Cheers,
Trond
diff -u --recursive --new-file linux-2.4.22-nodirect/Documentation/Configure.help linux-2.4.22-blech/Documentation/Configure.help
--- linux-2.4.22-nodirect/Documentation/Configure.help 2003-07-09 19:39:39.000000000 +0200
+++ linux-2.4.22-blech/Documentation/Configure.help 2003-07-09 20:07:36.000000000 +0200
@@ -15938,6 +15938,30 @@
If unsure, say N.
+Allow direct I/O on files in NFS
+CONFIG_NFS_DIRECTIO
+ There are important applications whose performance or correctness
+ depends on uncached access to file data. Database clusters (multiple
+ copies of the same instance running on separate hosts) implement their
+ own cache coherency protocol that subsumes the NFS cache protocols.
+ Applications that process datasets considerably larger than the client's
+ memory do not always benefit from a local cache. A streaming video
+ server, for instance, has no need to cache the contents of a file.
+
+ This option enables applications to perform direct I/O on files in NFS
+ file systems using the O_DIRECT open() flag. When O_DIRECT is set for
+ files, their data is not cached in the system's page cache. Direct
+ read and write operations are aligned to block boundaries. Data is
+ moved to and from user-level application buffers directly.
+
+ Unless your program is designed to use O_DIRECT properly, you are much
+ better off allowing the NFS client to manage caching for you. Misusing
+ O_DIRECT can cause poor server performance or network storms. This
+ kernel build option defaults OFF to avoid exposing system administrators
+ unwittingly to a potentially hazardous feature.
+
+ If unsure, say N.
+
Root file system on NFS
CONFIG_ROOT_NFS
If you want your Linux box to mount its whole root file system (the
diff -u --recursive --new-file linux-2.4.22-nodirect/fs/Config.in linux-2.4.22-blech/fs/Config.in
--- linux-2.4.22-nodirect/fs/Config.in 2003-07-09 19:39:39.000000000 +0200
+++ linux-2.4.22-blech/fs/Config.in 2003-07-09 20:08:20.000000000 +0200
@@ -106,6 +106,7 @@
dep_tristate 'InterMezzo file system support (replicating fs) (EXPERIMENTAL)' CONFIG_INTERMEZZO_FS $CONFIG_INET $CONFIG_EXPERIMENTAL
dep_tristate 'NFS file system support' CONFIG_NFS_FS $CONFIG_INET
dep_mbool ' Provide NFSv3 client support' CONFIG_NFS_V3 $CONFIG_NFS_FS
+ dep_mbool ' Allow direct I/O on NFS files (EXPERIMENTAL)' CONFIG_NFS_DIRECTIO $CONFIG_NFS_FS $CONFIG_EXPERIMENTAL
dep_bool ' Root file system on NFS' CONFIG_ROOT_NFS $CONFIG_NFS_FS $CONFIG_IP_PNP
dep_tristate 'NFS server support' CONFIG_NFSD $CONFIG_INET
diff -u --recursive --new-file linux-2.4.22-nodirect/fs/nfs/direct.c linux-2.4.22-blech/fs/nfs/direct.c
--- linux-2.4.22-nodirect/fs/nfs/direct.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.4.22-blech/fs/nfs/direct.c 2003-07-08 11:52:37.000000000 +0200
@@ -0,0 +1,382 @@
+/*
+ * linux/fs/nfs/direct.c
+ *
+ * High-performance direct I/O for the NFS client
+ *
+ * When an application requests uncached I/O, all read and write requests
+ * are made directly to the server; data stored or fetched via these
+ * requests is not cached in the Linux page cache. The client does not
+ * correct unaligned requests from applications. All requested bytes are
+ * held on permanent storage before a direct write system call returns to
+ * an application. Applications that manage their own data caching, such
+ * as databases, make very good use of direct I/O on local file systems.
+ *
+ * Solaris implements an uncached I/O facility called directio() that
+ * is used for backups and sequential I/O to very large files. Solaris
+ * also supports uncaching whole NFS partitions with "-o forcedirectio,"
+ * an undocumented mount option.
+ *
+ * Note that I/O to read in executables (e.g. kernel_read) cannot use
+ * direct (kiobuf) reads because there is no vma backing the passed-in
+ * data buffer.
+ *
+ * Designed by Jeff Kimmel, Chuck Lever, and Trond Myklebust.
+ *
+ * Initial implementation: 12/2001 by Chuck Lever <cel@netapp.com>
+ *
+ * TODO:
+ *
+ * 1. Use concurrent asynchronous network requests rather than
+ * serialized synchronous network requests for normal (non-sync)
+ * direct I/O.
+ */
+
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/file.h>
+#include <linux/errno.h>
+#include <linux/nfs_fs.h>
+#include <linux/smp_lock.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/iobuf.h>
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+#define NFSDBG_FACILITY (NFSDBG_PAGECACHE | NFSDBG_VFS)
+#define VERF_SIZE (2 * sizeof(__u32))
+
+static inline int
+nfs_direct_read_rpc(struct file *file, struct nfs_readargs *arg)
+{
+ int result;
+ struct inode * inode = file->f_dentry->d_inode;
+ struct nfs_fattr fattr;
+ struct rpc_message msg;
+ struct nfs_readres res = { &fattr, arg->count, 0 };
+
+#ifdef CONFIG_NFS_V3
+ msg.rpc_proc = (NFS_PROTO(inode)->version == 3) ?
+ NFS3PROC_READ : NFSPROC_READ;
+#else
+ msg.rpc_proc = NFSPROC_READ;
+#endif
+ msg.rpc_argp = arg;
+ msg.rpc_resp = &res;
+
+ lock_kernel();
+ msg.rpc_cred = nfs_file_cred(file);
+ fattr.valid = 0;
+ result = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
+ nfs_refresh_inode(inode, &fattr);
+ unlock_kernel();
+
+ return result;
+}
+
+static inline int
+nfs_direct_write_rpc(struct file *file, struct nfs_writeargs *arg,
+ struct nfs_writeverf *verf)
+{
+ int result;
+ struct inode *inode = file->f_dentry->d_inode;
+ struct nfs_fattr fattr;
+ struct rpc_message msg;
+ struct nfs_writeres res = { &fattr, verf, 0 };
+
+#ifdef CONFIG_NFS_V3
+ msg.rpc_proc = (NFS_PROTO(inode)->version == 3) ?
+ NFS3PROC_WRITE : NFSPROC_WRITE;
+#else
+ msg.rpc_proc = NFSPROC_WRITE;
+#endif
+ msg.rpc_argp = arg;
+ msg.rpc_resp = &res;
+
+ lock_kernel();
+ msg.rpc_cred = get_rpccred(nfs_file_cred(file));
+ fattr.valid = 0;
+ result = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
+ nfs_write_attributes(inode, &fattr);
+ put_rpccred(msg.rpc_cred);
+ unlock_kernel();
+
+#ifdef CONFIG_NFS_V3
+ if (NFS_PROTO(inode)->version == 3) {
+ if (result > 0) {
+ if ((arg->stable == NFS_FILE_SYNC) &&
+ (verf->committed != NFS_FILE_SYNC)) {
+ printk(KERN_ERR
+ "%s: server didn't sync stable write request\n",
+ __FUNCTION__);
+ return -EIO;
+ }
+
+ if (result != arg->count) {
+ printk(KERN_INFO
+ "%s: short write, count=%u, result=%d\n",
+ __FUNCTION__, arg->count, result);
+ }
+ }
+ return result;
+ } else {
+#endif
+ verf->committed = NFS_FILE_SYNC; /* NFSv2 always syncs data */
+ if (result == 0)
+ return arg->count;
+ return result;
+#ifdef CONFIG_NFS_V3
+ }
+#endif
+}
+
+#ifdef CONFIG_NFS_V3
+static inline int
+nfs_direct_commit_rpc(struct inode *inode, loff_t offset, size_t count,
+ struct nfs_writeverf *verf)
+{
+ int result;
+ struct nfs_fattr fattr;
+ struct nfs_writeargs arg = { NFS_FH(inode), offset, count, 0, 0,
+ NULL };
+ struct nfs_writeres res = { &fattr, verf, 0 };
+ struct rpc_message msg = { NFS3PROC_COMMIT, &arg, &res, NULL };
+
+ fattr.valid = 0;
+
+ lock_kernel();
+ result = rpc_call_sync(NFS_CLIENT(inode), &msg, 0);
+ nfs_write_attributes(inode, &fattr);
+ unlock_kernel();
+
+ return result;
+}
+#else
+static inline int
+nfs_direct_commit_rpc(struct inode *inode, loff_t offset, size_t count,
+ struct nfs_writeverf *verf)
+{
+ return 0;
+}
+#endif
+
+/*
+ * Walk through the iobuf and create an iovec for each "rsize" bytes.
+ */
+static int
+nfs_direct_read(struct file *file, struct kiobuf *iobuf, loff_t offset,
+ size_t count)
+{
+ int curpage, total;
+ int result = 0;
+ struct inode *inode = file->f_dentry->d_inode;
+ int rsize = NFS_SERVER(inode)->rsize;
+ struct page *pages[NFS_READ_MAXIOV];
+ struct nfs_readargs args = { NFS_FH(inode), offset, 0, iobuf->offset,
+ pages };
+
+ total = 0;
+ curpage = 0;
+ while (count) {
+ int len, request;
+ struct page **dest = pages;
+
+ request = count;
+ if (count > rsize)
+ request = rsize;
+ args.count = request;
+ args.offset = offset;
+ args.pgbase = (iobuf->offset + total) & ~PAGE_MASK;
+ len = PAGE_SIZE - args.pgbase;
+
+ do {
+ struct page *page = iobuf->maplist[curpage];
+
+ if (curpage >= iobuf->nr_pages || !page) {
+ result = -EFAULT;
+ goto out_err;
+ }
+
+ *dest++ = page;
+ /* zero after the first iov */
+ if (request < len)
+ break;
+ request -= len;
+ len = PAGE_SIZE;
+ curpage++;
+ } while (request != 0);
+
+ result = nfs_direct_read_rpc(file, &args);
+
+ if (result < 0)
+ break;
+
+ total += result;
+ if (result < args.count) /* NFSv2ism */
+ break;
+ count -= result;
+ offset += result;
+ };
+out_err:
+ if (!total)
+ return result;
+ return total;
+}
+
+/*
+ * Walk through the iobuf and create an iovec for each "wsize" bytes.
+ * If only one network write is necessary, or if the O_SYNC flag or
+ * 'sync' mount option are present, or if this is a V2 inode, use
+ * FILE_SYNC. Otherwise, use UNSTABLE and finish with a COMMIT.
+ *
+ * The mechanics of this function are much the same as nfs_direct_read,
+ * with the added complexity of committing unstable writes.
+ */
+static int
+nfs_direct_write(struct file *file, struct kiobuf *iobuf,
+ loff_t offset, size_t count)
+{
+ int curpage, total;
+ int need_commit = 0;
+ int result = 0;
+ loff_t save_offset = offset;
+ struct inode *inode = file->f_dentry->d_inode;
+ int wsize = NFS_SERVER(inode)->wsize;
+ struct nfs_writeverf first_verf, ret_verf;
+ struct page *pages[NFS_WRITE_MAXIOV];
+ struct nfs_writeargs args = { NFS_FH(inode), 0, 0, NFS_FILE_SYNC, 0,
+ pages };
+
+#ifdef CONFIG_NFS_V3
+ if ((NFS_PROTO(inode)->version == 3) && (count > wsize) &&
+ (!IS_SYNC(inode)))
+ args.stable = NFS_UNSTABLE;
+#endif
+
+retry:
+ total = 0;
+ curpage = 0;
+ while (count) {
+ int len, request;
+ struct page **dest = pages;
+
+ request = count;
+ if (count > wsize)
+ request = wsize;
+ args.count = request;
+ args.offset = offset;
+ args.pgbase = (iobuf->offset + total) & ~PAGE_MASK;
+ len = PAGE_SIZE - args.pgbase;
+
+ do {
+ struct page *page = iobuf->maplist[curpage];
+
+ if (curpage >= iobuf->nr_pages || !page) {
+ result = -EFAULT;
+ goto out_err;
+ }
+
+ *dest++ = page;
+ /* zero after the first iov */
+ if (request < len)
+ break;
+ request -= len;
+ len = PAGE_SIZE;
+ curpage++;
+ } while (request != 0);
+
+ result = nfs_direct_write_rpc(file, &args, &ret_verf);
+
+ if (result < 0)
+ break;
+
+ if (!total)
+ memcpy(&first_verf.verifier, &ret_verf.verifier,
+ VERF_SIZE);
+ if (ret_verf.committed != NFS_FILE_SYNC) {
+ need_commit = 1;
+ if (memcmp(&first_verf.verifier, &ret_verf.verifier,
+ VERF_SIZE))
+ goto print_retry;
+ }
+
+ total += result;
+ count -= result;
+ offset += result;
+ };
+
+out_err:
+ /*
+ * Commit data written so far, even in the event of an error
+ */
+ if (need_commit) {
+ if (nfs_direct_commit_rpc(inode, save_offset,
+ iobuf->length - count, &ret_verf))
+ goto print_retry;
+ if (memcmp(&first_verf.verifier, &ret_verf.verifier,
+ VERF_SIZE))
+ goto print_retry;
+ }
+
+ if (!total)
+ return result;
+ return total;
+
+print_retry:
+ printk(KERN_INFO "%s: detected server restart; retrying with FILE_SYNC\n",
+ __FUNCTION__);
+ args.stable = NFS_FILE_SYNC;
+ offset = save_offset;
+ count = iobuf->length;
+ goto retry;
+}
+
+/*
+ * Read or write data, moving the data directly to/from the
+ * application's buffer without caching in the page cache.
+ *
+ * Rules for direct I/O
+ *
+ * 1. block size = 512 bytes or more
+ * 2. file byte offset is block aligned
+ * 3. byte count is a multiple of block size
+ * 4. user buffer is not aligned
+ * 5. user buffer is faulted in and pinned
+ *
+ * These are verified before we get here.
+ */
+int
+nfs_direct_IO(int rw, struct file *file, struct kiobuf *iobuf,
+ unsigned long blocknr, int blocksize)
+{
+ int result = -EINVAL;
+ size_t count = iobuf->length;
+ struct dentry *dentry = file->f_dentry;
+ struct inode *inode = dentry->d_inode;
+ loff_t offset = blocknr << inode->i_blkbits;
+
+ switch (rw) {
+ case READ:
+ dfprintk(VFS,
+ "NFS: direct_IO(READ) (%s/%s) off/cnt(%Lu/%d)\n",
+ dentry->d_parent->d_name.name,
+ dentry->d_name.name, offset, count);
+
+ result = nfs_direct_read(file, iobuf, offset, count);
+ break;
+ case WRITE:
+ dfprintk(VFS,
+ "NFS: direct_IO(WRITE) (%s/%s) off/cnt(%Lu/%d)\n",
+ dentry->d_parent->d_name.name,
+ dentry->d_name.name, offset, count);
+
+ result = nfs_direct_write(file, iobuf, offset, count);
+ break;
+ default:
+ break;
+ }
+
+ dfprintk(VFS, "NFS: direct_IO result = %d\n", result);
+ return result;
+}
diff -u --recursive --new-file linux-2.4.22-nodirect/fs/nfs/file.c linux-2.4.22-blech/fs/nfs/file.c
--- linux-2.4.22-nodirect/fs/nfs/file.c 2003-07-09 19:39:39.000000000 +0200
+++ linux-2.4.22-blech/fs/nfs/file.c 2003-07-09 20:10:21.000000000 +0200
@@ -16,6 +16,7 @@
* nfs regular file handling functions
*/
+#include <linux/config.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
@@ -199,6 +200,9 @@
readpage: nfs_readpage,
sync_page: nfs_sync_page,
writepage: nfs_writepage,
+#ifdef CONFIG_NFS_DIRECTIO
+ direct_fileIO: nfs_direct_IO,
+#endif
prepare_write: nfs_prepare_write,
commit_write: nfs_commit_write
};
diff -u --recursive --new-file linux-2.4.22-nodirect/fs/nfs/Makefile linux-2.4.22-blech/fs/nfs/Makefile
--- linux-2.4.22-nodirect/fs/nfs/Makefile 2003-07-09 19:39:39.000000000 +0200
+++ linux-2.4.22-blech/fs/nfs/Makefile 2003-07-09 20:08:47.000000000 +0200
@@ -14,6 +14,7 @@
obj-$(CONFIG_ROOT_NFS) += nfsroot.o mount_clnt.o
obj-$(CONFIG_NFS_V3) += nfs3proc.o nfs3xdr.o
+obj-$(CONFIG_NFS_DIRECTIO) += direct.o
obj-m := $(O_TARGET)
diff -u --recursive --new-file linux-2.4.22-nodirect/fs/nfs/write.c linux-2.4.22-blech/fs/nfs/write.c
--- linux-2.4.22-nodirect/fs/nfs/write.c 2003-07-09 19:39:39.000000000 +0200
+++ linux-2.4.22-blech/fs/nfs/write.c 2003-07-09 20:11:04.000000000 +0200
@@ -123,23 +123,6 @@
}
/*
- * This function will be used to simulate weak cache consistency
- * under NFSv2 when the NFSv3 attribute patch is included.
- * For the moment, we just call nfs_refresh_inode().
- */
-static __inline__ int
-nfs_write_attributes(struct inode *inode, struct nfs_fattr *fattr)
-{
- if ((fattr->valid & NFS_ATTR_FATTR) && !(fattr->valid & NFS_ATTR_WCC)) {
- fattr->pre_size = NFS_CACHE_ISIZE(inode);
- fattr->pre_mtime = NFS_CACHE_MTIME(inode);
- fattr->pre_ctime = NFS_CACHE_CTIME(inode);
- fattr->valid |= NFS_ATTR_WCC;
- }
- return nfs_refresh_inode(inode, fattr);
-}
-
-/*
* Write a page synchronously.
* Offset is the data offset within the page.
*/
diff -u --recursive --new-file linux-2.4.22-nodirect/include/linux/fs.h linux-2.4.22-blech/include/linux/fs.h
--- linux-2.4.22-nodirect/include/linux/fs.h 2003-07-09 19:39:39.000000000 +0200
+++ linux-2.4.22-blech/include/linux/fs.h 2003-07-09 22:33:00.000000000 +0200
@@ -396,6 +396,8 @@
int (*releasepage) (struct page *, int);
#define KERNEL_HAS_O_DIRECT /* this is for modules out of the kernel */
int (*direct_IO)(int, struct inode *, struct kiobuf *, unsigned long, int);
+#define KERNEL_HAS_DIRECT_FILEIO /* Unfortunate kludge due to lack of foresight */
+ int (*direct_fileIO)(int, struct file *, struct kiobuf *, unsigned long, int);
void (*removepage)(struct page *); /* called when page gets removed from the inode */
};
diff -u --recursive --new-file linux-2.4.22-nodirect/include/linux/nfs_fs.h linux-2.4.22-blech/include/linux/nfs_fs.h
--- linux-2.4.22-nodirect/include/linux/nfs_fs.h 2003-07-09 19:39:39.000000000 +0200
+++ linux-2.4.22-blech/include/linux/nfs_fs.h 2003-07-09 22:33:07.000000000 +0200
@@ -274,6 +274,11 @@
#define NFS_TestClearPageSync(page) test_and_clear_bit(PG_fs_1, &(page)->flags)
/*
+ * linux/fs/nfs/direct.c
+ */
+extern int nfs_direct_IO(int, struct file *, struct kiobuf *, unsigned long, int);
+
+/*
* linux/fs/mount_clnt.c
* (Used only by nfsroot module)
*/
@@ -302,6 +307,23 @@
return __nfs_refresh_inode(inode,fattr);
}
+/*
+ * This function will be used to simulate weak cache consistency
+ * under NFSv2 when the NFSv3 attribute patch is included.
+ * For the moment, we just call nfs_refresh_inode().
+ */
+static __inline__ int
+nfs_write_attributes(struct inode *inode, struct nfs_fattr *fattr)
+{
+ if ((fattr->valid & NFS_ATTR_FATTR) && !(fattr->valid & NFS_ATTR_WCC)) {
+ fattr->pre_size = NFS_CACHE_ISIZE(inode);
+ fattr->pre_mtime = NFS_CACHE_MTIME(inode);
+ fattr->pre_ctime = NFS_CACHE_CTIME(inode);
+ fattr->valid |= NFS_ATTR_WCC;
+ }
+ return nfs_refresh_inode(inode, fattr);
+}
+
static inline loff_t
nfs_size_to_loff_t(__u64 size)
{
diff -u --recursive --new-file linux-2.4.22-nodirect/include/linux/nfs_xdr.h linux-2.4.22-blech/include/linux/nfs_xdr.h
--- linux-2.4.22-nodirect/include/linux/nfs_xdr.h 2003-07-09 19:39:39.000000000 +0200
+++ linux-2.4.22-blech/include/linux/nfs_xdr.h 2003-07-09 22:24:50.000000000 +0200
@@ -59,7 +59,7 @@
/* Arguments to the read call.
* Note that NFS_READ_MAXIOV must be <= (MAX_IOVEC-2) from sunrpc/xprt.h
*/
-#define NFS_READ_MAXIOV 8
+#define NFS_READ_MAXIOV (9)
struct nfs_readargs {
struct nfs_fh * fh;
@@ -78,7 +78,7 @@
/* Arguments to the write call.
* Note that NFS_WRITE_MAXIOV must be <= (MAX_IOVEC-2) from sunrpc/xprt.h
*/
-#define NFS_WRITE_MAXIOV 8
+#define NFS_WRITE_MAXIOV (9)
struct nfs_writeargs {
struct nfs_fh * fh;
__u64 offset;
diff -u --recursive --new-file linux-2.4.22-nodirect/mm/filemap.c linux-2.4.22-blech/mm/filemap.c
--- linux-2.4.22-nodirect/mm/filemap.c 2003-07-09 19:39:39.000000000 +0200
+++ linux-2.4.22-blech/mm/filemap.c 2003-07-09 22:29:39.000000000 +0200
@@ -1557,6 +1557,21 @@
UPDATE_ATIME(inode);
}
+static inline int have_mapping_directIO(struct address_space * mapping)
+{
+ return mapping->a_ops->direct_IO || mapping->a_ops->direct_fileIO;
+}
+
+/* Switch between old and new directIO formats */
+static inline int do_call_directIO(int rw, struct file *filp, struct kiobuf *iobuf, unsigned long offset, int blocksize)
+{
+ struct address_space * mapping = filp->f_dentry->d_inode->i_mapping;
+
+ if (mapping->a_ops->direct_fileIO)
+ return mapping->a_ops->direct_fileIO(rw, filp, iobuf, offset, blocksize);
+ return mapping->a_ops->direct_IO(rw, mapping->host, iobuf, offset, blocksize);
+}
+
/*
* i_sem and i_alloc_sem should be held already. i_sem may be dropped
* later once we've mapped the new IO. i_alloc_sem is kept until the IO
@@ -1593,7 +1608,7 @@
retval = -EINVAL;
if ((offset & blocksize_mask) || (count & blocksize_mask) || ((unsigned long) buf & blocksize_mask))
goto out_free;
- if (!mapping->a_ops->direct_IO)
+ if (!have_mapping_directIO(mapping))
goto out_free;
if ((rw == READ) && (offset + count > size))
@@ -1621,7 +1636,7 @@
if (retval)
break;
- retval = mapping->a_ops->direct_IO(rw, inode, iobuf, (offset+progress) >> blocksize_bits, blocksize);
+ retval = do_call_directIO(rw, filp, iobuf, (offset+progress) >> blocksize_bits, blocksize);
if (rw == READ && retval > 0)
mark_dirty_kiobuf(iobuf, retval);
-
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