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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 11:19:37 +00:00
ext4: Fix circular locking dependency with migrate and rm.
In order to prevent a circular locking dependency when an unlink operation is racing with an ext4 migration, we delay taking i_data_sem until just before switch the inode format, and use i_mutex to prevent writes and truncates during the first part of the migration operation. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
parent
0040d9875d
commit
8009f9fb30
1 changed files with 74 additions and 43 deletions
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@ -61,10 +61,9 @@ static int finish_range(handle_t *handle, struct inode *inode,
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retval = ext4_journal_restart(handle, needed);
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if (retval)
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goto err_out;
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}
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if (needed) {
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} else if (needed) {
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retval = ext4_journal_extend(handle, needed);
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if (retval != 0) {
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if (retval) {
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/*
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* IF not able to extend the journal restart the journal
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*/
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@ -220,6 +219,26 @@ static int update_tind_extent_range(handle_t *handle, struct inode *inode,
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}
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static int extend_credit_for_blkdel(handle_t *handle, struct inode *inode)
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{
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int retval = 0, needed;
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if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS)
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return 0;
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/*
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* We are freeing a blocks. During this we touch
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* superblock, group descriptor and block bitmap.
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* So allocate a credit of 3. We may update
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* quota (user and group).
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*/
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needed = 3 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
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if (ext4_journal_extend(handle, needed) != 0)
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retval = ext4_journal_restart(handle, needed);
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return retval;
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}
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static int free_dind_blocks(handle_t *handle,
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struct inode *inode, __le32 i_data)
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{
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@ -234,11 +253,14 @@ static int free_dind_blocks(handle_t *handle,
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tmp_idata = (__le32 *)bh->b_data;
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for (i = 0; i < max_entries; i++) {
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if (tmp_idata[i])
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if (tmp_idata[i]) {
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extend_credit_for_blkdel(handle, inode);
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ext4_free_blocks(handle, inode,
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le32_to_cpu(tmp_idata[i]), 1, 1);
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}
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}
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put_bh(bh);
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extend_credit_for_blkdel(handle, inode);
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ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1);
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return 0;
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}
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@ -267,29 +289,32 @@ static int free_tind_blocks(handle_t *handle,
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}
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}
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put_bh(bh);
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extend_credit_for_blkdel(handle, inode);
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ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1, 1);
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return 0;
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}
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static int free_ind_block(handle_t *handle, struct inode *inode)
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static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
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{
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int retval;
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struct ext4_inode_info *ei = EXT4_I(inode);
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if (ei->i_data[EXT4_IND_BLOCK])
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/* ei->i_data[EXT4_IND_BLOCK] */
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if (i_data[0]) {
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extend_credit_for_blkdel(handle, inode);
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ext4_free_blocks(handle, inode,
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le32_to_cpu(ei->i_data[EXT4_IND_BLOCK]), 1, 1);
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le32_to_cpu(i_data[0]), 1, 1);
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}
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if (ei->i_data[EXT4_DIND_BLOCK]) {
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retval = free_dind_blocks(handle, inode,
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ei->i_data[EXT4_DIND_BLOCK]);
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/* ei->i_data[EXT4_DIND_BLOCK] */
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if (i_data[1]) {
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retval = free_dind_blocks(handle, inode, i_data[1]);
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if (retval)
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return retval;
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}
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if (ei->i_data[EXT4_TIND_BLOCK]) {
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retval = free_tind_blocks(handle, inode,
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ei->i_data[EXT4_TIND_BLOCK]);
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/* ei->i_data[EXT4_TIND_BLOCK] */
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if (i_data[2]) {
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retval = free_tind_blocks(handle, inode, i_data[2]);
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if (retval)
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return retval;
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}
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@ -297,15 +322,13 @@ static int free_ind_block(handle_t *handle, struct inode *inode)
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}
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static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
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struct inode *tmp_inode, int retval)
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struct inode *tmp_inode)
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{
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int retval;
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__le32 i_data[3];
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struct ext4_inode_info *ei = EXT4_I(inode);
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struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
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retval = free_ind_block(handle, inode);
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if (retval)
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goto err_out;
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/*
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* One credit accounted for writing the
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* i_data field of the original inode
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@ -317,6 +340,11 @@ static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
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goto err_out;
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}
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i_data[0] = ei->i_data[EXT4_IND_BLOCK];
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i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
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i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
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down_write(&EXT4_I(inode)->i_data_sem);
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/*
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* We have the extent map build with the tmp inode.
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* Now copy the i_data across
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@ -336,8 +364,15 @@ static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
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spin_lock(&inode->i_lock);
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inode->i_blocks += tmp_inode->i_blocks;
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spin_unlock(&inode->i_lock);
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up_write(&EXT4_I(inode)->i_data_sem);
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/*
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* We mark the inode dirty after, because we decrement the
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* i_blocks when freeing the indirect meta-data blocks
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*/
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retval = free_ind_block(handle, inode, i_data);
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ext4_mark_inode_dirty(handle, inode);
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err_out:
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return retval;
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}
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@ -365,6 +400,7 @@ static int free_ext_idx(handle_t *handle, struct inode *inode,
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}
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}
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put_bh(bh);
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extend_credit_for_blkdel(handle, inode);
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ext4_free_blocks(handle, inode, block, 1, 1);
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return retval;
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}
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@ -420,7 +456,6 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
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*/
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return retval;
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down_write(&EXT4_I(inode)->i_data_sem);
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handle = ext4_journal_start(inode,
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EXT4_DATA_TRANS_BLOCKS(inode->i_sb) +
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EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
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@ -454,13 +489,6 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
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ext4_orphan_add(handle, tmp_inode);
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ext4_journal_stop(handle);
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ei = EXT4_I(inode);
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i_data = ei->i_data;
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memset(&lb, 0, sizeof(lb));
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/* 32 bit block address 4 bytes */
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max_entries = inode->i_sb->s_blocksize >> 2;
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/*
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* start with one credit accounted for
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* superblock modification.
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@ -469,7 +497,20 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
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* trascation that created the inode. Later as and
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* when we add extents we extent the journal
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*/
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/*
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* inode_mutex prevent write and truncate on the file. Read still goes
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* through. We take i_data_sem in ext4_ext_swap_inode_data before we
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* switch the inode format to prevent read.
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*/
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mutex_lock(&(inode->i_mutex));
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handle = ext4_journal_start(inode, 1);
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ei = EXT4_I(inode);
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i_data = ei->i_data;
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memset(&lb, 0, sizeof(lb));
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/* 32 bit block address 4 bytes */
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max_entries = inode->i_sb->s_blocksize >> 2;
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for (i = 0; i < EXT4_NDIR_BLOCKS; i++, blk_count++) {
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if (i_data[i]) {
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retval = update_extent_range(handle, tmp_inode,
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@ -507,19 +548,6 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
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*/
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retval = finish_range(handle, tmp_inode, &lb);
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err_out:
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/*
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* We are either freeing extent information or indirect
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* blocks. During this we touch superblock, group descriptor
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* and block bitmap. Later we mark the tmp_inode dirty
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* via ext4_ext_tree_init. So allocate a credit of 4
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* We may update quota (user and group).
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*
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* FIXME!! we may be touching bitmaps in different block groups.
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*/
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if (ext4_journal_extend(handle,
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4 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb)) != 0)
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ext4_journal_restart(handle,
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4 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb));
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if (retval)
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/*
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* Failure case delete the extent information with the
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@ -528,7 +556,11 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
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free_ext_block(handle, tmp_inode);
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else
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retval = ext4_ext_swap_inode_data(handle, inode,
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tmp_inode, retval);
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tmp_inode);
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/* We mark the tmp_inode dirty via ext4_ext_tree_init. */
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if (ext4_journal_extend(handle, 1) != 0)
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ext4_journal_restart(handle, 1);
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/*
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* Mark the tmp_inode as of size zero
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@ -556,8 +588,7 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
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tmp_inode->i_nlink = 0;
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ext4_journal_stop(handle);
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up_write(&EXT4_I(inode)->i_data_sem);
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mutex_unlock(&(inode->i_mutex));
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if (tmp_inode)
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iput(tmp_inode);
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