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authorSteven Whitehouse <swhiteho@redhat.com>2007-04-20 09:18:30 +0100
committerSteven Whitehouse <swhiteho@redhat.com>2007-05-01 09:11:46 +0100
commitbf126aee6d54fe1e509846abf3b27aba84c6d7ce (patch)
tree5d21f057b2d5ee00cab9ac25f5d0e160bf57d533 /fs/gfs2/ops_address.c
parent476c006be009d4121e401a9e9f49a3362a7a272f (diff)
downloadlwn-bf126aee6d54fe1e509846abf3b27aba84c6d7ce.tar.gz
lwn-bf126aee6d54fe1e509846abf3b27aba84c6d7ce.zip
[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>
Diffstat (limited to 'fs/gfs2/ops_address.c')
-rw-r--r--fs/gfs2/ops_address.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
index 90c287932d58..30c15622174f 100644
--- a/fs/gfs2/ops_address.c
+++ b/fs/gfs2/ops_address.c
@@ -197,7 +197,19 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
void *kaddr;
int error;
- BUG_ON(page->index);
+ /*
+ * Due to the order of unstuffing files and ->nopage(), we can be
+ * asked for a zero page in the case of a stuffed file being extended,
+ * so we need to supply one here. It doesn't happen often.
+ */
+ if (unlikely(page->index)) {
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr, 0, PAGE_CACHE_SIZE);
+ kunmap_atomic(kaddr, KM_USER0);
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ return 0;
+ }
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
@@ -208,9 +220,8 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
ip->i_di.di_size);
memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
kunmap_atomic(kaddr, KM_USER0);
-
+ flush_dcache_page(page);
brelse(dibh);
-
SetPageUptodate(page);
return 0;