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NFS: Minor read optimisation... 

Since PG_uptodate may now end up getting set during the call to
nfs_wb_page(), we can avoid putting a read request on the wire in those
situations.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2007-05-20 13:05:05 -04:00
parent 44dd151d5c
commit de05a0cc2a
1 changed files with 23 additions and 11 deletions
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34
fs/nfs/read.c
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@ -483,17 +483,19 @@ int nfs_readpage(struct file *file, struct page *page)
*/
error = nfs_wb_page(inode, page);
if (error)
goto out_error;
goto out_unlock;
if (PageUptodate(page))
goto out_unlock;
error = -ESTALE;
if (NFS_STALE(inode))
goto out_error;
goto out_unlock;
if (file == NULL) {
error = -EBADF;
ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
if (ctx == NULL)
goto out_error;
goto out_unlock;
} else
ctx = get_nfs_open_context((struct nfs_open_context *)
file->private_data);
@ -502,8 +504,7 @@ int nfs_readpage(struct file *file, struct page *page)
put_nfs_open_context(ctx);
return error;
out_error:
out_unlock:
unlock_page(page);
return error;
}
@ -520,21 +521,32 @@ readpage_async_filler(void *data, struct page *page)
struct inode *inode = page->mapping->host;
struct nfs_page *new;
unsigned int len;
int error;
error = nfs_wb_page(inode, page);
if (error)
goto out_unlock;
if (PageUptodate(page))
goto out_unlock;
nfs_wb_page(inode, page);
len = nfs_page_length(page);
if (len == 0)
return nfs_return_empty_page(page);
new = nfs_create_request(desc->ctx, inode, page, 0, len);
if (IS_ERR(new)) {
SetPageError(page);
unlock_page(page);
return PTR_ERR(new);
}
if (IS_ERR(new))
goto out_error;
if (len < PAGE_CACHE_SIZE)
zero_user_page(page, len, PAGE_CACHE_SIZE - len, KM_USER0);
nfs_pageio_add_request(desc->pgio, new);
return 0;
out_error:
error = PTR_ERR(new);
SetPageError(page);
out_unlock:
unlock_page(page);
return error;
}
int nfs_readpages(struct file *filp, struct address_space *mapping,