WeiWei Wang
2014-Oct-11 12:32 UTC
[Ocfs2-devel] [PATCH 7/7 v4] ocfs2: do not fallback to buffer I/O write if fill holes
Now append O_DIRECT write to a hole will try direct io first, then
fallback to buffered IO if fails.
Signed-off-by: Weiwei Wang <wangww631 at huawei.com>
Reviewed-by: Joseph Qi <joseph.qi at huawei.com>
---
fs/ocfs2/file.c | 93 ++++++++++++++++++++++++++-------------------------------
1 file changed, 42 insertions(+), 51 deletions(-)
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 19e372f..08f234e 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1353,44 +1353,6 @@ out:
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 int ocfs2_write_remove_suid(struct inode *inode)
{
int ret;
@@ -2206,18 +2168,6 @@ static int ocfs2_prepare_inode_for_write(struct file
*file,
break;
}
- /*
- * We don't fill holes during direct io, so
- * check for them here. If any are found, the
- * caller will have to retake some cluster
- * locks and initiate the io as buffered.
- */
- ret = ocfs2_check_range_for_holes(inode, saved_pos, count);
- if (ret == 1) {
- *direct_io = 0;
- ret = 0;
- } else if (ret < 0)
- mlog_errno(ret);
break;
}
@@ -2247,6 +2197,7 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
u32 old_clusters;
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
+ struct address_space *mapping = file->f_mapping;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
int full_coherency = !(osb->s_mount_opt &
OCFS2_MOUNT_COHERENCY_BUFFERED);
@@ -2361,11 +2312,51 @@ relock:
iov_iter_truncate(from, count);
if (direct_io) {
+ loff_t endbyte;
+ ssize_t written_buffered;
written = generic_file_direct_write(iocb, from, *ppos);
- if (written < 0) {
+ if (written < 0 || written == count) {
ret = written;
goto out_dio;
}
+ /*
+ * direct-io write to a hole: fall through to buffered I/O
+ * for completing the rest of the request.
+ */
+ *ppos += written;
+ count -= written;
+ written_buffered = generic_perform_write(file, from, *ppos);
+ /*
+ * If generic_file_buffered_write() retuned a synchronous error
+ * then we want to return the number of bytes which were
+ * direct-written, or the error code if that was zero. Note
+ * that this differs from normal direct-io semantics, which
+ * will return -EFOO even if some bytes were written.
+ */
+ if (written_buffered < 0) {
+ ret = written_buffered;
+ goto out;
+ }
+
+ /*
+ * We need to ensure that the page cache pages are written to
+ * disk and invalidated to preserve the expected O_DIRECT
+ * semantics.
+ */
+ endbyte = *ppos + written_buffered - written - 1;
+ ret = filemap_write_and_wait_range(file->f_mapping, *ppos,
+ endbyte);
+ if (ret == 0) {
+ written = written_buffered;
+ invalidate_mapping_pages(mapping,
+ *ppos >> PAGE_CACHE_SHIFT,
+ endbyte >> PAGE_CACHE_SHIFT);
+ } else {
+ /*
+ * We don't know how much we wrote, so just return
+ * the number of bytes which were direct-written
+ */
+ }
} else {
current->backing_dev_info = file->f_mapping->backing_dev_info;
written = generic_perform_write(file, from, *ppos);
--
1.8.4.3
Joseph Qi
2014-Oct-22 12:12 UTC
[Ocfs2-devel] [PATCH 7/7 v4] ocfs2: do not fallback to buffer I/O write if fill holes
On 2014/10/11 20:32, WeiWei Wang wrote:> Now append O_DIRECT write to a hole will try direct io first, then > fallback to buffered IO if fails. > > Signed-off-by: Weiwei Wang <wangww631 at huawei.com> > Reviewed-by: Joseph Qi <joseph.qi at huawei.com> > --- > fs/ocfs2/file.c | 93 ++++++++++++++++++++++++++------------------------------- > 1 file changed, 42 insertions(+), 51 deletions(-) > > diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c > index 19e372f..08f234e 100644 > --- a/fs/ocfs2/file.c > +++ b/fs/ocfs2/file.c > @@ -1353,44 +1353,6 @@ out: > 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 int ocfs2_write_remove_suid(struct inode *inode) > { > int ret; > @@ -2206,18 +2168,6 @@ static int ocfs2_prepare_inode_for_write(struct file *file, > break; > } > > - /* > - * We don't fill holes during direct io, so > - * check for them here. If any are found, the > - * caller will have to retake some cluster > - * locks and initiate the io as buffered. > - */ > - ret = ocfs2_check_range_for_holes(inode, saved_pos, count); > - if (ret == 1) { > - *direct_io = 0; > - ret = 0; > - } else if (ret < 0) > - mlog_errno(ret); > break; > } > > @@ -2247,6 +2197,7 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb, > u32 old_clusters; > struct file *file = iocb->ki_filp; > struct inode *inode = file_inode(file); > + struct address_space *mapping = file->f_mapping; > struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); > int full_coherency = !(osb->s_mount_opt & > OCFS2_MOUNT_COHERENCY_BUFFERED); > @@ -2361,11 +2312,51 @@ relock: > > iov_iter_truncate(from, count); > if (direct_io) { > + loff_t endbyte; > + ssize_t written_buffered; > written = generic_file_direct_write(iocb, from, *ppos); > - if (written < 0) { > + if (written < 0 || written == count) { > ret = written; > goto out_dio; > } > + /* > + * direct-io write to a hole: fall through to buffered I/O > + * for completing the rest of the request. > + */ > + *ppos += written;Here *ppos has already been changed in generic_file_direct_write.> + count -= written; > + written_buffered = generic_perform_write(file, from, *ppos); > + /* > + * If generic_file_buffered_write() retuned a synchronous error > + * then we want to return the number of bytes which were > + * direct-written, or the error code if that was zero. Note > + * that this differs from normal direct-io semantics, which > + * will return -EFOO even if some bytes were written. > + */ > + if (written_buffered < 0) { > + ret = written_buffered; > + goto out; > + } > + > + /* > + * We need to ensure that the page cache pages are written to > + * disk and invalidated to preserve the expected O_DIRECT > + * semantics. > + */ > + endbyte = *ppos + written_buffered - written - 1; > + ret = filemap_write_and_wait_range(file->f_mapping, *ppos, > + endbyte); > + if (ret == 0) { > + written = written_buffered; > + invalidate_mapping_pages(mapping, > + *ppos >> PAGE_CACHE_SHIFT, > + endbyte >> PAGE_CACHE_SHIFT); > + } else { > + /* > + * We don't know how much we wrote, so just return > + * the number of bytes which were direct-written > + */ > + } > } else { > current->backing_dev_info = file->f_mapping->backing_dev_info; > written = generic_perform_write(file, from, *ppos); >