linux-sg2042/fs/nfs/direct.c

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/*
* linux/fs/nfs/direct.c
*
* Copyright (C) 2003 by Chuck Lever <cel@netapp.com>
*
* High-performance uncached I/O for the Linux NFS client
*
* 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 file
* system 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.
*
* 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.
*
* 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.
*
* Designed by Jeff Kimmel, Chuck Lever, and Trond Myklebust, with
* help from Andrew Morton.
*
* 18 Dec 2001 Initial implementation for 2.4 --cel
* 08 Jul 2002 Version for 2.4.19, with bug fixes --trondmy
* 08 Jun 2003 Port to 2.5 APIs --cel
* 31 Mar 2004 Handle direct I/O without VFS support --cel
* 15 Sep 2004 Parallel async reads --cel
* 04 May 2005 support O_DIRECT with aio --cel
*
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/kref.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <linux/sunrpc/clnt.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>
#include "internal.h"
#include "iostat.h"
#define NFSDBG_FACILITY NFSDBG_VFS
static struct kmem_cache *nfs_direct_cachep;
/*
* This represents a set of asynchronous requests that we're waiting on
*/
struct nfs_direct_req {
struct kref kref; /* release manager */
/* I/O parameters */
struct nfs_open_context *ctx; /* file open context info */
struct kiocb * iocb; /* controlling i/o request */
struct inode * inode; /* target file of i/o */
/* completion state */
atomic_t io_count; /* i/os we're waiting for */
spinlock_t lock; /* protect completion state */
ssize_t count, /* bytes actually processed */
error; /* any reported error */
struct completion completion; /* wait for i/o completion */
/* commit state */
struct list_head rewrite_list; /* saved nfs_write_data structs */
struct nfs_write_data * commit_data; /* special write_data for commits */
int flags;
#define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */
#define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */
struct nfs_writeverf verf; /* unstable write verifier */
};
static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode);
static const struct rpc_call_ops nfs_write_direct_ops;
static inline void get_dreq(struct nfs_direct_req *dreq)
{
atomic_inc(&dreq->io_count);
}
static inline int put_dreq(struct nfs_direct_req *dreq)
{
return atomic_dec_and_test(&dreq->io_count);
}
/**
* nfs_direct_IO - NFS address space operation for direct I/O
* @rw: direction (read or write)
* @iocb: target I/O control block
* @iov: array of vectors that define I/O buffer
* @pos: offset in file to begin the operation
* @nr_segs: size of iovec array
*
* The presence of this routine in the address space ops vector means
* the NFS client supports direct I/O. However, we shunt off direct
* read and write requests before the VFS gets them, so this method
* should never be called.
*/
ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs)
{
dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n",
iocb->ki_filp->f_path.dentry->d_name.name,
(long long) pos, nr_segs);
return -EINVAL;
}
static void nfs_direct_dirty_pages(struct page **pages, unsigned int pgbase, size_t count)
{
unsigned int npages;
unsigned int i;
if (count == 0)
return;
pages += (pgbase >> PAGE_SHIFT);
npages = (count + (pgbase & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
for (i = 0; i < npages; i++) {
struct page *page = pages[i];
if (!PageCompound(page))
set_page_dirty(page);
}
}
static void nfs_direct_release_pages(struct page **pages, unsigned int npages)
{
unsigned int i;
for (i = 0; i < npages; i++)
page_cache_release(pages[i]);
}
static inline struct nfs_direct_req *nfs_direct_req_alloc(void)
{
struct nfs_direct_req *dreq;
dreq = kmem_cache_alloc(nfs_direct_cachep, GFP_KERNEL);
if (!dreq)
return NULL;
kref_init(&dreq->kref);
kref_get(&dreq->kref);
init_completion(&dreq->completion);
INIT_LIST_HEAD(&dreq->rewrite_list);
dreq->iocb = NULL;
dreq->ctx = NULL;
spin_lock_init(&dreq->lock);
atomic_set(&dreq->io_count, 0);
dreq->count = 0;
dreq->error = 0;
dreq->flags = 0;
return dreq;
}
static void nfs_direct_req_free(struct kref *kref)
{
struct nfs_direct_req *dreq = container_of(kref, struct nfs_direct_req, kref);
if (dreq->ctx != NULL)
put_nfs_open_context(dreq->ctx);
kmem_cache_free(nfs_direct_cachep, dreq);
}
static void nfs_direct_req_release(struct nfs_direct_req *dreq)
{
kref_put(&dreq->kref, nfs_direct_req_free);
}
/*
* Collects and returns the final error value/byte-count.
*/
static ssize_t nfs_direct_wait(struct nfs_direct_req *dreq)
{
ssize_t result = -EIOCBQUEUED;
/* Async requests don't wait here */
if (dreq->iocb)
goto out;
result = wait_for_completion_killable(&dreq->completion);
if (!result)
result = dreq->error;
if (!result)
result = dreq->count;
out:
return (ssize_t) result;
}
/*
* Synchronous I/O uses a stack-allocated iocb. Thus we can't trust
* the iocb is still valid here if this is a synchronous request.
*/
static void nfs_direct_complete(struct nfs_direct_req *dreq)
{
if (dreq->iocb) {
long res = (long) dreq->error;
if (!res)
res = (long) dreq->count;
aio_complete(dreq->iocb, res, 0);
}
complete_all(&dreq->completion);
nfs_direct_req_release(dreq);
}
/*
* We must hold a reference to all the pages in this direct read request
* until the RPCs complete. This could be long *after* we are woken up in
* nfs_direct_wait (for instance, if someone hits ^C on a slow server).
*/
static void nfs_direct_read_result(struct rpc_task *task, void *calldata)
{
struct nfs_read_data *data = calldata;
nfs_readpage_result(task, data);
}
static void nfs_direct_read_release(void *calldata)
{
struct nfs_read_data *data = calldata;
struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req;
int status = data->task.tk_status;
spin_lock(&dreq->lock);
if (unlikely(status < 0)) {
dreq->error = status;
spin_unlock(&dreq->lock);
} else {
dreq->count += data->res.count;
spin_unlock(&dreq->lock);
nfs_direct_dirty_pages(data->pagevec,
data->args.pgbase,
data->res.count);
}
nfs_direct_release_pages(data->pagevec, data->npages);
if (put_dreq(dreq))
nfs_direct_complete(dreq);
nfs_readdata_free(data);
}
static const struct rpc_call_ops nfs_read_direct_ops = {
#if defined(CONFIG_NFS_V4_1)
.rpc_call_prepare = nfs_read_prepare,
#endif /* CONFIG_NFS_V4_1 */
.rpc_call_done = nfs_direct_read_result,
.rpc_release = nfs_direct_read_release,
};
/*
* For each rsize'd chunk of the user's buffer, dispatch an NFS READ
* operation. If nfs_readdata_alloc() or get_user_pages() fails,
* bail and stop sending more reads. Read length accounting is
* handled automatically by nfs_direct_read_result(). Otherwise, if
* no requests have been sent, just return an error.
*/
static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,
const struct iovec *iov,
loff_t pos)
{
struct nfs_open_context *ctx = dreq->ctx;
struct inode *inode = ctx->path.dentry->d_inode;
unsigned long user_addr = (unsigned long)iov->iov_base;
size_t count = iov->iov_len;
size_t rsize = NFS_SERVER(inode)->rsize;
struct rpc_task *task;
struct rpc_message msg = {
.rpc_cred = ctx->cred,
};
struct rpc_task_setup task_setup_data = {
.rpc_client = NFS_CLIENT(inode),
.rpc_message = &msg,
.callback_ops = &nfs_read_direct_ops,
.workqueue = nfsiod_workqueue,
.flags = RPC_TASK_ASYNC,
};
unsigned int pgbase;
int result;
ssize_t started = 0;
do {
struct nfs_read_data *data;
size_t bytes;
pgbase = user_addr & ~PAGE_MASK;
bytes = min(rsize,count);
result = -ENOMEM;
data = nfs_readdata_alloc(nfs_page_array_len(pgbase, bytes));
if (unlikely(!data))
break;
down_read(&current->mm->mmap_sem);
result = get_user_pages(current, current->mm, user_addr,
data->npages, 1, 0, data->pagevec, NULL);
up_read(&current->mm->mmap_sem);
if (result < 0) {
nfs_readdata_free(data);
break;
}
if ((unsigned)result < data->npages) {
bytes = result * PAGE_SIZE;
if (bytes <= pgbase) {
nfs_direct_release_pages(data->pagevec, result);
nfs_readdata_free(data);
break;
}
bytes -= pgbase;
data->npages = result;
}
get_dreq(dreq);
data->req = (struct nfs_page *) dreq;
data->inode = inode;
data->cred = msg.rpc_cred;
data->args.fh = NFS_FH(inode);
data->args.context = ctx;
data->args.offset = pos;
data->args.pgbase = pgbase;
data->args.pages = data->pagevec;
data->args.count = bytes;
data->res.fattr = &data->fattr;
data->res.eof = 0;
data->res.count = bytes;
NFS: Too many GETATTR and ACCESS calls after direct I/O The cached read and write paths initialize fattr->time_start in their setup procedures. The value of fattr->time_start is propagated to read_cache_jiffies by nfs_update_inode(). Subsequent calls to nfs_attribute_timeout() will then use a good time stamp when computing the attribute cache timeout, and squelch unneeded GETATTR calls. Since the direct I/O paths erroneously leave the inode's fattr->time_start field set to zero, read_cache_jiffies for that inode is set to zero after any direct read or write operation. This triggers an otw GETATTR or ACCESS call to update the file's attribute and access caches properly, even when the NFS READ or WRITE replies have usable post-op attributes. Make sure the direct read and write setup code performs the same fattr initialization as the cached I/O paths to prevent unnecessary GETATTR calls. This was likely introduced by commit 0e574af1 in 2.6.15, which appears to add new nfs_fattr_init() call sites in the cached read and write paths, but not in the equivalent places in fs/nfs/direct.c. A subsequent commit in the same series, 33801147, introduces the fattr->time_start field. Interestingly, the direct write reschedule path already has a call to nfs_fattr_init() in the right place. Reported-by: Quentin Barnes <qbarnes@yahoo-inc.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Cc: stable@kernel.org Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-16 01:19:53 +08:00
nfs_fattr_init(&data->fattr);
msg.rpc_argp = &data->args;
msg.rpc_resp = &data->res;
task_setup_data.task = &data->task;
task_setup_data.callback_data = data;
NFS_PROTO(inode)->read_setup(data, &msg);
task = rpc_run_task(&task_setup_data);
if (IS_ERR(task))
break;
rpc_put_task(task);
dprintk("NFS: %5u initiated direct read call "
"(req %s/%Ld, %zu bytes @ offset %Lu)\n",
data->task.tk_pid,
inode->i_sb->s_id,
(long long)NFS_FILEID(inode),
bytes,
(unsigned long long)data->args.offset);
started += bytes;
user_addr += bytes;
pos += bytes;
/* FIXME: Remove this unnecessary math from final patch */
pgbase += bytes;
pgbase &= ~PAGE_MASK;
BUG_ON(pgbase != (user_addr & ~PAGE_MASK));
count -= bytes;
} while (count != 0);
if (started)
return started;
return result < 0 ? (ssize_t) result : -EFAULT;
}
static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
const struct iovec *iov,
unsigned long nr_segs,
loff_t pos)
{
ssize_t result = -EINVAL;
size_t requested_bytes = 0;
unsigned long seg;
get_dreq(dreq);
for (seg = 0; seg < nr_segs; seg++) {
const struct iovec *vec = &iov[seg];
result = nfs_direct_read_schedule_segment(dreq, vec, pos);
if (result < 0)
break;
requested_bytes += result;
if ((size_t)result < vec->iov_len)
break;
pos += vec->iov_len;
}
if (put_dreq(dreq))
nfs_direct_complete(dreq);
if (requested_bytes != 0)
return 0;
if (result < 0)
return result;
return -EIO;
}
static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
ssize_t result = 0;
struct inode *inode = iocb->ki_filp->f_mapping->host;
struct nfs_direct_req *dreq;
dreq = nfs_direct_req_alloc();
if (!dreq)
return -ENOMEM;
dreq->inode = inode;
dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
if (!is_sync_kiocb(iocb))
dreq->iocb = iocb;
result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos);
if (!result)
result = nfs_direct_wait(dreq);
nfs_direct_req_release(dreq);
return result;
}
static void nfs_direct_free_writedata(struct nfs_direct_req *dreq)
{
while (!list_empty(&dreq->rewrite_list)) {
struct nfs_write_data *data = list_entry(dreq->rewrite_list.next, struct nfs_write_data, pages);
list_del(&data->pages);
nfs_direct_release_pages(data->pagevec, data->npages);
nfs_writedata_free(data);
}
}
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq)
{
struct inode *inode = dreq->inode;
struct list_head *p;
struct nfs_write_data *data;
struct rpc_task *task;
struct rpc_message msg = {
.rpc_cred = dreq->ctx->cred,
};
struct rpc_task_setup task_setup_data = {
.rpc_client = NFS_CLIENT(inode),
.rpc_message = &msg,
.callback_ops = &nfs_write_direct_ops,
.workqueue = nfsiod_workqueue,
.flags = RPC_TASK_ASYNC,
};
dreq->count = 0;
get_dreq(dreq);
list_for_each(p, &dreq->rewrite_list) {
data = list_entry(p, struct nfs_write_data, pages);
get_dreq(dreq);
/* Use stable writes */
data->args.stable = NFS_FILE_SYNC;
/*
* Reset data->res.
*/
nfs_fattr_init(&data->fattr);
data->res.count = data->args.count;
memset(&data->verf, 0, sizeof(data->verf));
/*
* Reuse data->task; data->args should not have changed
* since the original request was sent.
*/
task_setup_data.task = &data->task;
task_setup_data.callback_data = data;
msg.rpc_argp = &data->args;
msg.rpc_resp = &data->res;
NFS_PROTO(inode)->write_setup(data, &msg);
/*
* We're called via an RPC callback, so BKL is already held.
*/
task = rpc_run_task(&task_setup_data);
if (!IS_ERR(task))
rpc_put_task(task);
dprintk("NFS: %5u rescheduled direct write call (req %s/%Ld, %u bytes @ offset %Lu)\n",
data->task.tk_pid,
inode->i_sb->s_id,
(long long)NFS_FILEID(inode),
data->args.count,
(unsigned long long)data->args.offset);
}
if (put_dreq(dreq))
nfs_direct_write_complete(dreq, inode);
}
static void nfs_direct_commit_result(struct rpc_task *task, void *calldata)
{
struct nfs_write_data *data = calldata;
/* Call the NFS version-specific code */
NFS_PROTO(data->inode)->commit_done(task, data);
}
static void nfs_direct_commit_release(void *calldata)
{
struct nfs_write_data *data = calldata;
struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req;
int status = data->task.tk_status;
if (status < 0) {
dprintk("NFS: %5u commit failed with error %d.\n",
data->task.tk_pid, status);
dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
} else if (memcmp(&dreq->verf, &data->verf, sizeof(data->verf))) {
dprintk("NFS: %5u commit verify failed\n", data->task.tk_pid);
dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
}
dprintk("NFS: %5u commit returned %d\n", data->task.tk_pid, status);
nfs_direct_write_complete(dreq, data->inode);
nfs_commit_free(data);
}
static const struct rpc_call_ops nfs_commit_direct_ops = {
#if defined(CONFIG_NFS_V4_1)
.rpc_call_prepare = nfs_write_prepare,
#endif /* CONFIG_NFS_V4_1 */
.rpc_call_done = nfs_direct_commit_result,
.rpc_release = nfs_direct_commit_release,
};
static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq)
{
struct nfs_write_data *data = dreq->commit_data;
struct rpc_task *task;
struct rpc_message msg = {
.rpc_argp = &data->args,
.rpc_resp = &data->res,
.rpc_cred = dreq->ctx->cred,
};
struct rpc_task_setup task_setup_data = {
.task = &data->task,
.rpc_client = NFS_CLIENT(dreq->inode),
.rpc_message = &msg,
.callback_ops = &nfs_commit_direct_ops,
.callback_data = data,
.workqueue = nfsiod_workqueue,
.flags = RPC_TASK_ASYNC,
};
data->inode = dreq->inode;
data->cred = msg.rpc_cred;
data->args.fh = NFS_FH(data->inode);
data->args.offset = 0;
data->args.count = 0;
data->args.context = dreq->ctx;
data->res.count = 0;
data->res.fattr = &data->fattr;
data->res.verf = &data->verf;
NFS: Too many GETATTR and ACCESS calls after direct I/O The cached read and write paths initialize fattr->time_start in their setup procedures. The value of fattr->time_start is propagated to read_cache_jiffies by nfs_update_inode(). Subsequent calls to nfs_attribute_timeout() will then use a good time stamp when computing the attribute cache timeout, and squelch unneeded GETATTR calls. Since the direct I/O paths erroneously leave the inode's fattr->time_start field set to zero, read_cache_jiffies for that inode is set to zero after any direct read or write operation. This triggers an otw GETATTR or ACCESS call to update the file's attribute and access caches properly, even when the NFS READ or WRITE replies have usable post-op attributes. Make sure the direct read and write setup code performs the same fattr initialization as the cached I/O paths to prevent unnecessary GETATTR calls. This was likely introduced by commit 0e574af1 in 2.6.15, which appears to add new nfs_fattr_init() call sites in the cached read and write paths, but not in the equivalent places in fs/nfs/direct.c. A subsequent commit in the same series, 33801147, introduces the fattr->time_start field. Interestingly, the direct write reschedule path already has a call to nfs_fattr_init() in the right place. Reported-by: Quentin Barnes <qbarnes@yahoo-inc.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Cc: stable@kernel.org Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-16 01:19:53 +08:00
nfs_fattr_init(&data->fattr);
NFS_PROTO(data->inode)->commit_setup(data, &msg);
/* Note: task.tk_ops->rpc_release will free dreq->commit_data */
dreq->commit_data = NULL;
dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
task = rpc_run_task(&task_setup_data);
if (!IS_ERR(task))
rpc_put_task(task);
}
static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode)
{
int flags = dreq->flags;
dreq->flags = 0;
switch (flags) {
case NFS_ODIRECT_DO_COMMIT:
nfs_direct_commit_schedule(dreq);
break;
case NFS_ODIRECT_RESCHED_WRITES:
nfs_direct_write_reschedule(dreq);
break;
default:
if (dreq->commit_data != NULL)
nfs_commit_free(dreq->commit_data);
nfs_direct_free_writedata(dreq);
nfs_zap_mapping(inode, inode->i_mapping);
nfs_direct_complete(dreq);
}
}
static void nfs_alloc_commit_data(struct nfs_direct_req *dreq)
{
dreq->commit_data = nfs_commitdata_alloc();
if (dreq->commit_data != NULL)
dreq->commit_data->req = (struct nfs_page *) dreq;
}
#else
static inline void nfs_alloc_commit_data(struct nfs_direct_req *dreq)
{
dreq->commit_data = NULL;
}
static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode)
{
nfs_direct_free_writedata(dreq);
nfs_zap_mapping(inode, inode->i_mapping);
nfs_direct_complete(dreq);
}
#endif
static void nfs_direct_write_result(struct rpc_task *task, void *calldata)
{
struct nfs_write_data *data = calldata;
if (nfs_writeback_done(task, data) != 0)
return;
}
/*
* NB: Return the value of the first error return code. Subsequent
* errors after the first one are ignored.
*/
static void nfs_direct_write_release(void *calldata)
{
struct nfs_write_data *data = calldata;
struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req;
int status = data->task.tk_status;
spin_lock(&dreq->lock);
if (unlikely(status < 0)) {
/* An error has occurred, so we should not commit */
dreq->flags = 0;
dreq->error = status;
}
if (unlikely(dreq->error != 0))
goto out_unlock;
dreq->count += data->res.count;
if (data->res.verf->committed != NFS_FILE_SYNC) {
switch (dreq->flags) {
case 0:
memcpy(&dreq->verf, &data->verf, sizeof(dreq->verf));
dreq->flags = NFS_ODIRECT_DO_COMMIT;
break;
case NFS_ODIRECT_DO_COMMIT:
if (memcmp(&dreq->verf, &data->verf, sizeof(dreq->verf))) {
dprintk("NFS: %5u write verify failed\n", data->task.tk_pid);
dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
}
}
}
out_unlock:
spin_unlock(&dreq->lock);
if (put_dreq(dreq))
nfs_direct_write_complete(dreq, data->inode);
}
static const struct rpc_call_ops nfs_write_direct_ops = {
#if defined(CONFIG_NFS_V4_1)
.rpc_call_prepare = nfs_write_prepare,
#endif /* CONFIG_NFS_V4_1 */
.rpc_call_done = nfs_direct_write_result,
.rpc_release = nfs_direct_write_release,
};
/*
* For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE
* operation. If nfs_writedata_alloc() or get_user_pages() fails,
* bail and stop sending more writes. Write length accounting is
* handled automatically by nfs_direct_write_result(). Otherwise, if
* no requests have been sent, just return an error.
*/
static ssize_t nfs_direct_write_schedule_segment(struct nfs_direct_req *dreq,
const struct iovec *iov,
loff_t pos, int sync)
{
struct nfs_open_context *ctx = dreq->ctx;
struct inode *inode = ctx->path.dentry->d_inode;
unsigned long user_addr = (unsigned long)iov->iov_base;
size_t count = iov->iov_len;
struct rpc_task *task;
struct rpc_message msg = {
.rpc_cred = ctx->cred,
};
struct rpc_task_setup task_setup_data = {
.rpc_client = NFS_CLIENT(inode),
.rpc_message = &msg,
.callback_ops = &nfs_write_direct_ops,
.workqueue = nfsiod_workqueue,
.flags = RPC_TASK_ASYNC,
};
size_t wsize = NFS_SERVER(inode)->wsize;
unsigned int pgbase;
int result;
ssize_t started = 0;
do {
struct nfs_write_data *data;
size_t bytes;
pgbase = user_addr & ~PAGE_MASK;
bytes = min(wsize,count);
result = -ENOMEM;
data = nfs_writedata_alloc(nfs_page_array_len(pgbase, bytes));
if (unlikely(!data))
break;
down_read(&current->mm->mmap_sem);
result = get_user_pages(current, current->mm, user_addr,
data->npages, 0, 0, data->pagevec, NULL);
up_read(&current->mm->mmap_sem);
if (result < 0) {
nfs_writedata_free(data);
break;
}
if ((unsigned)result < data->npages) {
bytes = result * PAGE_SIZE;
if (bytes <= pgbase) {
nfs_direct_release_pages(data->pagevec, result);
nfs_writedata_free(data);
break;
}
bytes -= pgbase;
data->npages = result;
}
get_dreq(dreq);
list_move_tail(&data->pages, &dreq->rewrite_list);
data->req = (struct nfs_page *) dreq;
data->inode = inode;
data->cred = msg.rpc_cred;
data->args.fh = NFS_FH(inode);
data->args.context = ctx;
data->args.offset = pos;
data->args.pgbase = pgbase;
data->args.pages = data->pagevec;
data->args.count = bytes;
data->args.stable = sync;
data->res.fattr = &data->fattr;
data->res.count = bytes;
data->res.verf = &data->verf;
NFS: Too many GETATTR and ACCESS calls after direct I/O The cached read and write paths initialize fattr->time_start in their setup procedures. The value of fattr->time_start is propagated to read_cache_jiffies by nfs_update_inode(). Subsequent calls to nfs_attribute_timeout() will then use a good time stamp when computing the attribute cache timeout, and squelch unneeded GETATTR calls. Since the direct I/O paths erroneously leave the inode's fattr->time_start field set to zero, read_cache_jiffies for that inode is set to zero after any direct read or write operation. This triggers an otw GETATTR or ACCESS call to update the file's attribute and access caches properly, even when the NFS READ or WRITE replies have usable post-op attributes. Make sure the direct read and write setup code performs the same fattr initialization as the cached I/O paths to prevent unnecessary GETATTR calls. This was likely introduced by commit 0e574af1 in 2.6.15, which appears to add new nfs_fattr_init() call sites in the cached read and write paths, but not in the equivalent places in fs/nfs/direct.c. A subsequent commit in the same series, 33801147, introduces the fattr->time_start field. Interestingly, the direct write reschedule path already has a call to nfs_fattr_init() in the right place. Reported-by: Quentin Barnes <qbarnes@yahoo-inc.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Cc: stable@kernel.org Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-16 01:19:53 +08:00
nfs_fattr_init(&data->fattr);
task_setup_data.task = &data->task;
task_setup_data.callback_data = data;
msg.rpc_argp = &data->args;
msg.rpc_resp = &data->res;
NFS_PROTO(inode)->write_setup(data, &msg);
task = rpc_run_task(&task_setup_data);
if (IS_ERR(task))
break;
rpc_put_task(task);
dprintk("NFS: %5u initiated direct write call "
"(req %s/%Ld, %zu bytes @ offset %Lu)\n",
data->task.tk_pid,
inode->i_sb->s_id,
(long long)NFS_FILEID(inode),
bytes,
(unsigned long long)data->args.offset);
started += bytes;
user_addr += bytes;
pos += bytes;
/* FIXME: Remove this useless math from the final patch */
pgbase += bytes;
pgbase &= ~PAGE_MASK;
BUG_ON(pgbase != (user_addr & ~PAGE_MASK));
count -= bytes;
} while (count != 0);
if (started)
return started;
return result < 0 ? (ssize_t) result : -EFAULT;
}
static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
const struct iovec *iov,
unsigned long nr_segs,
loff_t pos, int sync)
{
ssize_t result = 0;
size_t requested_bytes = 0;
unsigned long seg;
get_dreq(dreq);
for (seg = 0; seg < nr_segs; seg++) {
const struct iovec *vec = &iov[seg];
result = nfs_direct_write_schedule_segment(dreq, vec,
pos, sync);
if (result < 0)
break;
requested_bytes += result;
if ((size_t)result < vec->iov_len)
break;
pos += vec->iov_len;
}
if (put_dreq(dreq))
nfs_direct_write_complete(dreq, dreq->inode);
if (requested_bytes != 0)
return 0;
if (result < 0)
return result;
return -EIO;
}
static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos,
size_t count)
{
ssize_t result = 0;
struct inode *inode = iocb->ki_filp->f_mapping->host;
struct nfs_direct_req *dreq;
size_t wsize = NFS_SERVER(inode)->wsize;
int sync = NFS_UNSTABLE;
dreq = nfs_direct_req_alloc();
if (!dreq)
return -ENOMEM;
nfs_alloc_commit_data(dreq);
if (dreq->commit_data == NULL || count < wsize)
sync = NFS_FILE_SYNC;
dreq->inode = inode;
dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
if (!is_sync_kiocb(iocb))
dreq->iocb = iocb;
result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos, sync);
if (!result)
result = nfs_direct_wait(dreq);
nfs_direct_req_release(dreq);
return result;
}
/**
* nfs_file_direct_read - file direct read operation for NFS files
* @iocb: target I/O control block
* @iov: vector of user buffers into which to read data
* @nr_segs: size of iov vector
* @pos: byte offset in file where reading starts
*
* We use this function for direct reads instead of calling
* generic_file_aio_read() in order to avoid gfar's check to see if
* the request starts before the end of the file. For that check
* to work, we must generate a GETATTR before each direct read, and
* even then there is a window between the GETATTR and the subsequent
* READ where the file size could change. Our preference is simply
* to do all reads the application wants, and the server will take
* care of managing the end of file boundary.
*
* This function also eliminates unnecessarily updating the file's
* atime locally, as the NFS server sets the file's atime, and this
* client must read the updated atime from the server back into its
* cache.
*/
ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
ssize_t retval = -EINVAL;
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
size_t count;
count = iov_length(iov, nr_segs);
nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);
dfprintk(FILE, "NFS: direct read(%s/%s, %zd@%Ld)\n",
file->f_path.dentry->d_parent->d_name.name,
file->f_path.dentry->d_name.name,
count, (long long) pos);
retval = 0;
if (!count)
goto out;
retval = nfs_sync_mapping(mapping);
if (retval)
goto out;
retval = nfs_direct_read(iocb, iov, nr_segs, pos);
if (retval > 0)
iocb->ki_pos = pos + retval;
out:
return retval;
}
/**
* nfs_file_direct_write - file direct write operation for NFS files
* @iocb: target I/O control block
* @iov: vector of user buffers from which to write data
* @nr_segs: size of iov vector
* @pos: byte offset in file where writing starts
*
* We use this function for direct writes instead of calling
* generic_file_aio_write() in order to avoid taking the inode
* semaphore and updating the i_size. The NFS server will set
* the new i_size and this client must read the updated size
* back into its cache. We let the server do generic write
* parameter checking and report problems.
*
* We eliminate local atime updates, see direct read above.
*
* We avoid unnecessary page cache invalidations for normal cached
* readers of this file.
*
* Note that O_APPEND is not supported for NFS direct writes, as there
* is no atomic O_APPEND write facility in the NFS protocol.
*/
ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
ssize_t retval = -EINVAL;
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
size_t count;
count = iov_length(iov, nr_segs);
nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count);
dfprintk(FILE, "NFS: direct write(%s/%s, %zd@%Ld)\n",
file->f_path.dentry->d_parent->d_name.name,
file->f_path.dentry->d_name.name,
count, (long long) pos);
retval = generic_write_checks(file, &pos, &count, 0);
if (retval)
goto out;
retval = -EINVAL;
if ((ssize_t) count < 0)
goto out;
retval = 0;
if (!count)
goto out;
retval = nfs_sync_mapping(mapping);
if (retval)
goto out;
retval = nfs_direct_write(iocb, iov, nr_segs, pos, count);
if (retval > 0)
iocb->ki_pos = pos + retval;
out:
return retval;
}
/**
* nfs_init_directcache - create a slab cache for nfs_direct_req structures
*
*/
int __init nfs_init_directcache(void)
{
nfs_direct_cachep = kmem_cache_create("nfs_direct_cache",
sizeof(struct nfs_direct_req),
0, (SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD),
NULL);
if (nfs_direct_cachep == NULL)
return -ENOMEM;
return 0;
}
/**
* nfs_destroy_directcache - destroy the slab cache for nfs_direct_req structures
*
*/
void nfs_destroy_directcache(void)
{
kmem_cache_destroy(nfs_direct_cachep);
}