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alistair23-linux/fs/nfsd/nfsproc.c
David Shaw 31dec2538e Short write in nfsd becomes a full write to the client 
If a filesystem being written to via NFS returns a short write count
(as opposed to an error) to nfsd, nfsd treats that as a success for
the entire write, rather than the short count that actually succeeded.

For example, given a 8192 byte write, if the underlying filesystem
only writes 4096 bytes, nfsd will ack back to the nfs client that all
8192 bytes were written.  The nfs client does have retry logic for
short writes, but this is never called as the client is told the
complete write succeeded.

There are probably other ways it could happen, but in my case it
happened with a fuse (filesystem in userspace) filesystem which can
rather easily have a partial write.

Here is a patch to properly return the short write count to the
client.

Signed-off-by: David Shaw <dshaw@jabberwocky.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2009-03-18 17:38:40 -04:00

638 lines
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/*
* nfsproc2.c Process version 2 NFS requests.
* linux/fs/nfsd/nfs2proc.c
*
* Process version 2 NFS requests.
*
* Copyright (C) 1995-1997 Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/linkage.h>
#include <linux/time.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/namei.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/cache.h>
#include <linux/nfsd/xdr.h>
typedef struct svc_rqst svc_rqst;
typedef struct svc_buf svc_buf;
#define NFSDDBG_FACILITY NFSDDBG_PROC
static __be32
nfsd_proc_null(struct svc_rqst *rqstp, void *argp, void *resp)
{
return nfs_ok;
}
static __be32
nfsd_return_attrs(__be32 err, struct nfsd_attrstat *resp)
{
if (err) return err;
return nfserrno(vfs_getattr(resp->fh.fh_export->ex_path.mnt,
resp->fh.fh_dentry,
&resp->stat));
}
static __be32
nfsd_return_dirop(__be32 err, struct nfsd_diropres *resp)
{
if (err) return err;
return nfserrno(vfs_getattr(resp->fh.fh_export->ex_path.mnt,
resp->fh.fh_dentry,
&resp->stat));
}
/*
* Get a file's attributes
* N.B. After this call resp->fh needs an fh_put
*/
static __be32
nfsd_proc_getattr(struct svc_rqst *rqstp, struct nfsd_fhandle *argp,
struct nfsd_attrstat *resp)
{
__be32 nfserr;
dprintk("nfsd: GETATTR %s\n", SVCFH_fmt(&argp->fh));
fh_copy(&resp->fh, &argp->fh);
nfserr = fh_verify(rqstp, &resp->fh, 0,
NFSD_MAY_NOP | NFSD_MAY_BYPASS_GSS_ON_ROOT);
return nfsd_return_attrs(nfserr, resp);
}
/*
* Set a file's attributes
* N.B. After this call resp->fh needs an fh_put
*/
static __be32
nfsd_proc_setattr(struct svc_rqst *rqstp, struct nfsd_sattrargs *argp,
struct nfsd_attrstat *resp)
{
__be32 nfserr;
dprintk("nfsd: SETATTR %s, valid=%x, size=%ld\n",
SVCFH_fmt(&argp->fh),
argp->attrs.ia_valid, (long) argp->attrs.ia_size);
fh_copy(&resp->fh, &argp->fh);
nfserr = nfsd_setattr(rqstp, &resp->fh, &argp->attrs,0, (time_t)0);
return nfsd_return_attrs(nfserr, resp);
}
/*
* Look up a path name component
* Note: the dentry in the resp->fh may be negative if the file
* doesn't exist yet.
* N.B. After this call resp->fh needs an fh_put
*/
static __be32
nfsd_proc_lookup(struct svc_rqst *rqstp, struct nfsd_diropargs *argp,
struct nfsd_diropres *resp)
{
__be32 nfserr;
dprintk("nfsd: LOOKUP %s %.*s\n",
SVCFH_fmt(&argp->fh), argp->len, argp->name);
fh_init(&resp->fh, NFS_FHSIZE);
nfserr = nfsd_lookup(rqstp, &argp->fh, argp->name, argp->len,
&resp->fh);
fh_put(&argp->fh);
return nfsd_return_dirop(nfserr, resp);
}
/*
* Read a symlink.
*/
static __be32
nfsd_proc_readlink(struct svc_rqst *rqstp, struct nfsd_readlinkargs *argp,
struct nfsd_readlinkres *resp)
{
__be32 nfserr;
dprintk("nfsd: READLINK %s\n", SVCFH_fmt(&argp->fh));
/* Read the symlink. */
resp->len = NFS_MAXPATHLEN;
nfserr = nfsd_readlink(rqstp, &argp->fh, argp->buffer, &resp->len);
fh_put(&argp->fh);
return nfserr;
}
/*
* Read a portion of a file.
* N.B. After this call resp->fh needs an fh_put
*/
static __be32
nfsd_proc_read(struct svc_rqst *rqstp, struct nfsd_readargs *argp,
struct nfsd_readres *resp)
{
__be32 nfserr;
dprintk("nfsd: READ %s %d bytes at %d\n",
SVCFH_fmt(&argp->fh),
argp->count, argp->offset);
/* Obtain buffer pointer for payload. 19 is 1 word for
* status, 17 words for fattr, and 1 word for the byte count.
*/
if (NFSSVC_MAXBLKSIZE_V2 < argp->count) {
char buf[RPC_MAX_ADDRBUFLEN];
printk(KERN_NOTICE
"oversized read request from %s (%d bytes)\n",
svc_print_addr(rqstp, buf, sizeof(buf)),
argp->count);
argp->count = NFSSVC_MAXBLKSIZE_V2;
}
svc_reserve_auth(rqstp, (19<<2) + argp->count + 4);
resp->count = argp->count;
nfserr = nfsd_read(rqstp, fh_copy(&resp->fh, &argp->fh), NULL,
argp->offset,
rqstp->rq_vec, argp->vlen,
&resp->count);
if (nfserr) return nfserr;
return nfserrno(vfs_getattr(resp->fh.fh_export->ex_path.mnt,
resp->fh.fh_dentry,
&resp->stat));
}
/*
* Write data to a file
* N.B. After this call resp->fh needs an fh_put
*/
static __be32
nfsd_proc_write(struct svc_rqst *rqstp, struct nfsd_writeargs *argp,
struct nfsd_attrstat *resp)
{
__be32 nfserr;
int stable = 1;
unsigned long cnt = argp->len;
dprintk("nfsd: WRITE %s %d bytes at %d\n",
SVCFH_fmt(&argp->fh),
argp->len, argp->offset);
nfserr = nfsd_write(rqstp, fh_copy(&resp->fh, &argp->fh), NULL,
argp->offset,
rqstp->rq_vec, argp->vlen,
&cnt,
&stable);
return nfsd_return_attrs(nfserr, resp);
}
/*
* CREATE processing is complicated. The keyword here is `overloaded.'
* The parent directory is kept locked between the check for existence
* and the actual create() call in compliance with VFS protocols.
* N.B. After this call _both_ argp->fh and resp->fh need an fh_put
*/
static __be32
nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp,
struct nfsd_diropres *resp)
{
svc_fh *dirfhp = &argp->fh;
svc_fh *newfhp = &resp->fh;
struct iattr *attr = &argp->attrs;
struct inode *inode;
struct dentry *dchild;
int type, mode;
__be32 nfserr;
dev_t rdev = 0, wanted = new_decode_dev(attr->ia_size);
dprintk("nfsd: CREATE %s %.*s\n",
SVCFH_fmt(dirfhp), argp->len, argp->name);
/* First verify the parent file handle */
nfserr = fh_verify(rqstp, dirfhp, S_IFDIR, NFSD_MAY_EXEC);
if (nfserr)
goto done; /* must fh_put dirfhp even on error */
/* Check for NFSD_MAY_WRITE in nfsd_create if necessary */
nfserr = nfserr_acces;
if (!argp->len)
goto done;
nfserr = nfserr_exist;
if (isdotent(argp->name, argp->len))
goto done;
fh_lock_nested(dirfhp, I_MUTEX_PARENT);
dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len);
if (IS_ERR(dchild)) {
nfserr = nfserrno(PTR_ERR(dchild));
goto out_unlock;
}
fh_init(newfhp, NFS_FHSIZE);
nfserr = fh_compose(newfhp, dirfhp->fh_export, dchild, dirfhp);
if (!nfserr && !dchild->d_inode)
nfserr = nfserr_noent;
dput(dchild);
if (nfserr) {
if (nfserr != nfserr_noent)
goto out_unlock;
/*
* If the new file handle wasn't verified, we can't tell
* whether the file exists or not. Time to bail ...
*/
nfserr = nfserr_acces;
if (!newfhp->fh_dentry) {
printk(KERN_WARNING
"nfsd_proc_create: file handle not verified\n");
goto out_unlock;
}
}
inode = newfhp->fh_dentry->d_inode;
/* Unfudge the mode bits */
if (attr->ia_valid & ATTR_MODE) {
type = attr->ia_mode & S_IFMT;
mode = attr->ia_mode & ~S_IFMT;
if (!type) {
/* no type, so if target exists, assume same as that,
* else assume a file */
if (inode) {
type = inode->i_mode & S_IFMT;
switch(type) {
case S_IFCHR:
case S_IFBLK:
/* reserve rdev for later checking */
rdev = inode->i_rdev;
attr->ia_valid |= ATTR_SIZE;
/* FALLTHROUGH */
case S_IFIFO:
/* this is probably a permission check..
* at least IRIX implements perm checking on
* echo thing > device-special-file-or-pipe
* by doing a CREATE with type==0
*/
nfserr = nfsd_permission(rqstp,
newfhp->fh_export,
newfhp->fh_dentry,
NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS);
if (nfserr && nfserr != nfserr_rofs)
goto out_unlock;
}
} else
type = S_IFREG;
}
} else if (inode) {
type = inode->i_mode & S_IFMT;
mode = inode->i_mode & ~S_IFMT;
} else {
type = S_IFREG;
mode = 0; /* ??? */
}
attr->ia_valid |= ATTR_MODE;
attr->ia_mode = mode;
/* Special treatment for non-regular files according to the
* gospel of sun micro
*/
if (type != S_IFREG) {
int is_borc = 0;
if (type != S_IFBLK && type != S_IFCHR) {
rdev = 0;
} else if (type == S_IFCHR && !(attr->ia_valid & ATTR_SIZE)) {
/* If you think you've seen the worst, grok this. */
type = S_IFIFO;
} else {
/* Okay, char or block special */
is_borc = 1;
if (!rdev)
rdev = wanted;
}
/* we've used the SIZE information, so discard it */
attr->ia_valid &= ~ATTR_SIZE;
/* Make sure the type and device matches */
nfserr = nfserr_exist;
if (inode && type != (inode->i_mode & S_IFMT))
goto out_unlock;
}
nfserr = 0;
if (!inode) {
/* File doesn't exist. Create it and set attrs */
nfserr = nfsd_create(rqstp, dirfhp, argp->name, argp->len,
attr, type, rdev, newfhp);
} else if (type == S_IFREG) {
dprintk("nfsd: existing %s, valid=%x, size=%ld\n",
argp->name, attr->ia_valid, (long) attr->ia_size);
/* File already exists. We ignore all attributes except
* size, so that creat() behaves exactly like
* open(..., O_CREAT|O_TRUNC|O_WRONLY).
*/
attr->ia_valid &= ATTR_SIZE;
if (attr->ia_valid)
nfserr = nfsd_setattr(rqstp, newfhp, attr, 0, (time_t)0);
}
out_unlock:
/* We don't really need to unlock, as fh_put does it. */
fh_unlock(dirfhp);
done:
fh_put(dirfhp);
return nfsd_return_dirop(nfserr, resp);
}
static __be32
nfsd_proc_remove(struct svc_rqst *rqstp, struct nfsd_diropargs *argp,
void *resp)
{
__be32 nfserr;
dprintk("nfsd: REMOVE %s %.*s\n", SVCFH_fmt(&argp->fh),
argp->len, argp->name);
/* Unlink. -SIFDIR means file must not be a directory */
nfserr = nfsd_unlink(rqstp, &argp->fh, -S_IFDIR, argp->name, argp->len);
fh_put(&argp->fh);
return nfserr;
}
static __be32
nfsd_proc_rename(struct svc_rqst *rqstp, struct nfsd_renameargs *argp,
void *resp)
{
__be32 nfserr;
dprintk("nfsd: RENAME %s %.*s -> \n",
SVCFH_fmt(&argp->ffh), argp->flen, argp->fname);
dprintk("nfsd: -> %s %.*s\n",
SVCFH_fmt(&argp->tfh), argp->tlen, argp->tname);
nfserr = nfsd_rename(rqstp, &argp->ffh, argp->fname, argp->flen,
&argp->tfh, argp->tname, argp->tlen);
fh_put(&argp->ffh);
fh_put(&argp->tfh);
return nfserr;
}
static __be32
nfsd_proc_link(struct svc_rqst *rqstp, struct nfsd_linkargs *argp,
void *resp)
{
__be32 nfserr;
dprintk("nfsd: LINK %s ->\n",
SVCFH_fmt(&argp->ffh));
dprintk("nfsd: %s %.*s\n",
SVCFH_fmt(&argp->tfh),
argp->tlen,
argp->tname);
nfserr = nfsd_link(rqstp, &argp->tfh, argp->tname, argp->tlen,
&argp->ffh);
fh_put(&argp->ffh);
fh_put(&argp->tfh);
return nfserr;
}
static __be32
nfsd_proc_symlink(struct svc_rqst *rqstp, struct nfsd_symlinkargs *argp,
void *resp)
{
struct svc_fh newfh;
__be32 nfserr;
dprintk("nfsd: SYMLINK %s %.*s -> %.*s\n",
SVCFH_fmt(&argp->ffh), argp->flen, argp->fname,
argp->tlen, argp->tname);
fh_init(&newfh, NFS_FHSIZE);
/*
* Create the link, look up new file and set attrs.
*/
nfserr = nfsd_symlink(rqstp, &argp->ffh, argp->fname, argp->flen,
argp->tname, argp->tlen,
&newfh, &argp->attrs);
fh_put(&argp->ffh);
fh_put(&newfh);
return nfserr;
}
/*
* Make directory. This operation is not idempotent.
* N.B. After this call resp->fh needs an fh_put
*/
static __be32
nfsd_proc_mkdir(struct svc_rqst *rqstp, struct nfsd_createargs *argp,
struct nfsd_diropres *resp)
{
__be32 nfserr;
dprintk("nfsd: MKDIR %s %.*s\n", SVCFH_fmt(&argp->fh), argp->len, argp->name);
if (resp->fh.fh_dentry) {
printk(KERN_WARNING
"nfsd_proc_mkdir: response already verified??\n");
}
argp->attrs.ia_valid &= ~ATTR_SIZE;
fh_init(&resp->fh, NFS_FHSIZE);
nfserr = nfsd_create(rqstp, &argp->fh, argp->name, argp->len,
&argp->attrs, S_IFDIR, 0, &resp->fh);
fh_put(&argp->fh);
return nfsd_return_dirop(nfserr, resp);
}
/*
* Remove a directory
*/
static __be32
nfsd_proc_rmdir(struct svc_rqst *rqstp, struct nfsd_diropargs *argp,
void *resp)
{
__be32 nfserr;
dprintk("nfsd: RMDIR %s %.*s\n", SVCFH_fmt(&argp->fh), argp->len, argp->name);
nfserr = nfsd_unlink(rqstp, &argp->fh, S_IFDIR, argp->name, argp->len);
fh_put(&argp->fh);
return nfserr;
}
/*
* Read a portion of a directory.
*/
static __be32
nfsd_proc_readdir(struct svc_rqst *rqstp, struct nfsd_readdirargs *argp,
struct nfsd_readdirres *resp)
{
int count;
__be32 nfserr;
loff_t offset;
dprintk("nfsd: READDIR %s %d bytes at %d\n",
SVCFH_fmt(&argp->fh),
argp->count, argp->cookie);
/* Shrink to the client read size */
count = (argp->count >> 2) - 2;
/* Make sure we've room for the NULL ptr & eof flag */
count -= 2;
if (count < 0)
count = 0;
resp->buffer = argp->buffer;
resp->offset = NULL;
resp->buflen = count;
resp->common.err = nfs_ok;
/* Read directory and encode entries on the fly */
offset = argp->cookie;
nfserr = nfsd_readdir(rqstp, &argp->fh, &offset,
&resp->common, nfssvc_encode_entry);
resp->count = resp->buffer - argp->buffer;
if (resp->offset)
*resp->offset = htonl(offset);
fh_put(&argp->fh);
return nfserr;
}
/*
* Get file system info
*/
static __be32
nfsd_proc_statfs(struct svc_rqst * rqstp, struct nfsd_fhandle *argp,
struct nfsd_statfsres *resp)
{
__be32 nfserr;
dprintk("nfsd: STATFS %s\n", SVCFH_fmt(&argp->fh));
nfserr = nfsd_statfs(rqstp, &argp->fh, &resp->stats,
NFSD_MAY_BYPASS_GSS_ON_ROOT);
fh_put(&argp->fh);
return nfserr;
}
/*
* NFSv2 Server procedures.
* Only the results of non-idempotent operations are cached.
*/
#define nfsd_proc_none NULL
#define nfssvc_release_none NULL
struct nfsd_void { int dummy; };
#define PROC(name, argt, rest, relt, cache, respsize) \
{ (svc_procfunc) nfsd_proc_##name, \
(kxdrproc_t) nfssvc_decode_##argt, \
(kxdrproc_t) nfssvc_encode_##rest, \
(kxdrproc_t) nfssvc_release_##relt, \
sizeof(struct nfsd_##argt), \
sizeof(struct nfsd_##rest), \
0, \
cache, \
respsize, \
}
#define ST 1 /* status */
#define FH 8 /* filehandle */
#define AT 18 /* attributes */
static struct svc_procedure nfsd_procedures2[18] = {
PROC(null, void, void, none, RC_NOCACHE, ST),
PROC(getattr, fhandle, attrstat, fhandle, RC_NOCACHE, ST+AT),
PROC(setattr, sattrargs, attrstat, fhandle, RC_REPLBUFF, ST+AT),
PROC(none, void, void, none, RC_NOCACHE, ST),
PROC(lookup, diropargs, diropres, fhandle, RC_NOCACHE, ST+FH+AT),
PROC(readlink, readlinkargs, readlinkres, none, RC_NOCACHE, ST+1+NFS_MAXPATHLEN/4),
PROC(read, readargs, readres, fhandle, RC_NOCACHE, ST+AT+1+NFSSVC_MAXBLKSIZE_V2/4),
PROC(none, void, void, none, RC_NOCACHE, ST),
PROC(write, writeargs, attrstat, fhandle, RC_REPLBUFF, ST+AT),
PROC(create, createargs, diropres, fhandle, RC_REPLBUFF, ST+FH+AT),
PROC(remove, diropargs, void, none, RC_REPLSTAT, ST),
PROC(rename, renameargs, void, none, RC_REPLSTAT, ST),
PROC(link, linkargs, void, none, RC_REPLSTAT, ST),
PROC(symlink, symlinkargs, void, none, RC_REPLSTAT, ST),
PROC(mkdir, createargs, diropres, fhandle, RC_REPLBUFF, ST+FH+AT),
PROC(rmdir, diropargs, void, none, RC_REPLSTAT, ST),
PROC(readdir, readdirargs, readdirres, none, RC_NOCACHE, 0),
PROC(statfs, fhandle, statfsres, none, RC_NOCACHE, ST+5),
};
struct svc_version nfsd_version2 = {
.vs_vers = 2,
.vs_nproc = 18,
.vs_proc = nfsd_procedures2,
.vs_dispatch = nfsd_dispatch,
.vs_xdrsize = NFS2_SVC_XDRSIZE,
};
/*
* Map errnos to NFS errnos.
*/
__be32
nfserrno (int errno)
{
static struct {
__be32 nfserr;
int syserr;
} nfs_errtbl[] = {
{ nfs_ok, 0 },
{ nfserr_perm, -EPERM },
{ nfserr_noent, -ENOENT },
{ nfserr_io, -EIO },
{ nfserr_nxio, -ENXIO },
{ nfserr_acces, -EACCES },
{ nfserr_exist, -EEXIST },
{ nfserr_xdev, -EXDEV },
{ nfserr_mlink, -EMLINK },
{ nfserr_nodev, -ENODEV },
{ nfserr_notdir, -ENOTDIR },
{ nfserr_isdir, -EISDIR },
{ nfserr_inval, -EINVAL },
{ nfserr_fbig, -EFBIG },
{ nfserr_nospc, -ENOSPC },
{ nfserr_rofs, -EROFS },
{ nfserr_mlink, -EMLINK },
{ nfserr_nametoolong, -ENAMETOOLONG },
{ nfserr_notempty, -ENOTEMPTY },
#ifdef EDQUOT
{ nfserr_dquot, -EDQUOT },
#endif
{ nfserr_stale, -ESTALE },
{ nfserr_jukebox, -ETIMEDOUT },
{ nfserr_jukebox, -ERESTARTSYS },
{ nfserr_dropit, -EAGAIN },
{ nfserr_dropit, -ENOMEM },
{ nfserr_badname, -ESRCH },
{ nfserr_io, -ETXTBSY },
{ nfserr_notsupp, -EOPNOTSUPP },
{ nfserr_toosmall, -ETOOSMALL },
};
int i;
for (i = 0; i < ARRAY_SIZE(nfs_errtbl); i++) {
if (nfs_errtbl[i].syserr == errno)
return nfs_errtbl[i].nfserr;
}
printk (KERN_INFO "nfsd: non-standard errno: %d\n", errno);
return nfserr_io;
}
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