>From a7cadf8017626cd80fcd8ea5a0e4deff4f63e02e Mon Sep 17 00:00:00 2001 From: Dmitry Monakhov Date: Wed, 24 Feb 2010 18:17:58 +0300 Subject: [PATCH] ext3: add sanity checks to writeback There is theoretical possibility to perform writepage on RO superblock. Add explicit check for what case. In fact writepage may fail by a number of reasons. This is really rare case but sill may result in data loss. At least we have to dump a error message. Signed-off-by: Dmitry Monakhov --- fs/ext3/inode.c | 40 +++++++++++++++++++++++++++++++++++----- 1 files changed, 35 insertions(+), 5 deletions(-) diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c index 455e6e6..cf0e3aa 100644 --- a/fs/ext3/inode.c +++ b/fs/ext3/inode.c @@ -1536,6 +1536,11 @@ static int ext3_ordered_writepage(struct page *page, if (ext3_journal_current_handle()) goto out_fail; + if (inode->i_sb->s_flags & MS_RDONLY) { + err = -EROFS; + goto out_fail; + } + if (!page_has_buffers(page)) { create_empty_buffers(page, inode->i_sb->s_blocksize, (1 << BH_Dirty)|(1 << BH_Uptodate)); @@ -1546,7 +1551,8 @@ static int ext3_ordered_writepage(struct page *page, NULL, buffer_unmapped)) { /* Provide NULL get_block() to catch bugs if buffers * weren't really mapped */ - return block_write_full_page(page, NULL, wbc); + ret = block_write_full_page(page, NULL, wbc); + goto out; } } handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode)); @@ -1584,12 +1590,17 @@ static int ext3_ordered_writepage(struct page *page, err = ext3_journal_stop(handle); if (!ret) ret = err; +out: + if (ret) + ext3_msg(inode->i_sb, KERN_CRIT, "%s: failed " + "%ld pages, ino %lu; err %d\n", __func__, + wbc->nr_to_write, inode->i_ino, ret); return ret; out_fail: redirty_page_for_writepage(wbc, page); unlock_page(page); - return ret; + goto out; } static int ext3_writeback_writepage(struct page *page, @@ -1603,12 +1614,18 @@ static int ext3_writeback_writepage(struct page *page, if (ext3_journal_current_handle()) goto out_fail; + if (inode->i_sb->s_flags & MS_RDONLY) { + err = -EROFS; + goto out_fail; + } + if (page_has_buffers(page)) { if (!walk_page_buffers(NULL, page_buffers(page), 0, PAGE_CACHE_SIZE, NULL, buffer_unmapped)) { /* Provide NULL get_block() to catch bugs if buffers * weren't really mapped */ - return block_write_full_page(page, NULL, wbc); + ret = block_write_full_page(page, NULL, wbc); + goto out; } } @@ -1626,12 +1643,17 @@ static int ext3_writeback_writepage(struct page *page, err = ext3_journal_stop(handle); if (!ret) ret = err; +out: + if (ret) + ext3_msg(inode->i_sb, KERN_CRIT, "%s: failed " + "%ld pages, ino %lu; err %d\n", __func__, + wbc->nr_to_write, inode->i_ino, ret); return ret; out_fail: redirty_page_for_writepage(wbc, page); unlock_page(page); - return ret; + goto out; } static int ext3_journalled_writepage(struct page *page, @@ -1645,6 +1667,11 @@ static int ext3_journalled_writepage(struct page *page, if (ext3_journal_current_handle()) goto no_write; + if (inode->i_sb->s_flags & MS_RDONLY) { + err = -EROFS; + goto no_write; + } + handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode)); if (IS_ERR(handle)) { ret = PTR_ERR(handle); @@ -1684,8 +1711,11 @@ static int ext3_journalled_writepage(struct page *page, if (!ret) ret = err; out: + if (ret) + ext3_msg(inode->i_sb, KERN_CRIT, "%s: failed " + "%ld pages, ino %lu; err %d\n", __func__, + wbc->nr_to_write, inode->i_ino, ret); return ret; - no_write: redirty_page_for_writepage(wbc, page); out_unlock: -- 1.6.6