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699 lines
21 KiB
699 lines
21 KiB
// SPDX-License-Identifier: LGPL-2.1 |
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/* |
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* Copyright (c) 2008,2009 NEC Software Tohoku, Ltd. |
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* Written by Takashi Sato <[email protected]> |
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* Akira Fujita <[email protected]> |
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*/ |
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|
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#include <linux/fs.h> |
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#include <linux/quotaops.h> |
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#include <linux/slab.h> |
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#include "ext4_jbd2.h" |
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#include "ext4.h" |
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#include "ext4_extents.h" |
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|
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/** |
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* get_ext_path() - Find an extent path for designated logical block number. |
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* @inode: inode to be searched |
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* @lblock: logical block number to find an extent path |
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* @ppath: pointer to an extent path pointer (for output) |
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* |
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* ext4_find_extent wrapper. Return 0 on success, or a negative error value |
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* on failure. |
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*/ |
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static inline int |
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get_ext_path(struct inode *inode, ext4_lblk_t lblock, |
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struct ext4_ext_path **ppath) |
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{ |
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struct ext4_ext_path *path; |
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|
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path = ext4_find_extent(inode, lblock, ppath, EXT4_EX_NOCACHE); |
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if (IS_ERR(path)) |
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return PTR_ERR(path); |
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if (path[ext_depth(inode)].p_ext == NULL) { |
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ext4_ext_drop_refs(path); |
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kfree(path); |
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*ppath = NULL; |
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return -ENODATA; |
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} |
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*ppath = path; |
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return 0; |
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} |
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|
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/** |
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* ext4_double_down_write_data_sem() - write lock two inodes's i_data_sem |
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* @first: inode to be locked |
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* @second: inode to be locked |
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* |
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* Acquire write lock of i_data_sem of the two inodes |
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*/ |
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void |
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ext4_double_down_write_data_sem(struct inode *first, struct inode *second) |
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{ |
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if (first < second) { |
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down_write(&EXT4_I(first)->i_data_sem); |
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down_write_nested(&EXT4_I(second)->i_data_sem, I_DATA_SEM_OTHER); |
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} else { |
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down_write(&EXT4_I(second)->i_data_sem); |
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down_write_nested(&EXT4_I(first)->i_data_sem, I_DATA_SEM_OTHER); |
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|
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} |
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} |
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|
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/** |
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* ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem |
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* |
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* @orig_inode: original inode structure to be released its lock first |
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* @donor_inode: donor inode structure to be released its lock second |
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* Release write lock of i_data_sem of two inodes (orig and donor). |
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*/ |
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void |
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ext4_double_up_write_data_sem(struct inode *orig_inode, |
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struct inode *donor_inode) |
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{ |
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up_write(&EXT4_I(orig_inode)->i_data_sem); |
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up_write(&EXT4_I(donor_inode)->i_data_sem); |
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} |
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|
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/** |
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* mext_check_coverage - Check that all extents in range has the same type |
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* |
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* @inode: inode in question |
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* @from: block offset of inode |
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* @count: block count to be checked |
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* @unwritten: extents expected to be unwritten |
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* @err: pointer to save error value |
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* |
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* Return 1 if all extents in range has expected type, and zero otherwise. |
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*/ |
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static int |
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mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count, |
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int unwritten, int *err) |
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{ |
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struct ext4_ext_path *path = NULL; |
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struct ext4_extent *ext; |
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int ret = 0; |
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ext4_lblk_t last = from + count; |
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while (from < last) { |
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*err = get_ext_path(inode, from, &path); |
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if (*err) |
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goto out; |
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ext = path[ext_depth(inode)].p_ext; |
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if (unwritten != ext4_ext_is_unwritten(ext)) |
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goto out; |
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from += ext4_ext_get_actual_len(ext); |
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ext4_ext_drop_refs(path); |
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} |
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ret = 1; |
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out: |
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ext4_ext_drop_refs(path); |
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kfree(path); |
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return ret; |
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} |
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|
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/** |
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* mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2 |
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* |
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* @inode1: the inode structure |
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* @inode2: the inode structure |
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* @index1: page index |
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* @index2: page index |
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* @page: result page vector |
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* |
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* Grab two locked pages for inode's by inode order |
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*/ |
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static int |
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mext_page_double_lock(struct inode *inode1, struct inode *inode2, |
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pgoff_t index1, pgoff_t index2, struct page *page[2]) |
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{ |
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struct address_space *mapping[2]; |
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unsigned fl = AOP_FLAG_NOFS; |
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|
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BUG_ON(!inode1 || !inode2); |
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if (inode1 < inode2) { |
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mapping[0] = inode1->i_mapping; |
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mapping[1] = inode2->i_mapping; |
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} else { |
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swap(index1, index2); |
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mapping[0] = inode2->i_mapping; |
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mapping[1] = inode1->i_mapping; |
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} |
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page[0] = grab_cache_page_write_begin(mapping[0], index1, fl); |
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if (!page[0]) |
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return -ENOMEM; |
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page[1] = grab_cache_page_write_begin(mapping[1], index2, fl); |
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if (!page[1]) { |
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unlock_page(page[0]); |
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put_page(page[0]); |
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return -ENOMEM; |
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} |
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/* |
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* grab_cache_page_write_begin() may not wait on page's writeback if |
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* BDI not demand that. But it is reasonable to be very conservative |
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* here and explicitly wait on page's writeback |
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*/ |
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wait_on_page_writeback(page[0]); |
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wait_on_page_writeback(page[1]); |
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if (inode1 > inode2) |
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swap(page[0], page[1]); |
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|
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return 0; |
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} |
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|
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/* Force page buffers uptodate w/o dropping page's lock */ |
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static int |
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mext_page_mkuptodate(struct page *page, unsigned from, unsigned to) |
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{ |
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struct inode *inode = page->mapping->host; |
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sector_t block; |
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struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; |
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unsigned int blocksize, block_start, block_end; |
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int i, err, nr = 0, partial = 0; |
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BUG_ON(!PageLocked(page)); |
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BUG_ON(PageWriteback(page)); |
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if (PageUptodate(page)) |
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return 0; |
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blocksize = i_blocksize(inode); |
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if (!page_has_buffers(page)) |
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create_empty_buffers(page, blocksize, 0); |
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head = page_buffers(page); |
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block = (sector_t)page->index << (PAGE_SHIFT - inode->i_blkbits); |
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for (bh = head, block_start = 0; bh != head || !block_start; |
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block++, block_start = block_end, bh = bh->b_this_page) { |
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block_end = block_start + blocksize; |
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if (block_end <= from || block_start >= to) { |
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if (!buffer_uptodate(bh)) |
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partial = 1; |
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continue; |
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} |
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if (buffer_uptodate(bh)) |
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continue; |
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if (!buffer_mapped(bh)) { |
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err = ext4_get_block(inode, block, bh, 0); |
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if (err) { |
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SetPageError(page); |
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return err; |
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} |
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if (!buffer_mapped(bh)) { |
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zero_user(page, block_start, blocksize); |
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set_buffer_uptodate(bh); |
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continue; |
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} |
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} |
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BUG_ON(nr >= MAX_BUF_PER_PAGE); |
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arr[nr++] = bh; |
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} |
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/* No io required */ |
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if (!nr) |
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goto out; |
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|
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for (i = 0; i < nr; i++) { |
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bh = arr[i]; |
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if (!bh_uptodate_or_lock(bh)) { |
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err = ext4_read_bh(bh, 0, NULL); |
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if (err) |
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return err; |
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} |
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} |
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out: |
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if (!partial) |
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SetPageUptodate(page); |
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return 0; |
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} |
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|
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/** |
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* move_extent_per_page - Move extent data per page |
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* |
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* @o_filp: file structure of original file |
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* @donor_inode: donor inode |
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* @orig_page_offset: page index on original file |
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* @donor_page_offset: page index on donor file |
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* @data_offset_in_page: block index where data swapping starts |
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* @block_len_in_page: the number of blocks to be swapped |
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* @unwritten: orig extent is unwritten or not |
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* @err: pointer to save return value |
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* |
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* Save the data in original inode blocks and replace original inode extents |
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* with donor inode extents by calling ext4_swap_extents(). |
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* Finally, write out the saved data in new original inode blocks. Return |
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* replaced block count. |
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*/ |
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static int |
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move_extent_per_page(struct file *o_filp, struct inode *donor_inode, |
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pgoff_t orig_page_offset, pgoff_t donor_page_offset, |
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int data_offset_in_page, |
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int block_len_in_page, int unwritten, int *err) |
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{ |
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struct inode *orig_inode = file_inode(o_filp); |
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struct page *pagep[2] = {NULL, NULL}; |
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handle_t *handle; |
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ext4_lblk_t orig_blk_offset, donor_blk_offset; |
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unsigned long blocksize = orig_inode->i_sb->s_blocksize; |
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unsigned int tmp_data_size, data_size, replaced_size; |
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int i, err2, jblocks, retries = 0; |
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int replaced_count = 0; |
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int from = data_offset_in_page << orig_inode->i_blkbits; |
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int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits; |
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struct super_block *sb = orig_inode->i_sb; |
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struct buffer_head *bh = NULL; |
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|
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/* |
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* It needs twice the amount of ordinary journal buffers because |
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* inode and donor_inode may change each different metadata blocks. |
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*/ |
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again: |
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*err = 0; |
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jblocks = ext4_writepage_trans_blocks(orig_inode) * 2; |
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handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks); |
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if (IS_ERR(handle)) { |
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*err = PTR_ERR(handle); |
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return 0; |
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} |
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orig_blk_offset = orig_page_offset * blocks_per_page + |
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data_offset_in_page; |
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donor_blk_offset = donor_page_offset * blocks_per_page + |
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data_offset_in_page; |
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|
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/* Calculate data_size */ |
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if ((orig_blk_offset + block_len_in_page - 1) == |
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((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) { |
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/* Replace the last block */ |
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tmp_data_size = orig_inode->i_size & (blocksize - 1); |
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/* |
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* If data_size equal zero, it shows data_size is multiples of |
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* blocksize. So we set appropriate value. |
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*/ |
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if (tmp_data_size == 0) |
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tmp_data_size = blocksize; |
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data_size = tmp_data_size + |
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((block_len_in_page - 1) << orig_inode->i_blkbits); |
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} else |
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data_size = block_len_in_page << orig_inode->i_blkbits; |
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replaced_size = data_size; |
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*err = mext_page_double_lock(orig_inode, donor_inode, orig_page_offset, |
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donor_page_offset, pagep); |
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if (unlikely(*err < 0)) |
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goto stop_journal; |
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/* |
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* If orig extent was unwritten it can become initialized |
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* at any time after i_data_sem was dropped, in order to |
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* serialize with delalloc we have recheck extent while we |
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* hold page's lock, if it is still the case data copy is not |
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* necessary, just swap data blocks between orig and donor. |
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*/ |
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if (unwritten) { |
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ext4_double_down_write_data_sem(orig_inode, donor_inode); |
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/* If any of extents in range became initialized we have to |
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* fallback to data copying */ |
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unwritten = mext_check_coverage(orig_inode, orig_blk_offset, |
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block_len_in_page, 1, err); |
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if (*err) |
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goto drop_data_sem; |
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unwritten &= mext_check_coverage(donor_inode, donor_blk_offset, |
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block_len_in_page, 1, err); |
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if (*err) |
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goto drop_data_sem; |
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|
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if (!unwritten) { |
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ext4_double_up_write_data_sem(orig_inode, donor_inode); |
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goto data_copy; |
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} |
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if ((page_has_private(pagep[0]) && |
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!try_to_release_page(pagep[0], 0)) || |
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(page_has_private(pagep[1]) && |
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!try_to_release_page(pagep[1], 0))) { |
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*err = -EBUSY; |
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goto drop_data_sem; |
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} |
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replaced_count = ext4_swap_extents(handle, orig_inode, |
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donor_inode, orig_blk_offset, |
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donor_blk_offset, |
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block_len_in_page, 1, err); |
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drop_data_sem: |
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ext4_double_up_write_data_sem(orig_inode, donor_inode); |
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goto unlock_pages; |
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} |
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data_copy: |
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*err = mext_page_mkuptodate(pagep[0], from, from + replaced_size); |
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if (*err) |
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goto unlock_pages; |
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|
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/* At this point all buffers in range are uptodate, old mapping layout |
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* is no longer required, try to drop it now. */ |
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if ((page_has_private(pagep[0]) && !try_to_release_page(pagep[0], 0)) || |
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(page_has_private(pagep[1]) && !try_to_release_page(pagep[1], 0))) { |
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*err = -EBUSY; |
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goto unlock_pages; |
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} |
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ext4_double_down_write_data_sem(orig_inode, donor_inode); |
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replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode, |
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orig_blk_offset, donor_blk_offset, |
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block_len_in_page, 1, err); |
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ext4_double_up_write_data_sem(orig_inode, donor_inode); |
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if (*err) { |
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if (replaced_count) { |
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block_len_in_page = replaced_count; |
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replaced_size = |
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block_len_in_page << orig_inode->i_blkbits; |
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} else |
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goto unlock_pages; |
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} |
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/* Perform all necessary steps similar write_begin()/write_end() |
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* but keeping in mind that i_size will not change */ |
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if (!page_has_buffers(pagep[0])) |
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create_empty_buffers(pagep[0], 1 << orig_inode->i_blkbits, 0); |
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bh = page_buffers(pagep[0]); |
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for (i = 0; i < data_offset_in_page; i++) |
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bh = bh->b_this_page; |
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for (i = 0; i < block_len_in_page; i++) { |
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*err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0); |
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if (*err < 0) |
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break; |
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bh = bh->b_this_page; |
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} |
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if (!*err) |
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*err = block_commit_write(pagep[0], from, from + replaced_size); |
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|
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if (unlikely(*err < 0)) |
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goto repair_branches; |
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|
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/* Even in case of data=writeback it is reasonable to pin |
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* inode to transaction, to prevent unexpected data loss */ |
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*err = ext4_jbd2_inode_add_write(handle, orig_inode, |
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(loff_t)orig_page_offset << PAGE_SHIFT, replaced_size); |
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|
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unlock_pages: |
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unlock_page(pagep[0]); |
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put_page(pagep[0]); |
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unlock_page(pagep[1]); |
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put_page(pagep[1]); |
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stop_journal: |
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ext4_journal_stop(handle); |
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if (*err == -ENOSPC && |
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ext4_should_retry_alloc(sb, &retries)) |
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goto again; |
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/* Buffer was busy because probably is pinned to journal transaction, |
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* force transaction commit may help to free it. */ |
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if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal && |
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jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal)) |
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goto again; |
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return replaced_count; |
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|
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repair_branches: |
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/* |
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* This should never ever happen! |
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* Extents are swapped already, but we are not able to copy data. |
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* Try to swap extents to it's original places |
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*/ |
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ext4_double_down_write_data_sem(orig_inode, donor_inode); |
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replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode, |
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orig_blk_offset, donor_blk_offset, |
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block_len_in_page, 0, &err2); |
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ext4_double_up_write_data_sem(orig_inode, donor_inode); |
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if (replaced_count != block_len_in_page) { |
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ext4_error_inode_block(orig_inode, (sector_t)(orig_blk_offset), |
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EIO, "Unable to copy data block," |
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" data will be lost."); |
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*err = -EIO; |
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} |
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replaced_count = 0; |
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goto unlock_pages; |
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} |
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|
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/** |
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* mext_check_arguments - Check whether move extent can be done |
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* |
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* @orig_inode: original inode |
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* @donor_inode: donor inode |
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* @orig_start: logical start offset in block for orig |
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* @donor_start: logical start offset in block for donor |
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* @len: the number of blocks to be moved |
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* |
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* Check the arguments of ext4_move_extents() whether the files can be |
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* exchanged with each other. |
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* Return 0 on success, or a negative error value on failure. |
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*/ |
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static int |
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mext_check_arguments(struct inode *orig_inode, |
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struct inode *donor_inode, __u64 orig_start, |
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__u64 donor_start, __u64 *len) |
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{ |
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__u64 orig_eof, donor_eof; |
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unsigned int blkbits = orig_inode->i_blkbits; |
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unsigned int blocksize = 1 << blkbits; |
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|
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orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits; |
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donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits; |
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|
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|
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if (donor_inode->i_mode & (S_ISUID|S_ISGID)) { |
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ext4_debug("ext4 move extent: suid or sgid is set" |
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" to donor file [ino:orig %lu, donor %lu]\n", |
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orig_inode->i_ino, donor_inode->i_ino); |
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return -EINVAL; |
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} |
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|
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if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode)) |
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return -EPERM; |
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|
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/* Ext4 move extent does not support swapfile */ |
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if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) { |
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ext4_debug("ext4 move extent: The argument files should " |
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"not be swapfile [ino:orig %lu, donor %lu]\n", |
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orig_inode->i_ino, donor_inode->i_ino); |
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return -EBUSY; |
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} |
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|
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if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) { |
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ext4_debug("ext4 move extent: The argument files should " |
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"not be quota files [ino:orig %lu, donor %lu]\n", |
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orig_inode->i_ino, donor_inode->i_ino); |
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return -EBUSY; |
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} |
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|
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/* Ext4 move extent supports only extent based file */ |
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if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) { |
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ext4_debug("ext4 move extent: orig file is not extents " |
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"based file [ino:orig %lu]\n", orig_inode->i_ino); |
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return -EOPNOTSUPP; |
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} else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) { |
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ext4_debug("ext4 move extent: donor file is not extents " |
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"based file [ino:donor %lu]\n", donor_inode->i_ino); |
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return -EOPNOTSUPP; |
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} |
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|
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if ((!orig_inode->i_size) || (!donor_inode->i_size)) { |
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ext4_debug("ext4 move extent: File size is 0 byte\n"); |
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return -EINVAL; |
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} |
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|
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/* Start offset should be same */ |
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if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) != |
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(donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) { |
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ext4_debug("ext4 move extent: orig and donor's start " |
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"offsets are not aligned [ino:orig %lu, donor %lu]\n", |
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orig_inode->i_ino, donor_inode->i_ino); |
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return -EINVAL; |
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} |
|
|
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if ((orig_start >= EXT_MAX_BLOCKS) || |
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(donor_start >= EXT_MAX_BLOCKS) || |
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(*len > EXT_MAX_BLOCKS) || |
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(donor_start + *len >= EXT_MAX_BLOCKS) || |
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(orig_start + *len >= EXT_MAX_BLOCKS)) { |
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ext4_debug("ext4 move extent: Can't handle over [%u] blocks " |
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"[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS, |
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orig_inode->i_ino, donor_inode->i_ino); |
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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; |
|
|
|
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, 0); |
|
ext4_discard_preallocations(donor_inode, 0); |
|
} |
|
|
|
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; |
|
}
|
|
|