diff options
Diffstat (limited to 'fs/btrfs/file.c')
| -rw-r--r-- | fs/btrfs/file.c | 131 |
1 files changed, 84 insertions, 47 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 5591c67..6cd003c 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1235,27 +1235,18 @@ static int prepare_uptodate_page(struct page *page, u64 pos, } /* - * this gets pages into the page cache and locks them down, it also properly - * waits for data=ordered extents to finish before allowing the pages to be - * modified. + * this just gets pages into the page cache and locks them down. */ static noinline int prepare_pages(struct inode *inode, struct page **pages, size_t num_pages, loff_t pos, size_t write_bytes, bool force_uptodate) { - struct extent_state *cached_state = NULL; int i; unsigned long index = pos >> PAGE_CACHE_SHIFT; gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping); - int err = 0; - int faili = 0; - u64 start_pos; - u64 last_pos; - - start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1); - last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT; + int err; + int faili; -again: for (i = 0; i < num_pages; i++) { pages[i] = find_or_create_page(inode->i_mapping, index + i, mask | __GFP_WRITE); @@ -1278,57 +1269,85 @@ again: } wait_on_page_writeback(pages[i]); } - faili = num_pages - 1; - err = 0; + + return 0; +fail: + while (faili >= 0) { + unlock_page(pages[faili]); + page_cache_release(pages[faili]); + faili--; + } + return err; + +} + +/* + * This function locks the extent and properly waits for data=ordered extents + * to finish before allowing the pages to be modified if need. + * + * The return value: + * 1 - the extent is locked + * 0 - the extent is not locked, and everything is OK + * -EAGAIN - need re-prepare the pages + * the other < 0 number - Something wrong happens + */ +static noinline int +lock_and_cleanup_extent_if_need(struct inode *inode, struct page **pages, + size_t num_pages, loff_t pos, + u64 *lockstart, u64 *lockend, + struct extent_state **cached_state) +{ + u64 start_pos; + u64 last_pos; + int i; + int ret = 0; + + start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1); + last_pos = start_pos + ((u64)num_pages << PAGE_CACHE_SHIFT) - 1; + if (start_pos < inode->i_size) { struct btrfs_ordered_extent *ordered; lock_extent_bits(&BTRFS_I(inode)->io_tree, - start_pos, last_pos - 1, 0, &cached_state); - ordered = btrfs_lookup_first_ordered_extent(inode, - last_pos - 1); + start_pos, last_pos, 0, cached_state); + ordered = btrfs_lookup_first_ordered_extent(inode, last_pos); if (ordered && ordered->file_offset + ordered->len > start_pos && - ordered->file_offset < last_pos) { + ordered->file_offset <= last_pos) { btrfs_put_ordered_extent(ordered); unlock_extent_cached(&BTRFS_I(inode)->io_tree, - start_pos, last_pos - 1, - &cached_state, GFP_NOFS); + start_pos, last_pos, + cached_state, GFP_NOFS); for (i = 0; i < num_pages; i++) { unlock_page(pages[i]); page_cache_release(pages[i]); } - err = btrfs_wait_ordered_range(inode, start_pos, - last_pos - start_pos); - if (err) - goto fail; - goto again; + ret = btrfs_wait_ordered_range(inode, start_pos, + last_pos - start_pos + 1); + if (ret) + return ret; + else + return -EAGAIN; } if (ordered) btrfs_put_ordered_extent(ordered); clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos, - last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC | + last_pos, EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, - 0, 0, &cached_state, GFP_NOFS); - unlock_extent_cached(&BTRFS_I(inode)->io_tree, - start_pos, last_pos - 1, &cached_state, - GFP_NOFS); + 0, 0, cached_state, GFP_NOFS); + *lockstart = start_pos; + *lockend = last_pos; + ret = 1; } + for (i = 0; i < num_pages; i++) { if (clear_page_dirty_for_io(pages[i])) account_page_redirty(pages[i]); set_page_extent_mapped(pages[i]); WARN_ON(!PageLocked(pages[i])); } - return 0; -fail: - while (faili >= 0) { - unlock_page(pages[faili]); - page_cache_release(pages[faili]); - faili--; - } - return err; + return ret; } static noinline int check_can_nocow(struct inode *inode, loff_t pos, @@ -1379,13 +1398,17 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, struct inode *inode = file_inode(file); struct btrfs_root *root = BTRFS_I(inode)->root; struct page **pages = NULL; + struct extent_state *cached_state = NULL; u64 release_bytes = 0; + u64 lockstart; + u64 lockend; unsigned long first_index; size_t num_written = 0; int nrptrs; int ret = 0; bool only_release_metadata = false; bool force_page_uptodate = false; + bool need_unlock; nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE, PAGE_CACHE_SIZE / @@ -1454,7 +1477,8 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, } release_bytes = reserve_bytes; - + need_unlock = false; +again: /* * This is going to setup the pages array with the number of * pages we want, so we don't really need to worry about the @@ -1466,6 +1490,18 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, if (ret) break; + ret = lock_and_cleanup_extent_if_need(inode, pages, num_pages, + pos, &lockstart, &lockend, + &cached_state); + if (ret < 0) { + if (ret == -EAGAIN) + goto again; + break; + } else if (ret > 0) { + need_unlock = true; + ret = 0; + } + copied = btrfs_copy_from_user(pos, num_pages, write_bytes, pages, i); @@ -1510,19 +1546,20 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, } release_bytes = dirty_pages << PAGE_CACHE_SHIFT; - if (copied > 0) { + + if (copied > 0) ret = btrfs_dirty_pages(root, inode, pages, dirty_pages, pos, copied, NULL); - if (ret) { - btrfs_drop_pages(pages, num_pages); - break; - } - } - - release_bytes = 0; + if (need_unlock) + unlock_extent_cached(&BTRFS_I(inode)->io_tree, + lockstart, lockend, &cached_state, + GFP_NOFS); btrfs_drop_pages(pages, num_pages); + if (ret) + break; + release_bytes = 0; if (only_release_metadata && copied > 0) { u64 lockstart = round_down(pos, root->sectorsize); u64 lockend = lockstart + |
