As you know, VFS layer has introduced non-block aio
flag IOCB_NOWAIT, which informs kernel to bail out
if an AIO request will block for reasons such as file
allocations, or a writeback triggered, or would block
while allocating requests while performing direct I/O.
Subsequent, pwritev2/preadv2 also can leverage this
part kernel code.
So far, ext4/xfs/btrfs have supported this feature,
I'd like to add the related code for ocfs2 file system.
Compare with v1, some changes are as below,
use osb pointer in ocfs2_try_rw_lock() function,
modify ocfs2_overwrite_io() function to make all error
value can be returned to the upper code,
move invoking ocfs2_overwrite_io() function from
ocfs2_file_write_iter() to ocfs2_prepare_inode_for_write(),
this change can combine acquiring the related locks.
Gang He (3):
ocfs2: add ocfs2_try_rw_lock and ocfs2_try_inode_lock
ocfs2: add ocfs2_overwrite_io function
ocfs2: nowait aio support
fs/ocfs2/dir.c | 2 +-
fs/ocfs2/dlmglue.c | 41 +++++++++++++++++++---
fs/ocfs2/dlmglue.h | 6 +++-
fs/ocfs2/extent_map.c | 41 ++++++++++++++++++++++
fs/ocfs2/extent_map.h | 3 ++
fs/ocfs2/file.c | 95 +++++++++++++++++++++++++++++++++++++++-----------
fs/ocfs2/mmap.c | 2 +-
fs/ocfs2/ocfs2_trace.h | 10 +++---
8 files changed, 168 insertions(+), 32 deletions(-)
--
1.8.5.6
From 1585632918275334313@xxx Sat Dec 02 01:16:29 +0000 2017
X-GM-THRID: 1585337848965420889
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Add ocfs2_overwrite_io function, which is used to judge if
overwrite allocated blocks, otherwise, the write will bring extra
block allocation overhead.
Signed-off-by: Gang He <[email protected]>
---
fs/ocfs2/extent_map.c | 41 +++++++++++++++++++++++++++++++++++++++++
fs/ocfs2/extent_map.h | 3 +++
2 files changed, 44 insertions(+)
diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
index e4719e0..4da33e9 100644
--- a/fs/ocfs2/extent_map.c
+++ b/fs/ocfs2/extent_map.c
@@ -832,6 +832,47 @@ int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
return ret;
}
+/* Is IO overwriting allocated blocks? */
+int ocfs2_overwrite_io(struct inode *inode, struct buffer_head *di_bh,
+ u64 map_start, u64 map_len)
+{
+ int ret = 0, is_last;
+ u32 mapping_end, cpos;
+ struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+ struct ocfs2_extent_rec rec;
+
+ if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) &&
+ ((map_start + map_len) <= i_size_read(inode)))
+ goto out;
+
+ cpos = map_start >> osb->s_clustersize_bits;
+ mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
+ map_start + map_len);
+ is_last = 0;
+ while (cpos < mapping_end && !is_last) {
+ ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
+ NULL, &rec, &is_last);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ if (rec.e_blkno == 0ULL)
+ break;
+
+ if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
+ break;
+
+ cpos = le32_to_cpu(rec.e_cpos) +
+ le16_to_cpu(rec.e_leaf_clusters);
+ }
+
+ if (cpos < mapping_end)
+ ret = -EAGAIN;
+out:
+ return ret;
+}
+
int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int whence)
{
struct inode *inode = file->f_mapping->host;
diff --git a/fs/ocfs2/extent_map.h b/fs/ocfs2/extent_map.h
index 67ea57d..1057586 100644
--- a/fs/ocfs2/extent_map.h
+++ b/fs/ocfs2/extent_map.h
@@ -53,6 +53,9 @@ int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 map_start, u64 map_len);
+int ocfs2_overwrite_io(struct inode *inode, struct buffer_head *di_bh,
+ u64 map_start, u64 map_len);
+
int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int origin);
int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
--
1.8.5.6
From 1585402365724730614@xxx Wed Nov 29 12:11:57 +0000 2017
X-GM-THRID: 1585212205986077742
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