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/*
* linux/fs/nfs/write.c
*
* Writing file data over NFS.
*
* We do it like this: When a (user) process wishes to write data to an
* NFS file, a write request is allocated that contains the RPC task data
* plus some info on the page to be written, and added to the inode's
* write chain. If the process writes past the end of the page, an async
* RPC call to write the page is scheduled immediately; otherwise, the call
* is delayed for a few seconds.
*
* Just like readahead, no async I/O is performed if wsize < PAGE_SIZE.
*
* Write requests are kept on the inode's writeback list. Each entry in
* that list references the page (portion) to be written. When the
* cache timeout has expired, the RPC task is woken up, and tries to
* lock the page. As soon as it manages to do so, the request is moved
* from the writeback list to the writelock list.
*
* Note: we must make sure never to confuse the inode passed in the
* write_page request with the one in page->inode. As far as I understand
* it, these are different when doing a swap-out.
*
* To understand everything that goes on here and in the NFS read code,
* one should be aware that a page is locked in exactly one of the following
* cases:
*
* - A write request is in progress.
* - A user process is in generic_file_write/nfs_update_page
* - A user process is in generic_file_read
*
* Also note that because of the way pages are invalidated in
* nfs_revalidate_inode, the following assertions hold:
*
* - If a page is dirty, there will be no read requests (a page will
* not be re-read unless invalidated by nfs_revalidate_inode).
* - If the page is not uptodate, there will be no pending write
* requests, and no process will be in nfs_update_page.
*
* FIXME: Interaction with the vmscan routines is not optimal yet.
* Either vmscan must be made nfs-savvy, or we need a different page
* reclaim concept that supports something like FS-independent
* buffer_heads with a b_ops-> field.
*
* Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/config.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs_flushd.h>
#include <linux/nfs_page.h>
#include <asm/uaccess.h>
#include <linux/smp_lock.h>
#define NFSDBG_FACILITY NFSDBG_PAGECACHE
/*
* Local structures
*
* This is the struct where the WRITE/COMMIT arguments go.
*/
struct nfs_write_data {
struct rpc_task task;
struct inode *inode;
struct rpc_cred *cred;
struct nfs_writeargs args; /* argument struct */
struct nfs_writeres res; /* result struct */
struct nfs_fattr fattr;
struct nfs_writeverf verf;
struct list_head pages; /* Coalesced requests we wish to flush */
};
/*
* Local function declarations
*/
static struct nfs_page * nfs_update_request(struct file*, struct inode *,
struct page *,
unsigned int, unsigned int);
static void nfs_strategy(struct inode *inode);
static void nfs_writeback_done(struct rpc_task *);
#ifdef CONFIG_NFS_V3
static void nfs_commit_done(struct rpc_task *);
#endif
/* Hack for future NFS swap support */
#ifndef IS_SWAPFILE
# define IS_SWAPFILE(inode) (0)
#endif
static kmem_cache_t *nfs_wdata_cachep;
static __inline__ struct nfs_write_data *nfs_writedata_alloc(void)
{
struct nfs_write_data *p;
p = kmem_cache_alloc(nfs_wdata_cachep, SLAB_NOFS);
if (p) {
memset(p, 0, sizeof(*p));
INIT_LIST_HEAD(&p->pages);
}
return p;
}
static __inline__ void nfs_writedata_free(struct nfs_write_data *p)
{
kmem_cache_free(nfs_wdata_cachep, p);
}
static void nfs_writedata_release(struct rpc_task *task)
{
struct nfs_write_data *wdata = (struct nfs_write_data *)task->tk_calldata;
nfs_writedata_free(wdata);
}
/*
* 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.
*/
static int
nfs_writepage_sync(struct file *file, struct inode *inode, struct page *page,
unsigned int offset, unsigned int count)
{
struct rpc_cred *cred = NULL;
loff_t base;
unsigned int wsize = NFS_SERVER(inode)->wsize;
int result, refresh = 0, written = 0, flags;
u8 *buffer;
struct nfs_fattr fattr;
struct nfs_writeverf verf;
if (file)
cred = get_rpccred(nfs_file_cred(file));
if (!cred)
cred = get_rpccred(NFS_I(inode)->mm_cred);
dprintk("NFS: nfs_writepage_sync(%x/%Ld %d@%Ld)\n",
inode->i_dev, (long long)NFS_FILEID(inode),
count, (long long)(page_offset(page) + offset));
buffer = kmap(page) + offset;
base = page_offset(page) + offset;
flags = ((IS_SWAPFILE(inode)) ? NFS_RW_SWAP : 0) | NFS_RW_SYNC;
do {
if (count < wsize && !IS_SWAPFILE(inode))
wsize = count;
result = NFS_PROTO(inode)->write(inode, cred, &fattr, flags,
base, wsize, buffer, &verf);
nfs_write_attributes(inode, &fattr);
if (result < 0) {
/* Must mark the page invalid after I/O error */
ClearPageUptodate(page);
goto io_error;
}
if (result != wsize)
printk("NFS: short write, wsize=%u, result=%d\n",
wsize, result);
refresh = 1;
buffer += wsize;
base += wsize;
written += wsize;
count -= wsize;
/*
* If we've extended the file, update the inode
* now so we don't invalidate the cache.
*/
if (base > inode->i_size)
inode->i_size = base;
} while (count);
if (PageError(page))
ClearPageError(page);
io_error:
kunmap(page);
if (cred)
put_rpccred(cred);
return written? written : result;
}
static int
nfs_writepage_async(struct file *file, struct inode *inode, struct page *page,
unsigned int offset, unsigned int count)
{
struct nfs_page *req;
loff_t end;
int status;
req = nfs_update_request(file, inode, page, offset, count);
status = (IS_ERR(req)) ? PTR_ERR(req) : 0;
if (status < 0)
goto out;
if (!req->wb_cred)
req->wb_cred = get_rpccred(NFS_I(inode)->mm_cred);
nfs_unlock_request(req);
nfs_strategy(inode);
end = ((loff_t)page->index<<PAGE_CACHE_SHIFT) + (loff_t)(offset + count);
if (inode->i_size < end)
inode->i_size = end;
out:
return status;
}
/*
* Write an mmapped page to the server.
*/
int
nfs_writepage(struct page *page)
{
struct inode *inode;
unsigned long end_index;
unsigned offset = PAGE_CACHE_SIZE;
int err;
struct address_space *mapping = page->mapping;
if (!mapping)
BUG();
inode = mapping->host;
if (!inode)
BUG();
end_index = inode->i_size >> PAGE_CACHE_SHIFT;
/* Ensure we've flushed out any previous writes */
nfs_wb_page(inode,page);
/* easy case */
if (page->index < end_index)
goto do_it;
/* things got complicated... */
offset = inode->i_size & (PAGE_CACHE_SIZE-1);
/* OK, are we completely out? */
err = -EIO;
if (page->index >= end_index+1 || !offset)
goto out;
do_it:
lock_kernel();
if (NFS_SERVER(inode)->wsize >= PAGE_CACHE_SIZE && !IS_SYNC(inode)) {
err = nfs_writepage_async(NULL, inode, page, 0, offset);
if (err >= 0)
err = 0;
} else {
err = nfs_writepage_sync(NULL, inode, page, 0, offset);
if (err == offset)
err = 0;
}
unlock_kernel();
out:
UnlockPage(page);
return err;
}
/*
* Check whether the file range we want to write to is locked by
* us.
*/
static int
region_locked(struct inode *inode, struct nfs_page *req)
{
struct file_lock *fl;
loff_t rqstart, rqend;
/* Don't optimize writes if we don't use NLM */
if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
return 0;
rqstart = page_offset(req->wb_page) + req->wb_offset;
rqend = rqstart + req->wb_bytes;
for (fl = inode->i_flock; fl; fl = fl->fl_next) {
if (fl->fl_owner == current->files && (fl->fl_flags & FL_POSIX)
&& fl->fl_type == F_WRLCK
&& fl->fl_start <= rqstart && rqend <= fl->fl_end) {
return 1;
}
}
return 0;
}
/*
* Insert a write request into an inode
* Note: we sort the list in order to be able to optimize nfs_find_request()
* & co. for the 'write append' case. For 2.5 we may want to consider
* some form of hashing so as to perform well on random writes.
*/
static inline void
nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
{
struct list_head *pos, *head;
unsigned long pg_idx = page_index(req->wb_page);
if (!list_empty(&req->wb_hash))
return;
if (!NFS_WBACK_BUSY(req))
printk(KERN_ERR "NFS: unlocked request attempted hashed!\n");
head = &inode->u.nfs_i.writeback;
if (list_empty(head))
igrab(inode);
list_for_each_prev(pos, head) {
struct nfs_page *entry = nfs_inode_wb_entry(pos);
if (page_index(entry->wb_page) < pg_idx)
break;
}
inode->u.nfs_i.npages++;
list_add(&req->wb_hash, pos);
req->wb_count++;
}
/*
* Insert a write request into an inode
*/
static inline void
nfs_inode_remove_request(struct nfs_page *req)
{
struct inode *inode;
spin_lock(&nfs_wreq_lock);
if (list_empty(&req->wb_hash)) {
spin_unlock(&nfs_wreq_lock);
return;
}
if (!NFS_WBACK_BUSY(req))
printk(KERN_ERR "NFS: unlocked request attempted unhashed!\n");
inode = req->wb_inode;
list_del(&req->wb_hash);
INIT_LIST_HEAD(&req->wb_hash);
inode->u.nfs_i.npages--;
if ((inode->u.nfs_i.npages == 0) != list_empty(&inode->u.nfs_i.writeback))
printk(KERN_ERR "NFS: desynchronized value of nfs_i.npages.\n");
if (list_empty(&inode->u.nfs_i.writeback)) {
spin_unlock(&nfs_wreq_lock);
iput(inode);
} else
spin_unlock(&nfs_wreq_lock);
nfs_release_request(req);
}
/*
* Find a request
*/
static inline struct nfs_page *
_nfs_find_request(struct inode *inode, struct page *page)
{
struct list_head *head, *pos;
unsigned long pg_idx = page_index(page);
head = &inode->u.nfs_i.writeback;
list_for_each_prev(pos, head) {
struct nfs_page *req = nfs_inode_wb_entry(pos);
unsigned long found_idx = page_index(req->wb_page);
if (pg_idx < found_idx)
continue;
if (pg_idx != found_idx)
break;
req->wb_count++;
return req;
}
return NULL;
}
static struct nfs_page *
nfs_find_request(struct inode *inode, struct page *page)
{
struct nfs_page *req;
spin_lock(&nfs_wreq_lock);
req = _nfs_find_request(inode, page);
spin_unlock(&nfs_wreq_lock);
return req;
}
/*
* Add a request to the inode's dirty list.
*/
static inline void
nfs_mark_request_dirty(struct nfs_page *req)
{
struct inode *inode = req->wb_inode;
spin_lock(&nfs_wreq_lock);
nfs_list_add_request(req, &inode->u.nfs_i.dirty);
inode->u.nfs_i.ndirty++;
__nfs_del_lru(req);
__nfs_add_lru(&NFS_SERVER(inode)->lru_dirty, req);
spin_unlock(&nfs_wreq_lock);
mark_inode_dirty(inode);
}
/*
* Check if a request is dirty
*/
static inline int
nfs_dirty_request(struct nfs_page *req)
{
struct inode *inode = req->wb_inode;
return !list_empty(&req->wb_list) && req->wb_list_head == &inode->u.nfs_i.dirty;
}
#ifdef CONFIG_NFS_V3
/*
* Add a request to the inode's commit list.
*/
static inline void
nfs_mark_request_commit(struct nfs_page *req)
{
struct inode *inode = req->wb_inode;
spin_lock(&nfs_wreq_lock);
nfs_list_add_request(req, &inode->u.nfs_i.commit);
inode->u.nfs_i.ncommit++;
__nfs_del_lru(req);
__nfs_add_lru(&NFS_SERVER(inode)->lru_commit, req);
spin_unlock(&nfs_wreq_lock);
mark_inode_dirty(inode);
}
#endif
/*
* Wait for a request to complete.
*
* Interruptible by signals only if mounted with intr flag.
*/
static int
nfs_wait_on_requests(struct inode *inode, struct file *file, unsigned long idx_start, unsigned int npages)
{
struct list_head *p, *head;
unsigned long idx_end;
unsigned int res = 0;
int error;
if (npages == 0)
idx_end = ~0;
else
idx_end = idx_start + npages - 1;
head = &inode->u.nfs_i.writeback;
restart:
spin_lock(&nfs_wreq_lock);
list_for_each_prev(p, head) {
unsigned long pg_idx;
struct nfs_page *req = nfs_inode_wb_entry(p);
if (file && req->wb_file != file)
continue;
pg_idx = page_index(req->wb_page);
if (pg_idx < idx_start)
break;
if (pg_idx > idx_end)
continue;
if (!NFS_WBACK_BUSY(req))
continue;
req->wb_count++;
spin_unlock(&nfs_wreq_lock);
error = nfs_wait_on_request(req);
nfs_release_request(req);
if (error < 0)
return error;
res++;
goto restart;
}
spin_unlock(&nfs_wreq_lock);
return res;
}
/**
* nfs_scan_lru_dirty_timeout - Scan LRU list for timed out dirty requests
* @server: NFS superblock data
* @dst: destination list
*
* Moves a maximum of 'wpages' requests from the NFS dirty page LRU list.
* The elements are checked to ensure that they form a contiguous set
* of pages, and that they originated from the same file.
*/
int
nfs_scan_lru_dirty_timeout(struct nfs_server *server, struct list_head *dst)
{
struct inode *inode;
int npages;
npages = nfs_scan_lru_timeout(&server->lru_dirty, dst, server->wpages);
if (npages) {
inode = nfs_list_entry(dst->next)->wb_inode;
inode->u.nfs_i.ndirty -= npages;
}
return npages;
}
/**
* nfs_scan_lru_dirty - Scan LRU list for dirty requests
* @server: NFS superblock data
* @dst: destination list
*
* Moves a maximum of 'wpages' requests from the NFS dirty page LRU list.
* The elements are checked to ensure that they form a contiguous set
* of pages, and that they originated from the same file.
*/
int
nfs_scan_lru_dirty(struct nfs_server *server, struct list_head *dst)
{
struct inode *inode;
int npages;
npages = nfs_scan_lru(&server->lru_dirty, dst, server->wpages);
if (npages) {
inode = nfs_list_entry(dst->next)->wb_inode;
inode->u.nfs_i.ndirty -= npages;
}
return npages;
}
/*
* nfs_scan_dirty - Scan an inode for dirty requests
* @inode: NFS inode to scan
* @dst: destination list
* @file: if set, ensure we match requests from this file
* @idx_start: lower bound of page->index to scan.
* @npages: idx_start + npages sets the upper bound to scan.
*
* Moves requests from the inode's dirty page list.
* The requests are *not* checked to ensure that they form a contiguous set.
*/
static int
nfs_scan_dirty(struct inode *inode, struct list_head *dst, struct file *file, unsigned long idx_start, unsigned int npages)
{
int res;
res = nfs_scan_list(&inode->u.nfs_i.dirty, dst, file, idx_start, npages);
inode->u.nfs_i.ndirty -= res;
if ((inode->u.nfs_i.ndirty == 0) != list_empty(&inode->u.nfs_i.dirty))
printk(KERN_ERR "NFS: desynchronized value of nfs_i.ndirty.\n");
return res;
}
#ifdef CONFIG_NFS_V3
/**
* nfs_scan_lru_commit_timeout - Scan LRU list for timed out commit requests
* @server: NFS superblock data
* @dst: destination list
*
* Finds the first a timed out request in the NFS commit LRU list and moves it
* to the list dst. If such an element is found, we move all other commit
* requests that apply to the same inode.
* The assumption is that doing everything in a single commit-to-disk is
* the cheaper alternative.
*/
int
nfs_scan_lru_commit_timeout(struct nfs_server *server, struct list_head *dst)
{
struct inode *inode;
int npages;
npages = nfs_scan_lru_timeout(&server->lru_commit, dst, 1);
if (npages) {
inode = nfs_list_entry(dst->next)->wb_inode;
npages += nfs_scan_list(&inode->u.nfs_i.commit, dst, NULL, 0, 0);
inode->u.nfs_i.ncommit -= npages;
}
return npages;
}
/**
* nfs_scan_lru_commit_timeout - Scan LRU list for timed out commit requests
* @server: NFS superblock data
* @dst: destination list
*
* Finds the first request in the NFS commit LRU list and moves it
* to the list dst. If such an element is found, we move all other commit
* requests that apply to the same inode.
* The assumption is that doing everything in a single commit-to-disk is
* the cheaper alternative.
*/
int
nfs_scan_lru_commit(struct nfs_server *server, struct list_head *dst)
{
struct inode *inode;
int npages;
npages = nfs_scan_lru(&server->lru_commit, dst, 1);
if (npages) {
inode = nfs_list_entry(dst->next)->wb_inode;
npages += nfs_scan_list(&inode->u.nfs_i.commit, dst, NULL, 0, 0);
inode->u.nfs_i.ncommit -= npages;
}
return npages;
}
/*
* nfs_scan_commit - Scan an inode for commit requests
* @inode: NFS inode to scan
* @dst: destination list
* @file: if set, ensure we collect requests from this file only.
* @idx_start: lower bound of page->index to scan.
* @npages: idx_start + npages sets the upper bound to scan.
*
* Moves requests from the inode's 'commit' request list.
* The requests are *not* checked to ensure that they form a contiguous set.
*/
static int
nfs_scan_commit(struct inode *inode, struct list_head *dst, struct file *file, unsigned long idx_start, unsigned int npages)
{
int res;
res = nfs_scan_list(&inode->u.nfs_i.commit, dst, file, idx_start, npages);
inode->u.nfs_i.ncommit -= res;
if ((inode->u.nfs_i.ncommit == 0) != list_empty(&inode->u.nfs_i.commit))
printk(KERN_ERR "NFS: desynchronized value of nfs_i.ncommit.\n");
return res;
}
#endif
/*
* Try to update any existing write request, or create one if there is none.
* In order to match, the request's credentials must match those of
* the calling process.
*
* Note: Should always be called with the Page Lock held!
*/
static struct nfs_page *
nfs_update_request(struct file* file, struct inode *inode, struct page *page,
unsigned int offset, unsigned int bytes)
{
struct nfs_page *req, *new = NULL;
unsigned long rqend, end;
end = offset + bytes;
for (;;) {
/* Loop over all inode entries and see if we find
* A request for the page we wish to update
*/
spin_lock(&nfs_wreq_lock);
req = _nfs_find_request(inode, page);
if (req) {
if (!nfs_lock_request_dontget(req)) {
int error;
spin_unlock(&nfs_wreq_lock);
error = nfs_wait_on_request(req);
nfs_release_request(req);
if (error < 0)
return ERR_PTR(error);
continue;
}
spin_unlock(&nfs_wreq_lock);
if (new)
nfs_release_request(new);
break;
}
if (new) {
nfs_lock_request_dontget(new);
nfs_inode_add_request(inode, new);
spin_unlock(&nfs_wreq_lock);
nfs_mark_request_dirty(new);
return new;
}
spin_unlock(&nfs_wreq_lock);
new = nfs_create_request(file, inode, page, offset, bytes);
if (IS_ERR(new))
return new;
/* If the region is locked, adjust the timeout */
if (region_locked(inode, new))
new->wb_timeout = jiffies + NFS_WRITEBACK_LOCKDELAY;
else
new->wb_timeout = jiffies + NFS_WRITEBACK_DELAY;
}
/* We have a request for our page.
* If the creds don't match, or the
* page addresses don't match,
* tell the caller to wait on the conflicting
* request.
*/
rqend = req->wb_offset + req->wb_bytes;
if (req->wb_file != file
|| req->wb_page != page
|| !nfs_dirty_request(req)
|| offset > rqend || end < req->wb_offset) {
nfs_unlock_request(req);
return ERR_PTR(-EBUSY);
}
/* Okay, the request matches. Update the region */
if (offset < req->wb_offset) {
req->wb_offset = offset;
req->wb_bytes = rqend - req->wb_offset;
}
if (end > rqend)
req->wb_bytes = end - req->wb_offset;
return req;
}
/*
* This is the strategy routine for NFS.
* It is called by nfs_updatepage whenever the user wrote up to the end
* of a page.
*
* We always try to submit a set of requests in parallel so that the
* server's write code can gather writes. This is mainly for the benefit
* of NFSv2.
*
* We never submit more requests than we think the remote can handle.
* For UDP sockets, we make sure we don't exceed the congestion window;
* for TCP, we limit the number of requests to 8.
*
* NFS_STRATEGY_PAGES gives the minimum number of requests for NFSv2 that
* should be sent out in one go. This is for the benefit of NFSv2 servers
* that perform write gathering.
*
* FIXME: Different servers may have different sweet spots.
* Record the average congestion window in server struct?
*/
#define NFS_STRATEGY_PAGES 8
static void
nfs_strategy(struct inode *inode)
{
unsigned int dirty, wpages;
dirty = inode->u.nfs_i.ndirty;
wpages = NFS_SERVER(inode)->wpages;
#ifdef CONFIG_NFS_V3
if (NFS_PROTO(inode)->version == 2) {
if (dirty >= NFS_STRATEGY_PAGES * wpages)
nfs_flush_file(inode, NULL, 0, 0, 0);
} else if (dirty >= wpages)
nfs_flush_file(inode, NULL, 0, 0, 0);
#else
if (dirty >= NFS_STRATEGY_PAGES * wpages)
nfs_flush_file(inode, NULL, 0, 0, 0);
#endif
}
int
nfs_flush_incompatible(struct file *file, struct page *page)
{
struct inode *inode = file->f_dentry->d_inode;
struct nfs_page *req;
int status = 0;
/*
* Look for a request corresponding to this page. If there
* is one, and it belongs to another file, we flush it out
* before we try to copy anything into the page. Do this
* due to the lack of an ACCESS-type call in NFSv2.
* Also do the same if we find a request from an existing
* dropped page.
*/
req = nfs_find_request(inode,page);
if (req) {
if (req->wb_file != file || req->wb_page != page)
status = nfs_wb_page(inode, page);
nfs_release_request(req);
}
return (status < 0) ? status : 0;
}
/*
* Update and possibly write a cached page of an NFS file.
*
* XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
* things with a page scheduled for an RPC call (e.g. invalidate it).
*/
int
nfs_updatepage(struct file *file, struct page *page, unsigned int offset, unsigned int count)
{
struct dentry *dentry = file->f_dentry;
struct inode *inode = dentry->d_inode;
struct nfs_page *req;
loff_t end;
int status = 0;
dprintk("NFS: nfs_updatepage(%s/%s %d@%Ld)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
count, (long long)(page_offset(page) +offset));
/*
* If wsize is smaller than page size, update and write
* page synchronously.
*/
if (NFS_SERVER(inode)->wsize < PAGE_CACHE_SIZE || IS_SYNC(inode))
return nfs_writepage_sync(file, inode, page, offset, count);
/*
* Try to find an NFS request corresponding to this page
* and update it.
* If the existing request cannot be updated, we must flush
* it out now.
*/
do {
req = nfs_update_request(file, inode, page, offset, count);
status = (IS_ERR(req)) ? PTR_ERR(req) : 0;
if (status != -EBUSY)
break;
/* Request could not be updated. Flush it out and try again */
status = nfs_wb_page(inode, page);
} while (status >= 0);
if (status < 0)
goto done;
status = 0;
end = ((loff_t)page->index<<PAGE_CACHE_SHIFT) + (loff_t)(offset + count);
if (inode->i_size < end)
inode->i_size = end;
/* If we wrote past the end of the page.
* Call the strategy routine so it can send out a bunch
* of requests.
*/
if (req->wb_offset == 0 && req->wb_bytes == PAGE_CACHE_SIZE) {
SetPageUptodate(page);
nfs_unlock_request(req);
nfs_strategy(inode);
} else
nfs_unlock_request(req);
done:
dprintk("NFS: nfs_updatepage returns %d (isize %Ld)\n",
status, (long long)inode->i_size);
if (status < 0)
ClearPageUptodate(page);
return status;
}
/*
* Set up the argument/result storage required for the RPC call.
*/
static void
nfs_write_rpcsetup(struct list_head *head, struct nfs_write_data *data)
{
struct nfs_page *req;
struct iovec *iov;
unsigned int count;
/* Set up the RPC argument and reply structs
* NB: take care not to mess about with data->commit et al. */
iov = data->args.iov;
count = 0;
while (!list_empty(head)) {
struct nfs_page *req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_list_add_request(req, &data->pages);
iov->iov_base = kmap(req->wb_page) + req->wb_offset;
iov->iov_len = req->wb_bytes;
count += req->wb_bytes;
iov++;
data->args.nriov++;
}
req = nfs_list_entry(data->pages.next);
data->inode = req->wb_inode;
data->cred = req->wb_cred;
data->args.fh = NFS_FH(req->wb_inode);
data->args.offset = page_offset(req->wb_page) + req->wb_offset;
data->args.count = count;
data->res.fattr = &data->fattr;
data->res.count = count;
data->res.verf = &data->verf;
}
/*
* Create an RPC task for the given write request and kick it.
* The page must have been locked by the caller.
*
* It may happen that the page we're passed is not marked dirty.
* This is the case if nfs_updatepage detects a conflicting request
* that has been written but not committed.
*/
static int
nfs_flush_one(struct list_head *head, struct inode *inode, int how)
{
struct rpc_clnt *clnt = NFS_CLIENT(inode);
struct nfs_write_data *data;
struct rpc_task *task;
struct rpc_message msg;
int flags,
nfsvers = NFS_PROTO(inode)->version,
async = !(how & FLUSH_SYNC),
stable = (how & FLUSH_STABLE);
sigset_t oldset;
data = nfs_writedata_alloc();
if (!data)
goto out_bad;
task = &data->task;
/* Set the initial flags for the task. */
flags = (async) ? RPC_TASK_ASYNC : 0;
/* Set up the argument struct */
nfs_write_rpcsetup(head, data);
if (nfsvers < 3)
data->args.stable = NFS_FILE_SYNC;
else if (stable) {
if (!inode->u.nfs_i.ncommit)
data->args.stable = NFS_FILE_SYNC;
else
data->args.stable = NFS_DATA_SYNC;
} else
data->args.stable = NFS_UNSTABLE;
/* Finalize the task. */
rpc_init_task(task, clnt, nfs_writeback_done, flags);
task->tk_calldata = data;
/* Release requests */
task->tk_release = nfs_writedata_release;
#ifdef CONFIG_NFS_V3
msg.rpc_proc = (nfsvers == 3) ? NFS3PROC_WRITE : NFSPROC_WRITE;
#else
msg.rpc_proc = NFSPROC_WRITE;
#endif
msg.rpc_argp = &data->args;
msg.rpc_resp = &data->res;
msg.rpc_cred = data->cred;
dprintk("NFS: %4d initiated write call (req %x/%Ld count %d nriov %d)\n",
task->tk_pid,
inode->i_dev,
(long long)NFS_FILEID(inode),
data->args.count, data->args.nriov);
rpc_clnt_sigmask(clnt, &oldset);
rpc_call_setup(task, &msg, 0);
lock_kernel();
rpc_execute(task);
unlock_kernel();
rpc_clnt_sigunmask(clnt, &oldset);
return 0;
out_bad:
while (!list_empty(head)) {
struct nfs_page *req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_mark_request_dirty(req);
nfs_unlock_request(req);
}
return -ENOMEM;
}
int
nfs_flush_list(struct list_head *head, int wpages, int how)
{
LIST_HEAD(one_request);
struct nfs_page *req;
int error = 0;
unsigned int pages = 0;
while (!list_empty(head)) {
pages += nfs_coalesce_requests(head, &one_request, wpages);
req = nfs_list_entry(one_request.next);
error = nfs_flush_one(&one_request, req->wb_inode, how);
if (error < 0)
break;
}
if (error >= 0)
return pages;
while (!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_mark_request_dirty(req);
nfs_unlock_request(req);
}
return error;
}
/*
* This function is called when the WRITE call is complete.
*/
static void
nfs_writeback_done(struct rpc_task *task)
{
struct nfs_write_data *data = (struct nfs_write_data *) task->tk_calldata;
struct nfs_writeargs *argp = &data->args;
struct nfs_writeres *resp = &data->res;
struct inode *inode = data->inode;
struct nfs_page *req;
struct page *page;
dprintk("NFS: %4d nfs_writeback_done (status %d)\n",
task->tk_pid, task->tk_status);
if (nfs_async_handle_jukebox(task))
return;
/* We can't handle that yet but we check for it nevertheless */
if (resp->count < argp->count && task->tk_status >= 0) {
static unsigned long complain;
if (time_before(complain, jiffies)) {
printk(KERN_WARNING
"NFS: Server wrote less than requested.\n");
complain = jiffies + 300 * HZ;
}
/* Can't do anything about it right now except throw
* an error. */
task->tk_status = -EIO;
}
#ifdef CONFIG_NFS_V3
if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
/* We tried a write call, but the server did not
* commit data to stable storage even though we
* requested it.
* Note: There is a known bug in Tru64 < 5.0 in which
* the server reports NFS_DATA_SYNC, but performs
* NFS_FILE_SYNC. We therefore implement this checking
* as a dprintk() in order to avoid filling syslog.
*/
static unsigned long complain;
if (time_before(complain, jiffies)) {
dprintk("NFS: faulty NFSv3 server %s:"
" (committed = %d) != (stable = %d)\n",
NFS_SERVER(inode)->hostname,
resp->verf->committed, argp->stable);
complain = jiffies + 300 * HZ;
}
}
#endif
/*
* Update attributes as result of writeback.
* FIXME: There is an inherent race with invalidate_inode_pages and
* writebacks since the page->count is kept > 1 for as long
* as the page has a write request pending.
*/
nfs_write_attributes(inode, resp->fattr);
while (!list_empty(&data->pages)) {
req = nfs_list_entry(data->pages.next);
nfs_list_remove_request(req);
page = req->wb_page;
kunmap(page);
dprintk("NFS: write (%x/%Ld %d@%Ld)",
req->wb_inode->i_dev,
(long long)NFS_FILEID(req->wb_inode),
req->wb_bytes,
(long long)(page_offset(page) + req->wb_offset));
if (task->tk_status < 0) {
ClearPageUptodate(page);
SetPageError(page);
if (req->wb_file)
req->wb_file->f_error = task->tk_status;
nfs_inode_remove_request(req);
dprintk(", error = %d\n", task->tk_status);
goto next;
}
#ifdef CONFIG_NFS_V3
if (argp->stable != NFS_UNSTABLE || resp->verf->committed == NFS_FILE_SYNC) {
nfs_inode_remove_request(req);
dprintk(" OK\n");
goto next;
}
memcpy(&req->wb_verf, resp->verf, sizeof(req->wb_verf));
req->wb_timeout = jiffies + NFS_COMMIT_DELAY;
nfs_mark_request_commit(req);
dprintk(" marked for commit\n");
#else
nfs_inode_remove_request(req);
#endif
next:
nfs_unlock_request(req);
}
}
#ifdef CONFIG_NFS_V3
/*
* Set up the argument/result storage required for the RPC call.
*/
static void
nfs_commit_rpcsetup(struct list_head *head, struct nfs_write_data *data)
{
struct nfs_page *first, *last;
struct inode *inode;
loff_t start, end, len;
/* Set up the RPC argument and reply structs
* NB: take care not to mess about with data->commit et al. */
list_splice(head, &data->pages);
INIT_LIST_HEAD(head);
first = nfs_list_entry(data->pages.next);
last = nfs_list_entry(data->pages.prev);
inode = first->wb_inode;
/*
* Determine the offset range of requests in the COMMIT call.
* We rely on the fact that data->pages is an ordered list...
*/
start = page_offset(first->wb_page) + first->wb_offset;
end = page_offset(last->wb_page) + (last->wb_offset + last->wb_bytes);
len = end - start;
/* If 'len' is not a 32-bit quantity, pass '0' in the COMMIT call */
if (end >= inode->i_size || len < 0 || len > (~((u32)0) >> 1))
len = 0;
data->inode = inode;
data->cred = first->wb_cred;
data->args.fh = NFS_FH(inode);
data->args.offset = start;
data->res.count = data->args.count = (u32)len;
data->res.fattr = &data->fattr;
data->res.verf = &data->verf;
}
/*
* Commit dirty pages
*/
int
nfs_commit_list(struct list_head *head, int how)
{
struct rpc_message msg;
struct rpc_clnt *clnt;
struct nfs_write_data *data;
struct rpc_task *task;
struct nfs_page *req;
int flags,
async = !(how & FLUSH_SYNC);
sigset_t oldset;
data = nfs_writedata_alloc();
if (!data)
goto out_bad;
task = &data->task;
flags = (async) ? RPC_TASK_ASYNC : 0;
/* Set up the argument struct */
nfs_commit_rpcsetup(head, data);
req = nfs_list_entry(data->pages.next);
clnt = NFS_CLIENT(req->wb_inode);
rpc_init_task(task, clnt, nfs_commit_done, flags);
task->tk_calldata = data;
/* Release requests */
task->tk_release = nfs_writedata_release;
msg.rpc_proc = NFS3PROC_COMMIT;
msg.rpc_argp = &data->args;
msg.rpc_resp = &data->res;
msg.rpc_cred = data->cred;
dprintk("NFS: %4d initiated commit call\n", task->tk_pid);
rpc_clnt_sigmask(clnt, &oldset);
rpc_call_setup(task, &msg, 0);
lock_kernel();
rpc_execute(task);
unlock_kernel();
rpc_clnt_sigunmask(clnt, &oldset);
return 0;
out_bad:
while (!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_mark_request_commit(req);
nfs_unlock_request(req);
}
return -ENOMEM;
}
/*
* COMMIT call returned
*/
static void
nfs_commit_done(struct rpc_task *task)
{
struct nfs_write_data *data = (struct nfs_write_data *)task->tk_calldata;
struct nfs_writeres *resp = &data->res;
struct nfs_page *req;
struct inode *inode = data->inode;
dprintk("NFS: %4d nfs_commit_done (status %d)\n",
task->tk_pid, task->tk_status);
if (nfs_async_handle_jukebox(task))
return;
nfs_write_attributes(inode, resp->fattr);
while (!list_empty(&data->pages)) {
req = nfs_list_entry(data->pages.next);
nfs_list_remove_request(req);
dprintk("NFS: commit (%x/%Ld %d@%Ld)",
req->wb_inode->i_dev,
(long long)NFS_FILEID(req->wb_inode),
req->wb_bytes,
(long long)(page_offset(req->wb_page) + req->wb_offset));
if (task->tk_status < 0) {
if (req->wb_file)
req->wb_file->f_error = task->tk_status;
nfs_inode_remove_request(req);
dprintk(", error = %d\n", task->tk_status);
goto next;
}
/* Okay, COMMIT succeeded, apparently. Check the verifier
* returned by the server against all stored verfs. */
if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
/* We have a match */
nfs_inode_remove_request(req);
dprintk(" OK\n");
goto next;
}
/* We have a mismatch. Write the page again */
dprintk(" mismatch\n");
nfs_mark_request_dirty(req);
next:
nfs_unlock_request(req);
}
}
#endif
int nfs_flush_file(struct inode *inode, struct file *file, unsigned long idx_start,
unsigned int npages, int how)
{
LIST_HEAD(head);
int res,
error = 0;
spin_lock(&nfs_wreq_lock);
res = nfs_scan_dirty(inode, &head, file, idx_start, npages);
spin_unlock(&nfs_wreq_lock);
if (res)
error = nfs_flush_list(&head, NFS_SERVER(inode)->wpages, how);
if (error < 0)
return error;
return res;
}
#ifdef CONFIG_NFS_V3
int nfs_commit_file(struct inode *inode, struct file *file, unsigned long idx_start,
unsigned int npages, int how)
{
LIST_HEAD(head);
int res,
error = 0;
spin_lock(&nfs_wreq_lock);
res = nfs_scan_commit(inode, &head, file, idx_start, npages);
spin_unlock(&nfs_wreq_lock);
if (res)
error = nfs_commit_list(&head, how);
if (error < 0)
return error;
return res;
}
#endif
int nfs_sync_file(struct inode *inode, struct file *file, unsigned long idx_start,
unsigned int npages, int how)
{
int error,
wait;
wait = how & FLUSH_WAIT;
how &= ~FLUSH_WAIT;
if (!inode && file)
inode = file->f_dentry->d_inode;
do {
error = 0;
if (wait)
error = nfs_wait_on_requests(inode, file, idx_start, npages);
if (error == 0)
error = nfs_flush_file(inode, file, idx_start, npages, how);
#ifdef CONFIG_NFS_V3
if (error == 0)
error = nfs_commit_file(inode, file, idx_start, npages, how);
#endif
} while (error > 0);
return error;
}
int nfs_init_writepagecache(void)
{
nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
sizeof(struct nfs_write_data),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
if (nfs_wdata_cachep == NULL)
return -ENOMEM;
return 0;
}
void nfs_destroy_writepagecache(void)
{
if (kmem_cache_destroy(nfs_wdata_cachep))
printk(KERN_INFO "nfs_write_data: not all structures were freed\n");
}
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