Hi wengang, On 08/16/2010 12:55 PM, Wengang Wang wrote: > Hi tao, > > On 10-08-16 10:31, Tao Ma wrote: >> Durring orphan scan, if we are slot 0, and we are replaying >> orphan_dir:0001, the general process is that for every file >> in this dir: >> 1. we will iget orphan_dir:0001, since there is no inode for it. >> we will have to create an inode and read it from the disk. >> 2. do the normal work, such as delete_inode and remove it from >> the dir if it is allowed. >> 3. call iput orphan_dir:0001 when we are done. In this case, >> since we have no dcache for this inode, i_count will >> reach 0, and VFS will have to call clear_inode and in >> ocfs2_clear_inode we will checkpoint the inode which will let >> ocfs2_cmt and journald begin to work. >> 4. We loop back to 1 for the next file. >> >> So you see, actually for every deleted file, we have to read the >> orphan dir from the disk and checkpoint the journal. It is very >> time consuming and cause a lot of journal checkpoint I/O. >> A better solution is that we can have another reference for these >> inodes in ocfs2_super. So if there is no other race among >> nodes(which will let dlmglue to checkpoint the inode), for step 3, >> clear_inode won't be called and for step 1, we may only need to >> read the inode for the 1st time. This is a big win for us. >> >> So this patch will try to cache system inodes of other slots so >> that we will have one more reference for these inodes and avoid >> the extra inode read and journal checkpoint. >> >> Signed-off-by: Tao Ma<[email protected]> >> - u32 slot) >> +static struct inode **get_local_system_inode(struct ocfs2_super *osb, >> + int type, >> + u32 slot) >> { >> - return slot == osb->slot_num || is_global_system_inode(type); >> + int index; >> + >> + BUG_ON(slot == OCFS2_INVALID_SLOT); >> + BUG_ON(type< OCFS2_FIRST_LOCAL_SYSTEM_INODE || >> + type> OCFS2_LAST_LOCAL_SYSTEM_INODE); >> + >> + if (unlikely(!osb->local_system_inodes)) { >> + osb->local_system_inodes = kzalloc(sizeof(struct inode *) * >> + NUM_LOCAL_SYSTEM_INODES * >> + osb->max_slots, >> + GFP_NOFS); >> + if (!osb->local_system_inodes) { >> + mlog_errno(-ENOMEM); >> + /* >> + * return NULL here so that ocfs2_get_sytem_file_inodes >> + * will try to create an inode and use it. We will try >> + * to initialize local_system_inodes next time. >> + */ >> + return NULL; >> + } >> + } >> + > > Here, it's possible that get_local_system_inode() runs in parallel. > Since setting local_system_inodes is not protected, there be a memory leak. You are right. I will update it. Thanks.
Regards, Tao _______________________________________________ Ocfs2-devel mailing list [email protected] http://oss.oracle.com/mailman/listinfo/ocfs2-devel
