Hi Jaegeuk, > -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk@xxxxxxxxxx] > Sent: Thursday, December 24, 2015 10:15 AM > To: linux-kernel@xxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx; > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > Cc: Jaegeuk Kim > Subject: [f2fs-dev] [PATCH 3/4] f2fs: avoid f2fs_lock_op in f2fs_write_begin > > If f2fs_write_begin is to update data, we can bypass calling f2fs_lock_op() in > order to avoid the checkpoint latency in the write syscall. > > Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> > --- > fs/f2fs/data.c | 43 ++++++++++++++++++++++++++++++++++--------- > 1 file changed, 34 insertions(+), 9 deletions(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 49092da..d53cf4f 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -1418,10 +1418,16 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi, > pgoff_t index = page->index; > struct dnode_of_data dn; > struct page *ipage; > + bool locked = false; > + struct extent_info ei; > int err = 0; > > - f2fs_lock_op(sbi); > - > + if (f2fs_has_inline_data(inode) || > + (pos & PAGE_CACHE_MASK) >= i_size_read(inode)) { > + f2fs_lock_op(sbi); > + locked = true; > + } > +restart: > /* check inline_data */ > ipage = get_node_page(sbi, inode->i_ino); > if (IS_ERR(ipage)) { > @@ -1436,22 +1442,41 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi, > read_inline_data(page, ipage); > set_inode_flag(F2FS_I(inode), FI_DATA_EXIST); > sync_inode_page(&dn); > - goto done; > } else { > err = f2fs_convert_inline_page(&dn, page); > if (err) > - goto err_out; > + goto out; > + err = f2fs_get_block(&dn, index); Seems after f2fs_convert_inline_page, data_blkaddr and node_changed should have been set, so f2fs_get_block could be removed here. > + } > + } else if (locked) { > + err = f2fs_get_block(&dn, index); > + } else { > + if (f2fs_lookup_extent_cache(inode, index, &ei)) { > + dn.data_blkaddr = ei.blk + index - ei.fofs; > + } else { > + bool restart = false; > + > + /* hole case */ > + err = get_dnode_of_data(&dn, index, LOOKUP_NODE); Better to handle error case like -ENOMEM or -EIO. Thanks, > + if (err || (!err && dn.data_blkaddr == NULL_ADDR)) > + restart = true; > + if (restart) { > + f2fs_put_dnode(&dn); > + f2fs_lock_op(sbi); > + locked = true; > + goto restart; > + } > } > } > - err = f2fs_get_block(&dn, index); > -done: > + > /* convert_inline_page can make node_changed */ > *blk_addr = dn.data_blkaddr; > *node_changed = dn.node_changed; > -err_out: > +out: > f2fs_put_dnode(&dn); > unlock_out: > - f2fs_unlock_op(sbi); > + if (locked) > + f2fs_unlock_op(sbi); > return err; > } > > @@ -1488,7 +1513,7 @@ repeat: > > *pagep = page; > > - err = prepare_write_begin(sbi, page, pos + len, > + err = prepare_write_begin(sbi, page, pos, len, > &blkaddr, &need_balance); > if (err) > goto fail; > -- > 2.5.4 (Apple Git-61) > > > ------------------------------------------------------------------------------ > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
