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author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2006-03-20 13:44:36 -0500 |
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committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2006-03-20 13:44:36 -0500 |
commit | fad61490419b3e494f300e9b2579810ef3bcda31 (patch) | |
tree | 1bca68921a83d4dc0219aa8d46c3c8e8313965c2 /fs/nfs/direct.c | |
parent | e17b1fc4b35399935f00a635206e183d9292fe4f (diff) | |
download | lwn-fad61490419b3e494f300e9b2579810ef3bcda31.tar.gz lwn-fad61490419b3e494f300e9b2579810ef3bcda31.zip |
nfs: Use UNSTABLE + COMMIT for NFS O_DIRECT writes
Currently NFS O_DIRECT writes use FILE_SYNC so that a COMMIT is not
necessary. This simplifies the internal logic, but this could be a
difficult workload for some servers.
Instead, let's send UNSTABLE writes, and after they all complete, send a
COMMIT for the dirty range. After the COMMIT returns successfully, then do
the wake_up or fire off aio_complete().
Test plan:
Async direct I/O tests against Solaris (or any server that requires
committed unstable writes). Reboot server during test.
Based on an earlier patch by Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/direct.c')
-rw-r--r-- | fs/nfs/direct.c | 224 |
1 files changed, 199 insertions, 25 deletions
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 737990dd4dfe..f0f2053c7a61 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -69,11 +69,15 @@ struct nfs_direct_req { struct kref kref; /* release manager */ /* I/O parameters */ - struct list_head list; /* nfs_read/write_data structs */ + struct list_head list, /* nfs_read/write_data structs */ + rewrite_list; /* saved nfs_write_data structs */ struct file * filp; /* file descriptor */ struct kiocb * iocb; /* controlling i/o request */ wait_queue_head_t wait; /* wait for i/o completion */ struct inode * inode; /* target file of i/o */ + unsigned long user_addr; /* location of user's buffer */ + size_t user_count; /* total bytes to move */ + loff_t pos; /* starting offset in file */ struct page ** pages; /* pages in our buffer */ unsigned int npages; /* count of pages */ @@ -82,8 +86,18 @@ struct nfs_direct_req { int outstanding; /* i/os we're waiting for */ ssize_t count, /* bytes actually processed */ error; /* any reported error */ + + /* commit state */ + 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_schedule(struct nfs_direct_req *dreq, int sync); +static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode); + /** * nfs_direct_IO - NFS address space operation for direct I/O * @rw: direction (read or write) @@ -160,11 +174,13 @@ static inline struct nfs_direct_req *nfs_direct_req_alloc(void) kref_init(&dreq->kref); init_waitqueue_head(&dreq->wait); INIT_LIST_HEAD(&dreq->list); + INIT_LIST_HEAD(&dreq->rewrite_list); dreq->iocb = NULL; spin_lock_init(&dreq->lock); dreq->outstanding = 0; dreq->count = 0; dreq->error = 0; + dreq->flags = 0; return dreq; } @@ -299,7 +315,7 @@ static const struct rpc_call_ops nfs_read_direct_ops = { * For each nfs_read_data struct that was allocated on the list, dispatch * an NFS READ operation */ -static void nfs_direct_read_schedule(struct nfs_direct_req *dreq, unsigned long user_addr, size_t count, loff_t pos) +static void nfs_direct_read_schedule(struct nfs_direct_req *dreq) { struct file *file = dreq->filp; struct inode *inode = file->f_mapping->host; @@ -307,11 +323,13 @@ static void nfs_direct_read_schedule(struct nfs_direct_req *dreq, unsigned long file->private_data; struct list_head *list = &dreq->list; struct page **pages = dreq->pages; + size_t count = dreq->user_count; + loff_t pos = dreq->pos; size_t rsize = NFS_SERVER(inode)->rsize; unsigned int curpage, pgbase; curpage = 0; - pgbase = user_addr & ~PAGE_MASK; + pgbase = dreq->user_addr & ~PAGE_MASK; do { struct nfs_read_data *data; size_t bytes; @@ -373,6 +391,9 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, unsigned long user_addr, size if (!dreq) return -ENOMEM; + dreq->user_addr = user_addr; + dreq->user_count = count; + dreq->pos = pos; dreq->pages = pages; dreq->npages = nr_pages; igrab(inode); @@ -383,13 +404,137 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, unsigned long user_addr, size nfs_add_stats(inode, NFSIOS_DIRECTREADBYTES, count); rpc_clnt_sigmask(clnt, &oldset); - nfs_direct_read_schedule(dreq, user_addr, count, pos); + nfs_direct_read_schedule(dreq); result = nfs_direct_wait(dreq); rpc_clnt_sigunmask(clnt, &oldset); return result; } +static void nfs_direct_free_writedata(struct nfs_direct_req *dreq) +{ + list_splice_init(&dreq->rewrite_list, &dreq->list); + while (!list_empty(&dreq->list)) { + struct nfs_write_data *data = list_entry(dreq->list.next, struct nfs_write_data, pages); + list_del(&data->pages); + nfs_writedata_release(data); + } +} + +#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) +static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq) +{ + struct list_head *pos; + + list_splice_init(&dreq->rewrite_list, &dreq->list); + list_for_each(pos, &dreq->list) + dreq->outstanding++; + dreq->count = 0; + + nfs_direct_write_schedule(dreq, FLUSH_STABLE); +} + +static void nfs_direct_commit_result(struct rpc_task *task, void *calldata) +{ + struct nfs_write_data *data = calldata; + struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req; + + /* Call the NFS version-specific code */ + if (NFS_PROTO(data->inode)->commit_done(task, data) != 0) + return; + if (unlikely(task->tk_status < 0)) { + dreq->error = task->tk_status; + dreq->flags = NFS_ODIRECT_RESCHED_WRITES; + } + if (memcmp(&dreq->verf, &data->verf, sizeof(data->verf))) { + dprintk("NFS: %5u commit verify failed\n", task->tk_pid); + dreq->flags = NFS_ODIRECT_RESCHED_WRITES; + } + + dprintk("NFS: %5u commit returned %d\n", task->tk_pid, task->tk_status); + nfs_direct_write_complete(dreq, data->inode); +} + +static const struct rpc_call_ops nfs_commit_direct_ops = { + .rpc_call_done = nfs_direct_commit_result, + .rpc_release = nfs_commit_release, +}; + +static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq) +{ + struct file *file = dreq->filp; + struct nfs_open_context *ctx = (struct nfs_open_context *) + file->private_data; + struct nfs_write_data *data = dreq->commit_data; + struct rpc_task *task = &data->task; + + data->inode = dreq->inode; + data->cred = ctx->cred; + + data->args.fh = NFS_FH(data->inode); + data->args.offset = dreq->pos; + data->args.count = dreq->user_count; + data->res.count = 0; + data->res.fattr = &data->fattr; + data->res.verf = &data->verf; + + rpc_init_task(&data->task, NFS_CLIENT(dreq->inode), RPC_TASK_ASYNC, + &nfs_commit_direct_ops, data); + NFS_PROTO(data->inode)->commit_setup(data, 0); + + data->task.tk_priority = RPC_PRIORITY_NORMAL; + data->task.tk_cookie = (unsigned long)data->inode; + /* Note: task.tk_ops->rpc_release will free dreq->commit_data */ + dreq->commit_data = NULL; + + dprintk("NFS: %5u initiated commit call\n", task->tk_pid); + + lock_kernel(); + rpc_execute(&data->task); + unlock_kernel(); +} + +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: + nfs_end_data_update(inode); + if (dreq->commit_data != NULL) + nfs_commit_free(dreq->commit_data); + nfs_direct_free_writedata(dreq); + nfs_direct_complete(dreq); + } +} + +static void nfs_alloc_commit_data(struct nfs_direct_req *dreq) +{ + dreq->commit_data = nfs_commit_alloc(0); + 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_end_data_update(inode); + nfs_direct_free_writedata(dreq); + nfs_direct_complete(dreq); +} +#endif + static struct nfs_direct_req *nfs_direct_write_alloc(size_t nbytes, size_t wsize) { struct list_head *list; @@ -424,14 +569,13 @@ static struct nfs_direct_req *nfs_direct_write_alloc(size_t nbytes, size_t wsize break; nbytes -= wsize; } + + nfs_alloc_commit_data(dreq); + kref_get(&dreq->kref); return dreq; } -/* - * NB: Return the value of the first error return code. Subsequent - * errors after the first one are ignored. - */ static void nfs_direct_write_result(struct rpc_task *task, void *calldata) { struct nfs_write_data *data = calldata; @@ -440,41 +584,62 @@ static void nfs_direct_write_result(struct rpc_task *task, void *calldata) if (nfs_writeback_done(task, data) != 0) return; - /* If the server fell back to an UNSTABLE write, it's an error. */ - if (unlikely(data->res.verf->committed != NFS_FILE_SYNC)) - status = -EIO; spin_lock(&dreq->lock); if (likely(status >= 0)) dreq->count += data->res.count; else - dreq->error = status; + dreq->error = task->tk_status; + 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", task->tk_pid); + dreq->flags = NFS_ODIRECT_RESCHED_WRITES; + } + } + } + /* In case we have to resend */ + data->args.stable = NFS_FILE_SYNC; + + spin_unlock(&dreq->lock); +} + +/* + * 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; + + spin_lock(&dreq->lock); if (--dreq->outstanding) { spin_unlock(&dreq->lock); return; } - spin_unlock(&dreq->lock); - nfs_end_data_update(data->inode); - nfs_direct_complete(dreq); + nfs_direct_write_complete(dreq, data->inode); } static const struct rpc_call_ops nfs_write_direct_ops = { .rpc_call_done = nfs_direct_write_result, - .rpc_release = nfs_writedata_release, + .rpc_release = nfs_direct_write_release, }; /* * For each nfs_write_data struct that was allocated on the list, dispatch * an NFS WRITE operation - * - * XXX: For now, support only FILE_SYNC writes. Later we may add - * support for UNSTABLE + COMMIT. */ -static void nfs_direct_write_schedule(struct nfs_direct_req *dreq, unsigned long user_addr, size_t count, loff_t pos) +static void nfs_direct_write_schedule(struct nfs_direct_req *dreq, int sync) { struct file *file = dreq->filp; struct inode *inode = file->f_mapping->host; @@ -482,11 +647,13 @@ static void nfs_direct_write_schedule(struct nfs_direct_req *dreq, unsigned long file->private_data; struct list_head *list = &dreq->list; struct page **pages = dreq->pages; + size_t count = dreq->user_count; + loff_t pos = dreq->pos; size_t wsize = NFS_SERVER(inode)->wsize; unsigned int curpage, pgbase; curpage = 0; - pgbase = user_addr & ~PAGE_MASK; + pgbase = dreq->user_addr & ~PAGE_MASK; do { struct nfs_write_data *data; size_t bytes; @@ -496,7 +663,7 @@ static void nfs_direct_write_schedule(struct nfs_direct_req *dreq, unsigned long bytes = count; data = list_entry(list->next, struct nfs_write_data, pages); - list_del_init(&data->pages); + list_move_tail(&data->pages, &dreq->rewrite_list); data->inode = inode; data->cred = ctx->cred; @@ -512,7 +679,7 @@ static void nfs_direct_write_schedule(struct nfs_direct_req *dreq, unsigned long rpc_init_task(&data->task, NFS_CLIENT(inode), RPC_TASK_ASYNC, &nfs_write_direct_ops, data); - NFS_PROTO(inode)->write_setup(data, FLUSH_STABLE); + NFS_PROTO(inode)->write_setup(data, sync); data->task.tk_priority = RPC_PRIORITY_NORMAL; data->task.tk_cookie = (unsigned long) inode; @@ -544,11 +711,18 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, unsigned long user_addr, siz struct inode *inode = iocb->ki_filp->f_mapping->host; struct rpc_clnt *clnt = NFS_CLIENT(inode); struct nfs_direct_req *dreq; + size_t wsize = NFS_SERVER(inode)->wsize; + int sync = 0; - dreq = nfs_direct_write_alloc(count, NFS_SERVER(inode)->wsize); + dreq = nfs_direct_write_alloc(count, wsize); if (!dreq) return -ENOMEM; + if (dreq->commit_data == NULL || count < wsize) + sync = FLUSH_STABLE; + dreq->user_addr = user_addr; + dreq->user_count = count; + dreq->pos = pos; dreq->pages = pages; dreq->npages = nr_pages; igrab(inode); @@ -562,7 +736,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, unsigned long user_addr, siz nfs_begin_data_update(inode); rpc_clnt_sigmask(clnt, &oldset); - nfs_direct_write_schedule(dreq, user_addr, count, pos); + nfs_direct_write_schedule(dreq, sync); result = nfs_direct_wait(dreq); rpc_clnt_sigunmask(clnt, &oldset); |