erofs: use meta buffers for zmap operations

Get rid of old erofs_get_meta_page() within zmap operations by
using on-stack meta buffers in order to prepare subpage and folio
features.

Finally, erofs_get_meta_page() is useless. Get rid of it!

Link: https://lore.kernel.org/r/20220102040017.51352-6-hsiangkao@linux.alibaba.com
Reviewed-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index bd37f53f60cb652a52e1caaa4c64f48b2c6f3a68..e18476c85fa26dcf426eb50c13de2dc052bd5123 100644 (file)
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -9,19 +9,6 @@
 #include <linux/dax.h>
 #include <trace/events/erofs.h>
 
-struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
-{
-       struct address_space *const mapping = sb->s_bdev->bd_inode->i_mapping;
-       struct page *page;
-
-       page = read_cache_page_gfp(mapping, blkaddr,
-                                  mapping_gfp_constraint(mapping, ~__GFP_FS));
-       /* should already be PageUptodate */
-       if (!IS_ERR(page))
-               lock_page(page);
-       return page;
-}
-
 void erofs_unmap_metabuf(struct erofs_buf *buf)
 {
        if (buf->kmap_type == EROFS_KMAP)

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index f1e4eb3025f6ddfa144003026dd5331d2682a078..3db494a398b2d92c0feb3bec603461cf5cd3aa89 100644 (file)
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -419,14 +419,14 @@ enum {
 #define EROFS_MAP_FULL_MAPPED  (1 << BH_FullMapped)
 
 struct erofs_map_blocks {
+       struct erofs_buf buf;
+
        erofs_off_t m_pa, m_la;
        u64 m_plen, m_llen;
 
        unsigned short m_deviceid;
        char m_algorithmformat;
        unsigned int m_flags;
-
-       struct page *mpage;
 };
 
 /* Flags used by erofs_map_blocks_flatmode() */
@@ -474,7 +474,7 @@ struct erofs_map_dev {
 
 /* data.c */
 extern const struct file_operations erofs_file_fops;
-struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr);
+void erofs_unmap_metabuf(struct erofs_buf *buf);
 void erofs_put_metabuf(struct erofs_buf *buf);
 void *erofs_read_metabuf(struct erofs_buf *buf, struct super_block *sb,
                         erofs_blk_t blkaddr, enum erofs_kmap_type type);

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 49da3931b2e3033297cf706d13eb972c1e725cc2..498b7666efe852b94c93cc3379ee2b4216d10a94 100644 (file)
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -698,20 +698,18 @@ restart_now:
                goto err_out;
 
        if (z_erofs_is_inline_pcluster(clt->pcl)) {
-               struct page *mpage;
+               void *mp;
 
-               mpage = erofs_get_meta_page(inode->i_sb,
-                                           erofs_blknr(map->m_pa));
-               if (IS_ERR(mpage)) {
-                       err = PTR_ERR(mpage);
+               mp = erofs_read_metabuf(&fe->map.buf, inode->i_sb,
+                                       erofs_blknr(map->m_pa), EROFS_NO_KMAP);
+               if (IS_ERR(mp)) {
+                       err = PTR_ERR(mp);
                        erofs_err(inode->i_sb,
                                  "failed to get inline page, err %d", err);
                        goto err_out;
                }
-               /* TODO: new subpage feature will get rid of it */
-               unlock_page(mpage);
-
-               WRITE_ONCE(clt->pcl->compressed_pages[0], mpage);
+               get_page(fe->map.buf.page);
+               WRITE_ONCE(clt->pcl->compressed_pages[0], fe->map.buf.page);
                clt->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE;
        } else {
                /* preload all compressed pages (can change mode if needed) */
@@ -1529,9 +1527,7 @@ static int z_erofs_readpage(struct file *file, struct page *page)
        if (err)
                erofs_err(inode->i_sb, "failed to read, err [%d]", err);
 
-       if (f.map.mpage)
-               put_page(f.map.mpage);
-
+       erofs_put_metabuf(&f.map.buf);
        erofs_release_pages(&pagepool);
        return err;
 }
@@ -1576,8 +1572,7 @@ static void z_erofs_readahead(struct readahead_control *rac)
 
        z_erofs_runqueue(inode->i_sb, &f, &pagepool,
                         z_erofs_get_sync_decompress_policy(sbi, nr_pages));
-       if (f.map.mpage)
-               put_page(f.map.mpage);
+       erofs_put_metabuf(&f.map.buf);
        erofs_release_pages(&pagepool);
 }
 

diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 1037ac17b7a60351f4a4092ed72fa93607c7bd22..18d7fd1a50646039c29b6769cea3bbfd4a9d3766 100644 (file)
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -35,7 +35,7 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
        struct super_block *const sb = inode->i_sb;
        int err, headnr;
        erofs_off_t pos;
-       struct page *page;
+       struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
        void *kaddr;
        struct z_erofs_map_header *h;
 
@@ -61,14 +61,13 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
 
        pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
                    vi->xattr_isize, 8);
-       page = erofs_get_meta_page(sb, erofs_blknr(pos));
-       if (IS_ERR(page)) {
-               err = PTR_ERR(page);
+       kaddr = erofs_read_metabuf(&buf, sb, erofs_blknr(pos),
+                                  EROFS_KMAP_ATOMIC);
+       if (IS_ERR(kaddr)) {
+               err = PTR_ERR(kaddr);
                goto out_unlock;
        }
 
-       kaddr = kmap_atomic(page);
-
        h = kaddr + erofs_blkoff(pos);
        vi->z_advise = le16_to_cpu(h->h_advise);
        vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
@@ -101,20 +100,19 @@ static int z_erofs_fill_inode_lazy(struct inode *inode)
                goto unmap_done;
        }
 unmap_done:
-       kunmap_atomic(kaddr);
-       unlock_page(page);
-       put_page(page);
+       erofs_put_metabuf(&buf);
        if (err)
                goto out_unlock;
 
        if (vi->z_advise & Z_EROFS_ADVISE_INLINE_PCLUSTER) {
-               struct erofs_map_blocks map = { .mpage = NULL };
+               struct erofs_map_blocks map = {
+                       .buf = __EROFS_BUF_INITIALIZER
+               };
 
                vi->z_idata_size = le16_to_cpu(h->h_idata_size);
                err = z_erofs_do_map_blocks(inode, &map,
                                            EROFS_GET_BLOCKS_FINDTAIL);
-               if (map.mpage)
-                       put_page(map.mpage);
+               erofs_put_metabuf(&map.buf);
 
                if (!map.m_plen ||
                    erofs_blkoff(map.m_pa) + map.m_plen > EROFS_BLKSIZ) {
@@ -151,31 +149,11 @@ static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
                                  erofs_blk_t eblk)
 {
        struct super_block *const sb = m->inode->i_sb;
-       struct erofs_map_blocks *const map = m->map;
-       struct page *mpage = map->mpage;
-
-       if (mpage) {
-               if (mpage->index == eblk) {
-                       if (!m->kaddr)
-                               m->kaddr = kmap_atomic(mpage);
-                       return 0;
-               }
 
-               if (m->kaddr) {
-                       kunmap_atomic(m->kaddr);
-                       m->kaddr = NULL;
-               }
-               put_page(mpage);
-       }
-
-       mpage = erofs_get_meta_page(sb, eblk);
-       if (IS_ERR(mpage)) {
-               map->mpage = NULL;
-               return PTR_ERR(mpage);
-       }
-       m->kaddr = kmap_atomic(mpage);
-       unlock_page(mpage);
-       map->mpage = mpage;
+       m->kaddr = erofs_read_metabuf(&m->map->buf, sb, eblk,
+                                     EROFS_KMAP_ATOMIC);
+       if (IS_ERR(m->kaddr))
+               return PTR_ERR(m->kaddr);
        return 0;
 }
 
@@ -711,8 +689,7 @@ static int z_erofs_do_map_blocks(struct inode *inode,
                        map->m_flags |= EROFS_MAP_FULL_MAPPED;
        }
 unmap_out:
-       if (m.kaddr)
-               kunmap_atomic(m.kaddr);
+       erofs_unmap_metabuf(&m.map->buf);
 
 out:
        erofs_dbg("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
@@ -759,8 +736,7 @@ static int z_erofs_iomap_begin_report(struct inode *inode, loff_t offset,
        struct erofs_map_blocks map = { .m_la = offset };
 
        ret = z_erofs_map_blocks_iter(inode, &map, EROFS_GET_BLOCKS_FIEMAP);
-       if (map.mpage)
-               put_page(map.mpage);
+       erofs_put_metabuf(&map.buf);
        if (ret < 0)
                return ret;