
| io_end = ext4_init_io_end(inode, GFP_KERNEL); |
| if (!io_end) |
| return -ENOMEM; |
| bh_result->b_private = io_end; |
| ext4_set_io_unwritten_flag(inode, io_end); |
| } |
| set_buffer_defer_completion(bh_result); |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * Get block function for non-AIO DIO writes when we create unwritten extent if |
| * blocks are not allocated yet. The extent will be converted to written |
| * after IO is complete from ext4_ext_direct_IO() function. |
| */ |
| static int ext4_dio_get_block_unwritten_sync(struct inode *inode, |
| sector_t iblock, struct buffer_head *bh_result, int create) |
| { |
| int ret; |
| |
| /* We don't expect handle for direct IO */ |
| WARN_ON_ONCE(ext4_journal_current_handle()); |
| |
| ret = ext4_get_block_trans(inode, iblock, bh_result, |
| EXT4_GET_BLOCKS_IO_CREATE_EXT); |
| |
| /* |
| * Mark inode as having pending DIO writes to unwritten extents. |
| * ext4_ext_direct_IO() checks this flag and converts extents to |
| * written. |
| */ |
| if (!ret && buffer_unwritten(bh_result)) |
| ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); |
| |
| return ret; |
| } |
| |
| static int ext4_dio_get_block_overwrite(struct inode *inode, sector_t iblock, |
| struct buffer_head *bh_result, int create) |
| { |
| int ret; |
| |
| ext4_debug("ext4_dio_get_block_overwrite: inode %lu, create flag %d\n", |
| inode->i_ino, create); |
| /* We don't expect handle for direct IO */ |
| WARN_ON_ONCE(ext4_journal_current_handle()); |
| |
| ret = _ext4_get_block(inode, iblock, bh_result, 0); |
| /* |
| * Blocks should have been preallocated! ext4_file_write_iter() checks |
| * that. |
| */ |
| WARN_ON_ONCE(!buffer_mapped(bh_result) || buffer_unwritten(bh_result)); |
| |
| return ret; |
| } |
| |
| |
| /* |
| * `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 || buffer_uptodate(bh)) |
| return bh; |
| ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh); |
| wait_on_buffer(bh); |
| if (buffer_uptodate(bh)) |
| return bh; |
| put_bh(bh); |
| return ERR_PTR(-EIO); |
| } |
| |
| 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 |
| * 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, bh); |
| if (!ret && dirty) |
| ret = ext4_handle_dirty_metadata(handle, NULL, bh); |
| return ret; |
| } |
| |
| #ifdef CONFIG_EXT4_FS_ENCRYPTION |
| static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len, |
| get_block_t *get_block) |
| { |
| unsigned from = pos & (PAGE_SIZE - 1); |
| unsigned to = from + len; |
| struct inode *inode = page->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], **wait_bh = wait; |
| bool decrypt = false; |
| |
| BUG_ON(!PageLocked(page)); |
| BUG_ON(from > PAGE_SIZE); |
| BUG_ON(to > PAGE_SIZE); |
| BUG_ON(from > to); |
| |
| if (!page_has_buffers(page)) |
| create_empty_buffers(page, blocksize, 0); |
| head = page_buffers(page); |
| bbits = ilog2(blocksize); |
| block = (sector_t)page->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 (PageUptodate(page)) { |
| if (!buffer_uptodate(bh)) |
| 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)) { |
| unmap_underlying_metadata(bh->b_bdev, |
| bh->b_blocknr); |
| if (PageUptodate(page)) { |
| clear_buffer_new(bh); |
| set_buffer_uptodate(bh); |
| mark_buffer_dirty(bh); |
| continue; |
| } |
| if (block_end > to || block_start < from) |
| zero_user_segments(page, to, block_end, |
| block_start, from); |
| continue; |
| } |
| } |
| if (PageUptodate(page)) { |
| if (!buffer_uptodate(bh)) |
| set_buffer_uptodate(bh); |
| continue; |
| } |
| if (!buffer_uptodate(bh) && !buffer_delay(bh) && |
| !buffer_unwritten(bh) && |
| (block_start < from || block_end > to)) { |
| ll_rw_block(READ, 1, &bh); |
| *wait_bh++ = bh; |
| decrypt = ext4_encrypted_inode(inode) && |
| S_ISREG(inode->i_mode); |
| } |
| } |
| /* |
| * If we issued read requests, let them complete. |
| */ |
| while (wait_bh > wait) { |
| wait_on_buffer(*--wait_bh); |
| if (!buffer_uptodate(*wait_bh)) |
| err = -EIO; |
| } |
| if (unlikely(err)) |
| page_zero_new_buffers(page, from, to); |
| else if (decrypt) |
| err = ext4_decrypt(page); |
| return err; |
| } |
| #endif |
| |
| static int ext4_write_begin(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned flags, |
| struct page **pagep, void **fsdata) |
| { |
| struct inode *inode = mapping->host; |
| int ret, needed_blocks; |
| handle_t *handle; |
| int retries = 0; |
| struct page *page; |
| pgoff_t index; |
| unsigned from, to; |
| |
| trace_ext4_write_begin(inode, pos, len, flags); |
| /* |
| * 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, |
| flags, pagep); |
| if (ret < 0) |
| return ret; |
| if (ret == 1) |
| return 0; |
| } |
| |
| /* |
| * grab_cache_page_write_begin() can take a long time if the |
| * system is thrashing due to memory pressure, or if the page |
| * is being written back. So grab it first before we start |
| * the transaction handle. This also allows us to allocate |
| * the page (if needed) without using GFP_NOFS. |
| */ |
| retry_grab: |
| page = grab_cache_page_write_begin(mapping, index, flags); |
| if (!page) |
| return -ENOMEM; |
| unlock_page(page); |
| |
| retry_journal: |
| handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks); |
| if (IS_ERR(handle)) { |
| put_page(page); |
| return PTR_ERR(handle); |
| } |
| |
| lock_page(page); |
| if (page->mapping != mapping) { |
| /* The page got truncated from under us */ |
| unlock_page(page); |
| put_page(page); |
| ext4_journal_stop(handle); |
| goto retry_grab; |
| } |
| /* In case writeback began while the page was unlocked */ |
| wait_for_stable_page(page); |
| |
| #ifdef CONFIG_EXT4_FS_ENCRYPTION |
| if (ext4_should_dioread_nolock(inode)) |
| ret = ext4_block_write_begin(page, pos, len, |
| ext4_get_block_unwritten); |
| else |
| ret = ext4_block_write_begin(page, pos, len, |
| ext4_get_block); |
| #else |
| if (ext4_should_dioread_nolock(inode)) |
| ret = __block_write_begin(page, pos, len, |
| ext4_get_block_unwritten); |
| else |
| ret = __block_write_begin(page, pos, len, ext4_get_block); |
| #endif |
| if (!ret && ext4_should_journal_data(inode)) { |
| ret = ext4_walk_page_buffers(handle, page_buffers(page), |
| from, to, NULL, |
| do_journal_get_write_access); |
| } |
| |
| if (ret) { |
| unlock_page(page); |
| /* |
| * __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_mutex. |
| * |
| * Add inode to orphan list in case we crash before |
| * truncate finishes |
| */ |
| if (pos + len > inode->i_size && ext4_can_truncate(inode)) |
| ext4_orphan_add(handle, inode); |
| |
| ext4_journal_stop(handle); |
| if (pos + len > inode->i_size) { |
| 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; |
| put_page(page); |
| return ret; |
| } |
| *pagep = page; |
| return ret; |
| } |
| |
| /* For write_end() in data=journal mode */ |
| static int write_end_fn(handle_t *handle, struct buffer_head *bh) |
| { |
| int ret; |
| if (!buffer_mapped(bh) || buffer_freed(bh)) |
| return 0; |
| set_buffer_uptodate(bh); |
| ret = ext4_handle_dirty_metadata(handle, NULL, 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->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) |
| { |
| 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; |
| |
| trace_ext4_write_end(inode, pos, len, copied); |
| if (ext4_has_inline_data(inode)) { |
| ret = ext4_write_inline_data_end(inode, pos, len, |
| copied, page); |
| if (ret < 0) |
| goto errout; |
| copied = ret; |
| } else |
| copied = block_write_end(file, mapping, pos, |
| len, copied, page, fsdata); |
| /* |
| * it's important to update i_size while still holding page lock: |
| * page writeout could otherwise come in and zero beyond i_size. |
| */ |
| i_size_changed = ext4_update_inode_size(inode, pos + copied); |
| unlock_page(page); |
| put_page(page); |
| |
| if (old_size < pos) |
| pagecache_isize_extended(inode, old_size, pos); |
| /* |
| * Don't mark the inode dirty under page lock. First, it unnecessarily |
| * makes the holding time of page lock longer. Second, it forces lock |
| * ordering of page lock and transaction start for journaling |
| * filesystems. |
| */ |
| if (i_size_changed) |
| ext4_mark_inode_dirty(handle, inode); |
| |
| if (pos + len > inode->i_size && 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); |
| errout: |
| ret2 = ext4_journal_stop(handle); |
| if (!ret) |
| ret = ret2; |
| |
| if (pos + len > inode->i_size) { |
| 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 page_zero_new_buffers() which doesn't |
| * set the buffer to be dirty, since in data=journalled mode we need |
| * to call ext4_handle_dirty_metadata() instead. |
| */ |
| static void zero_new_buffers(struct page *page, unsigned from, unsigned to) |
| { |
| unsigned int block_start = 0, block_end; |
| struct buffer_head *head, *bh; |
| |
| bh = head = page_buffers(page); |
| do { |
| block_end = block_start + bh->b_size; |
| if (buffer_new(bh)) { |
| if (block_end > from && block_start < to) { |
| if (!PageUptodate(page)) { |
| unsigned start, size; |
| |
| start = max(from, block_start); |
| size = min(to, block_end) - start; |
| |
| zero_user(page, start, size); |
| set_buffer_uptodate(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) |
| { |
| 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; |
| |
| 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)) |
| copied = ext4_write_inline_data_end(inode, pos, len, |
| copied, page); |
| else { |
| if (copied < len) { |
| if (!PageUptodate(page)) |
| copied = 0; |
| zero_new_buffers(page, from+copied, to); |
| } |
| |
| ret = ext4_walk_page_buffers(handle, page_buffers(page), from, |
| to, &partial, write_end_fn); |
| if (!partial) |
| SetPageUptodate(page); |
| } |
| size_changed = ext4_update_inode_size(inode, pos + copied); |
| ext4_set_inode_state(inode, EXT4_STATE_JDATA); |
| EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid; |
| unlock_page(page); |
| put_page(page); |
| |
| if (old_size < pos) |
| 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 && 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) { |
| 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 a single cluster |
| */ |
| static int ext4_da_reserve_space(struct inode *inode) |
| { |
| 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, 1)); |
| if (ret) |
| return ret; |
| |
| spin_lock(&ei->i_block_reservation_lock); |
| if (ext4_claim_free_clusters(sbi, 1, 0)) { |
| spin_unlock(&ei->i_block_reservation_lock); |
| dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1)); |
| return -ENOSPC; |
| } |
| ei->i_reserved_data_blocks++; |
| trace_ext4_da_reserve_space(inode); |
| spin_unlock(&ei->i_block_reservation_lock); |
| |
| return 0; /* success */ |
| } |
| |
| static 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)); |
| } |
| |
| static void ext4_da_page_release_reservation(struct page *page, |
| unsigned int offset, |
| unsigned int length) |
| { |
| int to_release = 0, contiguous_blks = 0; |
| struct buffer_head *head, *bh; |
| unsigned int curr_off = 0; |
| struct inode *inode = page->mapping->host; |
| struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); |
| unsigned int stop = offset + length; |
| int num_clusters; |
| ext4_fsblk_t lblk; |
| |
| BUG_ON(stop > PAGE_SIZE || stop < length); |
| |
| head = page_buffers(page); |
| bh = head; |
| do { |
| unsigned int next_off = curr_off + bh->b_size; |
| |
| if (next_off > stop) |
| break; |
| |
| if ((offset <= curr_off) && (buffer_delay(bh))) { |
| to_release++; |
| contiguous_blks++; |
| clear_buffer_delay(bh); |
| } else if (contiguous_blks) { |
| lblk = page->index << |
| (PAGE_SHIFT - inode->i_blkbits); |
| lblk += (curr_off >> inode->i_blkbits) - |
| contiguous_blks; |
| ext4_es_remove_extent(inode, lblk, contiguous_blks); |
| contiguous_blks = 0; |
| } |
| curr_off = next_off; |
| } while ((bh = bh->b_this_page) != head); |
| |
| if (contiguous_blks) { |
| lblk = page->index << (PAGE_SHIFT - inode->i_blkbits); |
| lblk += (curr_off >> inode->i_blkbits) - contiguous_blks; |
| ext4_es_remove_extent(inode, lblk, contiguous_blks); |
| } |
| |
| /* If we have released all the blocks belonging to a cluster, then we |
| * need to release the reserved space for that cluster. */ |
| num_clusters = EXT4_NUM_B2C(sbi, to_release); |
| while (num_clusters > 0) { |
| lblk = (page->index << (PAGE_SHIFT - inode->i_blkbits)) + |
| ((num_clusters - 1) << sbi->s_cluster_bits); |
| if (sbi->s_cluster_ratio == 1 || |
| !ext4_find_delalloc_cluster(inode, lblk)) |
| ext4_da_release_space(inode, 1); |
| |
| num_clusters--; |
| } |
| } |
| |
| /* |
| * Delayed allocation stuff |
| */ |
| |
| struct mpage_da_data { |
| struct inode *inode; |
| struct writeback_control *wbc; |
| |
| 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 */ |
| }; |
| |
| static void mpage_release_unused_pages(struct mpage_da_data *mpd, |
| bool invalidate) |
| { |
| int nr_pages, i; |
| pgoff_t index, end; |
| struct pagevec pvec; |
| 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; |
| |
| 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); |
| ext4_es_remove_extent(inode, start, last - start + 1); |
| } |
| |
| pagevec_init(&pvec, 0); |
| while (index <= end) { |
| nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE); |
| if (nr_pages == 0) |
| break; |
| for (i = 0; i < nr_pages; i++) { |
| struct page *page = pvec.pages[i]; |
| if (page->index > end) |
| break; |
| BUG_ON(!PageLocked(page)); |
| BUG_ON(PageWriteback(page)); |
| if (invalidate) { |
| block_invalidatepage(page, 0, PAGE_SIZE); |
| ClearPageUptodate(page); |
| } |
| unlock_page(page); |
| } |
| index = pvec.pages[nr_pages - 1]->index + 1; |
| pagevec_release(&pvec); |
| } |
| } |
| |
| 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; |
| } |
| |
| static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh) |
| { |
| return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh); |
| } |
| |
| /* |
| * This function is grabs code from the very beginning of |
| * ext4_map_blocks, but assumes that the caller is from delayed write |
| * time. This function looks up the requested blocks and sets the |
| * buffer delay bit under the protection of i_data_sem. |
| */ |
| static int ext4_da_map_blocks(struct inode *inode, sector_t iblock, |
| struct ext4_map_blocks *map, |
| struct buffer_head *bh) |
| { |
| struct extent_status es; |
| int retval; |
| sector_t invalid_block = ~((sector_t) 0xffff); |
| #ifdef ES_AGGRESSIVE_TEST |
| struct ext4_map_blocks orig_map; |
| |
| memcpy(&orig_map, map, sizeof(*map)); |
| #endif |
| |
| if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es)) |
| invalid_block = ~0; |
| |
| map->m_flags = 0; |
| ext_debug("ext4_da_map_blocks(): inode %lu, max_blocks %u," |
| "logical block %lu\n", inode->i_ino, map->m_len, |
| (unsigned long) map->m_lblk); |
| |
| /* Lookup extent status tree firstly */ |
| if (ext4_es_lookup_extent(inode, iblock, &es)) { |
| if (ext4_es_is_hole(&es)) { |
| retval = 0; |
| down_read(&EXT4_I(inode)->i_data_sem); |
| goto add_delayed; |
| } |
| |
| /* |
| * Delayed extent could be allocated by fallocate. |
| * So we need to check it. |
| */ |
| if (ext4_es_is_delayed(&es) && !ext4_es_is_unwritten(&es)) { |
| map_bh(bh, inode->i_sb, invalid_block); |
| set_buffer_new(bh); |
| set_buffer_delay(bh); |
| return 0; |
| } |
| |
| map->m_pblk = ext4_es_pblock(&es) + iblock - es.es_lblk; |
| retval = es.es_len - (iblock - es.es_lblk); |
| if (retval > map->m_len) |
| retval = map->m_len; |
| map->m_len = retval; |
| 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_ON(1); |
| |
| #ifdef ES_AGGRESSIVE_TEST |
| ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0); |
| #endif |
| return retval; |
| } |
| |
| /* |
| * 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 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) |
| retval = ext4_ext_map_blocks(NULL, inode, map, 0); |
| else |
| retval = ext4_ind_map_blocks(NULL, inode, map, 0); |
| |
| add_delayed: |
| if (retval == 0) { |
| int ret; |
| /* |
| * XXX: __block_prepare_write() unmaps passed block, |
| * is it OK? |
| */ |
| /* |
| * If the block was allocated from previously allocated cluster, |
| * then we don't need to reserve it again. However we still need |
| * to reserve metadata for every block we're going to write. |
| */ |
| if (EXT4_SB(inode->i_sb)->s_cluster_ratio == 1 || |
| !ext4_find_delalloc_cluster(inode, map->m_lblk)) { |
| ret = ext4_da_reserve_space(inode); |
| if (ret) { |
| /* not enough space to reserve */ |
| retval = ret; |
| goto out_unlock; |
| } |
| } |
| |
| ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len, |
| ~0, EXTENT_STATUS_DELAYED); |
| if (ret) { |
| retval = ret; |
| goto out_unlock; |
| } |
| |
| map_bh(bh, inode->i_sb, invalid_block); |
| set_buffer_new(bh); |
| set_buffer_delay(bh); |
| } else if (retval > 0) { |
| int ret; |
| 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; |
| ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len, |
| map->m_pblk, status); |
| if (ret != 0) |
| retval = ret; |
| } |
| |
| out_unlock: |
| up_read((&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; |
| int ret = 0; |
| |
| BUG_ON(create == 0); |
| BUG_ON(bh->b_size != inode->i_sb->s_blocksize); |
| |
| 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, iblock, &map, bh); |
| if (ret <= 0) |
| return ret; |
| |
| 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 int bget_one(handle_t *handle, struct buffer_head *bh) |
| { |
| get_bh(bh); |
| return 0; |
| } |
| |
| static int bput_one(handle_t *handle, struct buffer_head *bh) |
| { |
| put_bh(bh); |
| return 0; |
| } |
| |
| static int __ext4_journalled_writepage(struct page *page, |
| unsigned int len) |
| { |
| struct address_space *mapping = page->mapping; |
| struct inode *inode = mapping->host; |
| struct buffer_head *page_bufs = NULL; |
| handle_t *handle = NULL; |
| int ret = 0, err = 0; |
| int inline_data = ext4_has_inline_data(inode); |
| struct buffer_head *inode_bh = NULL; |
| |
| ClearPageChecked(page); |
| |
| if (inline_data) { |
| BUG_ON(page->index != 0); |
| BUG_ON(len > ext4_get_max_inline_size(inode)); |
| inode_bh = ext4_journalled_write_inline_data(inode, len, page); |
| if (inode_bh == NULL) |
| goto out; |
| } else { |
| page_bufs = page_buffers(page); |
| if (!page_bufs) { |
| BUG(); |
| goto out; |
| } |
| ext4_walk_page_buffers(handle, page_bufs, 0, len, |
| NULL, bget_one); |
| } |
| /* |
| * We need to release the page lock before we start the |
| * journal, so grab a reference so the page won't disappear |
| * out from under us. |
| */ |
| get_page(page); |
| unlock_page(page); |
| |
| handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, |
| ext4_writepage_trans_blocks(inode)); |
| if (IS_ERR(handle)) { |
| ret = PTR_ERR(handle); |
| put_page(page); |
| goto out_no_pagelock; |
| } |
| BUG_ON(!ext4_handle_valid(handle)); |
| |
| lock_page(page); |
| put_page(page); |
| if (page->mapping != mapping) { |
| /* The page got truncated from under us */ |
| ext4_journal_stop(handle); |
| ret = 0; |
| goto out; |
| } |
| |
| if (inline_data) { |
| BUFFER_TRACE(inode_bh, "get write access"); |
| ret = ext4_journal_get_write_access(handle, inode_bh); |
| |
| err = ext4_handle_dirty_metadata(handle, inode, inode_bh); |
| |
| } else { |
| ret = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL, |
| do_journal_get_write_access); |
| |
| err = ext4_walk_page_buffers(handle, page_bufs, 0, len, NULL, |
| write_end_fn); |
| } |
| if (ret == 0) |
| ret = err; |
| EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid; |
| err = ext4_journal_stop(handle); |
| if (!ret) |
| ret = err; |
| |
| if (!ext4_has_inline_data(inode)) |
| ext4_walk_page_buffers(NULL, page_bufs, 0, len, |
| NULL, bput_one); |
| ext4_set_inode_state(inode, EXT4_STATE_JDATA); |
| out: |
| unlock_page(page); |
| out_no_pagelock: |
| brelse(inode_bh); |
| return ret; |
| } |
| |
| /* |
| * Note that we don't need to start a transaction unless we're journaling data |
| * because we should have holes filled from ext4_page_mkwrite(). We even don't |
| * need to file the inode to the transaction's list in ordered mode because if |
| * we are writing back data added by write(), the inode is already there and if |
| * we are writing back data modified via mmap(), no one guarantees in which |
| * transaction the data will hit the disk. In case we are journaling data, we |
| * cannot start transaction directly because transaction start ranks above page |
| * lock so we have to do some magic. |
| * |
| * This function can get called via... |
| * - ext4_writepages after taking page lock (have journal handle) |
| * - journal_submit_inode_data_buffers (no journal handle) |
| * - shrink_page_list via the kswapd/direct reclaim (no journal handle) |
| * - grab_page_cache when doing write_begin (have journal handle) |
| * |
| * We don't do any block allocation in this function. If we have page with |
| * multiple blocks we need to write those buffer_heads that are mapped. This |
| * is important for mmaped based write. So if we do with blocksize 1K |
| * truncate(f, 1024); |
| * a = mmap(f, 0, 4096); |
| * a[0] = 'a'; |
| * truncate(f, 4096); |
| * we have in the page first buffer_head mapped via page_mkwrite call back |
| * but other buffer_heads would be unmapped but dirty (dirty done via the |
| * do_wp_page). So writepage should write the first block. If we modify |
| * the mmap area beyond 1024 we will again get a page_fault and the |
| * page_mkwrite callback will do the block allocation and mark the |
| * buffer_heads mapped. |
| * |
| * We redirty the page if we have any buffer_heads that is either delay or |
| * unwritten in the page. |
| * |
| * We can get recursively called as show below. |
| * |
| * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() -> |
| * ext4_writepage() |
| * |
| * But since we don't do any block allocation we should not deadlock. |
| * Page also have the dirty flag cleared so we don't get recurive page_lock. |
| */ |
| static int ext4_writepage(struct page *page, |
| struct writeback_control *wbc) |
| { |
| int ret = 0; |
| loff_t size; |
| unsigned int len; |
| struct buffer_head *page_bufs = NULL; |
| struct inode *inode = page->mapping->host; |
| struct ext4_io_submit io_submit; |
| bool keep_towrite = false; |
| |
| trace_ext4_writepage(page); |
| size = i_size_read(inode); |
| if (page->index == size >> PAGE_SHIFT) |
| len = size & ~PAGE_MASK; |
| else |
| len = PAGE_SIZE; |
| |
| page_bufs = page_buffers(page); |
| /* |
| * We cannot do block allocation or other extent handling in this |
| * function. If there are buffers needing that, we have to redirty |
| * the page. But we may reach here when we do a journal commit via |
| * journal_submit_inode_data_buffers() and in that case we must write |
| * allocated buffers to achieve data=ordered mode guarantees. |
| * |
| * Also, if there is only one buffer per page (the fs block |
| * size == the page size), if one buffer needs block |
| * allocation or needs to modify the extent tree to clear the |
| * unwritten flag, we know that the page can't be written at |
| * all, so we might as well refuse the write immediately. |
| * Unfortunately if the block size != page size, we can't as |
| * easily detect this case using ext4_walk_page_buffers(), but |
| * for the extremely common case, this is an optimization that |
| * skips a useless round trip through ext4_bio_write_page(). |
| */ |
| if (ext4_walk_page_buffers(NULL, page_bufs, 0, len, NULL, |
| ext4_bh_delay_or_unwritten)) { |
| redirty_page_for_writepage(wbc, page); |
| if ((current->flags & PF_MEMALLOC) || |
| (inode->i_sb->s_blocksize == PAGE_SIZE)) { |
| /* |
| * For memory cleaning there's no point in writing only |
| * some buffers. So just bail out. Warn if we came here |
| * from direct reclaim. |
| */ |
| WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) |
| == PF_MEMALLOC); |
| unlock_page(page); |
| return 0; |
| } |
| keep_towrite = true; |
| } |
| |
| if (PageChecked(page) && ext4_should_journal_data(inode)) |
| /* |
| * It's mmapped pagecache. Add buffers and journal it. There |
| * doesn't seem much point in redirtying the page here. |
| */ |
| return __ext4_journalled_writepage(page, len); |
| |
| ext4_io_submit_init(&io_submit, wbc); |
| io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS); |
| if (!io_submit.io_end) { |
| redirty_page_for_writepage(wbc, page); |
| unlock_page(page); |
| return -ENOMEM; |
| } |
| ret = ext4_bio_write_page(&io_submit, page, len, wbc, keep_towrite); |
| ext4_io_submit(&io_submit); |
| /* Drop io_end reference we got from init */ |
| ext4_put_io_end_defer(io_submit.io_end); |
| return ret; |
| } |
| |
| static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page) |
| { |
| int len; |
| loff_t size = i_size_read(mpd->inode); |
| int err; |
| |
| BUG_ON(page->index != mpd->first_page); |
| if (page->index == size >> PAGE_SHIFT) |
| len = size & ~PAGE_MASK; |
| else |
| len = PAGE_SIZE; |
| clear_page_dirty_for_io(page); |
| err = ext4_bio_write_page(&mpd->io_submit, page, len, mpd->wbc, false); |
| if (!err) |
| mpd->wbc->nr_to_write--; |
| mpd->first_page++; |
| |
| return err; |
| } |
| |
| #define BH_FLAGS ((1 << BH_Unwritten) | (1 << 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) { |
| 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) + (1 << inode->i_blkbits) - 1) |
| >> inode->i_blkbits; |
| |
| 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; |
| /* 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_page(mpd, head->b_page); |
| if (err < 0) |
| return err; |
| } |
| return lblk < blocks; |
| } |
| |
| /* |
| * 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 pagevec pvec; |
| int nr_pages, i; |
| struct inode *inode = mpd->inode; |
| struct buffer_head *head, *bh; |
| int bpp_bits = PAGE_SHIFT - inode->i_blkbits; |
| pgoff_t start, end; |
| ext4_lblk_t lblk; |
| sector_t pblock; |
| int err; |
| |
| 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; |
| |
| pagevec_init(&pvec, 0); |
| while (start <= end) { |
| nr_pages = pagevec_lookup(&pvec, inode->i_mapping, start, |
| PAGEVEC_SIZE); |
| if (nr_pages == 0) |
| break; |
| for (i = 0; i < nr_pages; i++) { |
| struct page *page = pvec.pages[i]; |
| |
| if (page->index > end) |
| break; |
| /* Up to 'end' pages must be contiguous */ |
| BUG_ON(page->index != start); |
| bh = head = page_buffers(page); |
| 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 page to map. |
| */ |
| mpd->map.m_len = 0; |
| mpd->map.m_flags = 0; |
| /* |
| * FIXME: If dioread_nolock supports |
| * blocksize < pagesize, we need to make |
| * sure we add size mapped so far to |
| * io_end->size as the following call |
| * can submit the page for IO. |
| */ |
| err = mpage_process_page_bufs(mpd, head, |
| bh, lblk); |
| pagevec_release(&pvec); |
| if (err > 0) |
| err = 0; |
| return err; |
| } |
| if (buffer_delay(bh)) { |
| clear_buffer_delay(bh); |
| bh->b_blocknr = pblock++; |
| } |
| clear_buffer_unwritten(bh); |
| } while (lblk++, (bh = bh->b_this_page) != head); |
| |
| /* |
| * FIXME: This is going to break if dioread_nolock |
| * supports blocksize < pagesize as we will try to |
| * convert potentially unmapped parts of inode. |
| */ |
| mpd->io_submit.io_end->size += PAGE_SIZE; |
| /* Page fully mapped - let IO run! */ |
| err = mpage_submit_page(mpd, page); |
| if (err < 0) { |
| pagevec_release(&pvec); |
| return err; |
| } |
| start++; |
| } |
| pagevec_release(&pvec); |
| } |
| /* Extent fully mapped and matches with page boundary. We are done. */ |
| mpd->map.m_len = 0; |
| mpd->map.m_flags = 0; |
| return 0; |
| } |
| |
| 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 & (1 << 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); |
| if (map->m_flags & EXT4_MAP_NEW) { |
| struct block_device *bdev = inode->i_sb->s_bdev; |
| int i; |
| |
| for (i = 0; i < map->m_len; i++) |
| unmap_underlying_metadata(bdev, map->m_pblk + i); |
| } |
| 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; |
| |
| mpd->io_submit.io_end->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_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED) |
| 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 > 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; |
| err2 = ext4_mark_inode_dirty(handle, inode); |
| up_write(&EXT4_I(inode)->i_data_sem); |
| if (err2) |
| ext4_error(inode->i_sb, |
| "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); |
| } |
| |
| /* |
| * mpage_prepare_extent_to_map - find & lock contiguous range of dirty pages |
| * and underlying extent to map |
| * |
| * @mpd - where to look for pages |
| * |
| * Walk dirty pages in the mapping. If they are fully mapped, submit them for |
| * IO immediately. When 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 pagevec pvec; |
| unsigned int nr_pages; |
| long left = mpd->wbc->nr_to_write; |
| pgoff_t index = mpd->first_page; |
| pgoff_t end = mpd->last_page; |
| int tag; |
| int i, err = 0; |
| int blkbits = mpd->inode->i_blkbits; |
| ext4_lblk_t lblk; |
| struct buffer_head *head; |
| |
| if (mpd->wbc->sync_mode == WB_SYNC_ALL || mpd->wbc->tagged_writepages) |
| tag = PAGECACHE_TAG_TOWRITE; |
| else |
| tag = PAGECACHE_TAG_DIRTY; |
| |
| pagevec_init(&pvec, 0); |
| mpd->map.m_len = 0; |
| mpd->next_page = index; |
| while (index <= end) { |
| nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag, |
| min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1); |
| if (nr_pages == 0) |
| goto out; |
| |
| for (i = 0; i < nr_pages; i++) { |
| struct page *page = pvec.pages[i]; |
| |
| /* |
| * At this point, the page may be truncated or |
| * invalidated (changing page->mapping to NULL), or |
| * even swizzled back from swapper_space to tmpfs file |
| * mapping. However, page->index will not change |
| * because we have a reference on the page. |
| */ |
| if (page->index > end) |
| goto out; |
| |
| /* |
| * 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 && left <= 0) |
| goto out; |
| |
| /* If we can't merge this page, we are done. */ |
| if (mpd->map.m_len > 0 && mpd->next_page != page->index) |
| goto out; |
| |
| lock_page(page); |
| /* |
| * 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 (!PageDirty(page) || |
| (PageWriteback(page) && |
| (mpd->wbc->sync_mode == WB_SYNC_NONE)) || |
| unlikely(page->mapping != mapping)) { |
| unlock_page(page); |
| continue; |
| } |
| |
| wait_on_page_writeback(page); |
| BUG_ON(PageWriteback(page)); |
| |
| if (mpd->map.m_len == 0) |
| mpd->first_page = page->index; |
| mpd->next_page = page->index + 1; |
| /* Add all dirty buffers to mpd */ |
| lblk = ((ext4_lblk_t)page->index) << |
| (PAGE_SHIFT - blkbits); |
| head = page_buffers(page); |
| err = mpage_process_page_bufs(mpd, head, head, lblk); |
| if (err <= 0) |
| goto out; |
| err = 0; |
| left--; |
| } |
| pagevec_release(&pvec); |
| cond_resched(); |
| } |
| return 0; |
| out: |
| pagevec_release(&pvec); |
| return err; |
| } |
| |
| static int __writepage(struct page *page, struct writeback_control *wbc, |
| void *data) |
| { |
| struct address_space *mapping = data; |
| int ret = ext4_writepage(page, wbc); |
| mapping_set_error(mapping, ret); |
| return ret; |
| } |
| |
| static int ext4_writepages(struct address_space *mapping, |
| struct writeback_control *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 mpage_da_data mpd; |
| struct inode *inode = mapping->host; |
| int needed_blocks, rsv_blocks = 0, ret = 0; |
| struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb); |
| bool done; |
| struct blk_plug plug; |
| bool give_up_on_write = false; |
| |
| percpu_down_read(&sbi->s_journal_flag_rwsem); |
| trace_ext4_writepages(inode, wbc); |
| |
| if (dax_mapping(mapping)) { |
| ret = dax_writeback_mapping_range(mapping, inode->i_sb->s_bdev, |
| wbc); |
| goto out_writepages; |
| } |
| |
| /* |
| * 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 (ext4_should_journal_data(inode)) { |
| struct blk_plug plug; |
| |
| blk_start_plug(&plug); |
| ret = write_cache_pages(mapping, wbc, __writepage, mapping); |
| blk_finish_plug(&plug); |
| 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 |
| * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_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(sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) { |
| ret = -EROFS; |
| goto out_writepages; |
| } |
| |
| 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 + (PAGE_SIZE >> inode->i_blkbits); |
| } |
| |
| /* |
| * 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); |
| } |
| |
| 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; |
| } |
| |
| mpd.inode = inode; |
| mpd.wbc = wbc; |
| 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); |
| done = false; |
| blk_start_plug(&plug); |
| while (!done && mpd.first_page <= mpd.last_page) { |
| /* 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; |
| } |
| |
| /* |
| * 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); |
| break; |
| } |
| |
| trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc); |
| ret = mpage_prepare_extent_to_map(&mpd); |
| if (!ret) { |
| if (mpd.map.m_len) |
| ret = mpage_map_and_submit_extent(handle, &mpd, |
| &give_up_on_write); |
| else { |
| /* |
| * We scanned the whole range (or exhausted |
| * nr_to_write), submitted what was mapped and |
| * didn't find anything needing mapping. We are |
| * done. |
| */ |
| done = true; |
| } |
| } |
| ext4_journal_stop(handle); |
| /* Submit prepared bio */ |
| ext4_io_submit(&mpd.io_submit); |
| /* Unlock pages we didn't use */ |
| mpage_release_unused_pages(&mpd, give_up_on_write); |
| /* Drop our io_end reference we got from init */ |
| ext4_put_io_end(mpd.io_submit.io_end); |
| |
| 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; |
| } |
| 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); |
| percpu_up_read(&sbi->s_journal_flag_rwsem); |
| 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; |
| } |
| |
| /* We always reserve for an inode update; the superblock could be there too */ |
| static int ext4_da_write_credits(struct inode *inode, loff_t pos, unsigned len) |
| { |
| if (likely(ext4_has_feature_large_file(inode->i_sb))) |
| return 1; |
| |
| if (pos + len <= 0x7fffffffULL) |
| return 1; |
| |
| /* We might need to update the superblock to set LARGE_FILE */ |
| return 2; |
| } |
| |
| static int ext4_da_write_begin(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned flags, |
| struct page **pagep, void **fsdata) |
| { |
| int ret, retries = 0; |
| struct page *page; |
| pgoff_t index; |
| struct inode *inode = mapping->host; |
| handle_t *handle; |
| |
| index = pos >> PAGE_SHIFT; |
| |
| if (ext4_nonda_switch(inode->i_sb)) { |
| *fsdata = (void *)FALL_BACK_TO_NONDELALLOC; |
| return ext4_write_begin(file, mapping, pos, |
| len, flags, pagep, fsdata); |
| } |
| *fsdata = (void *)0; |
| trace_ext4_da_write_begin(inode, pos, len, flags); |
| |
| if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) { |
| ret = ext4_da_write_inline_data_begin(mapping, inode, |
| pos, len, flags, |
| pagep, fsdata); |
| if (ret < 0) |
| return ret; |
| if (ret == 1) |
| return 0; |
| } |
| |
| /* |
| * grab_cache_page_write_begin() can take a long time if the |
| * system is thrashing due to memory pressure, or if the page |
| * is being written back. So grab it first before we start |
| * the transaction handle. This also allows us to allocate |
| * the page (if needed) without using GFP_NOFS. |
| */ |
| retry_grab: |
| page = grab_cache_page_write_begin(mapping, index, flags); |
| if (!page) |
| return -ENOMEM; |
| unlock_page(page); |
| |
| /* |
| * With delayed allocation, we don't log the i_disksize update |
| * if there is delayed block allocation. But we still need |
| * to journalling the i_disksize update if writes to the end |
| * of file which has an already mapped buffer. |
| */ |
| retry_journal: |
| handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, |
| ext4_da_write_credits(inode, pos, len)); |
| if (IS_ERR(handle)) { |
| put_page(page); |
| return PTR_ERR(handle); |
| } |
| |
| lock_page(page); |
| if (page->mapping != mapping) { |
| /* The page got truncated from under us */ |
| unlock_page(page); |
| put_page(page); |
| ext4_journal_stop(handle); |
| goto retry_grab; |
| } |
| /* In case writeback began while the page was unlocked */ |
| wait_for_stable_page(page); |
| |
| #ifdef CONFIG_EXT4_FS_ENCRYPTION |
| ret = ext4_block_write_begin(page, pos, len, |
| ext4_da_get_block_prep); |
| #else |
| ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep); |
| #endif |
| if (ret < 0) { |
| unlock_page(page); |
| ext4_journal_stop(handle); |
| /* |
| * 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_mutex. |
| */ |
| if (pos + len > inode->i_size) |
| ext4_truncate_failed_write(inode); |
| |
| if (ret == -ENOSPC && |
| ext4_should_retry_alloc(inode->i_sb, &retries)) |
| goto retry_journal; |
| |
| put_page(page); |
| return ret; |
| } |
| |
| *pagep = 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 page *page, |
| unsigned long offset) |
| { |
| struct buffer_head *bh; |
| struct inode *inode = page->mapping->host; |
| unsigned int idx; |
| int i; |
| |
| bh = page_buffers(page); |
| 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_write_end(struct file *file, |
| struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned copied, |
| struct page *page, void *fsdata) |
| { |
| struct inode *inode = mapping->host; |
| int ret = 0, ret2; |
| handle_t *handle = ext4_journal_current_handle(); |
| loff_t new_i_size; |
| unsigned long start, end; |
| int write_mode = (int)(unsigned long)fsdata; |
| |
| if (write_mode == FALL_BACK_TO_NONDELALLOC) |
| return ext4_write_end(file, mapping, pos, |
| len, copied, page, fsdata); |
| |
| trace_ext4_da_write_end(inode, pos, len, copied); |
| start = pos & (PAGE_SIZE - 1); |
| end = start + copied - 1; |
| |
| /* |
| * generic_write_end() will run mark_inode_dirty() if i_size |
| * changes. So let's piggyback the i_disksize mark_inode_dirty |
| * into that. |
| */ |
| new_i_size = pos + copied; |
| if (copied && new_i_size > EXT4_I(inode)->i_disksize) { |
| if (ext4_has_inline_data(inode) || |
| ext4_da_should_update_i_disksize(page, end)) { |
| ext4_update_i_disksize(inode, new_i_size); |
| /* We need to mark inode dirty even if |
| * new_i_size is less that inode->i_size |
| * bu greater than i_disksize.(hint delalloc) |
| */ |
| ext4_mark_inode_dirty(handle, inode); |
| } |
| } |
| |
| if (write_mode != CONVERT_INLINE_DATA && |
| ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA) && |
| ext4_has_inline_data(inode)) |
| ret2 = ext4_da_write_inline_data_end(inode, pos, len, copied, |
| page); |
| else |
| ret2 = generic_write_end(file, mapping, pos, len, copied, |
| page, fsdata); |
| |
| copied = ret2; |
| if (ret2 < 0) |
| ret = ret2; |
| ret2 = ext4_journal_stop(handle); |
| if (!ret) |
| ret = ret2; |
| |
| return ret ? ret : copied; |
| } |
| |
| static void ext4_da_invalidatepage(struct page *page, unsigned int offset, |
| unsigned int length) |
| { |
| /* |
| * Drop reserved blocks |
| */ |
| BUG_ON(!PageLocked(page)); |
| if (!page_has_buffers(page)) |
| goto out; |
| |
| ext4_da_page_release_reservation(page, offset, length); |
| |
| out: |
| ext4_invalidatepage(page, offset, length); |
| |
| return; |
| } |
| |
| /* |
| * Force all delayed allocation blocks to be allocated for a given inode. |
| */ |
| int ext4_alloc_da_blocks(struct inode *inode) |
| { |
| trace_ext4_alloc_da_blocks(inode); |
| |
| if (!EXT4_I(inode)->i_reserved_data_blocks) |
| return 0; |
| |
| /* |
| * We do something simple for now. The filemap_flush() will |
| * also start triggering a write of the data blocks, which is |
| * not strictly speaking necessary (and for users of |
| * laptop_mode, not even desirable). However, to do otherwise |
| * would require replicating code paths in: |
| * |
| * ext4_writepages() -> |
| * write_cache_pages() ---> (via passed in callback function) |
| * __mpage_da_writepage() --> |
| * mpage_add_bh_to_extent() |
| * mpage_da_map_blocks() |
| * |
| * The problem is that write_cache_pages(), located in |
| * mm/page-writeback.c, marks pages clean in preparation for |
| * doing I/O, which is not desirable if we're not planning on |
| * doing I/O at all. |
| * |
| * We could call write_cache_pages(), and then redirty all of |
| * the pages by calling redirty_page_for_writepage() but that |
| * would be ugly in the extreme. So instead we would need to |
| * replicate parts of the code in the above functions, |
| * simplifying them because we wouldn't actually intend to |
| * write out the pages, but rather only collect contiguous |
| * logical block extents, call the multi-block allocator, and |
| * then update the buffer heads with the block allocations. |
| * |
| * For now, though, we'll cheat by calling filemap_flush(), |
| * which will map the blocks, and start the I/O, but not |
| * actually wait for the I/O to complete. |
| */ |
| return filemap_flush(inode->i_mapping); |
| } |
| |
| /* |
| * bmap() is special. It gets used by applications such as lilo and by |
| * the swapper to find the on-disk block of a specific piece of data. |
| * |
| * Naturally, this is dangerous if the block concerned is still in the |
| * journal. If somebody makes a swapfile on an ext4 data-journaling |
| * filesystem and enables swap, then they may get a nasty shock when the |
| * data getting swapped to that swapfile suddenly gets overwritten by |
| * the original zero's written out previously to the journal and |
| * awaiting writeback in the kernel's buffer cache. |
| * |
| * So, if we see any bmap calls here on a modified, data-journaled file, |
| * take extra steps to flush any blocks which might be in the cache. |
| */ |
| static sector_t ext4_bmap(struct address_space *mapping, sector_t block) |
| { |
| struct inode *inode = mapping->host; |
| journal_t *journal; |
| int err; |
| |
| /* |
| * We can get here for an inline file via the FIBMAP ioctl |
| */ |
| if (ext4_has_inline_data(inode)) |
| return 0; |
| |
| if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && |
| test_opt(inode->i_sb, DELALLOC)) { |
| /* |
| * With delalloc we want to sync the file |
| * so that we can make sure we allocate |
| * blocks for file |
| */ |
| filemap_write_and_wait(mapping); |
| } |
| |
| if (EXT4_JOURNAL(inode) && |
| ext4_test_inode_state(inode, EXT4_STATE_JDATA)) { |
| /* |
| * This is a REALLY heavyweight approach, but the use of |
| * bmap on dirty files is expected to be extremely rare: |
| * only if we run lilo or swapon on a freshly made file |
| * do we expect this to happen. |
| * |
| * (bmap requires CAP_SYS_RAWIO so this does not |
| * represent an unprivileged user DOS attack --- we'd be |
| * in trouble if mortal users could trigger this path at |
| * will.) |
| * |
| * NB. EXT4_STATE_JDATA is not set on files other than |
| * regular files. If somebody wants to bmap a directory |
| * or symlink and gets confused because the buffer |
| * hasn't yet been flushed to disk, they deserve |
| * everything they get. |
| */ |
| |
| ext4_clear_inode_state(inode, EXT4_STATE_JDATA); |
| journal = EXT4_JOURNAL(inode); |
| <
|