// SPDX-License-Identifier: LGPL-2.1 /* * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd. * Written by Takashi Sato * Akira Fujita */ #include #include #include #include #include "ext4_jbd2.h" #include "ext4.h" #include "ext4_extents.h" /** * get_ext_path() - Find an extent path for designated logical block number. * @inode: inode to be searched * @lblock: logical block number to find an extent path * @ppath: pointer to an extent path pointer (for output) * * ext4_find_extent wrapper. Return 0 on success, or a negative error value * on failure. */ static inline int get_ext_path(struct inode *inode, ext4_lblk_t lblock, struct ext4_ext_path **ppath) { struct ext4_ext_path *path; path = ext4_find_extent(inode, lblock, ppath, EXT4_EX_NOCACHE); if (IS_ERR(path)) return PTR_ERR(path); if (path[ext_depth(inode)].p_ext == NULL) { ext4_free_ext_path(path); *ppath = NULL; return -ENODATA; } return 0; } /** * ext4_double_down_write_data_sem() - write lock two inodes's i_data_sem * @first: inode to be locked * @second: inode to be locked * * Acquire write lock of i_data_sem of the two inodes */ void ext4_double_down_write_data_sem(struct inode *first, struct inode *second) { if (first < second) { down_write(&EXT4_I(first)->i_data_sem); down_write_nested(&EXT4_I(second)->i_data_sem, I_DATA_SEM_OTHER); } else { down_write(&EXT4_I(second)->i_data_sem); down_write_nested(&EXT4_I(first)->i_data_sem, I_DATA_SEM_OTHER); } } /** * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem * * @orig_inode: original inode structure to be released its lock first * @donor_inode: donor inode structure to be released its lock second * Release write lock of i_data_sem of two inodes (orig and donor). */ void ext4_double_up_write_data_sem(struct inode *orig_inode, struct inode *donor_inode) { up_write(&EXT4_I(orig_inode)->i_data_sem); up_write(&EXT4_I(donor_inode)->i_data_sem); } /** * mext_check_coverage - Check that all extents in range has the same type * * @inode: inode in question * @from: block offset of inode * @count: block count to be checked * @unwritten: extents expected to be unwritten * @err: pointer to save error value * * Return 1 if all extents in range has expected type, and zero otherwise. */ static int mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count, int unwritten, int *err) { struct ext4_ext_path *path = NULL; struct ext4_extent *ext; int ret = 0; ext4_lblk_t last = from + count; while (from < last) { *err = get_ext_path(inode, from, &path); if (*err) goto out; ext = path[ext_depth(inode)].p_ext; if (unwritten != ext4_ext_is_unwritten(ext)) goto out; from += ext4_ext_get_actual_len(ext); } ret = 1; out: ext4_free_ext_path(path); return ret; } /** * mext_folio_double_lock - Grab and lock folio on both @inode1 and @inode2 * * @inode1: the inode structure * @inode2: the inode structure * @index1: folio index * @index2: folio index * @folio: result folio vector * * Grab two locked folio for inode's by inode order */ static int mext_folio_double_lock(struct inode *inode1, struct inode *inode2, pgoff_t index1, pgoff_t index2, struct folio *folio[2]) { struct address_space *mapping[2]; unsigned int flags; BUG_ON(!inode1 || !inode2); if (inode1 < inode2) { mapping[0] = inode1->i_mapping; mapping[1] = inode2->i_mapping; } else { swap(index1, index2); mapping[0] = inode2->i_mapping; mapping[1] = inode1->i_mapping; } flags = memalloc_nofs_save(); folio[0] = __filemap_get_folio(mapping[0], index1, FGP_WRITEBEGIN, mapping_gfp_mask(mapping[0])); if (IS_ERR(folio[0])) { memalloc_nofs_restore(flags); return PTR_ERR(folio[0]); } folio[1] = __filemap_get_folio(mapping[1], index2, FGP_WRITEBEGIN, mapping_gfp_mask(mapping[1])); memalloc_nofs_restore(flags); if (IS_ERR(folio[1])) { folio_unlock(folio[0]); folio_put(folio[0]); return PTR_ERR(folio[1]); } /* * __filemap_get_folio() may not wait on folio's writeback if * BDI not demand that. But it is reasonable to be very conservative * here and explicitly wait on folio's writeback */ folio_wait_writeback(folio[0]); folio_wait_writeback(folio[1]); if (inode1 > inode2) swap(folio[0], folio[1]); return 0; } /* Force folio buffers uptodate w/o dropping folio's lock */ static int mext_page_mkuptodate(struct folio *folio, size_t from, size_t to) { struct inode *inode = folio->mapping->host; sector_t block; struct buffer_head *bh, *head; unsigned int blocksize, block_start, block_end; int nr = 0; bool partial = false; BUG_ON(!folio_test_locked(folio)); BUG_ON(folio_test_writeback(folio)); if (folio_test_uptodate(folio)) return 0; blocksize = i_blocksize(inode); head = folio_buffers(folio); if (!head) head = create_empty_buffers(folio, blocksize, 0); block = folio_pos(folio) >> inode->i_blkbits; block_end = 0; bh = head; do { block_start = block_end; block_end = block_start + blocksize; if (block_end <= from || block_start >= to) { if (!buffer_uptodate(bh)) partial = true; continue; } if (buffer_uptodate(bh)) continue; if (!buffer_mapped(bh)) { int err = ext4_get_block(inode, block, bh, 0); if (err) return err; if (!buffer_mapped(bh)) { folio_zero_range(folio, block_start, blocksize); set_buffer_uptodate(bh); continue; } } lock_buffer(bh); if (buffer_uptodate(bh)) { unlock_buffer(bh); continue; } ext4_read_bh_nowait(bh, 0, NULL); nr++; } while (block++, (bh = bh->b_this_page) != head); /* No io required */ if (!nr) goto out; bh = head; do { if (bh_offset(bh) + blocksize <= from) continue; if (bh_offset(bh) > to) break; wait_on_buffer(bh); if (buffer_uptodate(bh)) continue; return -EIO; } while ((bh = bh->b_this_page) != head); out: if (!partial) folio_mark_uptodate(folio); return 0; } /** * move_extent_per_page - Move extent data per page * * @o_filp: file structure of original file * @donor_inode: donor inode * @orig_page_offset: page index on original file * @donor_page_offset: page index on donor file * @data_offset_in_page: block index where data swapping starts * @block_len_in_page: the number of blocks to be swapped * @unwritten: orig extent is unwritten or not * @err: pointer to save return value * * Save the data in original inode blocks and replace original inode extents * with donor inode extents by calling ext4_swap_extents(). * Finally, write out the saved data in new original inode blocks. Return * replaced block count. */ static int move_extent_per_page(struct file *o_filp, struct inode *donor_inode, pgoff_t orig_page_offset, pgoff_t donor_page_offset, int data_offset_in_page, int block_len_in_page, int unwritten, int *err) { struct inode *orig_inode = file_inode(o_filp); struct folio *folio[2] = {NULL, NULL}; handle_t *handle; ext4_lblk_t orig_blk_offset, donor_blk_offset; unsigned long blocksize = orig_inode->i_sb->s_blocksize; unsigned int tmp_data_size, data_size, replaced_size; int i, err2, jblocks, retries = 0; int replaced_count = 0; int from = data_offset_in_page << orig_inode->i_blkbits; int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; struct super_block *sb = orig_inode->i_sb; struct buffer_head *bh = NULL; /* * It needs twice the amount of ordinary journal buffers because * inode and donor_inode may change each different metadata blocks. */ again: *err = 0; jblocks = ext4_writepage_trans_blocks(orig_inode) * 2; handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks); if (IS_ERR(handle)) { *err = PTR_ERR(handle); return 0; } orig_blk_offset = orig_page_offset * blocks_per_page + data_offset_in_page; donor_blk_offset = donor_page_offset * blocks_per_page + data_offset_in_page; /* Calculate data_size */ if ((orig_blk_offset + block_len_in_page - 1) == ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) { /* Replace the last block */ tmp_data_size = orig_inode->i_size & (blocksize - 1); /* * If data_size equal zero, it shows data_size is multiples of * blocksize. So we set appropriate value. */ if (tmp_data_size == 0) tmp_data_size = blocksize; data_size = tmp_data_size + ((block_len_in_page - 1) << orig_inode->i_blkbits); } else data_size = block_len_in_page << orig_inode->i_blkbits; replaced_size = data_size; *err = mext_folio_double_lock(orig_inode, donor_inode, orig_page_offset, donor_page_offset, folio); if (unlikely(*err < 0)) goto stop_journal; /* * If orig extent was unwritten it can become initialized * at any time after i_data_sem was dropped, in order to * serialize with delalloc we have recheck extent while we * hold page's lock, if it is still the case data copy is not * necessary, just swap data blocks between orig and donor. */ VM_BUG_ON_FOLIO(folio_test_large(folio[0]), folio[0]); VM_BUG_ON_FOLIO(folio_test_large(folio[1]), folio[1]); VM_BUG_ON_FOLIO(folio_nr_pages(folio[0]) != folio_nr_pages(folio[1]), folio[1]); if (unwritten) { ext4_double_down_write_data_sem(orig_inode, donor_inode); /* If any of extents in range became initialized we have to * fallback to data copying */ unwritten = mext_check_coverage(orig_inode, orig_blk_offset, block_len_in_page, 1, err); if (*err) goto drop_data_sem; unwritten &= mext_check_coverage(donor_inode, donor_blk_offset, block_len_in_page, 1, err); if (*err) goto drop_data_sem; if (!unwritten) { ext4_double_up_write_data_sem(orig_inode, donor_inode); goto data_copy; } if (!filemap_release_folio(folio[0], 0) || !filemap_release_folio(folio[1], 0)) { *err = -EBUSY; goto drop_data_sem; } replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode, orig_blk_offset, donor_blk_offset, block_len_in_page, 1, err); drop_data_sem: ext4_double_up_write_data_sem(orig_inode, donor_inode); goto unlock_folios; } data_copy: *err = mext_page_mkuptodate(folio[0], from, from + replaced_size); if (*err) goto unlock_folios; /* At this point all buffers in range are uptodate, old mapping layout * is no longer required, try to drop it now. */ if (!filemap_release_folio(folio[0], 0) || !filemap_release_folio(folio[1], 0)) { *err = -EBUSY; goto unlock_folios; } ext4_double_down_write_data_sem(orig_inode, donor_inode); replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode, orig_blk_offset, donor_blk_offset, block_len_in_page, 1, err); ext4_double_up_write_data_sem(orig_inode, donor_inode); if (*err) { if (replaced_count) { block_len_in_page = replaced_count; replaced_size = block_len_in_page << orig_inode->i_blkbits; } else goto unlock_folios; } /* Perform all necessary steps similar write_begin()/write_end() * but keeping in mind that i_size will not change */ bh = folio_buffers(folio[0]); if (!bh) bh = create_empty_buffers(folio[0], 1 << orig_inode->i_blkbits, 0); for (i = 0; i < data_offset_in_page; i++) bh = bh->b_this_page; for (i = 0; i < block_len_in_page; i++) { *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0); if (*err < 0) goto repair_branches; bh = bh->b_this_page; } block_commit_write(&folio[0]->page, from, from + replaced_size); /* Even in case of data=writeback it is reasonable to pin * inode to transaction, to prevent unexpected data loss */ *err = ext4_jbd2_inode_add_write(handle, orig_inode, (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size); unlock_folios: folio_unlock(folio[0]); folio_put(folio[0]); folio_unlock(folio[1]); folio_put(folio[1]); stop_journal: ext4_journal_stop(handle); if (*err == -ENOSPC && ext4_should_retry_alloc(sb, &retries)) goto again; /* Buffer was busy because probably is pinned to journal transaction, * force transaction commit may help to free it. */ if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal && jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal)) goto again; return replaced_count; repair_branches: /* * This should never ever happen! * Extents are swapped already, but we are not able to copy data. * Try to swap extents to it's original places */ ext4_double_down_write_data_sem(orig_inode, donor_inode); replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode, orig_blk_offset, donor_blk_offset, block_len_in_page, 0, &err2); ext4_double_up_write_data_sem(orig_inode, donor_inode); if (replaced_count != block_len_in_page) { ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset), EIO, "Unable to copy data block," " data will be lost."); *err = -EIO; } replaced_count = 0; goto unlock_folios; } /** * mext_check_arguments - Check whether move extent can be done * * @orig_inode: original inode * @donor_inode: donor inode * @orig_start: logical start offset in block for orig * @donor_start: logical start offset in block for donor * @len: the number of blocks to be moved * * Check the arguments of ext4_move_extents() whether the files can be * exchanged with each other. * Return 0 on success, or a negative error value on failure. */ static int mext_check_arguments(struct inode *orig_inode, struct inode *donor_inode, __u64 orig_start, __u64 donor_start, __u64 *len) { __u64 orig_eof, donor_eof; unsigned int blkbits = orig_inode->i_blkbits; unsigned int blocksize = 1 << blkbits; orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits; donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits; if (donor_inode->i_mode & (S_ISUID|S_ISGID)) { ext4_debug("ext4 move extent: suid or sgid is set" " to donor file [ino:orig %lu, donor %lu]\n", orig_inode->i_ino, donor_inode->i_ino); return -EINVAL; } if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode)) return -EPERM; /* Ext4 move extent does not support swap files */ if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { ext4_debug("ext4 move extent: The argument files should not be swap files [ino:orig %lu, donor %lu]\n", orig_inode->i_ino, donor_inode->i_ino); return -ETXTBSY; } if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) { ext4_debug("ext4 move extent: The argument files should not be quota files [ino:orig %lu, donor %lu]\n", orig_inode->i_ino, donor_inode->i_ino); return -EOPNOTSUPP; } /* Ext4 move extent supports only extent based file */ if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) { ext4_debug("ext4 move extent: orig file is not extents " "based file [ino:orig %lu]\n", orig_inode->i_ino); return -EOPNOTSUPP; } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) { ext4_debug("ext4 move extent: donor file is not extents " "based file [ino:donor %lu]\n", donor_inode->i_ino); return -EOPNOTSUPP; } if ((!orig_inode->i_size) || (!donor_inode->i_size)) { ext4_debug("ext4 move extent: File size is 0 byte\n"); return -EINVAL; } /* Start offset should be same */ if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) != (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) { ext4_debug("ext4 move extent: orig and donor's start " "offsets are not aligned [ino:orig %lu, donor %lu]\n", orig_inode->i_ino, donor_inode->i_ino); return -EINVAL; } if ((orig_start >= EXT_MAX_BLOCKS) || (donor_start >= EXT_MAX_BLOCKS) || (*len > EXT_MAX_BLOCKS) || (donor_start + *len >= EXT_MAX_BLOCKS) || (orig_start + *len >= EXT_MAX_BLOCKS)) { ext4_debug("ext4 move extent: Can't handle over [%u] blocks " "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS, orig_inode->i_ino, donor_inode->i_ino); return -EINVAL; } if (orig_eof <= orig_start) *len = 0; else if (orig_eof < orig_start + *len - 1) *len = orig_eof - orig_start; if (donor_eof <= donor_start) *len = 0; else if (donor_eof < donor_start + *len - 1) *len = donor_eof - donor_start; if (!*len) { ext4_debug("ext4 move extent: len should not be 0 " "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino, donor_inode->i_ino); return -EINVAL; } return 0; } /** * ext4_move_extents - Exchange the specified range of a file * * @o_filp: file structure of the original file * @d_filp: file structure of the donor file * @orig_blk: start offset in block for orig * @donor_blk: start offset in block for donor * @len: the number of blocks to be moved * @moved_len: moved block length * * This function returns 0 and moved block length is set in moved_len * if succeed, otherwise returns error value. * */ int ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk, __u64 donor_blk, __u64 len, __u64 *moved_len) { struct inode *orig_inode = file_inode(o_filp); struct inode *donor_inode = file_inode(d_filp); struct ext4_ext_path *path = NULL; int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; ext4_lblk_t o_end, o_start = orig_blk; ext4_lblk_t d_start = donor_blk; int ret; if (orig_inode->i_sb != donor_inode->i_sb) { ext4_debug("ext4 move extent: The argument files " "should be in same FS [ino:orig %lu, donor %lu]\n", orig_inode->i_ino, donor_inode->i_ino); return -EINVAL; } /* orig and donor should be different inodes */ if (orig_inode == donor_inode) { ext4_debug("ext4 move extent: The argument files should not " "be same inode [ino:orig %lu, donor %lu]\n", orig_inode->i_ino, donor_inode->i_ino); return -EINVAL; } /* Regular file check */ if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) { ext4_debug("ext4 move extent: The argument files should be " "regular file [ino:orig %lu, donor %lu]\n", orig_inode->i_ino, donor_inode->i_ino); return -EINVAL; } /* TODO: it's not obvious how to swap blocks for inodes with full journaling enabled */ if (ext4_should_journal_data(orig_inode) || ext4_should_journal_data(donor_inode)) { ext4_msg(orig_inode->i_sb, KERN_ERR, "Online defrag not supported with data journaling"); return -EOPNOTSUPP; } if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) { ext4_msg(orig_inode->i_sb, KERN_ERR, "Online defrag not supported for encrypted files"); return -EOPNOTSUPP; } /* Protect orig and donor inodes against a truncate */ lock_two_nondirectories(orig_inode, donor_inode); /* Wait for all existing dio workers */ inode_dio_wait(orig_inode); inode_dio_wait(donor_inode); /* Protect extent tree against block allocations via delalloc */ ext4_double_down_write_data_sem(orig_inode, donor_inode); /* Check the filesystem environment whether move_extent can be done */ ret = mext_check_arguments(orig_inode, donor_inode, orig_blk, donor_blk, &len); if (ret) goto out; o_end = o_start + len; *moved_len = 0; while (o_start < o_end) { struct ext4_extent *ex; ext4_lblk_t cur_blk, next_blk; pgoff_t orig_page_index, donor_page_index; int offset_in_page; int unwritten, cur_len; ret = get_ext_path(orig_inode, o_start, &path); if (ret) goto out; ex = path[path->p_depth].p_ext; cur_blk = le32_to_cpu(ex->ee_block); cur_len = ext4_ext_get_actual_len(ex); /* Check hole before the start pos */ if (cur_blk + cur_len - 1 < o_start) { next_blk = ext4_ext_next_allocated_block(path); if (next_blk == EXT_MAX_BLOCKS) { ret = -ENODATA; goto out; } d_start += next_blk - o_start; o_start = next_blk; continue; /* Check hole after the start pos */ } else if (cur_blk > o_start) { /* Skip hole */ d_start += cur_blk - o_start; o_start = cur_blk; /* Extent inside requested range ?*/ if (cur_blk >= o_end) goto out; } else { /* in_range(o_start, o_blk, o_len) */ cur_len += cur_blk - o_start; } unwritten = ext4_ext_is_unwritten(ex); if (o_end - o_start < cur_len) cur_len = o_end - o_start; orig_page_index = o_start >> (PAGE_SHIFT - orig_inode->i_blkbits); donor_page_index = d_start >> (PAGE_SHIFT - donor_inode->i_blkbits); offset_in_page = o_start % blocks_per_page; if (cur_len > blocks_per_page - offset_in_page) cur_len = blocks_per_page - offset_in_page; /* * Up semaphore to avoid following problems: * a. transaction deadlock among ext4_journal_start, * ->write_begin via pagefault, and jbd2_journal_commit * b. racing with ->read_folio, ->write_begin, and * ext4_get_block in move_extent_per_page */ ext4_double_up_write_data_sem(orig_inode, donor_inode); /* Swap original branches with new branches */ *moved_len += move_extent_per_page(o_filp, donor_inode, orig_page_index, donor_page_index, offset_in_page, cur_len, unwritten, &ret); ext4_double_down_write_data_sem(orig_inode, donor_inode); if (ret < 0) break; o_start += cur_len; d_start += cur_len; } out: if (*moved_len) { ext4_discard_preallocations(orig_inode); ext4_discard_preallocations(donor_inode); } ext4_free_ext_path(path); ext4_double_up_write_data_sem(orig_inode, donor_inode); unlock_two_nondirectories(orig_inode, donor_inode); return ret; }