diff options
Diffstat (limited to 'fs/ext4/move_extent.c')
| -rw-r--r-- | fs/ext4/move_extent.c | 700 |
1 files changed, 700 insertions, 0 deletions
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c new file mode 100644 index 000000000..287631bb0 --- /dev/null +++ b/fs/ext4/move_extent.c @@ -0,0 +1,700 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd. + * Written by Takashi Sato <t-sato@yk.jp.nec.com> + * Akira Fujita <a-fujita@rs.jp.nec.com> + */ + +#include <linux/fs.h> +#include <linux/quotaops.h> +#include <linux/slab.h> +#include "ext4_jbd2.h" +#include "ext4.h" +#include "ext4_extents.h" + +/** + * get_ext_path - Find an extent path for designated logical block number. + * + * @inode: an inode which is searched + * @lblock: logical block number to find an extent path + * @path: 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_ext_drop_refs(path); + kfree(path); + *ppath = NULL; + return -ENODATA; + } + *ppath = path; + return 0; +} + +/** + * ext4_double_down_write_data_sem - Acquire two inodes' write lock + * of i_data_sem + * + * 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); + ext4_ext_drop_refs(path); + } + ret = 1; +out: + ext4_ext_drop_refs(path); + kfree(path); + return ret; +} + +/** + * mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2 + * + * @inode1: the inode structure + * @inode2: the inode structure + * @index1: page index + * @index2: page index + * @page: result page vector + * + * Grab two locked pages for inode's by inode order + */ +static int +mext_page_double_lock(struct inode *inode1, struct inode *inode2, + pgoff_t index1, pgoff_t index2, struct page *page[2]) +{ + struct address_space *mapping[2]; + unsigned fl = AOP_FLAG_NOFS; + + 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; + } + + page[0] = grab_cache_page_write_begin(mapping[0], index1, fl); + if (!page[0]) + return -ENOMEM; + + page[1] = grab_cache_page_write_begin(mapping[1], index2, fl); + if (!page[1]) { + unlock_page(page[0]); + put_page(page[0]); + return -ENOMEM; + } + /* + * grab_cache_page_write_begin() may not wait on page's writeback if + * BDI not demand that. But it is reasonable to be very conservative + * here and explicitly wait on page's writeback + */ + wait_on_page_writeback(page[0]); + wait_on_page_writeback(page[1]); + if (inode1 > inode2) + swap(page[0], page[1]); + + return 0; +} + +/* Force page buffers uptodate w/o dropping page's lock */ +static int +mext_page_mkuptodate(struct page *page, unsigned from, unsigned to) +{ + struct inode *inode = page->mapping->host; + sector_t block; + struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; + unsigned int blocksize, block_start, block_end; + int i, err, nr = 0, partial = 0; + BUG_ON(!PageLocked(page)); + BUG_ON(PageWriteback(page)); + + if (PageUptodate(page)) + return 0; + + blocksize = i_blocksize(inode); + if (!page_has_buffers(page)) + create_empty_buffers(page, blocksize, 0); + + head = page_buffers(page); + block = (sector_t)page->index << (PAGE_SHIFT - inode->i_blkbits); + 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 (!buffer_uptodate(bh)) + partial = 1; + continue; + } + if (buffer_uptodate(bh)) + continue; + if (!buffer_mapped(bh)) { + err = ext4_get_block(inode, block, bh, 0); + if (err) { + SetPageError(page); + return err; + } + if (!buffer_mapped(bh)) { + zero_user(page, block_start, blocksize); + set_buffer_uptodate(bh); + continue; + } + } + BUG_ON(nr >= MAX_BUF_PER_PAGE); + arr[nr++] = bh; + } + /* No io required */ + if (!nr) + goto out; + + for (i = 0; i < nr; i++) { + bh = arr[i]; + if (!bh_uptodate_or_lock(bh)) { + err = bh_submit_read(bh); + if (err) + return err; + } + } +out: + if (!partial) + SetPageUptodate(page); + 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 page *pagep[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_page_double_lock(orig_inode, donor_inode, orig_page_offset, + donor_page_offset, pagep); + 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. + */ + 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 ((page_has_private(pagep[0]) && + !try_to_release_page(pagep[0], 0)) || + (page_has_private(pagep[1]) && + !try_to_release_page(pagep[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_pages; + } +data_copy: + *err = mext_page_mkuptodate(pagep[0], from, from + replaced_size); + if (*err) + goto unlock_pages; + + /* At this point all buffers in range are uptodate, old mapping layout + * is no longer required, try to drop it now. */ + if ((page_has_private(pagep[0]) && !try_to_release_page(pagep[0], 0)) || + (page_has_private(pagep[1]) && !try_to_release_page(pagep[1], 0))) { + *err = -EBUSY; + goto unlock_pages; + } + 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_pages; + } + /* Perform all necessary steps similar write_begin()/write_end() + * but keeping in mind that i_size will not change */ + if (!page_has_buffers(pagep[0])) + create_empty_buffers(pagep[0], 1 << orig_inode->i_blkbits, 0); + bh = page_buffers(pagep[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) + break; + bh = bh->b_this_page; + } + if (!*err) + *err = block_commit_write(pagep[0], from, from + replaced_size); + + if (unlikely(*err < 0)) + goto repair_branches; + + /* 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_pages: + unlock_page(pagep[0]); + put_page(pagep[0]); + unlock_page(pagep[1]); + put_page(pagep[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), + "Unable to copy data block," + " data will be lost."); + *err = -EIO; + } + replaced_count = 0; + goto unlock_pages; +} + +/** + * 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 swapfile */ + if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { + ext4_debug("ext4 move extent: The argument files should " + "not be swapfile [ino:orig %lu, donor %lu]\n", + orig_inode->i_ino, donor_inode->i_ino); + return -EBUSY; + } + + 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 -EBUSY; + } + + /* 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 (ext4_encrypted_inode(orig_inode) || + ext4_encrypted_inode(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; + + 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; + next_blk = ext4_ext_next_allocated_block(path); + 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) { + if (next_blk == EXT_MAX_BLOCKS) { + o_start = o_end; + 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 ->readpage, ->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 */ + 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; + } + *moved_len = o_start - orig_blk; + if (*moved_len > len) + *moved_len = len; + +out: + if (*moved_len) { + ext4_discard_preallocations(orig_inode); + ext4_discard_preallocations(donor_inode); + } + + ext4_ext_drop_refs(path); + kfree(path); + ext4_double_up_write_data_sem(orig_inode, donor_inode); + unlock_two_nondirectories(orig_inode, donor_inode); + + return ret; +} |