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NFS: Don't discard readdir results 

If a readdir call returns more data than we can fit into one page
cache page, then allocate a new one for that data rather than
discarding the data.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
This commit is contained in:
Trond Myklebust 2020-11-01 13:14:10 -05:00
parent 1f1d4aa4e4
commit 3b2a09f127
1 changed files with 42 additions and 4 deletions
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46
fs/nfs/dir.c
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@ -320,6 +320,26 @@ static void nfs_readdir_page_set_eof(struct page *page)
kunmap_atomic(array);
}
static void nfs_readdir_page_unlock_and_put(struct page *page)
{
unlock_page(page);
put_page(page);
}
static struct page *nfs_readdir_page_get_next(struct address_space *mapping,
pgoff_t index, u64 cookie)
{
struct page *page;
page = nfs_readdir_page_get_locked(mapping, index, cookie);
if (page) {
if (nfs_readdir_page_last_cookie(page) == cookie)
return page;
nfs_readdir_page_unlock_and_put(page);
}
return NULL;
}
static inline
int is_32bit_api(void)
{
@ -637,13 +657,15 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry,
}
/* Perform conversion from xdr to cache array */
static
int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
struct page **xdr_pages, struct page *page, unsigned int buflen)
static int nfs_readdir_page_filler(struct nfs_readdir_descriptor *desc,
struct nfs_entry *entry,
struct page **xdr_pages,
struct page *fillme, unsigned int buflen)
{
struct address_space *mapping = desc->file->f_mapping;
struct xdr_stream stream;
struct xdr_buf buf;
struct page *scratch;
struct page *scratch, *new, *page = fillme;
int status;
scratch = alloc_page(GFP_KERNEL);
@ -666,6 +688,19 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
desc->dir_verifier);
status = nfs_readdir_add_to_array(entry, page);
if (status != -ENOSPC)
continue;
if (page->mapping != mapping)
break;
new = nfs_readdir_page_get_next(mapping, page->index + 1,
entry->prev_cookie);
if (!new)
break;
if (page != fillme)
nfs_readdir_page_unlock_and_put(page);
page = new;
status = nfs_readdir_add_to_array(entry, page);
} while (!status && !entry->eof);
switch (status) {
@ -681,6 +716,9 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
break;
}
if (page != fillme)
nfs_readdir_page_unlock_and_put(page);
put_page(scratch);
return status;
}