Messages in this thread | | | Date | Wed, 23 Jan 2008 19:14:54 -0800 | From | Mark Fasheh <> | Subject | Re: [PATCH 12/30] ocfs2: Add group extend for online resize |
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On Wed, Jan 23, 2008 at 02:05:48PM -0800, Andrew Morton wrote: > > On Thu, 17 Jan 2008 14:35:38 -0800 Mark Fasheh <mark.fasheh@oracle.com> wrote: > > From: Tao Ma <tao.ma@oracle.com> > > > > This patch adds the ability for a userspace program to request an extend of > > last cluster group on an Ocfs2 file system. The request is made via ioctl, > > OCFS2_IOC_GROUP_EXTEND. This is derived from EXT3_IOC_GROUP_EXTEND, but is > > obviously Ocfs2 specific. > > > > tunefs.ocfs2 would call this for an online-resize operation if the last > > cluster group isn't full. > > > > ... > > > > +/* Check whether the blkno is the super block or one of the backups. */ > > +static inline void ocfs2_check_super_or_backup(struct super_block *sb, > > + sector_t blkno) > > +{ > > + int i; > > + u64 backup_blkno; > > + > > + if (blkno == OCFS2_SUPER_BLOCK_BLKNO) > > + return; > > + > > + for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) { > > + backup_blkno = ocfs2_backup_super_blkno(sb, i); > > + if (backup_blkno == blkno) > > + return; > > + } > > + > > + BUG(); > > ow, harsh. > > > +} > > ocfs2_check_super_or_backup() is too large to inline. As is > ocfs2_backup_super_blkno() and probably lots of other stuff.
Ok, I added a patch to un-inline ocfs2_check_super_or_backup().
Give me some time to fix up ocfs2_backup_super_blkno() - I'll need to update the ocfs2-tools tree accordingly.
> Should ocfs2_backup_super_blkno() return sector_t?
Possibly? I think we're safe as-is because a 32 bit machine should not be able to mount a file system where overflow of this could happen. Internally, ocfs2 uses u64 to describe file system blocks, which is why ocfs2_backup_super_blkno() returns that.
> > + * so we don't need to lock ip_io_mutex and inode doesn't need to bea passed > > + * into this function. > > + */ > > +int ocfs2_write_super_or_backup(struct ocfs2_super *osb, > > + struct buffer_head *bh) > > +{ > > + int ret = 0; > > + > > + mlog_entry_void(); > > + > > + BUG_ON(buffer_jbd(bh)); > > + ocfs2_check_super_or_backup(osb->sb, bh->b_blocknr); > > + > > + if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb)) { > > + ret = -EROFS; > > + goto out; > > + } > > + > > + lock_buffer(bh); > > + set_buffer_uptodate(bh); > > + > > + /* remove from dirty list before I/O. */ > > + clear_buffer_dirty(bh); > > + > > + get_bh(bh); /* for end_buffer_write_sync() */ > > + bh->b_end_io = end_buffer_write_sync; > > + submit_bh(WRITE, bh); > > + > > + wait_on_buffer(bh); > > + > > + if (!buffer_uptodate(bh)) { > > + ret = -EIO; > > + brelse(bh); > > Only use brelse() when the bh might be NULL. put_bh() is cleaner and quicker.
Ok, fixed. There was other places in fs/ocfs2/buffer_head_io.c which got the same cleanup.
I also took care of the new:
if (bh) brelse(bh);
patterns in resize.c. Unfortunately, Ocfs2 is littered with this code pattern.
> > + } > > + > > +out: > > + mlog_exit(ret); > > + return ret; > > +} > > Did we just reimplement sync_dirty_buffer()?
For a bit of background: What Tao did was copy a small core from the other I/O functions into a new one for backup super block writes. This was done for cleanliness. The actual method used for buffer_head I/O in Ocfs2 has been unchanged for years.
At first glance, there *does* seem to be some similarity to sync_dirty_buffer(), but there are key differences in that dirty/uptodate state is forced in the ocfs2/buffer_head_io.c case. As such, I'm not sure that sync_dirty_buffer() is a drop-in replacement.
> > + first_new_cluster, > > + cl_cpg, 1); > > + le16_add_cpu(&group->bg_free_bits_count, -1 * backups); > > + } > > + > > + ret = ocfs2_journal_dirty(handle, group_bh); > > + if (ret < 0) { > > + mlog_errno(ret); > > + goto out_rollback; > > + } > > + > > + /* update the inode accordingly. */ > > + ret = ocfs2_journal_access(handle, bm_inode, bm_bh, > > + OCFS2_JOURNAL_ACCESS_WRITE); > > + if (ret < 0) { > > + mlog_errno(ret); > > + goto out_rollback; > > + } > > + > > + chain = le16_to_cpu(group->bg_chain); > > + cr = (&cl->cl_recs[chain]); > > + le32_add_cpu(&cr->c_total, num_bits); > > + le32_add_cpu(&cr->c_free, num_bits); > > + le32_add_cpu(&fe->id1.bitmap1.i_total, num_bits); > > + le32_add_cpu(&fe->i_clusters, new_clusters); > > + > > + if (backups) { > > + le32_add_cpu(&cr->c_free, -1 * backups); > > + le32_add_cpu(&fe->id1.bitmap1.i_used, backups); > > + } > > + > > + spin_lock(&OCFS2_I(bm_inode)->ip_lock); > > + OCFS2_I(bm_inode)->ip_clusters = le32_to_cpu(fe->i_clusters); > > + le64_add_cpu(&fe->i_size, new_clusters << osb->s_clustersize_bits); > > + spin_unlock(&OCFS2_I(bm_inode)->ip_lock); > > + i_size_write(bm_inode, le64_to_cpu(fe->i_size)); > > Is i_mutex held here? If not, i_size_write() can cause i_size_read() > deadlocks.
Yeah - this is called from ocfs2_group_extend() which takes i_mutex after looking up the bitmap inode.
> > +static int update_backups(struct inode * inode, u32 clusters, char *data) > > +{ > > + int i, ret = 0; > > + u32 cluster; > > + u64 blkno; > > + struct buffer_head *backup = NULL; > > + struct ocfs2_dinode *backup_di = NULL; > > + struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); > > + > > + /* calculate the real backups we need to update. */ > > + for (i = 0; i < OCFS2_MAX_BACKUP_SUPERBLOCKS; i++) { > > + blkno = ocfs2_backup_super_blkno(inode->i_sb, i); > > + cluster = ocfs2_blocks_to_clusters(inode->i_sb, blkno); > > + if (cluster > clusters) > > stray whitespace here. checkpatch doesn't (probably can't) detect this. > But you apparently don't run checkpatch anwyay..
Not enough, no. And you're right - I should. I'll be much more strict about running it in the future, thanks for pointing this out. --Mark
-- Mark Fasheh Principal Software Developer, Oracle mark.fasheh@oracle.com
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