[patch 02/25] romfs_readpage: dont report errors for pages beyond i_size

Greg KH
2008-08-04T21:34:50Z

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2.6.26-stable review patch. If anyone has any objections, please let us
know.

------------------

From: Linus Torvalds <torvalds@linux-foundation.org>

commit 0056e65f9e28d83ee1a3fb4f7d0041e838f03c34 upstream

We zero-fill them like we are supposed to, and that's all fine. It's
only an error if the 'romfs_copyfrom()' routine isn't able to fill the
data that is supposed to be there.

Most of the patch is really just re-organizing the code a bit, and using
separate variables for the error value and for how much of the page we
actually filled from the filesystem.

Reported-and-tested-by: Chris Fester <cfester@wms.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Matt Waddel <matt.waddel@freescale.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-of-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/romfs/inode.c | 37 +++++++++++++++++++++++--------------
1 file changed, 23 insertions(+), 14 deletions(-)

--- a/fs/romfs/inode.c
+++ b/fs/romfs/inode.c
@@ -418,7 +418,8 @@ static int
romfs_readpage(struct file *file, struct page * page)
{
struct inode *inode = page->mapping->host;
- loff_t offset, avail, readlen;
+ loff_t offset, size;
+ unsigned long filled;
void *buf;
int result = -EIO;

@@ -430,21 +431,29 @@ romfs_readpage(struct file *file, struct

/* 32 bit warning -- but not for us :) */
offset = page_offset(page);
- if (offset < i_size_read(inode)) {
- avail = inode->i_size-offset;
- readlen = min_t(unsigned long, avail, PAGE_SIZE);
- if (romfs_copyfrom(inode, buf, ROMFS_I(inode)->i_dataoffset+offset, readlen) == readlen) {
- if (readlen < PAGE_SIZE) {
- memset(buf + readlen,0,PAGE_SIZE-readlen);
- }
- SetPageUptodate(page);
- result = 0;
+ size = i_size_read(inode);
+ filled = 0;
+ result = 0;
+ if (offset < size) {
+ unsigned long readlen;
+
+ size -= offset;
+ readlen = size > PAGE_SIZE ? PAGE_SIZE : size;
+
+ filled = romfs_copyfrom(inode, buf, ROMFS_I(inode)->i_dataoffset+offset, readlen);
+
+ if (filled != readlen) {
+ SetPageError(page);
+ filled = 0;
+ result = -EIO;
}
}
- if (result) {
- memset(buf, 0, PAGE_SIZE);
- SetPageError(page);
- }
+
+ if (filled < PAGE_SIZE)
+ memset(buf + filled, 0, PAGE_SIZE-filled);
+
+ if (!result)
+ SetPageUptodate(page);
flush_dcache_page(page);

unlock_page(page);

--