Hi Changwei, On 2017/12/18 20:06, Changwei Ge wrote: > Before ocfs2 supporting allocating clusters while doing append-dio, all append > dio will fall back to buffer io to allocate clusters firstly. Also, when it > steps on a file hole, it will fall back to buffer io, too. But for current > code, writing to file hole will leverage dio to allocate clusters. This is not > right, since whether append-io is enabled tells the capability whether ocfs2 > can > allocate space while doing dio. > So introduce file hole check function back into ocfs2. > Once ocfs2 is doing dio upon a file hole with append-dio disabled, it will > fall > back to buffer IO to allocate clusters. > 1. Do you mean that filling hole can't go with dio when append-dio is disabled? 2. Is your checking-hole just for 'append-dio' or for 'all-common-dio'? > Signed-off-by: Changwei Ge <ge.chang...@h3c.com> > --- > fs/ocfs2/aops.c | 44 ++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 42 insertions(+), 2 deletions(-) > > diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c > index d151632..a982cf6 100644 > --- a/fs/ocfs2/aops.c > +++ b/fs/ocfs2/aops.c > @@ -2414,6 +2414,44 @@ static int ocfs2_dio_end_io(struct kiocb *iocb, > return ret; > } > > +/* > + * Will look for holes and unwritten extents in the range starting at > + * pos for count bytes (inclusive). > + */ > +static int ocfs2_check_range_for_holes(struct inode *inode, loff_t pos, > + size_t count) > +{ > + int ret = 0; > + unsigned int extent_flags; > + u32 cpos, clusters, extent_len, phys_cpos; > + struct super_block *sb = inode->i_sb; > + > + cpos = pos >> OCFS2_SB(sb)->s_clustersize_bits; > + clusters = ocfs2_clusters_for_bytes(sb, pos + count) - cpos; > + > + while (clusters) { > + ret = ocfs2_get_clusters(inode, cpos, &phys_cpos, &extent_len, > + &extent_flags); > + if (ret < 0) { > + mlog_errno(ret); > + goto out; > + } > + > + if (phys_cpos == 0 || (extent_flags & OCFS2_EXT_UNWRITTEN)) { > + ret = 1; > + break; > + } > + > + if (extent_len > clusters) > + extent_len = clusters; > + > + clusters -= extent_len; > + cpos += extent_len; > + } > +out: > + return ret; > +} > + > static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter) > { > struct file *file = iocb->ki_filp; > @@ -2429,8 +2467,10 @@ static ssize_t ocfs2_direct_IO(struct kiocb *iocb, > struct iov_iter *iter) > return 0; > > /* Fallback to buffered I/O if we do not support append dio. */ > - if (iocb->ki_pos + iter->count > i_size_read(inode) && > - !ocfs2_supports_append_dio(osb)) > + if (!ocfs2_supports_append_dio(osb) && > + (iocb->ki_pos + iter->count > i_size_read(inode) || > + ocfs2_check_range_for_holes(inode, iocb->ki_pos, > + iter->count))) we should check error here, right?
thanks, Jun > return 0; > > if (iov_iter_rw(iter) == READ) > _______________________________________________ Ocfs2-devel mailing list Ocfs2-devel@oss.oracle.com https://oss.oracle.com/mailman/listinfo/ocfs2-devel