[GFS2] Patch to fix mmap of stuffed files
If a stuffed file is mmaped and a page fault is generated at some offset above the initial page, we need to create a zero page to hang the buffer heads off before we can unstuff the file. This is a fix for bz #236087 Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
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@ -197,7 +197,19 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
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void *kaddr;
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void *kaddr;
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int error;
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int error;
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BUG_ON(page->index);
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/*
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* Due to the order of unstuffing files and ->nopage(), we can be
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* asked for a zero page in the case of a stuffed file being extended,
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* so we need to supply one here. It doesn't happen often.
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*/
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if (unlikely(page->index)) {
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kaddr = kmap_atomic(page, KM_USER0);
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memset(kaddr, 0, PAGE_CACHE_SIZE);
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kunmap_atomic(kaddr, KM_USER0);
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flush_dcache_page(page);
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SetPageUptodate(page);
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return 0;
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}
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error = gfs2_meta_inode_buffer(ip, &dibh);
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error = gfs2_meta_inode_buffer(ip, &dibh);
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if (error)
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if (error)
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@ -208,9 +220,8 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
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ip->i_di.di_size);
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ip->i_di.di_size);
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memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
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memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
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kunmap_atomic(kaddr, KM_USER0);
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kunmap_atomic(kaddr, KM_USER0);
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flush_dcache_page(page);
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brelse(dibh);
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brelse(dibh);
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SetPageUptodate(page);
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SetPageUptodate(page);
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return 0;
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return 0;
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