Ocfs2/move_extents: move/defrag extents within a certain range.

the basic logic of moving extents for a file is pretty like punching-hole
sequence, walk the extents within the range as user specified, calculating
an appropriate len to defrag/move, then let ocfs2_defrag/move_extent() to
do the actual moving.

This func ends up setting 'OCFS2_MOVE_EXT_FL_COMPLETE' to userpace if operation
gets done successfully.

Signed-off-by: Tristan Ye <tristan.ye@oracle.com>

3 files changed, 315 insertions, 0 deletions

diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index fd248ed53df7..59100598b0cb 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -26,6 +26,7 @@
 #include "dir.h"
 #include "buffer_head_io.h"
 #include "suballoc.h"
+#include "move_extents.h"
 
 #include <linux/ext2_fs.h>
 
@@ -951,6 +952,8 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                         return -EFAULT;
 
                 return ocfs2_info_handle(inode, &info, 0);
+        case OCFS2_IOC_MOVE_EXT:
+                return ocfs2_ioctl_move_extents(filp, (void __user *)arg);
         default:
                 return -ENOTTY;
         }
@@ -993,6 +996,8 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd, unsigned long arg)
                         return -EFAULT;
 
                 return ocfs2_info_handle(inode, &info, 1);
+        case OCFS2_IOC_MOVE_EXT:
+                break;
         default:
                 return -ENOIOCTLCMD;
         }
diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c
index 1c822e08fea0..800552168d8a 100644
--- a/fs/ocfs2/move_extents.c
+++ b/fs/ocfs2/move_extents.c
@@ -827,3 +827,311 @@ static void ocfs2_calc_extent_defrag_len(u32 *alloc_size, u32 *len_defraged,
                 *len_defraged = 0;
         }
 }
+
+static int __ocfs2_move_extents_range(struct buffer_head *di_bh,
+                                struct ocfs2_move_extents_context *context)
+{
+        int ret = 0, flags, do_defrag, skip = 0;
+        u32 cpos, phys_cpos, move_start, len_to_move, alloc_size;
+        u32 len_defraged = 0, defrag_thresh = 0, new_phys_cpos = 0;
+
+        struct inode *inode = context->inode;
+        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+        struct ocfs2_move_extents *range = context->range;
+        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+        if ((inode->i_size == 0) || (range->me_len == 0))
+                return 0;
+
+        if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
+                return 0;
+
+        context->refcount_loc = le64_to_cpu(di->i_refcount_loc);
+
+        ocfs2_init_dinode_extent_tree(&context->et, INODE_CACHE(inode), di_bh);
+        ocfs2_init_dealloc_ctxt(&context->dealloc);
+
+        /*
+         * TO-DO XXX:
+         *
+         * - xattr extents.
+         */
+
+        do_defrag = context->auto_defrag;
+
+        /*
+         * extents moving happens in unit of clusters, for the sake
+         * of simplicity, we may ignore two clusters where 'byte_start'
+         * and 'byte_start + len' were within.
+         */
+        move_start = ocfs2_clusters_for_bytes(osb->sb, range->me_start);
+        len_to_move = (range->me_start + range->me_len) >>
+                                                osb->s_clustersize_bits;
+        if (len_to_move >= move_start)
+                len_to_move -= move_start;
+        else
+                len_to_move = 0;
+
+        if (do_defrag)
+                defrag_thresh = range->me_threshold >> osb->s_clustersize_bits;
+        else
+                new_phys_cpos = ocfs2_blocks_to_clusters(inode->i_sb,
+                                                         range->me_goal);
+
+        mlog(0, "Inode: %llu, start: %llu, len: %llu, cstart: %u, clen: %u, "
+             "thresh: %u\n",
+             (unsigned long long)OCFS2_I(inode)->ip_blkno,
+             (unsigned long long)range->me_start,
+             (unsigned long long)range->me_len,
+             move_start, len_to_move, defrag_thresh);
+
+        cpos = move_start;
+        while (len_to_move) {
+                ret = ocfs2_get_clusters(inode, cpos, &phys_cpos, &alloc_size,
+                                         &flags);
+                if (ret) {
+                        mlog_errno(ret);
+                        goto out;
+                }
+
+                if (alloc_size > len_to_move)
+                        alloc_size = len_to_move;
+
+                /*
+                 * XXX: how to deal with a hole:
+                 *
+                 * - skip the hole of course
+                 * - force a new defragmentation
+                 */
+                if (!phys_cpos) {
+                        if (do_defrag)
+                                len_defraged = 0;
+
+                        goto next;
+                }
+
+                if (do_defrag) {
+                        ocfs2_calc_extent_defrag_len(&alloc_size, &len_defraged,
+                                                     defrag_thresh, &skip);
+                        /*
+                         * skip large extents
+                         */
+                        if (skip) {
+                                skip = 0;
+                                goto next;
+                        }
+
+                        mlog(0, "#Defrag: cpos: %u, phys_cpos: %u, "
+                             "alloc_size: %u, len_defraged: %u\n",
+                             cpos, phys_cpos, alloc_size, len_defraged);
+
+                        ret = ocfs2_defrag_extent(context, cpos, phys_cpos,
+                                                  alloc_size, flags);
+                } else {
+                        ret = ocfs2_move_extent(context, cpos, phys_cpos,
+                                                &new_phys_cpos, alloc_size,
+                                                flags);
+
+                        new_phys_cpos += alloc_size;
+                }
+
+                if (ret < 0) {
+                        mlog_errno(ret);
+                        goto out;
+                }
+
+                context->clusters_moved += alloc_size;
+next:
+                cpos += alloc_size;
+                len_to_move -= alloc_size;
+        }
+
+        range->me_flags |= OCFS2_MOVE_EXT_FL_COMPLETE;
+
+out:
+        range->me_moved_len = ocfs2_clusters_to_bytes(osb->sb,
+                                                      context->clusters_moved);
+        range->me_new_offset = ocfs2_clusters_to_bytes(osb->sb,
+                                                       context->new_phys_cpos);
+
+        ocfs2_schedule_truncate_log_flush(osb, 1);
+        ocfs2_run_deallocs(osb, &context->dealloc);
+
+        return ret;
+}
+
+static int ocfs2_move_extents(struct ocfs2_move_extents_context *context)
+{
+        int status;
+        handle_t *handle;
+        struct inode *inode = context->inode;
+        struct ocfs2_dinode *di;
+        struct buffer_head *di_bh = NULL;
+        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+        if (!inode)
+                return -ENOENT;
+
+        if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
+                return -EROFS;
+
+        mutex_lock(&inode->i_mutex);
+
+        /*
+         * This prevents concurrent writes from other nodes
+         */
+        status = ocfs2_rw_lock(inode, 1);
+        if (status) {
+                mlog_errno(status);
+                goto out;
+        }
+
+        status = ocfs2_inode_lock(inode, &di_bh, 1);
+        if (status) {
+                mlog_errno(status);
+                goto out_rw_unlock;
+        }
+
+        /*
+         * rememer ip_xattr_sem also needs to be held if necessary
+         */
+        down_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+        status = __ocfs2_move_extents_range(di_bh, context);
+
+        up_write(&OCFS2_I(inode)->ip_alloc_sem);
+        if (status) {
+                mlog_errno(status);
+                goto out_inode_unlock;
+        }
+
+        /*
+         * We update ctime for these changes
+         */
+        handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
+        if (IS_ERR(handle)) {
+                status = PTR_ERR(handle);
+                mlog_errno(status);
+                goto out_inode_unlock;
+        }
+
+        status = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
+                                         OCFS2_JOURNAL_ACCESS_WRITE);
+        if (status) {
+                mlog_errno(status);
+                goto out_commit;
+        }
+
+        di = (struct ocfs2_dinode *)di_bh->b_data;
+        inode->i_ctime = CURRENT_TIME;
+        di->i_ctime = cpu_to_le64(inode->i_ctime.tv_sec);
+        di->i_ctime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);
+
+        ocfs2_journal_dirty(handle, di_bh);
+
+out_commit:
+        ocfs2_commit_trans(osb, handle);
+
+out_inode_unlock:
+        brelse(di_bh);
+        ocfs2_inode_unlock(inode, 1);
+out_rw_unlock:
+        ocfs2_rw_unlock(inode, 1);
+out:
+        mutex_unlock(&inode->i_mutex);
+
+        return status;
+}
+
+int ocfs2_ioctl_move_extents(struct file *filp, void __user *argp)
+{
+        int status;
+
+        struct inode *inode = filp->f_path.dentry->d_inode;
+        struct ocfs2_move_extents range;
+        struct ocfs2_move_extents_context *context = NULL;
+
+        status = mnt_want_write(filp->f_path.mnt);
+        if (status)
+                return status;
+
+        if ((!S_ISREG(inode->i_mode)) || !(filp->f_mode & FMODE_WRITE))
+                goto out;
+
+        if (inode->i_flags & (S_IMMUTABLE|S_APPEND)) {
+                status = -EPERM;
+                goto out;
+        }
+
+        context = kzalloc(sizeof(struct ocfs2_move_extents_context), GFP_NOFS);
+        if (!context) {
+                status = -ENOMEM;
+                mlog_errno(status);
+                goto out;
+        }
+
+        context->inode = inode;
+        context->file = filp;
+
+        if (argp) {
+                if (copy_from_user(&range, (struct ocfs2_move_extents *)argp,
+                                   sizeof(range))) {
+                        status = -EFAULT;
+                        goto out;
+                }
+        } else {
+                status = -EINVAL;
+                goto out;
+        }
+
+        if (range.me_start > i_size_read(inode))
+                goto out;
+
+        if (range.me_start + range.me_len > i_size_read(inode))
+                        range.me_len = i_size_read(inode) - range.me_start;
+
+        context->range = &range;
+
+        if (range.me_flags & OCFS2_MOVE_EXT_FL_AUTO_DEFRAG) {
+                context->auto_defrag = 1;
+                if (!range.me_threshold)
+                        /*
+                         * ok, the default theshold for the defragmentation
+                         * is 1M, since our maximum clustersize was 1M also.
+                         * any thought?
+                         */
+                        range.me_threshold = 1024 * 1024;
+        } else {
+                /*
+                 * first best-effort attempt to validate and adjust the goal
+                 * (physical address in block), while it can't guarantee later
+                 * operation can succeed all the time since global_bitmap may
+                 * change a bit over time.
+                 */
+
+                status = ocfs2_validate_and_adjust_move_goal(inode, &range);
+                if (status)
+                        goto out;
+        }
+
+        status = ocfs2_move_extents(context);
+        if (status)
+                mlog_errno(status);
+out:
+        /*
+         * movement/defragmentation may end up being partially completed,
+         * that's the reason why we need to return userspace the finished
+         * length and new_offset even if failure happens somewhere.
+         */
+        if (argp) {
+                if (copy_to_user((struct ocfs2_move_extents *)argp, &range,
+                                sizeof(range)))
+                        status = -EFAULT;
+        }
+
+        kfree(context);
+
+        mnt_drop_write(filp->f_path.mnt);
+
+        return status;
+}
diff --git a/fs/ocfs2/move_extents.h b/fs/ocfs2/move_extents.h
index 27570f7f6909..4e143e811441 100644
--- a/fs/ocfs2/move_extents.h
+++ b/fs/ocfs2/move_extents.h
@@ -17,4 +17,6 @@
 #ifndef OCFS2_MOVE_EXTENTS_H
 #define OCFS2_MOVE_EXTENTS_H
 
+int ocfs2_ioctl_move_extents(struct file *filp,  void __user *argp);
+
 #endif /* OCFS2_MOVE_EXTENTS_H */