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Date: Wed, 27 May 2009 15:01:05 +0200 From: Jan Kara <jack@...e.cz> To: LKML <linux-kernel@...r.kernel.org> Cc: npiggin@...e.de, linux-ext4@...r.kernel.org, Jan Kara <jack@...e.cz> Subject: [PATCH 08/11] vfs: Unmap underlying metadata of new data buffers only when buffer is mapped When we do delayed allocation of some buffer, we want to signal to VFS that the buffer is new (set buffer_new) so that it properly zeros out everything. But we don't have the buffer mapped yet so we cannot really unmap underlying metadata in this state. Make VFS avoid doing unmapping of metadata when the buffer is not yet mapped. Signed-off-by: Jan Kara <jack@...e.cz> --- fs/buffer.c | 12 +++++++----- 1 files changed, 7 insertions(+), 5 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index ddfcade..3d0bced 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1683,8 +1683,9 @@ static int __block_write_full_page(struct inode *inode, struct page *page, if (buffer_new(bh)) { /* blockdev mappings never come here */ clear_buffer_new(bh); - unmap_underlying_metadata(bh->b_bdev, - bh->b_blocknr); + if (buffer_mapped(bh)) + unmap_underlying_metadata(bh->b_bdev, + bh->b_blocknr); } } bh = bh->b_this_page; @@ -1869,8 +1870,9 @@ static int __block_prepare_write(struct inode *inode, struct page *page, if (err) break; if (buffer_new(bh)) { - unmap_underlying_metadata(bh->b_bdev, - bh->b_blocknr); + if (buffer_mapped(bh)) + unmap_underlying_metadata(bh->b_bdev, + bh->b_blocknr); if (PageUptodate(page)) { clear_buffer_new(bh); set_buffer_uptodate(bh); @@ -2683,7 +2685,7 @@ int nobh_write_begin(struct file *file, struct address_space *mapping, goto failed; if (!buffer_mapped(bh)) is_mapped_to_disk = 0; - if (buffer_new(bh)) + if (buffer_new(bh) && buffer_mapped(bh)) unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); if (PageUptodate(page)) { set_buffer_uptodate(bh); -- 1.6.0.2 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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