forked from Minki/linux
ext4: move_extent code cleanup
- Remove usless checks, because it is too late to check that inode != NULL at the moment it was referenced several times. - Double lock routines looks very ugly and locking ordering relays on order of i_ino, but other kernel code rely on order of pointers. Let's make them simple and clean. - check that inodes belongs to the same SB as soon as possible. Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: stable@vger.kernel.org
This commit is contained in:
Dmitry Monakhov
Theodore Ts'o
parent
0acdb8876f
commit
03bd8b9b89
@ -140,56 +140,22 @@ mext_next_extent(struct inode *inode, struct ext4_ext_path *path,
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return 1;
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}
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/**
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* mext_check_null_inode - NULL check for two inodes
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*
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* If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
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*/
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static int
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mext_check_null_inode(struct inode *inode1, struct inode *inode2,
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const char *function, unsigned int line)
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{
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int ret = 0;
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if (inode1 == NULL) {
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__ext4_error(inode2->i_sb, function, line,
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"Both inodes should not be NULL: "
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"inode1 NULL inode2 %lu", inode2->i_ino);
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ret = -EIO;
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} else if (inode2 == NULL) {
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__ext4_error(inode1->i_sb, function, line,
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"Both inodes should not be NULL: "
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"inode1 %lu inode2 NULL", inode1->i_ino);
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ret = -EIO;
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}
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return ret;
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}
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/**
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* double_down_write_data_sem - Acquire two inodes' write lock of i_data_sem
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*
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* @orig_inode: original inode structure
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* @donor_inode: donor inode structure
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* Acquire write lock of i_data_sem of the two inodes (orig and donor) by
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* i_ino order.
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* Acquire write lock of i_data_sem of the two inodes
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*/
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static void
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double_down_write_data_sem(struct inode *orig_inode, struct inode *donor_inode)
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double_down_write_data_sem(struct inode *first, struct inode *second)
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{
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struct inode *first = orig_inode, *second = donor_inode;
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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, SINGLE_DEPTH_NESTING);
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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, SINGLE_DEPTH_NESTING);
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/*
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* Use the inode number to provide the stable locking order instead
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* of its address, because the C language doesn't guarantee you can
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* compare pointers that don't come from the same array.
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*/
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if (donor_inode->i_ino < orig_inode->i_ino) {
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first = donor_inode;
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second = orig_inode;
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}
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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, SINGLE_DEPTH_NESTING);
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}
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/**
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@ -969,14 +935,6 @@ mext_check_arguments(struct inode *orig_inode,
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return -EINVAL;
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}
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/* Files should be in the same ext4 FS */
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if (orig_inode->i_sb != donor_inode->i_sb) {
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ext4_debug("ext4 move extent: The argument files "
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"should be in same FS [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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/* 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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@ -1072,35 +1030,19 @@ mext_check_arguments(struct inode *orig_inode,
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* @inode1: the inode structure
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* @inode2: the inode structure
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*
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* Lock two inodes' i_mutex by i_ino order.
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* If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
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* Lock two inodes' i_mutex
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*/
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static int
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static void
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mext_inode_double_lock(struct inode *inode1, struct inode *inode2)
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{
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int ret = 0;
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BUG_ON(inode1 == NULL && inode2 == NULL);
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ret = mext_check_null_inode(inode1, inode2, __func__, __LINE__);
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if (ret < 0)
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goto out;
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if (inode1 == inode2) {
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mutex_lock(&inode1->i_mutex);
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goto out;
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}
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if (inode1->i_ino < inode2->i_ino) {
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BUG_ON(inode1 == inode2);
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if (inode1 < inode2) {
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mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
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mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
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} else {
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mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
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mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
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}
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out:
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return ret;
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}
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/**
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@ -1109,28 +1051,13 @@ out:
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* @inode1: the inode that is released first
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* @inode2: the inode that is released second
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*
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* If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
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*/
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static int
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static void
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mext_inode_double_unlock(struct inode *inode1, struct inode *inode2)
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{
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int ret = 0;
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BUG_ON(inode1 == NULL && inode2 == NULL);
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ret = mext_check_null_inode(inode1, inode2, __func__, __LINE__);
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if (ret < 0)
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goto out;
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if (inode1)
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mutex_unlock(&inode1->i_mutex);
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if (inode2 && inode2 != inode1)
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mutex_unlock(&inode2->i_mutex);
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out:
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return ret;
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mutex_unlock(&inode1->i_mutex);
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mutex_unlock(&inode2->i_mutex);
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}
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/**
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@ -1187,16 +1114,23 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
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ext4_lblk_t block_end, seq_start, add_blocks, file_end, seq_blocks = 0;
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ext4_lblk_t rest_blocks;
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pgoff_t orig_page_offset = 0, seq_end_page;
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int ret1, ret2, depth, last_extent = 0;
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int ret, depth, last_extent = 0;
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int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
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int data_offset_in_page;
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int block_len_in_page;
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int uninit;
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/* orig and donor should be different file */
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if (orig_inode->i_ino == donor_inode->i_ino) {
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if (orig_inode->i_sb != donor_inode->i_sb) {
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ext4_debug("ext4 move extent: The argument files "
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"should be in same FS [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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/* orig and donor should be different inodes */
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if (orig_inode == donor_inode) {
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ext4_debug("ext4 move extent: The argument files should not "
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"be same file [ino:orig %lu, donor %lu]\n",
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"be same inode [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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@ -1210,16 +1144,14 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
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}
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/* Protect orig and donor inodes against a truncate */
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ret1 = mext_inode_double_lock(orig_inode, donor_inode);
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if (ret1 < 0)
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return ret1;
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mext_inode_double_lock(orig_inode, donor_inode);
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/* Protect extent tree against block allocations via delalloc */
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double_down_write_data_sem(orig_inode, donor_inode);
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/* Check the filesystem environment whether move_extent can be done */
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ret1 = mext_check_arguments(orig_inode, donor_inode, orig_start,
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ret = mext_check_arguments(orig_inode, donor_inode, orig_start,
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donor_start, &len);
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if (ret1)
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if (ret)
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goto out;
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file_end = (i_size_read(orig_inode) - 1) >> orig_inode->i_blkbits;
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@ -1227,13 +1159,13 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
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if (file_end < block_end)
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len -= block_end - file_end;
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ret1 = get_ext_path(orig_inode, block_start, &orig_path);
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if (ret1)
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ret = get_ext_path(orig_inode, block_start, &orig_path);
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if (ret)
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goto out;
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/* Get path structure to check the hole */
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ret1 = get_ext_path(orig_inode, block_start, &holecheck_path);
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if (ret1)
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ret = get_ext_path(orig_inode, block_start, &holecheck_path);
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if (ret)
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goto out;
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depth = ext_depth(orig_inode);
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@ -1252,13 +1184,13 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
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last_extent = mext_next_extent(orig_inode,
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holecheck_path, &ext_cur);
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if (last_extent < 0) {
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ret1 = last_extent;
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ret = last_extent;
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goto out;
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}
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last_extent = mext_next_extent(orig_inode, orig_path,
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&ext_dummy);
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if (last_extent < 0) {
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ret1 = last_extent;
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ret = last_extent;
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goto out;
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}
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seq_start = le32_to_cpu(ext_cur->ee_block);
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@ -1272,7 +1204,7 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
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if (le32_to_cpu(ext_cur->ee_block) > block_end) {
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ext4_debug("ext4 move extent: The specified range of file "
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"may be the hole\n");
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ret1 = -EINVAL;
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ret = -EINVAL;
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goto out;
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}
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@ -1292,7 +1224,7 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
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last_extent = mext_next_extent(orig_inode, holecheck_path,
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&ext_cur);
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if (last_extent < 0) {
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ret1 = last_extent;
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ret = last_extent;
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break;
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}
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add_blocks = ext4_ext_get_actual_len(ext_cur);
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@ -1349,18 +1281,18 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
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orig_page_offset,
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data_offset_in_page,
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block_len_in_page, uninit,
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&ret1);
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&ret);
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/* Count how many blocks we have exchanged */
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*moved_len += block_len_in_page;
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if (ret1 < 0)
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if (ret < 0)
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break;
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if (*moved_len > len) {
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EXT4_ERROR_INODE(orig_inode,
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"We replaced blocks too much! "
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"sum of replaced: %llu requested: %llu",
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*moved_len, len);
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ret1 = -EIO;
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ret = -EIO;
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break;
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}
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@ -1374,22 +1306,22 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp,
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}
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double_down_write_data_sem(orig_inode, donor_inode);
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if (ret1 < 0)
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if (ret < 0)
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break;
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/* Decrease buffer counter */
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if (holecheck_path)
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ext4_ext_drop_refs(holecheck_path);
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ret1 = get_ext_path(orig_inode, seq_start, &holecheck_path);
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if (ret1)
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ret = get_ext_path(orig_inode, seq_start, &holecheck_path);
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if (ret)
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break;
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depth = holecheck_path->p_depth;
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/* Decrease buffer counter */
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if (orig_path)
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ext4_ext_drop_refs(orig_path);
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ret1 = get_ext_path(orig_inode, seq_start, &orig_path);
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if (ret1)
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ret = get_ext_path(orig_inode, seq_start, &orig_path);
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if (ret)
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break;
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ext_cur = holecheck_path[depth].p_ext;
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@ -1412,12 +1344,7 @@ out:
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kfree(holecheck_path);
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}
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double_up_write_data_sem(orig_inode, donor_inode);
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ret2 = mext_inode_double_unlock(orig_inode, donor_inode);
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mext_inode_double_unlock(orig_inode, donor_inode);
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if (ret1)
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return ret1;
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else if (ret2)
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return ret2;
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return 0;
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return ret;
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}
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