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afs: Set up the iov_iter before calling afs_extract_data()

Browse Source 
afs_extract_data() sets up a temporary iov_iter and passes it to AF_RXRPC
each time it is called to describe the remaining buffer to be filled.

Instead:

 (1) Put an iterator in the afs_call struct.

 (2) Set the iterator for each marshalling stage to load data into the
     appropriate places.  A number of convenience functions are provided to
     this end (eg. afs_extract_to_buf()).

     This iterator is then passed to afs_extract_data().

 (3) Use the new ITER_XARRAY iterator when reading data to load directly
     into the inode's pages without needing to create a list of them.

This will allow O_DIRECT calls to be supported in future patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/152898380012.11616.12094591785228251717.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/153685394431.14766.3178466345696987059.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/153999787395.866.11218209749223643998.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/154033911195.12041.3882700371848894587.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/158861250059.340223.1248231474865140653.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/159465827399.1377938.11181327349704960046.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/160588533776.3465195.3612752083351956948.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161118151238.1232039.17015723405750601161.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161047240.2537118.14721975104810564022.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340410333.1303470.16260122230371140878.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539554187.286939.15305559004905459852.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653810525.2770958.4630666029125411789.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789093719.6155.7877160739235087723.stgit@warthog.procyon.org.uk/ # v6
This commit is contained in:
David Howells 2020-02-06 14:22:28 +00:00
parent 05092755aa
commit c450846461
6 changed files with 317 additions and 252 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

228
fs/afs/dir.c
View File

@ -102,6 +102,35 @@ struct afs_lookup_cookie {
struct afs_fid fids[50];
};
/*
* Drop the refs that we're holding on the pages we were reading into. We've
* got refs on the first nr_pages pages.
*/
static void afs_dir_read_cleanup(struct afs_read *req)
{
struct address_space *mapping = req->vnode->vfs_inode.i_mapping;
struct page *page;
pgoff_t last = req->nr_pages - 1;
XA_STATE(xas, &mapping->i_pages, 0);
if (unlikely(!req->nr_pages))
return;
rcu_read_lock();
xas_for_each(&xas, page, last) {
if (xas_retry(&xas, page))
continue;
BUG_ON(xa_is_value(page));
BUG_ON(PageCompound(page));
ASSERTCMP(page->mapping, ==, mapping);
put_page(page);
}
rcu_read_unlock();
}
/*
* check that a directory page is valid
*/
@ -127,7 +156,7 @@ static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
qty /= sizeof(union afs_xdr_dir_block);
/* check them */
dbuf = kmap(page);
dbuf = kmap_atomic(page);
for (tmp = 0; tmp < qty; tmp++) {
if (dbuf->blocks[tmp].hdr.magic != AFS_DIR_MAGIC) {
printk("kAFS: %s(%lx): bad magic %d/%d is %04hx\n",
@ -146,7 +175,7 @@ static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
((u8 *)&dbuf->blocks[tmp])[AFS_DIR_BLOCK_SIZE - 1] = 0;
}
kunmap(page);
kunmap_atomic(dbuf);
checked:
afs_stat_v(dvnode, n_read_dir);
@ -157,35 +186,74 @@ error:
}
/*
* Check the contents of a directory that we've just read.
* Dump the contents of a directory.
*/
static bool afs_dir_check_pages(struct afs_vnode *dvnode, struct afs_read *req)
static void afs_dir_dump(struct afs_vnode *dvnode, struct afs_read *req)
{
struct afs_xdr_dir_page *dbuf;
unsigned int i, j, qty = PAGE_SIZE / sizeof(union afs_xdr_dir_block);
struct address_space *mapping = dvnode->vfs_inode.i_mapping;
struct page *page;
unsigned int i, qty = PAGE_SIZE / sizeof(union afs_xdr_dir_block);
pgoff_t last = req->nr_pages - 1;
for (i = 0; i < req->nr_pages; i++)
if (!afs_dir_check_page(dvnode, req->pages[i], req->actual_len))
goto bad;
return true;
XA_STATE(xas, &mapping->i_pages, 0);
bad:
pr_warn("DIR %llx:%llx f=%llx l=%llx al=%llx r=%llx\n",
pr_warn("DIR %llx:%llx f=%llx l=%llx al=%llx\n",
dvnode->fid.vid, dvnode->fid.vnode,
req->file_size, req->len, req->actual_len, req->remain);
pr_warn("DIR %llx %x %x %x\n",
req->pos, req->index, req->nr_pages, req->offset);
req->file_size, req->len, req->actual_len);
pr_warn("DIR %llx %x %zx %zx\n",
req->pos, req->nr_pages,
req->iter->iov_offset, iov_iter_count(req->iter));
for (i = 0; i < req->nr_pages; i++) {
dbuf = kmap(req->pages[i]);
for (j = 0; j < qty; j++) {
union afs_xdr_dir_block *block = &dbuf->blocks[j];
xas_for_each(&xas, page, last) {
if (xas_retry(&xas, page))
continue;
pr_warn("[%02x] %32phN\n", i * qty + j, block);
BUG_ON(PageCompound(page));
BUG_ON(page->mapping != mapping);
dbuf = kmap_atomic(page);
for (i = 0; i < qty; i++) {
union afs_xdr_dir_block *block = &dbuf->blocks[i];
pr_warn("[%02lx] %32phN\n", page->index * qty + i, block);
}
kunmap(req->pages[i]);
kunmap_atomic(dbuf);
}
return false;
}
/*
* Check all the pages in a directory. All the pages are held pinned.
*/
static int afs_dir_check(struct afs_vnode *dvnode, struct afs_read *req)
{
struct address_space *mapping = dvnode->vfs_inode.i_mapping;
struct page *page;
pgoff_t last = req->nr_pages - 1;
int ret = 0;
XA_STATE(xas, &mapping->i_pages, 0);
if (unlikely(!req->nr_pages))
return 0;
rcu_read_lock();
xas_for_each(&xas, page, last) {
if (xas_retry(&xas, page))
continue;
BUG_ON(PageCompound(page));
BUG_ON(page->mapping != mapping);
if (!afs_dir_check_page(dvnode, page, req->file_size)) {
afs_dir_dump(dvnode, req);
ret = -EIO;
break;
}
}
rcu_read_unlock();
return ret;
}
/*
@ -214,58 +282,57 @@ static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)
{
struct afs_read *req;
loff_t i_size;
int nr_pages, nr_inline, i, n;
int ret = -ENOMEM;
int nr_pages, i, n;
int ret;
retry:
i_size = i_size_read(&dvnode->vfs_inode);
if (i_size < 2048)
return ERR_PTR(afs_bad(dvnode, afs_file_error_dir_small));
if (i_size > 2048 * 1024) {
trace_afs_file_error(dvnode, -EFBIG, afs_file_error_dir_big);
return ERR_PTR(-EFBIG);
}
_enter("");
_enter("%llu", i_size);
/* Get a request record to hold the page list. We want to hold it
* inline if we can, but we don't want to make an order 1 allocation.
*/
nr_pages = (i_size + PAGE_SIZE - 1) / PAGE_SIZE;
nr_inline = nr_pages;
if (nr_inline > (PAGE_SIZE - sizeof(*req)) / sizeof(struct page *))
nr_inline = 0;
req = kzalloc(struct_size(req, array, nr_inline), GFP_KERNEL);
req = kzalloc(sizeof(*req), GFP_KERNEL);
if (!req)
return ERR_PTR(-ENOMEM);
refcount_set(&req->usage, 1);
req->vnode = dvnode;
req->key = key_get(key);
req->nr_pages = nr_pages;
req->cleanup = afs_dir_read_cleanup;
expand:
i_size = i_size_read(&dvnode->vfs_inode);
if (i_size < 2048) {
ret = afs_bad(dvnode, afs_file_error_dir_small);
goto error;
}
if (i_size > 2048 * 1024) {
trace_afs_file_error(dvnode, -EFBIG, afs_file_error_dir_big);
ret = -EFBIG;
goto error;
}
_enter("%llu", i_size);
nr_pages = (i_size + PAGE_SIZE - 1) / PAGE_SIZE;
req->actual_len = i_size; /* May change */
req->len = nr_pages * PAGE_SIZE; /* We can ask for more than there is */
req->data_version = dvnode->status.data_version; /* May change */
if (nr_inline > 0) {
req->pages = req->array;
} else {
req->pages = kcalloc(nr_pages, sizeof(struct page *),
GFP_KERNEL);
if (!req->pages)
goto error;
}
iov_iter_xarray(&req->def_iter, READ, &dvnode->vfs_inode.i_mapping->i_pages,
0, i_size);
req->iter = &req->def_iter;
/* Get a list of all the pages that hold or will hold the directory
* content. We need to fill in any gaps that we might find where the
* memory reclaimer has been at work. If there are any gaps, we will
/* Fill in any gaps that we might find where the memory reclaimer has
* been at work and pin all the pages. If there are any gaps, we will
* need to reread the entire directory contents.
*/
i = 0;
do {
i = req->nr_pages;
while (i < nr_pages) {
struct page *pages[8], *page;
n = find_get_pages_contig(dvnode->vfs_inode.i_mapping, i,
req->nr_pages - i,
req->pages + i);
_debug("find %u at %u/%u", n, i, req->nr_pages);
min_t(unsigned int, nr_pages - i,
ARRAY_SIZE(pages)),
pages);
_debug("find %u at %u/%u", n, i, nr_pages);
if (n == 0) {
gfp_t gfp = dvnode->vfs_inode.i_mapping->gfp_mask;
@ -273,22 +340,24 @@ retry:
afs_stat_v(dvnode, n_inval);
ret = -ENOMEM;
req->pages[i] = __page_cache_alloc(gfp);
if (!req->pages[i])
page = __page_cache_alloc(gfp);
if (!page)
goto error;
ret = add_to_page_cache_lru(req->pages[i],
ret = add_to_page_cache_lru(page,
dvnode->vfs_inode.i_mapping,
i, gfp);
if (ret < 0)
goto error;
attach_page_private(req->pages[i], (void *)1);
unlock_page(req->pages[i]);
attach_page_private(page, (void *)1);
unlock_page(page);
req->nr_pages++;
i++;
} else {
req->nr_pages += n;
i += n;
}
} while (i < req->nr_pages);
}
/* If we're going to reload, we need to lock all the pages to prevent
* races.
@ -312,12 +381,17 @@ retry:
task_io_account_read(PAGE_SIZE * req->nr_pages);
if (req->len < req->file_size)
goto content_has_grown;
if (req->len < req->file_size) {
/* The content has grown, so we need to expand the
* buffer.
*/
up_write(&dvnode->validate_lock);
goto expand;
}
/* Validate the data we just read. */
ret = -EIO;
if (!afs_dir_check_pages(dvnode, req))
ret = afs_dir_check(dvnode, req);
if (ret < 0)
goto error_unlock;
// TODO: Trim excess pages
@ -335,11 +409,6 @@ error:
afs_put_read(req);
_leave(" = %d", ret);
return ERR_PTR(ret);
content_has_grown:
up_write(&dvnode->validate_lock);
afs_put_read(req);
goto retry;
}
/*
@ -449,6 +518,7 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
struct afs_read *req;
struct page *page;
unsigned blkoff, limit;
void __rcu **slot;
int ret;
_enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);
@ -473,9 +543,15 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
blkoff = ctx->pos & ~(sizeof(union afs_xdr_dir_block) - 1);
/* Fetch the appropriate page from the directory and re-add it
* to the LRU.
* to the LRU. We have all the pages pinned with an extra ref.
*/
page = req->pages[blkoff / PAGE_SIZE];
rcu_read_lock();
page = NULL;
slot = radix_tree_lookup_slot(&dvnode->vfs_inode.i_mapping->i_pages,
blkoff / PAGE_SIZE);
if (slot)
page = radix_tree_deref_slot(slot);
rcu_read_unlock();
if (!page) {
ret = afs_bad(dvnode, afs_file_error_dir_missing_page);
break;

190
fs/afs/file.c
View File

@ -183,21 +183,72 @@ int afs_release(struct inode *inode, struct file *file)
return ret;
}
/*
* Handle completion of a read operation.
*/
static void afs_file_read_done(struct afs_read *req)
{
struct afs_vnode *vnode = req->vnode;
struct page *page;
pgoff_t index = req->pos >> PAGE_SHIFT;
pgoff_t last = index + req->nr_pages - 1;
XA_STATE(xas, &vnode->vfs_inode.i_mapping->i_pages, index);
if (iov_iter_count(req->iter) > 0) {
/* The read was short - clear the excess buffer. */
_debug("afterclear %zx %zx %llx/%llx",
req->iter->iov_offset,
iov_iter_count(req->iter),
req->actual_len, req->len);
iov_iter_zero(iov_iter_count(req->iter), req->iter);
}
rcu_read_lock();
xas_for_each(&xas, page, last) {
page_endio(page, false, 0);
put_page(page);
}
rcu_read_unlock();
task_io_account_read(req->len);
req->cleanup = NULL;
}
/*
* Dispose of our locks and refs on the pages if the read failed.
*/
static void afs_file_read_cleanup(struct afs_read *req)
{
struct page *page;
pgoff_t index = req->pos >> PAGE_SHIFT;
pgoff_t last = index + req->nr_pages - 1;
if (req->iter) {
XA_STATE(xas, &req->vnode->vfs_inode.i_mapping->i_pages, index);
_enter("%lu,%u,%zu", index, req->nr_pages, iov_iter_count(req->iter));
rcu_read_lock();
xas_for_each(&xas, page, last) {
BUG_ON(xa_is_value(page));
BUG_ON(PageCompound(page));
page_endio(page, false, req->error);
put_page(page);
}
rcu_read_unlock();
}
}
/*
* Dispose of a ref to a read record.
*/
void afs_put_read(struct afs_read *req)
{
int i;
if (refcount_dec_and_test(&req->usage)) {
if (req->pages) {
for (i = 0; i < req->nr_pages; i++)
if (req->pages[i])
put_page(req->pages[i]);
if (req->pages != req->array)
kfree(req->pages);
}
if (req->cleanup)
req->cleanup(req);
key_put(req->key);
kfree(req);
}
@ -215,6 +266,7 @@ static void afs_fetch_data_success(struct afs_operation *op)
static void afs_fetch_data_put(struct afs_operation *op)
{
op->fetch.req->error = op->error;
afs_put_read(op->fetch.req);
}
@ -254,12 +306,11 @@ int afs_fetch_data(struct afs_vnode *vnode, struct afs_read *req)
/*
* read page from file, directory or symlink, given a key to use
*/
int afs_page_filler(void *data, struct page *page)
static int afs_page_filler(struct key *key, struct page *page)
{
struct inode *inode = page->mapping->host;
struct afs_vnode *vnode = AFS_FS_I(inode);
struct afs_read *req;
struct key *key = data;
int ret;
_enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
@ -270,53 +321,52 @@ int afs_page_filler(void *data, struct page *page)
if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
goto error;
req = kzalloc(struct_size(req, array, 1), GFP_KERNEL);
req = kzalloc(sizeof(struct afs_read), GFP_KERNEL);
if (!req)
goto enomem;
/* We request a full page. If the page is a partial one at the
* end of the file, the server will return a short read and the
* unmarshalling code will clear the unfilled space.
*/
refcount_set(&req->usage, 1);
req->key = key_get(key);
req->pos = (loff_t)page->index << PAGE_SHIFT;
req->len = PAGE_SIZE;
req->nr_pages = 1;
req->pages = req->array;
req->pages[0] = page;
req->vnode = vnode;
req->key = key_get(key);
req->pos = (loff_t)page->index << PAGE_SHIFT;
req->len = PAGE_SIZE;
req->nr_pages = 1;
req->done = afs_file_read_done;
req->cleanup = afs_file_read_cleanup;
get_page(page);
iov_iter_xarray(&req->def_iter, READ, &page->mapping->i_pages,
req->pos, req->len);
req->iter = &req->def_iter;
/* read the contents of the file from the server into the
* page */
ret = afs_fetch_data(vnode, req);
if (ret < 0)
goto fetch_error;
afs_put_read(req);
if (ret < 0) {
if (ret == -ENOENT) {
_debug("got NOENT from server"
" - marking file deleted and stale");
set_bit(AFS_VNODE_DELETED, &vnode->flags);
ret = -ESTALE;
}
if (ret == -EINTR ||
ret == -ENOMEM ||
ret == -ERESTARTSYS ||
ret == -EAGAIN)
goto error;
goto io_error;
}
SetPageUptodate(page);
unlock_page(page);
_leave(" = 0");
return 0;
io_error:
SetPageError(page);
goto error;
fetch_error:
switch (ret) {
case -EINTR:
case -ENOMEM:
case -ERESTARTSYS:
case -EAGAIN:
afs_put_read(req);
goto error;
case -ENOENT:
_debug("got NOENT from server - marking file deleted and stale");
set_bit(AFS_VNODE_DELETED, &vnode->flags);
ret = -ESTALE;
/* Fall through */
default:
page_endio(page, false, ret);
afs_put_read(req);
_leave(" = %d", ret);
return ret;
}
enomem:
ret = -ENOMEM;
error:
@ -351,19 +401,6 @@ static int afs_readpage(struct file *file, struct page *page)
return ret;
}
/*
* Make pages available as they're filled.
*/
static void afs_readpages_page_done(struct afs_read *req)
{
struct page *page = req->pages[req->index];
req->pages[req->index] = NULL;
SetPageUptodate(page);
unlock_page(page);
put_page(page);
}
/*
* Read a contiguous set of pages.
*/
@ -375,7 +412,7 @@ static int afs_readpages_one(struct file *file, struct address_space *mapping,
struct list_head *p;
struct page *first, *page;
pgoff_t index;
int ret, n, i;
int ret, n;
/* Count the number of contiguous pages at the front of the list. Note
* that the list goes prev-wards rather than next-wards.
@ -391,21 +428,20 @@ static int afs_readpages_one(struct file *file, struct address_space *mapping,
n++;
}
req = kzalloc(struct_size(req, array, n), GFP_NOFS);
req = kzalloc(sizeof(struct afs_read), GFP_NOFS);
if (!req)
return -ENOMEM;
refcount_set(&req->usage, 1);
req->vnode = vnode;
req->key = key_get(afs_file_key(file));
req->page_done = afs_readpages_page_done;
req->done = afs_file_read_done;
req->cleanup = afs_file_read_cleanup;
req->pos = first->index;
req->pos <<= PAGE_SHIFT;
req->pages = req->array;
/* Transfer the pages to the request. We add them in until one fails
* to add to the LRU and then we stop (as that'll make a hole in the
* contiguous run.
/* Add pages to the LRU until it fails. We keep the pages ref'd and
* locked until the read is complete.
*
* Note that it's possible for the file size to change whilst we're
* doing this, but we rely on the server returning less than we asked
@ -422,8 +458,7 @@ static int afs_readpages_one(struct file *file, struct address_space *mapping,
break;
}
req->pages[req->nr_pages++] = page;
req->len += PAGE_SIZE;
req->nr_pages++;
} while (req->nr_pages < n);
if (req->nr_pages == 0) {
@ -431,30 +466,25 @@ static int afs_readpages_one(struct file *file, struct address_space *mapping,
return 0;
}
req->len = req->nr_pages * PAGE_SIZE;
iov_iter_xarray(&req->def_iter, READ, &file->f_mapping->i_pages,
req->pos, req->len);
req->iter = &req->def_iter;
ret = afs_fetch_data(vnode, req);
if (ret < 0)
goto error;
task_io_account_read(PAGE_SIZE * req->nr_pages);
afs_put_read(req);
return 0;
error:
if (ret == -ENOENT) {
_debug("got NOENT from server"
" - marking file deleted and stale");
_debug("got NOENT from server - marking file deleted and stale");
set_bit(AFS_VNODE_DELETED, &vnode->flags);
ret = -ESTALE;
}
for (i = 0; i < req->nr_pages; i++) {
page = req->pages[i];
if (page) {
SetPageError(page);
unlock_page(page);
}
}
afs_put_read(req);
return ret;
}

54
fs/afs/fsclient.c
View File

@ -302,7 +302,6 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
struct afs_vnode_param *vp = &op->file[0];
struct afs_read *req = op->fetch.req;
const __be32 *bp;
unsigned int size;
int ret;
_enter("{%u,%zu,%zu/%llu}",
@ -312,8 +311,6 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
switch (call->unmarshall) {
case 0:
req->actual_len = 0;
req->index = 0;
req->offset = req->pos & (PAGE_SIZE - 1);
call->unmarshall++;
if (call->operation_ID == FSFETCHDATA64) {
afs_extract_to_tmp64(call);
@ -323,7 +320,10 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
}
fallthrough;
/* extract the returned data length */
/* Extract the returned data length into
* ->actual_len. This may indicate more or less data than was
* requested will be returned.
*/
case 1:
_debug("extract data length");
ret = afs_extract_data(call, true);
@ -332,45 +332,25 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
req->actual_len = be64_to_cpu(call->tmp64);
_debug("DATA length: %llu", req->actual_len);
req->remain = min(req->len, req->actual_len);
if (req->remain == 0)
if (req->actual_len == 0)
goto no_more_data;
call->iter = req->iter;
call->iov_len = min(req->actual_len, req->len);
call->unmarshall++;
begin_page:
ASSERTCMP(req->index, <, req->nr_pages);
if (req->remain > PAGE_SIZE - req->offset)
size = PAGE_SIZE - req->offset;
else
size = req->remain;
call->iov_len = size;
call->bvec[0].bv_len = size;
call->bvec[0].bv_offset = req->offset;
call->bvec[0].bv_page = req->pages[req->index];
iov_iter_bvec(&call->def_iter, READ, call->bvec, 1, size);
ASSERTCMP(size, <=, PAGE_SIZE);
fallthrough;
/* extract the returned data */
case 2:
_debug("extract data %zu/%llu",
iov_iter_count(call->iter), req->remain);
iov_iter_count(call->iter), req->actual_len);
ret = afs_extract_data(call, true);
if (ret < 0)
return ret;
req->remain -= call->bvec[0].bv_len;
req->offset += call->bvec[0].bv_len;
ASSERTCMP(req->offset, <=, PAGE_SIZE);
if (req->offset == PAGE_SIZE) {
req->offset = 0;
req->index++;
if (req->remain > 0)
goto begin_page;
}
ASSERTCMP(req->remain, ==, 0);
call->iter = &call->def_iter;
if (req->actual_len <= req->len)
goto no_more_data;
@ -412,16 +392,8 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
break;
}
for (; req->index < req->nr_pages; req->index++) {
if (req->offset < PAGE_SIZE)
zero_user_segment(req->pages[req->index],
req->offset, PAGE_SIZE);
req->offset = 0;
}
if (req->page_done)
for (req->index = 0; req->index < req->nr_pages; req->index++)
req->page_done(req);
if (req->done)
req->done(req);
_leave(" = 0 [done]");
return 0;
@ -496,6 +468,8 @@ void afs_fs_fetch_data(struct afs_operation *op)
if (!call)
return afs_op_nomem(op);
req->call_debug_id = call->debug_id;
/* marshall the parameters */
bp = call->request;
bp[0] = htonl(FSFETCHDATA);

16
fs/afs/internal.h
View File

@ -31,6 +31,7 @@
struct pagevec;
struct afs_call;
struct afs_vnode;
/*
* Partial file-locking emulation mode. (The problem being that AFS3 only
@ -203,18 +204,18 @@ struct afs_read {
loff_t pos; /* Where to start reading */
loff_t len; /* How much we're asking for */
loff_t actual_len; /* How much we're actually getting */
loff_t remain; /* Amount remaining */
loff_t file_size; /* File size returned by server */
struct key *key; /* The key to use to reissue the read */
struct afs_vnode *vnode; /* The file being read into. */
afs_dataversion_t data_version; /* Version number returned by server */
refcount_t usage;
unsigned int index; /* Which page we're reading into */
unsigned int call_debug_id;
unsigned int nr_pages;
unsigned int offset; /* offset into current page */
struct afs_vnode *vnode;
void (*page_done)(struct afs_read *);
struct page **pages;
struct page *array[];
int error;
void (*done)(struct afs_read *);
void (*cleanup)(struct afs_read *);
struct iov_iter *iter; /* Iterator representing the buffer */
struct iov_iter def_iter; /* Default iterator */
};
/*
@ -1048,7 +1049,6 @@ extern void afs_put_wb_key(struct afs_wb_key *);
extern int afs_open(struct inode *, struct file *);
extern int afs_release(struct inode *, struct file *);
extern int afs_fetch_data(struct afs_vnode *, struct afs_read *);
extern int afs_page_filler(void *, struct page *);
extern void afs_put_read(struct afs_read *);
static inline struct afs_read *afs_get_read(struct afs_read *req)

27
fs/afs/write.c
View File

@ -22,6 +22,16 @@ int afs_set_page_dirty(struct page *page)
return __set_page_dirty_nobuffers(page);
}
/*
* Handle completion of a read operation to fill a page.
*/
static void afs_fill_hole(struct afs_read *req)
{
if (iov_iter_count(req->iter) > 0)
/* The read was short - clear the excess buffer. */
iov_iter_zero(iov_iter_count(req->iter), req->iter);
}
/*
* partly or wholly fill a page that's under preparation for writing
*/
@ -45,18 +55,19 @@ static int afs_fill_page(struct file *file,
return 0;
}
req = kzalloc(struct_size(req, array, 1), GFP_KERNEL);
req = kzalloc(sizeof(struct afs_read), GFP_KERNEL);
if (!req)
return -ENOMEM;
refcount_set(&req->usage, 1);
req->key = key_get(afs_file_key(file));
req->pos = pos;
req->len = len;
req->nr_pages = 1;
req->pages = req->array;
req->pages[0] = page;
get_page(page);
req->vnode = vnode;
req->done = afs_fill_hole;
req->key = key_get(afs_file_key(file));
req->pos = pos;
req->len = len;
req->nr_pages = 1;
req->iter = &req->def_iter;
iov_iter_xarray(&req->def_iter, READ, &file->f_mapping->i_pages, pos, len);
ret = afs_fetch_data(vnode, req);
afs_put_read(req);

54
fs/afs/yfsclient.c
View File

@ -360,7 +360,6 @@ static int yfs_deliver_fs_fetch_data64(struct afs_call *call)
struct afs_vnode_param *vp = &op->file[0];
struct afs_read *req = op->fetch.req;
const __be32 *bp;
unsigned int size;
int ret;
_enter("{%u,%zu, %zu/%llu}",
@ -370,13 +369,14 @@ static int yfs_deliver_fs_fetch_data64(struct afs_call *call)
switch (call->unmarshall) {
case 0:
req->actual_len = 0;
req->index = 0;
req->offset = req->pos & (PAGE_SIZE - 1);
afs_extract_to_tmp64(call);
call->unmarshall++;
fallthrough;
/* extract the returned data length */
/* Extract the returned data length into ->actual_len. This
* may indicate more or less data than was requested will be
* returned.
*/
case 1:
_debug("extract data length");
ret = afs_extract_data(call, true);
@ -385,45 +385,25 @@ static int yfs_deliver_fs_fetch_data64(struct afs_call *call)
req->actual_len = be64_to_cpu(call->tmp64);
_debug("DATA length: %llu", req->actual_len);
req->remain = min(req->len, req->actual_len);
if (req->remain == 0)
if (req->actual_len == 0)
goto no_more_data;
call->iter = req->iter;
call->iov_len = min(req->actual_len, req->len);
call->unmarshall++;
begin_page:
ASSERTCMP(req->index, <, req->nr_pages);
if (req->remain > PAGE_SIZE - req->offset)
size = PAGE_SIZE - req->offset;
else
size = req->remain;
call->iov_len = size;
call->bvec[0].bv_len = size;
call->bvec[0].bv_offset = req->offset;
call->bvec[0].bv_page = req->pages[req->index];
iov_iter_bvec(&call->def_iter, READ, call->bvec, 1, size);
ASSERTCMP(size, <=, PAGE_SIZE);
fallthrough;
/* extract the returned data */
case 2:
_debug("extract data %zu/%llu",
iov_iter_count(call->iter), req->remain);
iov_iter_count(call->iter), req->actual_len);
ret = afs_extract_data(call, true);
if (ret < 0)
return ret;
req->remain -= call->bvec[0].bv_len;
req->offset += call->bvec[0].bv_len;
ASSERTCMP(req->offset, <=, PAGE_SIZE);
if (req->offset == PAGE_SIZE) {
req->offset = 0;
req->index++;
if (req->remain > 0)
goto begin_page;
}
ASSERTCMP(req->remain, ==, 0);
call->iter = &call->def_iter;
if (req->actual_len <= req->len)
goto no_more_data;
@ -469,16 +449,8 @@ static int yfs_deliver_fs_fetch_data64(struct afs_call *call)
break;
}
for (; req->index < req->nr_pages; req->index++) {
if (req->offset < PAGE_SIZE)
zero_user_segment(req->pages[req->index],
req->offset, PAGE_SIZE);
req->offset = 0;
}
if (req->page_done)
for (req->index = 0; req->index < req->nr_pages; req->index++)
req->page_done(req);
if (req->done)
req->done(req);
_leave(" = 0 [done]");
return 0;
@ -518,6 +490,8 @@ void yfs_fs_fetch_data(struct afs_operation *op)
if (!call)
return afs_op_nomem(op);
req->call_debug_id = call->debug_id;
/* marshall the parameters */
bp = call->request;
bp = xdr_encode_u32(bp, YFSFETCHDATA64);