AFS: write support fixes

AFS write support fixes:

 (1) Support large files using the 64-bit file access operations if available
     on the server.

 (2) Use kmap_atomic() rather than kmap() in afs_prepare_page().

 (3) Don't do stuff in afs_writepage() that's done by the caller.

[akpm@linux-foundation.org: fix right shift count >= width of type]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 216 insertions, 17 deletions

diff --git a/fs/afs/afs_fs.h b/fs/afs/afs_fs.h
index 2198006d2d03..d963ef4daee8 100644
--- a/fs/afs/afs_fs.h
+++ b/fs/afs/afs_fs.h
@@ -31,6 +31,8 @@ enum AFS_FS_Operations {
         FSGETVOLUMEINFO         = 148,  /* AFS Get root volume information */
         FSGETROOTVOLUME         = 151,  /* AFS Get root volume name */
         FSLOOKUP                = 161,  /* AFS lookup file in directory */
+        FSFETCHDATA64           = 65537, /* AFS Fetch file data */
+        FSSTOREDATA64           = 65538, /* AFS Store file data */
 };
 
 enum AFS_FS_Errors {
diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c
index 025b1903d9e1..56cc0efa2a0c 100644
--- a/fs/afs/fsclient.c
+++ b/fs/afs/fsclient.c
@@ -293,9 +293,33 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call,
         case 0:
                 call->offset = 0;
                 call->unmarshall++;
+                if (call->operation_ID != FSFETCHDATA64) {
+                        call->unmarshall++;
+                        goto no_msw;
+                }
 
-                /* extract the returned data length */
+                /* extract the upper part of the returned data length of an
+                 * FSFETCHDATA64 op (which should always be 0 using this
+                 * client) */
         case 1:
+                _debug("extract data length (MSW)");
+                ret = afs_extract_data(call, skb, last, &call->tmp, 4);
+                switch (ret) {
+                case 0:         break;
+                case -EAGAIN:   return 0;
+                default:        return ret;
+                }
+
+                call->count = ntohl(call->tmp);
+                _debug("DATA length MSW: %u", call->count);
+                if (call->count > 0)
+                        return -EBADMSG;
+                call->offset = 0;
+                call->unmarshall++;
+
+        no_msw:
+                /* extract the returned data length */
+        case 2:
                 _debug("extract data length");
                 ret = afs_extract_data(call, skb, last, &call->tmp, 4);
                 switch (ret) {
@@ -312,7 +336,7 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call,
                 call->unmarshall++;
 
                 /* extract the returned data */
-        case 2:
+        case 3:
                 _debug("extract data");
                 if (call->count > 0) {
                         page = call->reply3;
@@ -331,7 +355,7 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call,
                 call->unmarshall++;
 
                 /* extract the metadata */
-        case 3:
+        case 4:
                 ret = afs_extract_data(call, skb, last, call->buffer,
                                        (21 + 3 + 6) * 4);
                 switch (ret) {
@@ -349,7 +373,7 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call,
                 call->offset = 0;
                 call->unmarshall++;
 
-        case 4:
+        case 5:
                 _debug("trailer");
                 if (skb->len != 0)
                         return -EBADMSG;
@@ -381,6 +405,56 @@ static const struct afs_call_type afs_RXFSFetchData = {
         .destructor     = afs_flat_call_destructor,
 };
 
+static const struct afs_call_type afs_RXFSFetchData64 = {
+        .name           = "FS.FetchData64",
+        .deliver        = afs_deliver_fs_fetch_data,
+        .abort_to_error = afs_abort_to_error,
+        .destructor     = afs_flat_call_destructor,
+};
+
+/*
+ * fetch data from a very large file
+ */
+static int afs_fs_fetch_data64(struct afs_server *server,
+                               struct key *key,
+                               struct afs_vnode *vnode,
+                               off_t offset, size_t length,
+                               struct page *buffer,
+                               const struct afs_wait_mode *wait_mode)
+{
+        struct afs_call *call;
+        __be32 *bp;
+
+        _enter("");
+
+        ASSERTCMP(length, <, ULONG_MAX);
+
+        call = afs_alloc_flat_call(&afs_RXFSFetchData64, 32, (21 + 3 + 6) * 4);
+        if (!call)
+                return -ENOMEM;
+
+        call->key = key;
+        call->reply = vnode;
+        call->reply2 = NULL; /* volsync */
+        call->reply3 = buffer;
+        call->service_id = FS_SERVICE;
+        call->port = htons(AFS_FS_PORT);
+        call->operation_ID = FSFETCHDATA64;
+
+        /* marshall the parameters */
+        bp = call->request;
+        bp[0] = htonl(FSFETCHDATA64);
+        bp[1] = htonl(vnode->fid.vid);
+        bp[2] = htonl(vnode->fid.vnode);
+        bp[3] = htonl(vnode->fid.unique);
+        bp[4] = htonl(upper_32_bits(offset));
+        bp[5] = htonl((u32) offset);
+        bp[6] = 0;
+        bp[7] = htonl((u32) length);
+
+        return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
+}
+
 /*
  * fetch data from a file
  */
@@ -394,6 +468,10 @@ int afs_fs_fetch_data(struct afs_server *server,
         struct afs_call *call;
         __be32 *bp;
 
+        if (upper_32_bits(offset) || upper_32_bits(offset + length))
+                return afs_fs_fetch_data64(server, key, vnode, offset, length,
+                                           buffer, wait_mode);
+
         _enter("");
 
         call = afs_alloc_flat_call(&afs_RXFSFetchData, 24, (21 + 3 + 6) * 4);
@@ -406,6 +484,7 @@ int afs_fs_fetch_data(struct afs_server *server,
         call->reply3 = buffer;
         call->service_id = FS_SERVICE;
         call->port = htons(AFS_FS_PORT);
+        call->operation_ID = FSFETCHDATA;
 
         /* marshall the parameters */
         bp = call->request;
@@ -1032,6 +1111,73 @@ static const struct afs_call_type afs_RXFSStoreData = {
         .destructor     = afs_flat_call_destructor,
 };
 
+static const struct afs_call_type afs_RXFSStoreData64 = {
+        .name           = "FS.StoreData64",
+        .deliver        = afs_deliver_fs_store_data,
+        .abort_to_error = afs_abort_to_error,
+        .destructor     = afs_flat_call_destructor,
+};
+
+/*
+ * store a set of pages to a very large file
+ */
+static int afs_fs_store_data64(struct afs_server *server,
+                               struct afs_writeback *wb,
+                               pgoff_t first, pgoff_t last,
+                               unsigned offset, unsigned to,
+                               loff_t size, loff_t pos, loff_t i_size,
+                               const struct afs_wait_mode *wait_mode)
+{
+        struct afs_vnode *vnode = wb->vnode;
+        struct afs_call *call;
+        __be32 *bp;
+
+        _enter(",%x,{%x:%u},,",
+               key_serial(wb->key), vnode->fid.vid, vnode->fid.vnode);
+
+        call = afs_alloc_flat_call(&afs_RXFSStoreData64,
+                                   (4 + 6 + 3 * 2) * 4,
+                                   (21 + 6) * 4);
+        if (!call)
+                return -ENOMEM;
+
+        call->wb = wb;
+        call->key = wb->key;
+        call->reply = vnode;
+        call->service_id = FS_SERVICE;
+        call->port = htons(AFS_FS_PORT);
+        call->mapping = vnode->vfs_inode.i_mapping;
+        call->first = first;
+        call->last = last;
+        call->first_offset = offset;
+        call->last_to = to;
+        call->send_pages = true;
+        call->store_version = vnode->status.data_version + 1;
+
+        /* marshall the parameters */
+        bp = call->request;
+        *bp++ = htonl(FSSTOREDATA64);
+        *bp++ = htonl(vnode->fid.vid);
+        *bp++ = htonl(vnode->fid.vnode);
+        *bp++ = htonl(vnode->fid.unique);
+
+        *bp++ = 0; /* mask */
+        *bp++ = 0; /* mtime */
+        *bp++ = 0; /* owner */
+        *bp++ = 0; /* group */
+        *bp++ = 0; /* unix mode */
+        *bp++ = 0; /* segment size */
+
+        *bp++ = htonl(pos >> 32);
+        *bp++ = htonl((u32) pos);
+        *bp++ = htonl(size >> 32);
+        *bp++ = htonl((u32) size);
+        *bp++ = htonl(i_size >> 32);
+        *bp++ = htonl((u32) i_size);
+
+        return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
+}
+
 /*
  * store a set of pages
  */
@@ -1062,7 +1208,9 @@ int afs_fs_store_data(struct afs_server *server, struct afs_writeback *wb,
                (unsigned long long) size, (unsigned long long) pos,
                (unsigned long long) i_size);
 
-        BUG_ON(i_size > 0xffffffff); // TODO: use 64-bit store
+        if (pos >> 32 || i_size >> 32 || size >> 32 || (pos + size) >> 32)
+                return afs_fs_store_data64(server, wb, first, last, offset, to,
+                                           size, pos, i_size, wait_mode);
 
         call = afs_alloc_flat_call(&afs_RXFSStoreData,
                                    (4 + 6 + 3) * 4,
@@ -1158,6 +1306,61 @@ static const struct afs_call_type afs_RXFSStoreData_as_Status = {
         .destructor     = afs_flat_call_destructor,
 };
 
+static const struct afs_call_type afs_RXFSStoreData64_as_Status = {
+        .name           = "FS.StoreData64",
+        .deliver        = afs_deliver_fs_store_status,
+        .abort_to_error = afs_abort_to_error,
+        .destructor     = afs_flat_call_destructor,
+};
+
+/*
+ * set the attributes on a very large file, using FS.StoreData rather than
+ * FS.StoreStatus so as to alter the file size also
+ */
+static int afs_fs_setattr_size64(struct afs_server *server, struct key *key,
+                                 struct afs_vnode *vnode, struct iattr *attr,
+                                 const struct afs_wait_mode *wait_mode)
+{
+        struct afs_call *call;
+        __be32 *bp;
+
+        _enter(",%x,{%x:%u},,",
+               key_serial(key), vnode->fid.vid, vnode->fid.vnode);
+
+        ASSERT(attr->ia_valid & ATTR_SIZE);
+
+        call = afs_alloc_flat_call(&afs_RXFSStoreData64_as_Status,
+                                   (4 + 6 + 3 * 2) * 4,
+                                   (21 + 6) * 4);
+        if (!call)
+                return -ENOMEM;
+
+        call->key = key;
+        call->reply = vnode;
+        call->service_id = FS_SERVICE;
+        call->port = htons(AFS_FS_PORT);
+        call->store_version = vnode->status.data_version + 1;
+        call->operation_ID = FSSTOREDATA;
+
+        /* marshall the parameters */
+        bp = call->request;
+        *bp++ = htonl(FSSTOREDATA64);
+        *bp++ = htonl(vnode->fid.vid);
+        *bp++ = htonl(vnode->fid.vnode);
+        *bp++ = htonl(vnode->fid.unique);
+
+        xdr_encode_AFS_StoreStatus(&bp, attr);
+
+        *bp++ = 0;                              /* position of start of write */
+        *bp++ = 0;
+        *bp++ = 0;                              /* size of write */
+        *bp++ = 0;
+        *bp++ = htonl(attr->ia_size >> 32);     /* new file length */
+        *bp++ = htonl((u32) attr->ia_size);
+
+        return afs_make_call(&server->addr, call, GFP_NOFS, wait_mode);
+}
+
 /*
  * set the attributes on a file, using FS.StoreData rather than FS.StoreStatus
  * so as to alter the file size also
@@ -1173,7 +1376,9 @@ static int afs_fs_setattr_size(struct afs_server *server, struct key *key,
                key_serial(key), vnode->fid.vid, vnode->fid.vnode);
 
         ASSERT(attr->ia_valid & ATTR_SIZE);
-        ASSERTCMP(attr->ia_size, <=, 0xffffffff); // TODO: use 64-bit store
+        if (attr->ia_size >> 32)
+                return afs_fs_setattr_size64(server, key, vnode, attr,
+                                             wait_mode);
 
         call = afs_alloc_flat_call(&afs_RXFSStoreData_as_Status,
                                    (4 + 6 + 3) * 4,
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 83ff29262816..aa03d43984b3 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -122,7 +122,7 @@ static int afs_prepare_page(struct afs_vnode *vnode, struct page *page,
         if (offset == 0 && to == PAGE_SIZE)
                 return 0;
 
-        p = kmap(page);
+        p = kmap_atomic(page, KM_USER0);
 
         i_size = i_size_read(&vnode->vfs_inode);
         pos = (loff_t) page->index << PAGE_SHIFT;
@@ -133,7 +133,7 @@ static int afs_prepare_page(struct afs_vnode *vnode, struct page *page,
                         memset(p, 0, offset);
                 if (to < PAGE_SIZE)
                         memset(p + to, 0, PAGE_SIZE - to);
-                kunmap(page);
+                kunmap_atomic(p, KM_USER0);
                 return 0;
         }
 
@@ -152,7 +152,7 @@ static int afs_prepare_page(struct afs_vnode *vnode, struct page *page,
                         memset(p + eof, 0, PAGE_SIZE - eof);
         }
 
-        kunmap(p);
+        kunmap_atomic(p, KM_USER0);
 
         ret = 0;
         if (offset > 0 || eof > to) {
@@ -489,14 +489,6 @@ int afs_writepage(struct page *page, struct writeback_control *wbc)
 
         _enter("{%lx},", page->index);
 
-        if (wbc->sync_mode != WB_SYNC_NONE)
-                wait_on_page_writeback(page);
-
-        if (PageWriteback(page) || !PageDirty(page)) {
-                unlock_page(page);
-                return 0;
-        }
-
         wb = (struct afs_writeback *) page_private(page);
         ASSERT(wb != NULL);