]> www.infradead.org Git - users/dwmw2/linux.git/commitdiff
btrfs: convert btrfs_buffered_write() to use folios
authorQu Wenruo <wqu@suse.com>
Thu, 10 Oct 2024 04:46:13 +0000 (15:16 +1030)
committerDavid Sterba <dsterba@suse.com>
Mon, 11 Nov 2024 13:34:19 +0000 (14:34 +0100)
The buffered write path is still heavily utilizing the page interface.
Since we have converted it to do a page-by-page copying, it's much easier
to convert all involved functions to folio interface, this involves:

- btrfs_copy_from_user()
- btrfs_drop_folio()
- prepare_uptodate_page()
- prepare_one_page()
- lock_and_cleanup_extent_if_need()
- btrfs_dirty_page()

All function are changed to accept a folio parameter, and if the word
"page" is in the function name, change that to "folio" too.

The function btrfs_dirty_page() is exported for v1 space cache, convert
v1 cache call site to convert its page to folio for the new interface.

And there is a small enhancement for prepare_one_folio(), instead of
manually waiting for the page writeback, let __filemap_get_folio() to
handle that by using FGP_WRITEBEGIN, which implies
(FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE).

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
fs/btrfs/file.c
fs/btrfs/file.h
fs/btrfs/free-space-cache.c

index 0c5fc0e73c550b268321ea717ea4c6977a43aa47..5e0a1805e8979b2be0079b7a6ba966d4cbd405f5 100644 (file)
@@ -42,7 +42,7 @@
  * calls into generic code.
  */
 static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
-                                        struct page *page, struct iov_iter *i)
+                                        struct folio *folio, struct iov_iter *i)
 {
        size_t copied = 0;
        size_t total_copied = 0;
@@ -53,10 +53,10 @@ static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
                /*
                 * Copy data from userspace to the current page
                 */
-               copied = copy_page_from_iter_atomic(page, offset, count, i);
+               copied = copy_folio_from_iter_atomic(folio, offset, count, i);
 
                /* Flush processor's dcache for this page */
-               flush_dcache_page(page);
+               flush_dcache_folio(folio);
 
                /*
                 * if we get a partial write, we can end up with
@@ -68,7 +68,7 @@ static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
                 * back to page at a time copies after we return 0.
                 */
                if (unlikely(copied < count)) {
-                       if (!PageUptodate(page)) {
+                       if (!folio_test_uptodate(folio)) {
                                iov_iter_revert(i, copied);
                                copied = 0;
                        }
@@ -84,37 +84,36 @@ static noinline int btrfs_copy_from_user(loff_t pos, size_t write_bytes,
 }
 
 /*
- * unlocks pages after btrfs_file_write is done with them
+ * Unlock folio after btrfs_file_write() is done with it.
  */
-static void btrfs_drop_page(struct btrfs_fs_info *fs_info, struct page *page,
-                           u64 pos, u64 copied)
+static void btrfs_drop_folio(struct btrfs_fs_info *fs_info, struct folio *folio,
+                            u64 pos, u64 copied)
 {
        u64 block_start = round_down(pos, fs_info->sectorsize);
        u64 block_len = round_up(pos + copied, fs_info->sectorsize) - block_start;
 
        ASSERT(block_len <= U32_MAX);
        /*
-        * Page checked is some magic around finding pages that have been
-        * modified without going through btrfs_set_page_dirty clear it here.
+        * Folio checked is some magic around finding folios that have been
+        * modified without going through btrfs_dirty_folio().  Clear it here.
         * There should be no need to mark the pages accessed as
-        * prepare_one_page() should have marked them accessed in
-        * prepare_one_page() via find_or_create_page()
+        * prepare_one_folio() should have marked them accessed in
+        * prepare_one_folio() via find_or_create_page()
         */
-       btrfs_folio_clamp_clear_checked(fs_info, page_folio(page), block_start,
-                                       block_len);
-       unlock_page(page);
-       put_page(page);
+       btrfs_folio_clamp_clear_checked(fs_info, folio, block_start, block_len);
+       folio_unlock(folio);
+       folio_put(folio);
 }
 
 /*
  * After btrfs_copy_from_user(), update the following things for delalloc:
- * - Mark newly dirtied pages as DELALLOC in the io tree.
+ * - Mark newly dirtied folio as DELALLOC in the io tree.
  *   Used to advise which range is to be written back.
- * - Mark modified pages as Uptodate/Dirty and not needing COW fixup
+ * - Mark modified folio as Uptodate/Dirty and not needing COW fixup
  * - Update inode size for past EOF write
  */
-int btrfs_dirty_page(struct btrfs_inode *inode, struct page *page, loff_t pos,
-                    size_t write_bytes, struct extent_state **cached, bool noreserve)
+int btrfs_dirty_folio(struct btrfs_inode *inode, struct folio *folio, loff_t pos,
+                     size_t write_bytes, struct extent_state **cached, bool noreserve)
 {
        struct btrfs_fs_info *fs_info = inode->root->fs_info;
        int ret = 0;
@@ -122,7 +121,6 @@ int btrfs_dirty_page(struct btrfs_inode *inode, struct page *page, loff_t pos,
        u64 start_pos;
        u64 end_of_last_block;
        u64 end_pos = pos + write_bytes;
-       struct folio *folio = page_folio(page);
        loff_t isize = i_size_read(&inode->vfs_inode);
        unsigned int extra_bits = 0;
 
@@ -835,14 +833,12 @@ out:
 }
 
 /*
- * on error we return an unlocked page and the error value
- * on success we return a locked page and 0
+ * On error return an unlocked folio and the error value
+ * On success return a locked folio and 0
  */
-static int prepare_uptodate_page(struct inode *inode,
-                                struct page *page, u64 pos,
-                                u64 len, bool force_uptodate)
+static int prepare_uptodate_folio(struct inode *inode, struct folio *folio, u64 pos,
+                                 u64 len, bool force_uptodate)
 {
-       struct folio *folio = page_folio(page);
        u64 clamp_start = max_t(u64, pos, folio_pos(folio));
        u64 clamp_end = min_t(u64, pos + len, folio_pos(folio) + folio_size(folio));
        int ret = 0;
@@ -873,23 +869,13 @@ static int prepare_uptodate_page(struct inode *inode,
         * The private flag check is essential for subpage as we need to store
         * extra bitmap using folio private.
         */
-       if (page->mapping != inode->i_mapping || !folio_test_private(folio)) {
+       if (folio->mapping != inode->i_mapping || !folio_test_private(folio)) {
                folio_unlock(folio);
                return -EAGAIN;
        }
        return 0;
 }
 
-static fgf_t get_prepare_fgp_flags(bool nowait)
-{
-       fgf_t fgp_flags = FGP_LOCK | FGP_ACCESSED | FGP_CREAT;
-
-       if (nowait)
-               fgp_flags |= FGP_NOWAIT;
-
-       return fgp_flags;
-}
-
 static gfp_t get_prepare_gfp_flags(struct inode *inode, bool nowait)
 {
        gfp_t gfp;
@@ -904,60 +890,60 @@ static gfp_t get_prepare_gfp_flags(struct inode *inode, bool nowait)
 }
 
 /*
- * this just gets page into the page cache and locks them down.
+ * Get folio into the page cache and lock it.
  */
-static noinline int prepare_one_page(struct inode *inode, struct page **page_ret,
-                                    loff_t pos, size_t write_bytes,
-                                    bool force_uptodate, bool nowait)
+static noinline int prepare_one_folio(struct inode *inode, struct folio **folio_ret,
+                                     loff_t pos, size_t write_bytes,
+                                     bool force_uptodate, bool nowait)
 {
        unsigned long index = pos >> PAGE_SHIFT;
        gfp_t mask = get_prepare_gfp_flags(inode, nowait);
-       fgf_t fgp_flags = get_prepare_fgp_flags(nowait);
-       struct page *page;
+       fgf_t fgp_flags = (nowait ? FGP_WRITEBEGIN | FGP_NOWAIT : FGP_WRITEBEGIN);
+       struct folio *folio;
        int ret = 0;
 
 again:
-       page = pagecache_get_page(inode->i_mapping, index, fgp_flags,
-                                 mask | __GFP_WRITE);
-       if (!page) {
+       folio = __filemap_get_folio(inode->i_mapping, index, fgp_flags, mask);
+       if (IS_ERR(folio)) {
                if (nowait)
                        ret = -EAGAIN;
                else
-                       ret = -ENOMEM;
+                       ret = PTR_ERR(folio);
                return ret;
        }
-       ret = set_page_extent_mapped(page);
+       /* Only support page sized folio yet. */
+       ASSERT(folio_order(folio) == 0);
+       ret = set_folio_extent_mapped(folio);
        if (ret < 0) {
-               unlock_page(page);
-               put_page(page);
+               folio_unlock(folio);
+               folio_put(folio);
                return ret;
        }
-       ret = prepare_uptodate_page(inode, page, pos, write_bytes, force_uptodate);
+       ret = prepare_uptodate_folio(inode, folio, pos, write_bytes, force_uptodate);
        if (ret) {
-               /* The page is already unlocked. */
-               put_page(page);
+               /* The folio is already unlocked. */
+               folio_put(folio);
                if (!nowait && ret == -EAGAIN) {
                        ret = 0;
                        goto again;
                }
                return ret;
        }
-       wait_on_page_writeback(page);
-       *page_ret = page;
+       *folio_ret = folio;
        return 0;
 }
 
 /*
- * This function locks the extent and properly waits for data=ordered extents
- * to finish before allowing the pages to be modified if need.
+ * Locks the extent and properly waits for data=ordered extents to finish
+ * before allowing the folios to be modified if need.
  *
- * The return value:
+ * Return:
  * 1 - the extent is locked
  * 0 - the extent is not locked, and everything is OK
- * -EAGAIN - need re-prepare the pages
+ * -EAGAIN - need to prepare the folios again
  */
 static noinline int
-lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page *page,
+lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct folio *folio,
                                loff_t pos, size_t write_bytes,
                                u64 *lockstart, u64 *lockend, bool nowait,
                                struct extent_state **cached_state)
@@ -976,8 +962,8 @@ lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page *page,
                if (nowait) {
                        if (!try_lock_extent(&inode->io_tree, start_pos, last_pos,
                                             cached_state)) {
-                               unlock_page(page);
-                               put_page(page);
+                               folio_unlock(folio);
+                               folio_put(folio);
                                return -EAGAIN;
                        }
                } else {
@@ -991,8 +977,8 @@ lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page *page,
                    ordered->file_offset <= last_pos) {
                        unlock_extent(&inode->io_tree, start_pos, last_pos,
                                      cached_state);
-                       unlock_page(page);
-                       put_page(page);
+                       folio_unlock(folio);
+                       folio_put(folio);
                        btrfs_start_ordered_extent(ordered);
                        btrfs_put_ordered_extent(ordered);
                        return -EAGAIN;
@@ -1006,10 +992,10 @@ lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page *page,
        }
 
        /*
-        * We should be called after prepare_one_page() which should have locked
+        * We should be called after prepare_one_folio() which should have locked
         * all pages in the range.
         */
-       WARN_ON(!PageLocked(page));
+       WARN_ON(!folio_test_locked(folio));
 
        return ret;
 }
@@ -1190,12 +1176,12 @@ ssize_t btrfs_buffered_write(struct kiocb *iocb, struct iov_iter *i)
                size_t copied;
                size_t dirty_sectors;
                size_t num_sectors;
-               struct page *page = NULL;
+               struct folio *folio = NULL;
                int extents_locked;
                bool force_page_uptodate = false;
 
                /*
-                * Fault pages before locking them in prepare_one_page()
+                * Fault pages before locking them in prepare_one_folio()
                 * to avoid recursive lock
                 */
                if (unlikely(fault_in_iov_iter_readable(i, write_bytes))) {
@@ -1261,8 +1247,8 @@ again:
                        break;
                }
 
-               ret = prepare_one_page(inode, &page, pos, write_bytes,
-                                      force_page_uptodate, false);
+               ret = prepare_one_folio(inode, &folio, pos, write_bytes,
+                                       force_page_uptodate, false);
                if (ret) {
                        btrfs_delalloc_release_extents(BTRFS_I(inode),
                                                       reserve_bytes);
@@ -1270,7 +1256,7 @@ again:
                }
 
                extents_locked = lock_and_cleanup_extent_if_need(BTRFS_I(inode),
-                                               page, pos, write_bytes, &lockstart,
+                                               folio, pos, write_bytes, &lockstart,
                                                &lockend, nowait, &cached_state);
                if (extents_locked < 0) {
                        if (!nowait && extents_locked == -EAGAIN)
@@ -1282,7 +1268,7 @@ again:
                        break;
                }
 
-               copied = btrfs_copy_from_user(pos, write_bytes, page, i);
+               copied = btrfs_copy_from_user(pos, write_bytes, folio, i);
 
                num_sectors = BTRFS_BYTES_TO_BLKS(fs_info, reserve_bytes);
                dirty_sectors = round_up(copied + sector_offset,
@@ -1314,8 +1300,8 @@ again:
                release_bytes = round_up(copied + sector_offset,
                                        fs_info->sectorsize);
 
-               ret = btrfs_dirty_page(BTRFS_I(inode), page, pos, copied,
-                                      &cached_state, only_release_metadata);
+               ret = btrfs_dirty_folio(BTRFS_I(inode), folio, pos, copied,
+                                       &cached_state, only_release_metadata);
 
                /*
                 * If we have not locked the extent range, because the range's
@@ -1332,7 +1318,7 @@ again:
 
                btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
                if (ret) {
-                       btrfs_drop_page(fs_info, page, pos, copied);
+                       btrfs_drop_folio(fs_info, folio, pos, copied);
                        break;
                }
 
@@ -1340,7 +1326,7 @@ again:
                if (only_release_metadata)
                        btrfs_check_nocow_unlock(BTRFS_I(inode));
 
-               btrfs_drop_page(fs_info, page, pos, copied);
+               btrfs_drop_folio(fs_info, folio, pos, copied);
 
                cond_resched();
 
index 69a7b78d99bb3b48568a5c8b4107104649a264c4..de89e644be2965eb0ceff9c74eae75e7b5828217 100644 (file)
@@ -34,8 +34,8 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
 ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
                            const struct btrfs_ioctl_encoded_io_args *encoded);
 int btrfs_release_file(struct inode *inode, struct file *file);
-int btrfs_dirty_page(struct btrfs_inode *inode, struct page *page, loff_t pos,
-                    size_t write_bytes, struct extent_state **cached, bool noreserve);
+int btrfs_dirty_folio(struct btrfs_inode *inode, struct folio *folio, loff_t pos,
+                     size_t write_bytes, struct extent_state **cached, bool noreserve);
 int btrfs_fdatawrite_range(struct btrfs_inode *inode, loff_t start, loff_t end);
 int btrfs_check_nocow_lock(struct btrfs_inode *inode, loff_t pos,
                           size_t *write_bytes, bool nowait);
index 207aff5f1957778e2c22b29b68d7a654446b37a7..cfa52ef40b06e44b9866ed8fc0ad073081646e39 100644 (file)
@@ -1464,8 +1464,8 @@ static int __btrfs_write_out_cache(struct inode *inode,
                u64 dirty_start = i * PAGE_SIZE;
                u64 dirty_len = min_t(u64, dirty_start + PAGE_SIZE, i_size) - dirty_start;
 
-               ret = btrfs_dirty_page(BTRFS_I(inode), io_ctl->pages[i],
-                                      dirty_start, dirty_len, &cached_state, false);
+               ret = btrfs_dirty_folio(BTRFS_I(inode), page_folio(io_ctl->pages[i]),
+                                       dirty_start, dirty_len, &cached_state, false);
                if (ret < 0)
                        goto out_nospc;
        }