LCOV - code coverage report
Current view: top level - fs/ext4 - move_extent.c (source / functions) Hit Total Coverage
Test: gcov_data_raspi2_real_modules_combined.info Lines: 0 251 0.0 %
Date: 2020-09-30 20:25:40 Functions: 0 9 0.0 %
Branches: 0 204 0.0 %

           Branch data     Line data    Source code
       1                 :            : // SPDX-License-Identifier: LGPL-2.1
       2                 :            : /*
       3                 :            :  * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd.
       4                 :            :  * Written by Takashi Sato <t-sato@yk.jp.nec.com>
       5                 :            :  *            Akira Fujita <a-fujita@rs.jp.nec.com>
       6                 :            :  */
       7                 :            : 
       8                 :            : #include <linux/fs.h>
       9                 :            : #include <linux/quotaops.h>
      10                 :            : #include <linux/slab.h>
      11                 :            : #include "ext4_jbd2.h"
      12                 :            : #include "ext4.h"
      13                 :            : #include "ext4_extents.h"
      14                 :            : 
      15                 :            : /**
      16                 :            :  * get_ext_path() - Find an extent path for designated logical block number.
      17                 :            :  * @inode:      inode to be searched
      18                 :            :  * @lblock:     logical block number to find an extent path
      19                 :            :  * @ppath:      pointer to an extent path pointer (for output)
      20                 :            :  *
      21                 :            :  * ext4_find_extent wrapper. Return 0 on success, or a negative error value
      22                 :            :  * on failure.
      23                 :            :  */
      24                 :            : static inline int
      25                 :          0 : get_ext_path(struct inode *inode, ext4_lblk_t lblock,
      26                 :            :                 struct ext4_ext_path **ppath)
      27                 :            : {
      28                 :            :         struct ext4_ext_path *path;
      29                 :            : 
      30                 :          0 :         path = ext4_find_extent(inode, lblock, ppath, EXT4_EX_NOCACHE);
      31         [ #  # ]:          0 :         if (IS_ERR(path))
      32                 :          0 :                 return PTR_ERR(path);
      33         [ #  # ]:          0 :         if (path[ext_depth(inode)].p_ext == NULL) {
      34                 :          0 :                 ext4_ext_drop_refs(path);
      35                 :          0 :                 kfree(path);
      36                 :          0 :                 *ppath = NULL;
      37                 :          0 :                 return -ENODATA;
      38                 :            :         }
      39                 :          0 :         *ppath = path;
      40                 :          0 :         return 0;
      41                 :            : }
      42                 :            : 
      43                 :            : /**
      44                 :            :  * ext4_double_down_write_data_sem() - write lock two inodes's i_data_sem
      45                 :            :  * @first: inode to be locked
      46                 :            :  * @second: inode to be locked
      47                 :            :  *
      48                 :            :  * Acquire write lock of i_data_sem of the two inodes
      49                 :            :  */
      50                 :            : void
      51                 :          0 : ext4_double_down_write_data_sem(struct inode *first, struct inode *second)
      52                 :            : {
      53         [ #  # ]:          0 :         if (first < second) {
      54                 :          0 :                 down_write(&EXT4_I(first)->i_data_sem);
      55                 :          0 :                 down_write_nested(&EXT4_I(second)->i_data_sem, I_DATA_SEM_OTHER);
      56                 :            :         } else {
      57                 :          0 :                 down_write(&EXT4_I(second)->i_data_sem);
      58                 :          0 :                 down_write_nested(&EXT4_I(first)->i_data_sem, I_DATA_SEM_OTHER);
      59                 :            : 
      60                 :            :         }
      61                 :          0 : }
      62                 :            : 
      63                 :            : /**
      64                 :            :  * ext4_double_up_write_data_sem - Release two inodes' write lock of i_data_sem
      65                 :            :  *
      66                 :            :  * @orig_inode:         original inode structure to be released its lock first
      67                 :            :  * @donor_inode:        donor inode structure to be released its lock second
      68                 :            :  * Release write lock of i_data_sem of two inodes (orig and donor).
      69                 :            :  */
      70                 :            : void
      71                 :          0 : ext4_double_up_write_data_sem(struct inode *orig_inode,
      72                 :            :                               struct inode *donor_inode)
      73                 :            : {
      74                 :          0 :         up_write(&EXT4_I(orig_inode)->i_data_sem);
      75                 :          0 :         up_write(&EXT4_I(donor_inode)->i_data_sem);
      76                 :          0 : }
      77                 :            : 
      78                 :            : /**
      79                 :            :  * mext_check_coverage - Check that all extents in range has the same type
      80                 :            :  *
      81                 :            :  * @inode:              inode in question
      82                 :            :  * @from:               block offset of inode
      83                 :            :  * @count:              block count to be checked
      84                 :            :  * @unwritten:          extents expected to be unwritten
      85                 :            :  * @err:                pointer to save error value
      86                 :            :  *
      87                 :            :  * Return 1 if all extents in range has expected type, and zero otherwise.
      88                 :            :  */
      89                 :            : static int
      90                 :          0 : mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
      91                 :            :                     int unwritten, int *err)
      92                 :            : {
      93                 :          0 :         struct ext4_ext_path *path = NULL;
      94                 :            :         struct ext4_extent *ext;
      95                 :            :         int ret = 0;
      96                 :          0 :         ext4_lblk_t last = from + count;
      97         [ #  # ]:          0 :         while (from < last) {
      98                 :          0 :                 *err = get_ext_path(inode, from, &path);
      99         [ #  # ]:          0 :                 if (*err)
     100                 :            :                         goto out;
     101                 :          0 :                 ext = path[ext_depth(inode)].p_ext;
     102         [ #  # ]:          0 :                 if (unwritten != ext4_ext_is_unwritten(ext))
     103                 :            :                         goto out;
     104                 :          0 :                 from += ext4_ext_get_actual_len(ext);
     105                 :          0 :                 ext4_ext_drop_refs(path);
     106                 :            :         }
     107                 :            :         ret = 1;
     108                 :            : out:
     109                 :          0 :         ext4_ext_drop_refs(path);
     110                 :          0 :         kfree(path);
     111                 :          0 :         return ret;
     112                 :            : }
     113                 :            : 
     114                 :            : /**
     115                 :            :  * mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2
     116                 :            :  *
     117                 :            :  * @inode1:     the inode structure
     118                 :            :  * @inode2:     the inode structure
     119                 :            :  * @index1:     page index
     120                 :            :  * @index2:     page index
     121                 :            :  * @page:       result page vector
     122                 :            :  *
     123                 :            :  * Grab two locked pages for inode's by inode order
     124                 :            :  */
     125                 :            : static int
     126                 :          0 : mext_page_double_lock(struct inode *inode1, struct inode *inode2,
     127                 :            :                       pgoff_t index1, pgoff_t index2, struct page *page[2])
     128                 :            : {
     129                 :            :         struct address_space *mapping[2];
     130                 :            :         unsigned fl = AOP_FLAG_NOFS;
     131                 :            : 
     132         [ #  # ]:          0 :         BUG_ON(!inode1 || !inode2);
     133         [ #  # ]:          0 :         if (inode1 < inode2) {
     134                 :          0 :                 mapping[0] = inode1->i_mapping;
     135                 :          0 :                 mapping[1] = inode2->i_mapping;
     136                 :            :         } else {
     137                 :            :                 swap(index1, index2);
     138                 :          0 :                 mapping[0] = inode2->i_mapping;
     139                 :          0 :                 mapping[1] = inode1->i_mapping;
     140                 :            :         }
     141                 :            : 
     142                 :          0 :         page[0] = grab_cache_page_write_begin(mapping[0], index1, fl);
     143         [ #  # ]:          0 :         if (!page[0])
     144                 :            :                 return -ENOMEM;
     145                 :            : 
     146                 :          0 :         page[1] = grab_cache_page_write_begin(mapping[1], index2, fl);
     147         [ #  # ]:          0 :         if (!page[1]) {
     148                 :          0 :                 unlock_page(page[0]);
     149                 :          0 :                 put_page(page[0]);
     150                 :          0 :                 return -ENOMEM;
     151                 :            :         }
     152                 :            :         /*
     153                 :            :          * grab_cache_page_write_begin() may not wait on page's writeback if
     154                 :            :          * BDI not demand that. But it is reasonable to be very conservative
     155                 :            :          * here and explicitly wait on page's writeback
     156                 :            :          */
     157                 :          0 :         wait_on_page_writeback(page[0]);
     158                 :          0 :         wait_on_page_writeback(page[1]);
     159         [ #  # ]:          0 :         if (inode1 > inode2)
     160                 :          0 :                 swap(page[0], page[1]);
     161                 :            : 
     162                 :            :         return 0;
     163                 :            : }
     164                 :            : 
     165                 :            : /* Force page buffers uptodate w/o dropping page's lock */
     166                 :            : static int
     167                 :          0 : mext_page_mkuptodate(struct page *page, unsigned from, unsigned to)
     168                 :            : {
     169                 :          0 :         struct inode *inode = page->mapping->host;
     170                 :            :         sector_t block;
     171                 :            :         struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
     172                 :            :         unsigned int blocksize, block_start, block_end;
     173                 :            :         int i, err,  nr = 0, partial = 0;
     174         [ #  # ]:          0 :         BUG_ON(!PageLocked(page));
     175         [ #  # ]:          0 :         BUG_ON(PageWriteback(page));
     176                 :            : 
     177         [ #  # ]:          0 :         if (PageUptodate(page))
     178                 :            :                 return 0;
     179                 :            : 
     180                 :            :         blocksize = i_blocksize(inode);
     181         [ #  # ]:          0 :         if (!page_has_buffers(page))
     182                 :          0 :                 create_empty_buffers(page, blocksize, 0);
     183                 :            : 
     184         [ #  # ]:          0 :         head = page_buffers(page);
     185                 :          0 :         block = (sector_t)page->index << (PAGE_SHIFT - inode->i_blkbits);
     186         [ #  # ]:          0 :         for (bh = head, block_start = 0; bh != head || !block_start;
     187                 :          0 :              block++, block_start = block_end, bh = bh->b_this_page) {
     188                 :          0 :                 block_end = block_start + blocksize;
     189         [ #  # ]:          0 :                 if (block_end <= from || block_start >= to) {
     190         [ #  # ]:          0 :                         if (!buffer_uptodate(bh))
     191                 :            :                                 partial = 1;
     192                 :          0 :                         continue;
     193                 :            :                 }
     194         [ #  # ]:          0 :                 if (buffer_uptodate(bh))
     195                 :          0 :                         continue;
     196         [ #  # ]:          0 :                 if (!buffer_mapped(bh)) {
     197                 :          0 :                         err = ext4_get_block(inode, block, bh, 0);
     198         [ #  # ]:          0 :                         if (err) {
     199                 :            :                                 SetPageError(page);
     200                 :          0 :                                 return err;
     201                 :            :                         }
     202         [ #  # ]:          0 :                         if (!buffer_mapped(bh)) {
     203                 :            :                                 zero_user(page, block_start, blocksize);
     204                 :            :                                 set_buffer_uptodate(bh);
     205                 :          0 :                                 continue;
     206                 :            :                         }
     207                 :            :                 }
     208         [ #  # ]:          0 :                 BUG_ON(nr >= MAX_BUF_PER_PAGE);
     209                 :          0 :                 arr[nr++] = bh;
     210                 :            :         }
     211                 :            :         /* No io required */
     212         [ #  # ]:          0 :         if (!nr)
     213                 :            :                 goto out;
     214                 :            : 
     215         [ #  # ]:          0 :         for (i = 0; i < nr; i++) {
     216                 :          0 :                 bh = arr[i];
     217         [ #  # ]:          0 :                 if (!bh_uptodate_or_lock(bh)) {
     218                 :          0 :                         err = bh_submit_read(bh);
     219         [ #  # ]:          0 :                         if (err)
     220                 :          0 :                                 return err;
     221                 :            :                 }
     222                 :            :         }
     223                 :            : out:
     224         [ #  # ]:          0 :         if (!partial)
     225                 :            :                 SetPageUptodate(page);
     226                 :            :         return 0;
     227                 :            : }
     228                 :            : 
     229                 :            : /**
     230                 :            :  * move_extent_per_page - Move extent data per page
     231                 :            :  *
     232                 :            :  * @o_filp:                     file structure of original file
     233                 :            :  * @donor_inode:                donor inode
     234                 :            :  * @orig_page_offset:           page index on original file
     235                 :            :  * @donor_page_offset:          page index on donor file
     236                 :            :  * @data_offset_in_page:        block index where data swapping starts
     237                 :            :  * @block_len_in_page:          the number of blocks to be swapped
     238                 :            :  * @unwritten:                  orig extent is unwritten or not
     239                 :            :  * @err:                        pointer to save return value
     240                 :            :  *
     241                 :            :  * Save the data in original inode blocks and replace original inode extents
     242                 :            :  * with donor inode extents by calling ext4_swap_extents().
     243                 :            :  * Finally, write out the saved data in new original inode blocks. Return
     244                 :            :  * replaced block count.
     245                 :            :  */
     246                 :            : static int
     247                 :          0 : move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
     248                 :            :                      pgoff_t orig_page_offset, pgoff_t donor_page_offset,
     249                 :            :                      int data_offset_in_page,
     250                 :            :                      int block_len_in_page, int unwritten, int *err)
     251                 :            : {
     252                 :            :         struct inode *orig_inode = file_inode(o_filp);
     253                 :          0 :         struct page *pagep[2] = {NULL, NULL};
     254                 :            :         handle_t *handle;
     255                 :            :         ext4_lblk_t orig_blk_offset, donor_blk_offset;
     256                 :          0 :         unsigned long blocksize = orig_inode->i_sb->s_blocksize;
     257                 :            :         unsigned int tmp_data_size, data_size, replaced_size;
     258                 :          0 :         int i, err2, jblocks, retries = 0;
     259                 :            :         int replaced_count = 0;
     260                 :          0 :         int from = data_offset_in_page << orig_inode->i_blkbits;
     261                 :          0 :         int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits;
     262                 :            :         struct super_block *sb = orig_inode->i_sb;
     263                 :            :         struct buffer_head *bh = NULL;
     264                 :            : 
     265                 :            :         /*
     266                 :            :          * It needs twice the amount of ordinary journal buffers because
     267                 :            :          * inode and donor_inode may change each different metadata blocks.
     268                 :            :          */
     269                 :            : again:
     270                 :          0 :         *err = 0;
     271                 :          0 :         jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
     272                 :            :         handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, jblocks);
     273         [ #  # ]:          0 :         if (IS_ERR(handle)) {
     274                 :          0 :                 *err = PTR_ERR(handle);
     275                 :          0 :                 return 0;
     276                 :            :         }
     277                 :            : 
     278                 :          0 :         orig_blk_offset = orig_page_offset * blocks_per_page +
     279                 :            :                 data_offset_in_page;
     280                 :            : 
     281                 :          0 :         donor_blk_offset = donor_page_offset * blocks_per_page +
     282                 :            :                 data_offset_in_page;
     283                 :            : 
     284                 :            :         /* Calculate data_size */
     285         [ #  # ]:          0 :         if ((orig_blk_offset + block_len_in_page - 1) ==
     286                 :          0 :             ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
     287                 :            :                 /* Replace the last block */
     288                 :          0 :                 tmp_data_size = orig_inode->i_size & (blocksize - 1);
     289                 :            :                 /*
     290                 :            :                  * If data_size equal zero, it shows data_size is multiples of
     291                 :            :                  * blocksize. So we set appropriate value.
     292                 :            :                  */
     293         [ #  # ]:          0 :                 if (tmp_data_size == 0)
     294                 :            :                         tmp_data_size = blocksize;
     295                 :            : 
     296                 :          0 :                 data_size = tmp_data_size +
     297                 :          0 :                         ((block_len_in_page - 1) << orig_inode->i_blkbits);
     298                 :            :         } else
     299                 :          0 :                 data_size = block_len_in_page << orig_inode->i_blkbits;
     300                 :            : 
     301                 :            :         replaced_size = data_size;
     302                 :            : 
     303                 :          0 :         *err = mext_page_double_lock(orig_inode, donor_inode, orig_page_offset,
     304                 :            :                                      donor_page_offset, pagep);
     305         [ #  # ]:          0 :         if (unlikely(*err < 0))
     306                 :            :                 goto stop_journal;
     307                 :            :         /*
     308                 :            :          * If orig extent was unwritten it can become initialized
     309                 :            :          * at any time after i_data_sem was dropped, in order to
     310                 :            :          * serialize with delalloc we have recheck extent while we
     311                 :            :          * hold page's lock, if it is still the case data copy is not
     312                 :            :          * necessary, just swap data blocks between orig and donor.
     313                 :            :          */
     314         [ #  # ]:          0 :         if (unwritten) {
     315                 :          0 :                 ext4_double_down_write_data_sem(orig_inode, donor_inode);
     316                 :            :                 /* If any of extents in range became initialized we have to
     317                 :            :                  * fallback to data copying */
     318                 :          0 :                 unwritten = mext_check_coverage(orig_inode, orig_blk_offset,
     319                 :            :                                                 block_len_in_page, 1, err);
     320         [ #  # ]:          0 :                 if (*err)
     321                 :            :                         goto drop_data_sem;
     322                 :            : 
     323                 :          0 :                 unwritten &= mext_check_coverage(donor_inode, donor_blk_offset,
     324                 :            :                                                  block_len_in_page, 1, err);
     325         [ #  # ]:          0 :                 if (*err)
     326                 :            :                         goto drop_data_sem;
     327                 :            : 
     328         [ #  # ]:          0 :                 if (!unwritten) {
     329                 :            :                         ext4_double_up_write_data_sem(orig_inode, donor_inode);
     330                 :            :                         goto data_copy;
     331                 :            :                 }
     332   [ #  #  #  # ]:          0 :                 if ((page_has_private(pagep[0]) &&
     333         [ #  # ]:          0 :                      !try_to_release_page(pagep[0], 0)) ||
     334         [ #  # ]:          0 :                     (page_has_private(pagep[1]) &&
     335                 :          0 :                      !try_to_release_page(pagep[1], 0))) {
     336                 :          0 :                         *err = -EBUSY;
     337                 :          0 :                         goto drop_data_sem;
     338                 :            :                 }
     339                 :          0 :                 replaced_count = ext4_swap_extents(handle, orig_inode,
     340                 :            :                                                    donor_inode, orig_blk_offset,
     341                 :            :                                                    donor_blk_offset,
     342                 :            :                                                    block_len_in_page, 1, err);
     343                 :            :         drop_data_sem:
     344                 :            :                 ext4_double_up_write_data_sem(orig_inode, donor_inode);
     345                 :            :                 goto unlock_pages;
     346                 :            :         }
     347                 :            : data_copy:
     348                 :          0 :         *err = mext_page_mkuptodate(pagep[0], from, from + replaced_size);
     349         [ #  # ]:          0 :         if (*err)
     350                 :            :                 goto unlock_pages;
     351                 :            : 
     352                 :            :         /* At this point all buffers in range are uptodate, old mapping layout
     353                 :            :          * is no longer required, try to drop it now. */
     354   [ #  #  #  #  :          0 :         if ((page_has_private(pagep[0]) && !try_to_release_page(pagep[0], 0)) ||
                   #  # ]
     355         [ #  # ]:          0 :             (page_has_private(pagep[1]) && !try_to_release_page(pagep[1], 0))) {
     356                 :          0 :                 *err = -EBUSY;
     357                 :          0 :                 goto unlock_pages;
     358                 :            :         }
     359                 :          0 :         ext4_double_down_write_data_sem(orig_inode, donor_inode);
     360                 :          0 :         replaced_count = ext4_swap_extents(handle, orig_inode, donor_inode,
     361                 :            :                                                orig_blk_offset, donor_blk_offset,
     362                 :            :                                            block_len_in_page, 1, err);
     363                 :            :         ext4_double_up_write_data_sem(orig_inode, donor_inode);
     364         [ #  # ]:          0 :         if (*err) {
     365         [ #  # ]:          0 :                 if (replaced_count) {
     366                 :            :                         block_len_in_page = replaced_count;
     367                 :          0 :                         replaced_size =
     368                 :          0 :                                 block_len_in_page << orig_inode->i_blkbits;
     369                 :            :                 } else
     370                 :            :                         goto unlock_pages;
     371                 :            :         }
     372                 :            :         /* Perform all necessary steps similar write_begin()/write_end()
     373                 :            :          * but keeping in mind that i_size will not change */
     374         [ #  # ]:          0 :         if (!page_has_buffers(pagep[0]))
     375                 :          0 :                 create_empty_buffers(pagep[0], 1 << orig_inode->i_blkbits, 0);
     376         [ #  # ]:          0 :         bh = page_buffers(pagep[0]);
     377         [ #  # ]:          0 :         for (i = 0; i < data_offset_in_page; i++)
     378                 :          0 :                 bh = bh->b_this_page;
     379         [ #  # ]:          0 :         for (i = 0; i < block_len_in_page; i++) {
     380                 :          0 :                 *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0);
     381         [ #  # ]:          0 :                 if (*err < 0)
     382                 :            :                         break;
     383                 :          0 :                 bh = bh->b_this_page;
     384                 :            :         }
     385         [ #  # ]:          0 :         if (!*err)
     386                 :          0 :                 *err = block_commit_write(pagep[0], from, from + replaced_size);
     387                 :            : 
     388         [ #  # ]:          0 :         if (unlikely(*err < 0))
     389                 :            :                 goto repair_branches;
     390                 :            : 
     391                 :            :         /* Even in case of data=writeback it is reasonable to pin
     392                 :            :          * inode to transaction, to prevent unexpected data loss */
     393                 :          0 :         *err = ext4_jbd2_inode_add_write(handle, orig_inode,
     394                 :          0 :                         (loff_t)orig_page_offset << PAGE_SHIFT, replaced_size);
     395                 :            : 
     396                 :            : unlock_pages:
     397                 :          0 :         unlock_page(pagep[0]);
     398                 :          0 :         put_page(pagep[0]);
     399                 :          0 :         unlock_page(pagep[1]);
     400                 :          0 :         put_page(pagep[1]);
     401                 :            : stop_journal:
     402                 :          0 :         ext4_journal_stop(handle);
     403   [ #  #  #  # ]:          0 :         if (*err == -ENOSPC &&
     404                 :          0 :             ext4_should_retry_alloc(sb, &retries))
     405                 :            :                 goto again;
     406                 :            :         /* Buffer was busy because probably is pinned to journal transaction,
     407                 :            :          * force transaction commit may help to free it. */
     408   [ #  #  #  #  :          0 :         if (*err == -EBUSY && retries++ < 4 && EXT4_SB(sb)->s_journal &&
             #  #  #  # ]
     409                 :          0 :             jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal))
     410                 :            :                 goto again;
     411                 :          0 :         return replaced_count;
     412                 :            : 
     413                 :            : repair_branches:
     414                 :            :         /*
     415                 :            :          * This should never ever happen!
     416                 :            :          * Extents are swapped already, but we are not able to copy data.
     417                 :            :          * Try to swap extents to it's original places
     418                 :            :          */
     419                 :          0 :         ext4_double_down_write_data_sem(orig_inode, donor_inode);
     420                 :          0 :         replaced_count = ext4_swap_extents(handle, donor_inode, orig_inode,
     421                 :            :                                                orig_blk_offset, donor_blk_offset,
     422                 :            :                                            block_len_in_page, 0, &err2);
     423                 :            :         ext4_double_up_write_data_sem(orig_inode, donor_inode);
     424         [ #  # ]:          0 :         if (replaced_count != block_len_in_page) {
     425                 :          0 :                 EXT4_ERROR_INODE_BLOCK(orig_inode, (sector_t)(orig_blk_offset),
     426                 :            :                                        "Unable to copy data block,"
     427                 :            :                                        " data will be lost.");
     428                 :          0 :                 *err = -EIO;
     429                 :            :         }
     430                 :            :         replaced_count = 0;
     431                 :            :         goto unlock_pages;
     432                 :            : }
     433                 :            : 
     434                 :            : /**
     435                 :            :  * mext_check_arguments - Check whether move extent can be done
     436                 :            :  *
     437                 :            :  * @orig_inode:         original inode
     438                 :            :  * @donor_inode:        donor inode
     439                 :            :  * @orig_start:         logical start offset in block for orig
     440                 :            :  * @donor_start:        logical start offset in block for donor
     441                 :            :  * @len:                the number of blocks to be moved
     442                 :            :  *
     443                 :            :  * Check the arguments of ext4_move_extents() whether the files can be
     444                 :            :  * exchanged with each other.
     445                 :            :  * Return 0 on success, or a negative error value on failure.
     446                 :            :  */
     447                 :            : static int
     448                 :          0 : mext_check_arguments(struct inode *orig_inode,
     449                 :            :                      struct inode *donor_inode, __u64 orig_start,
     450                 :            :                      __u64 donor_start, __u64 *len)
     451                 :            : {
     452                 :            :         __u64 orig_eof, donor_eof;
     453                 :          0 :         unsigned int blkbits = orig_inode->i_blkbits;
     454                 :          0 :         unsigned int blocksize = 1 << blkbits;
     455                 :            : 
     456                 :          0 :         orig_eof = (i_size_read(orig_inode) + blocksize - 1) >> blkbits;
     457                 :          0 :         donor_eof = (i_size_read(donor_inode) + blocksize - 1) >> blkbits;
     458                 :            : 
     459                 :            : 
     460         [ #  # ]:          0 :         if (donor_inode->i_mode & (S_ISUID|S_ISGID)) {
     461                 :            :                 ext4_debug("ext4 move extent: suid or sgid is set"
     462                 :            :                            " to donor file [ino:orig %lu, donor %lu]\n",
     463                 :            :                            orig_inode->i_ino, donor_inode->i_ino);
     464                 :            :                 return -EINVAL;
     465                 :            :         }
     466                 :            : 
     467         [ #  # ]:          0 :         if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
     468                 :            :                 return -EPERM;
     469                 :            : 
     470                 :            :         /* Ext4 move extent does not support swapfile */
     471   [ #  #  #  # ]:          0 :         if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
     472                 :            :                 ext4_debug("ext4 move extent: The argument files should "
     473                 :            :                         "not be swapfile [ino:orig %lu, donor %lu]\n",
     474                 :            :                         orig_inode->i_ino, donor_inode->i_ino);
     475                 :            :                 return -EBUSY;
     476                 :            :         }
     477                 :            : 
     478   [ #  #  #  # ]:          0 :         if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) {
     479                 :            :                 ext4_debug("ext4 move extent: The argument files should "
     480                 :            :                         "not be quota files [ino:orig %lu, donor %lu]\n",
     481                 :            :                         orig_inode->i_ino, donor_inode->i_ino);
     482                 :            :                 return -EBUSY;
     483                 :            :         }
     484                 :            : 
     485                 :            :         /* Ext4 move extent supports only extent based file */
     486         [ #  # ]:          0 :         if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) {
     487                 :            :                 ext4_debug("ext4 move extent: orig file is not extents "
     488                 :            :                         "based file [ino:orig %lu]\n", orig_inode->i_ino);
     489                 :            :                 return -EOPNOTSUPP;
     490         [ #  # ]:          0 :         } else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) {
     491                 :            :                 ext4_debug("ext4 move extent: donor file is not extents "
     492                 :            :                         "based file [ino:donor %lu]\n", donor_inode->i_ino);
     493                 :            :                 return -EOPNOTSUPP;
     494                 :            :         }
     495                 :            : 
     496   [ #  #  #  # ]:          0 :         if ((!orig_inode->i_size) || (!donor_inode->i_size)) {
     497                 :            :                 ext4_debug("ext4 move extent: File size is 0 byte\n");
     498                 :            :                 return -EINVAL;
     499                 :            :         }
     500                 :            : 
     501                 :            :         /* Start offset should be same */
     502         [ #  # ]:          0 :         if ((orig_start & ~(PAGE_MASK >> orig_inode->i_blkbits)) !=
     503                 :            :             (donor_start & ~(PAGE_MASK >> orig_inode->i_blkbits))) {
     504                 :            :                 ext4_debug("ext4 move extent: orig and donor's start "
     505                 :            :                         "offsets are not aligned [ino:orig %lu, donor %lu]\n",
     506                 :            :                         orig_inode->i_ino, donor_inode->i_ino);
     507                 :            :                 return -EINVAL;
     508                 :            :         }
     509                 :            : 
     510         [ #  # ]:          0 :         if ((orig_start >= EXT_MAX_BLOCKS) ||
     511         [ #  # ]:          0 :             (donor_start >= EXT_MAX_BLOCKS) ||
     512         [ #  # ]:          0 :             (*len > EXT_MAX_BLOCKS) ||
     513         [ #  # ]:          0 :             (donor_start + *len >= EXT_MAX_BLOCKS) ||
     514                 :          0 :             (orig_start + *len >= EXT_MAX_BLOCKS))  {
     515                 :            :                 ext4_debug("ext4 move extent: Can't handle over [%u] blocks "
     516                 :            :                         "[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS,
     517                 :            :                         orig_inode->i_ino, donor_inode->i_ino);
     518                 :            :                 return -EINVAL;
     519                 :            :         }
     520         [ #  # ]:          0 :         if (orig_eof <= orig_start)
     521                 :          0 :                 *len = 0;
     522         [ #  # ]:          0 :         else if (orig_eof < orig_start + *len - 1)
     523                 :          0 :                 *len = orig_eof - orig_start;
     524         [ #  # ]:          0 :         if (donor_eof <= donor_start)
     525                 :          0 :                 *len = 0;
     526         [ #  # ]:          0 :         else if (donor_eof < donor_start + *len - 1)
     527                 :          0 :                 *len = donor_eof - donor_start;
     528         [ #  # ]:          0 :         if (!*len) {
     529                 :            :                 ext4_debug("ext4 move extent: len should not be 0 "
     530                 :            :                         "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
     531                 :            :                         donor_inode->i_ino);
     532                 :            :                 return -EINVAL;
     533                 :            :         }
     534                 :            : 
     535                 :          0 :         return 0;
     536                 :            : }
     537                 :            : 
     538                 :            : /**
     539                 :            :  * ext4_move_extents - Exchange the specified range of a file
     540                 :            :  *
     541                 :            :  * @o_filp:             file structure of the original file
     542                 :            :  * @d_filp:             file structure of the donor file
     543                 :            :  * @orig_blk:           start offset in block for orig
     544                 :            :  * @donor_blk:          start offset in block for donor
     545                 :            :  * @len:                the number of blocks to be moved
     546                 :            :  * @moved_len:          moved block length
     547                 :            :  *
     548                 :            :  * This function returns 0 and moved block length is set in moved_len
     549                 :            :  * if succeed, otherwise returns error value.
     550                 :            :  *
     551                 :            :  */
     552                 :            : int
     553                 :          0 : ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
     554                 :            :                   __u64 donor_blk, __u64 len, __u64 *moved_len)
     555                 :            : {
     556                 :            :         struct inode *orig_inode = file_inode(o_filp);
     557                 :            :         struct inode *donor_inode = file_inode(d_filp);
     558                 :          0 :         struct ext4_ext_path *path = NULL;
     559                 :          0 :         int blocks_per_page = PAGE_SIZE >> orig_inode->i_blkbits;
     560                 :          0 :         ext4_lblk_t o_end, o_start = orig_blk;
     561                 :          0 :         ext4_lblk_t d_start = donor_blk;
     562                 :            :         int ret;
     563                 :            : 
     564         [ #  # ]:          0 :         if (orig_inode->i_sb != donor_inode->i_sb) {
     565                 :            :                 ext4_debug("ext4 move extent: The argument files "
     566                 :            :                         "should be in same FS [ino:orig %lu, donor %lu]\n",
     567                 :            :                         orig_inode->i_ino, donor_inode->i_ino);
     568                 :            :                 return -EINVAL;
     569                 :            :         }
     570                 :            : 
     571                 :            :         /* orig and donor should be different inodes */
     572         [ #  # ]:          0 :         if (orig_inode == donor_inode) {
     573                 :            :                 ext4_debug("ext4 move extent: The argument files should not "
     574                 :            :                         "be same inode [ino:orig %lu, donor %lu]\n",
     575                 :            :                         orig_inode->i_ino, donor_inode->i_ino);
     576                 :            :                 return -EINVAL;
     577                 :            :         }
     578                 :            : 
     579                 :            :         /* Regular file check */
     580   [ #  #  #  # ]:          0 :         if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
     581                 :            :                 ext4_debug("ext4 move extent: The argument files should be "
     582                 :            :                         "regular file [ino:orig %lu, donor %lu]\n",
     583                 :            :                         orig_inode->i_ino, donor_inode->i_ino);
     584                 :            :                 return -EINVAL;
     585                 :            :         }
     586                 :            : 
     587                 :            :         /* TODO: it's not obvious how to swap blocks for inodes with full
     588                 :            :            journaling enabled */
     589   [ #  #  #  # ]:          0 :         if (ext4_should_journal_data(orig_inode) ||
     590                 :            :             ext4_should_journal_data(donor_inode)) {
     591                 :          0 :                 ext4_msg(orig_inode->i_sb, KERN_ERR,
     592                 :            :                          "Online defrag not supported with data journaling");
     593                 :          0 :                 return -EOPNOTSUPP;
     594                 :            :         }
     595                 :            : 
     596   [ #  #  #  # ]:          0 :         if (IS_ENCRYPTED(orig_inode) || IS_ENCRYPTED(donor_inode)) {
     597                 :          0 :                 ext4_msg(orig_inode->i_sb, KERN_ERR,
     598                 :            :                          "Online defrag not supported for encrypted files");
     599                 :          0 :                 return -EOPNOTSUPP;
     600                 :            :         }
     601                 :            : 
     602                 :            :         /* Protect orig and donor inodes against a truncate */
     603                 :          0 :         lock_two_nondirectories(orig_inode, donor_inode);
     604                 :            : 
     605                 :            :         /* Wait for all existing dio workers */
     606                 :          0 :         inode_dio_wait(orig_inode);
     607                 :          0 :         inode_dio_wait(donor_inode);
     608                 :            : 
     609                 :            :         /* Protect extent tree against block allocations via delalloc */
     610                 :          0 :         ext4_double_down_write_data_sem(orig_inode, donor_inode);
     611                 :            :         /* Check the filesystem environment whether move_extent can be done */
     612                 :          0 :         ret = mext_check_arguments(orig_inode, donor_inode, orig_blk,
     613                 :            :                                     donor_blk, &len);
     614         [ #  # ]:          0 :         if (ret)
     615                 :            :                 goto out;
     616                 :          0 :         o_end = o_start + len;
     617                 :            : 
     618         [ #  # ]:          0 :         while (o_start < o_end) {
     619                 :            :                 struct ext4_extent *ex;
     620                 :            :                 ext4_lblk_t cur_blk, next_blk;
     621                 :            :                 pgoff_t orig_page_index, donor_page_index;
     622                 :            :                 int offset_in_page;
     623                 :            :                 int unwritten, cur_len;
     624                 :            : 
     625                 :          0 :                 ret = get_ext_path(orig_inode, o_start, &path);
     626         [ #  # ]:          0 :                 if (ret)
     627                 :            :                         goto out;
     628                 :          0 :                 ex = path[path->p_depth].p_ext;
     629                 :          0 :                 next_blk = ext4_ext_next_allocated_block(path);
     630                 :          0 :                 cur_blk = le32_to_cpu(ex->ee_block);
     631                 :            :                 cur_len = ext4_ext_get_actual_len(ex);
     632                 :            :                 /* Check hole before the start pos */
     633         [ #  # ]:          0 :                 if (cur_blk + cur_len - 1 < o_start) {
     634         [ #  # ]:          0 :                         if (next_blk == EXT_MAX_BLOCKS) {
     635                 :            :                                 o_start = o_end;
     636                 :          0 :                                 ret = -ENODATA;
     637                 :          0 :                                 goto out;
     638                 :            :                         }
     639                 :          0 :                         d_start += next_blk - o_start;
     640                 :            :                         o_start = next_blk;
     641                 :          0 :                         continue;
     642                 :            :                 /* Check hole after the start pos */
     643         [ #  # ]:          0 :                 } else if (cur_blk > o_start) {
     644                 :            :                         /* Skip hole */
     645                 :          0 :                         d_start += cur_blk - o_start;
     646                 :            :                         o_start = cur_blk;
     647                 :            :                         /* Extent inside requested range ?*/
     648         [ #  # ]:          0 :                         if (cur_blk >= o_end)
     649                 :            :                                 goto out;
     650                 :            :                 } else { /* in_range(o_start, o_blk, o_len) */
     651                 :          0 :                         cur_len += cur_blk - o_start;
     652                 :            :                 }
     653                 :            :                 unwritten = ext4_ext_is_unwritten(ex);
     654         [ #  # ]:          0 :                 if (o_end - o_start < cur_len)
     655                 :          0 :                         cur_len = o_end - o_start;
     656                 :            : 
     657                 :          0 :                 orig_page_index = o_start >> (PAGE_SHIFT -
     658                 :          0 :                                                orig_inode->i_blkbits);
     659                 :          0 :                 donor_page_index = d_start >> (PAGE_SHIFT -
     660                 :          0 :                                                donor_inode->i_blkbits);
     661                 :          0 :                 offset_in_page = o_start % blocks_per_page;
     662         [ #  # ]:          0 :                 if (cur_len > blocks_per_page- offset_in_page)
     663                 :            :                         cur_len = blocks_per_page - offset_in_page;
     664                 :            :                 /*
     665                 :            :                  * Up semaphore to avoid following problems:
     666                 :            :                  * a. transaction deadlock among ext4_journal_start,
     667                 :            :                  *    ->write_begin via pagefault, and jbd2_journal_commit
     668                 :            :                  * b. racing with ->readpage, ->write_begin, and ext4_get_block
     669                 :            :                  *    in move_extent_per_page
     670                 :            :                  */
     671                 :            :                 ext4_double_up_write_data_sem(orig_inode, donor_inode);
     672                 :            :                 /* Swap original branches with new branches */
     673                 :          0 :                 move_extent_per_page(o_filp, donor_inode,
     674                 :            :                                      orig_page_index, donor_page_index,
     675                 :            :                                      offset_in_page, cur_len,
     676                 :            :                                      unwritten, &ret);
     677                 :          0 :                 ext4_double_down_write_data_sem(orig_inode, donor_inode);
     678         [ #  # ]:          0 :                 if (ret < 0)
     679                 :            :                         break;
     680                 :          0 :                 o_start += cur_len;
     681                 :          0 :                 d_start += cur_len;
     682                 :            :         }
     683                 :          0 :         *moved_len = o_start - orig_blk;
     684         [ #  # ]:          0 :         if (*moved_len > len)
     685                 :          0 :                 *moved_len = len;
     686                 :            : 
     687                 :            : out:
     688         [ #  # ]:          0 :         if (*moved_len) {
     689                 :          0 :                 ext4_discard_preallocations(orig_inode);
     690                 :          0 :                 ext4_discard_preallocations(donor_inode);
     691                 :            :         }
     692                 :            : 
     693                 :          0 :         ext4_ext_drop_refs(path);
     694                 :          0 :         kfree(path);
     695                 :            :         ext4_double_up_write_data_sem(orig_inode, donor_inode);
     696                 :          0 :         unlock_two_nondirectories(orig_inode, donor_inode);
     697                 :            : 
     698                 :          0 :         return ret;
     699                 :            : }

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