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vfs.c
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vfs.c
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#define MSNFS /* HACK HACK */
/*
* linux/fs/nfsd/vfs.c
*
* File operations used by nfsd. Some of these have been ripped from
* other parts of the kernel because they weren't exported, others
* are partial duplicates with added or changed functionality.
*
* Note that several functions dget() the dentry upon which they want
* to act, most notably those that create directory entries. Response
* dentry's are dput()'d if necessary in the release callback.
* So if you notice code paths that apparently fail to dput() the
* dentry, don't worry--they have been taken care of.
*
* Copyright (C) 1995-1999 Olaf Kirch <[email protected]>
* Zerocpy NFS support (C) 2002 Hirokazu Takahashi <[email protected]>
*/
#include <linux/string.h>
#include <linux/time.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/major.h>
#include <linux/ext2_fs.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/net.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/in.h>
#include <linux/module.h>
#include <linux/namei.h>
#include <linux/vfs.h>
#include <linux/delay.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
#ifdef CONFIG_NFSD_V3
#include <linux/nfs3.h>
#include <linux/nfsd/xdr3.h>
#endif /* CONFIG_NFSD_V3 */
#include <linux/nfsd/nfsfh.h>
#include <linux/quotaops.h>
#include <linux/fsnotify.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
#ifdef CONFIG_NFSD_V4
#include <linux/nfs4.h>
#include <linux/nfs4_acl.h>
#include <linux/nfsd_idmap.h>
#include <linux/security.h>
#endif /* CONFIG_NFSD_V4 */
#include <asm/uaccess.h>
#define NFSDDBG_FACILITY NFSDDBG_FILEOP
#define NFSD_PARANOIA
/* We must ignore files (but only files) which might have mandatory
* locks on them because there is no way to know if the accesser has
* the lock.
*/
#define IS_ISMNDLK(i) (S_ISREG((i)->i_mode) && MANDATORY_LOCK(i))
/*
* This is a cache of readahead params that help us choose the proper
* readahead strategy. Initially, we set all readahead parameters to 0
* and let the VFS handle things.
* If you increase the number of cached files very much, you'll need to
* add a hash table here.
*/
struct raparms {
struct raparms *p_next;
unsigned int p_count;
ino_t p_ino;
dev_t p_dev;
int p_set;
struct file_ra_state p_ra;
};
static struct raparms * raparml;
static struct raparms * raparm_cache;
/*
* Called from nfsd_lookup and encode_dirent. Check if we have crossed
* a mount point.
* Returns -EAGAIN leaving *dpp and *expp unchanged,
* or nfs_ok having possibly changed *dpp and *expp
*/
int
nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
struct svc_export **expp)
{
struct svc_export *exp = *expp, *exp2 = NULL;
struct dentry *dentry = *dpp;
struct vfsmount *mnt = mntget(exp->ex_mnt);
struct dentry *mounts = dget(dentry);
int err = nfs_ok;
while (follow_down(&mnt,&mounts)&&d_mountpoint(mounts));
exp2 = exp_get_by_name(exp->ex_client, mnt, mounts, &rqstp->rq_chandle);
if (IS_ERR(exp2)) {
err = PTR_ERR(exp2);
dput(mounts);
mntput(mnt);
goto out;
}
if (exp2 && ((exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2))) {
/* successfully crossed mount point */
exp_put(exp);
*expp = exp2;
dput(dentry);
*dpp = mounts;
} else {
if (exp2) exp_put(exp2);
dput(mounts);
}
mntput(mnt);
out:
return err;
}
/*
* Look up one component of a pathname.
* N.B. After this call _both_ fhp and resfh need an fh_put
*
* If the lookup would cross a mountpoint, and the mounted filesystem
* is exported to the client with NFSEXP_NOHIDE, then the lookup is
* accepted as it stands and the mounted directory is
* returned. Otherwise the covered directory is returned.
* NOTE: this mountpoint crossing is not supported properly by all
* clients and is explicitly disallowed for NFSv3
* NeilBrown <[email protected]>
*/
int
nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
int len, struct svc_fh *resfh)
{
struct svc_export *exp;
struct dentry *dparent;
struct dentry *dentry;
int err;
dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);
/* Obtain dentry and export. */
err = fh_verify(rqstp, fhp, S_IFDIR, MAY_EXEC);
if (err)
return err;
dparent = fhp->fh_dentry;
exp = fhp->fh_export;
exp_get(exp);
err = nfserr_acces;
/* Lookup the name, but don't follow links */
if (isdotent(name, len)) {
if (len==1)
dentry = dget(dparent);
else if (dparent != exp->ex_dentry) {
dentry = dget_parent(dparent);
} else if (!EX_NOHIDE(exp))
dentry = dget(dparent); /* .. == . just like at / */
else {
/* checking mountpoint crossing is very different when stepping up */
struct svc_export *exp2 = NULL;
struct dentry *dp;
struct vfsmount *mnt = mntget(exp->ex_mnt);
dentry = dget(dparent);
while(dentry == mnt->mnt_root && follow_up(&mnt, &dentry))
;
dp = dget_parent(dentry);
dput(dentry);
dentry = dp;
exp2 = exp_parent(exp->ex_client, mnt, dentry,
&rqstp->rq_chandle);
if (IS_ERR(exp2)) {
err = PTR_ERR(exp2);
dput(dentry);
mntput(mnt);
goto out_nfserr;
}
if (!exp2) {
dput(dentry);
dentry = dget(dparent);
} else {
exp_put(exp);
exp = exp2;
}
mntput(mnt);
}
} else {
fh_lock(fhp);
dentry = lookup_one_len(name, dparent, len);
err = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_nfserr;
/*
* check if we have crossed a mount point ...
*/
if (d_mountpoint(dentry)) {
if ((err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
dput(dentry);
goto out_nfserr;
}
}
}
/*
* Note: we compose the file handle now, but as the
* dentry may be negative, it may need to be updated.
*/
err = fh_compose(resfh, exp, dentry, fhp);
if (!err && !dentry->d_inode)
err = nfserr_noent;
dput(dentry);
out:
exp_put(exp);
return err;
out_nfserr:
err = nfserrno(err);
goto out;
}
/*
* Set various file attributes.
* N.B. After this call fhp needs an fh_put
*/
int
nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
int check_guard, time_t guardtime)
{
struct dentry *dentry;
struct inode *inode;
int accmode = MAY_SATTR;
int ftype = 0;
int imode;
int err;
int size_change = 0;
if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
accmode |= MAY_WRITE|MAY_OWNER_OVERRIDE;
if (iap->ia_valid & ATTR_SIZE)
ftype = S_IFREG;
/* Get inode */
err = fh_verify(rqstp, fhp, ftype, accmode);
if (err)
goto out;
dentry = fhp->fh_dentry;
inode = dentry->d_inode;
/* Ignore any mode updates on symlinks */
if (S_ISLNK(inode->i_mode))
iap->ia_valid &= ~ATTR_MODE;
if (!iap->ia_valid)
goto out;
/* NFSv2 does not differentiate between "set-[ac]time-to-now"
* which only requires access, and "set-[ac]time-to-X" which
* requires ownership.
* So if it looks like it might be "set both to the same time which
* is close to now", and if inode_change_ok fails, then we
* convert to "set to now" instead of "set to explicit time"
*
* We only call inode_change_ok as the last test as technically
* it is not an interface that we should be using. It is only
* valid if the filesystem does not define it's own i_op->setattr.
*/
#define BOTH_TIME_SET (ATTR_ATIME_SET | ATTR_MTIME_SET)
#define MAX_TOUCH_TIME_ERROR (30*60)
if ((iap->ia_valid & BOTH_TIME_SET) == BOTH_TIME_SET
&& iap->ia_mtime.tv_sec == iap->ia_atime.tv_sec
) {
/* Looks probable. Now just make sure time is in the right ballpark.
* Solaris, at least, doesn't seem to care what the time request is.
* We require it be within 30 minutes of now.
*/
time_t delta = iap->ia_atime.tv_sec - get_seconds();
if (delta<0) delta = -delta;
if (delta < MAX_TOUCH_TIME_ERROR &&
inode_change_ok(inode, iap) != 0) {
/* turn off ATTR_[AM]TIME_SET but leave ATTR_[AM]TIME
* this will cause notify_change to set these times to "now"
*/
iap->ia_valid &= ~BOTH_TIME_SET;
}
}
/* The size case is special. It changes the file as well as the attributes. */
if (iap->ia_valid & ATTR_SIZE) {
if (iap->ia_size < inode->i_size) {
err = nfsd_permission(fhp->fh_export, dentry, MAY_TRUNC|MAY_OWNER_OVERRIDE);
if (err)
goto out;
}
/*
* If we are changing the size of the file, then
* we need to break all leases.
*/
err = break_lease(inode, FMODE_WRITE | O_NONBLOCK);
if (err == -EWOULDBLOCK)
err = -ETIMEDOUT;
if (err) /* ENOMEM or EWOULDBLOCK */
goto out_nfserr;
err = get_write_access(inode);
if (err)
goto out_nfserr;
size_change = 1;
err = locks_verify_truncate(inode, NULL, iap->ia_size);
if (err) {
put_write_access(inode);
goto out_nfserr;
}
DQUOT_INIT(inode);
}
imode = inode->i_mode;
if (iap->ia_valid & ATTR_MODE) {
iap->ia_mode &= S_IALLUGO;
imode = iap->ia_mode |= (imode & ~S_IALLUGO);
}
/* Revoke setuid/setgid bit on chown/chgrp */
if ((iap->ia_valid & ATTR_UID) && iap->ia_uid != inode->i_uid)
iap->ia_valid |= ATTR_KILL_SUID;
if ((iap->ia_valid & ATTR_GID) && iap->ia_gid != inode->i_gid)
iap->ia_valid |= ATTR_KILL_SGID;
/* Change the attributes. */
iap->ia_valid |= ATTR_CTIME;
err = nfserr_notsync;
if (!check_guard || guardtime == inode->i_ctime.tv_sec) {
fh_lock(fhp);
err = notify_change(dentry, iap);
err = nfserrno(err);
fh_unlock(fhp);
}
if (size_change)
put_write_access(inode);
if (!err)
if (EX_ISSYNC(fhp->fh_export))
write_inode_now(inode, 1);
out:
return err;
out_nfserr:
err = nfserrno(err);
goto out;
}
#if defined(CONFIG_NFSD_V2_ACL) || \
defined(CONFIG_NFSD_V3_ACL) || \
defined(CONFIG_NFSD_V4)
static ssize_t nfsd_getxattr(struct dentry *dentry, char *key, void **buf)
{
ssize_t buflen;
buflen = vfs_getxattr(dentry, key, NULL, 0);
if (buflen <= 0)
return buflen;
*buf = kmalloc(buflen, GFP_KERNEL);
if (!*buf)
return -ENOMEM;
return vfs_getxattr(dentry, key, *buf, buflen);
}
#endif
#if defined(CONFIG_NFSD_V4)
static int
set_nfsv4_acl_one(struct dentry *dentry, struct posix_acl *pacl, char *key)
{
int len;
size_t buflen;
char *buf = NULL;
int error = 0;
buflen = posix_acl_xattr_size(pacl->a_count);
buf = kmalloc(buflen, GFP_KERNEL);
error = -ENOMEM;
if (buf == NULL)
goto out;
len = posix_acl_to_xattr(pacl, buf, buflen);
if (len < 0) {
error = len;
goto out;
}
error = vfs_setxattr(dentry, key, buf, len, 0);
out:
kfree(buf);
return error;
}
int
nfsd4_set_nfs4_acl(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct nfs4_acl *acl)
{
int error;
struct dentry *dentry;
struct inode *inode;
struct posix_acl *pacl = NULL, *dpacl = NULL;
unsigned int flags = 0;
/* Get inode */
error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, MAY_SATTR);
if (error)
goto out;
dentry = fhp->fh_dentry;
inode = dentry->d_inode;
if (S_ISDIR(inode->i_mode))
flags = NFS4_ACL_DIR;
error = nfs4_acl_nfsv4_to_posix(acl, &pacl, &dpacl, flags);
if (error == -EINVAL) {
error = nfserr_attrnotsupp;
goto out;
} else if (error < 0)
goto out_nfserr;
if (pacl) {
error = set_nfsv4_acl_one(dentry, pacl, POSIX_ACL_XATTR_ACCESS);
if (error < 0)
goto out_nfserr;
}
if (dpacl) {
error = set_nfsv4_acl_one(dentry, dpacl, POSIX_ACL_XATTR_DEFAULT);
if (error < 0)
goto out_nfserr;
}
error = nfs_ok;
out:
posix_acl_release(pacl);
posix_acl_release(dpacl);
return (error);
out_nfserr:
error = nfserrno(error);
goto out;
}
static struct posix_acl *
_get_posix_acl(struct dentry *dentry, char *key)
{
void *buf = NULL;
struct posix_acl *pacl = NULL;
int buflen;
buflen = nfsd_getxattr(dentry, key, &buf);
if (!buflen)
buflen = -ENODATA;
if (buflen <= 0)
return ERR_PTR(buflen);
pacl = posix_acl_from_xattr(buf, buflen);
kfree(buf);
return pacl;
}
int
nfsd4_get_nfs4_acl(struct svc_rqst *rqstp, struct dentry *dentry, struct nfs4_acl **acl)
{
struct inode *inode = dentry->d_inode;
int error = 0;
struct posix_acl *pacl = NULL, *dpacl = NULL;
unsigned int flags = 0;
pacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_ACCESS);
if (IS_ERR(pacl) && PTR_ERR(pacl) == -ENODATA)
pacl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
if (IS_ERR(pacl)) {
error = PTR_ERR(pacl);
pacl = NULL;
goto out;
}
if (S_ISDIR(inode->i_mode)) {
dpacl = _get_posix_acl(dentry, POSIX_ACL_XATTR_DEFAULT);
if (IS_ERR(dpacl) && PTR_ERR(dpacl) == -ENODATA)
dpacl = NULL;
else if (IS_ERR(dpacl)) {
error = PTR_ERR(dpacl);
dpacl = NULL;
goto out;
}
flags = NFS4_ACL_DIR;
}
*acl = nfs4_acl_posix_to_nfsv4(pacl, dpacl, flags);
if (IS_ERR(*acl)) {
error = PTR_ERR(*acl);
*acl = NULL;
}
out:
posix_acl_release(pacl);
posix_acl_release(dpacl);
return error;
}
#endif /* defined(CONFIG_NFS_V4) */
#ifdef CONFIG_NFSD_V3
/*
* Check server access rights to a file system object
*/
struct accessmap {
u32 access;
int how;
};
static struct accessmap nfs3_regaccess[] = {
{ NFS3_ACCESS_READ, MAY_READ },
{ NFS3_ACCESS_EXECUTE, MAY_EXEC },
{ NFS3_ACCESS_MODIFY, MAY_WRITE|MAY_TRUNC },
{ NFS3_ACCESS_EXTEND, MAY_WRITE },
{ 0, 0 }
};
static struct accessmap nfs3_diraccess[] = {
{ NFS3_ACCESS_READ, MAY_READ },
{ NFS3_ACCESS_LOOKUP, MAY_EXEC },
{ NFS3_ACCESS_MODIFY, MAY_EXEC|MAY_WRITE|MAY_TRUNC },
{ NFS3_ACCESS_EXTEND, MAY_EXEC|MAY_WRITE },
{ NFS3_ACCESS_DELETE, MAY_REMOVE },
{ 0, 0 }
};
static struct accessmap nfs3_anyaccess[] = {
/* Some clients - Solaris 2.6 at least, make an access call
* to the server to check for access for things like /dev/null
* (which really, the server doesn't care about). So
* We provide simple access checking for them, looking
* mainly at mode bits, and we make sure to ignore read-only
* filesystem checks
*/
{ NFS3_ACCESS_READ, MAY_READ },
{ NFS3_ACCESS_EXECUTE, MAY_EXEC },
{ NFS3_ACCESS_MODIFY, MAY_WRITE|MAY_LOCAL_ACCESS },
{ NFS3_ACCESS_EXTEND, MAY_WRITE|MAY_LOCAL_ACCESS },
{ 0, 0 }
};
int
nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *supported)
{
struct accessmap *map;
struct svc_export *export;
struct dentry *dentry;
u32 query, result = 0, sresult = 0;
unsigned int error;
error = fh_verify(rqstp, fhp, 0, MAY_NOP);
if (error)
goto out;
export = fhp->fh_export;
dentry = fhp->fh_dentry;
if (S_ISREG(dentry->d_inode->i_mode))
map = nfs3_regaccess;
else if (S_ISDIR(dentry->d_inode->i_mode))
map = nfs3_diraccess;
else
map = nfs3_anyaccess;
query = *access;
for (; map->access; map++) {
if (map->access & query) {
unsigned int err2;
sresult |= map->access;
err2 = nfsd_permission(export, dentry, map->how);
switch (err2) {
case nfs_ok:
result |= map->access;
break;
/* the following error codes just mean the access was not allowed,
* rather than an error occurred */
case nfserr_rofs:
case nfserr_acces:
case nfserr_perm:
/* simply don't "or" in the access bit. */
break;
default:
error = err2;
goto out;
}
}
}
*access = result;
if (supported)
*supported = sresult;
out:
return error;
}
#endif /* CONFIG_NFSD_V3 */
/*
* Open an existing file or directory.
* The access argument indicates the type of open (read/write/lock)
* N.B. After this call fhp needs an fh_put
*/
int
nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
int access, struct file **filp)
{
struct dentry *dentry;
struct inode *inode;
int flags = O_RDONLY|O_LARGEFILE, err;
/*
* If we get here, then the client has already done an "open",
* and (hopefully) checked permission - so allow OWNER_OVERRIDE
* in case a chmod has now revoked permission.
*/
err = fh_verify(rqstp, fhp, type, access | MAY_OWNER_OVERRIDE);
if (err)
goto out;
dentry = fhp->fh_dentry;
inode = dentry->d_inode;
/* Disallow write access to files with the append-only bit set
* or any access when mandatory locking enabled
*/
err = nfserr_perm;
if (IS_APPEND(inode) && (access & MAY_WRITE))
goto out;
if (IS_ISMNDLK(inode))
goto out;
if (!inode->i_fop)
goto out;
/*
* Check to see if there are any leases on this file.
* This may block while leases are broken.
*/
err = break_lease(inode, O_NONBLOCK | ((access & MAY_WRITE) ? FMODE_WRITE : 0));
if (err == -EWOULDBLOCK)
err = -ETIMEDOUT;
if (err) /* NOMEM or WOULDBLOCK */
goto out_nfserr;
if (access & MAY_WRITE) {
if (access & MAY_READ)
flags = O_RDWR|O_LARGEFILE;
else
flags = O_WRONLY|O_LARGEFILE;
DQUOT_INIT(inode);
}
*filp = dentry_open(dget(dentry), mntget(fhp->fh_export->ex_mnt), flags);
if (IS_ERR(*filp))
err = PTR_ERR(*filp);
out_nfserr:
if (err)
err = nfserrno(err);
out:
return err;
}
/*
* Close a file.
*/
void
nfsd_close(struct file *filp)
{
fput(filp);
}
/*
* Sync a file
* As this calls fsync (not fdatasync) there is no need for a write_inode
* after it.
*/
static inline int nfsd_dosync(struct file *filp, struct dentry *dp,
const struct file_operations *fop)
{
struct inode *inode = dp->d_inode;
int (*fsync) (struct file *, struct dentry *, int);
int err;
err = filemap_fdatawrite(inode->i_mapping);
if (err == 0 && fop && (fsync = fop->fsync))
err = fsync(filp, dp, 0);
if (err == 0)
err = filemap_fdatawait(inode->i_mapping);
return err;
}
static int
nfsd_sync(struct file *filp)
{
int err;
struct inode *inode = filp->f_dentry->d_inode;
dprintk("nfsd: sync file %s\n", filp->f_dentry->d_name.name);
mutex_lock(&inode->i_mutex);
err=nfsd_dosync(filp, filp->f_dentry, filp->f_op);
mutex_unlock(&inode->i_mutex);
return err;
}
int
nfsd_sync_dir(struct dentry *dp)
{
return nfsd_dosync(NULL, dp, dp->d_inode->i_fop);
}
/*
* Obtain the readahead parameters for the file
* specified by (dev, ino).
*/
static DEFINE_SPINLOCK(ra_lock);
static inline struct raparms *
nfsd_get_raparms(dev_t dev, ino_t ino)
{
struct raparms *ra, **rap, **frap = NULL;
int depth = 0;
spin_lock(&ra_lock);
for (rap = &raparm_cache; (ra = *rap); rap = &ra->p_next) {
if (ra->p_ino == ino && ra->p_dev == dev)
goto found;
depth++;
if (ra->p_count == 0)
frap = rap;
}
depth = nfsdstats.ra_size*11/10;
if (!frap) {
spin_unlock(&ra_lock);
return NULL;
}
rap = frap;
ra = *frap;
ra->p_dev = dev;
ra->p_ino = ino;
ra->p_set = 0;
found:
if (rap != &raparm_cache) {
*rap = ra->p_next;
ra->p_next = raparm_cache;
raparm_cache = ra;
}
ra->p_count++;
nfsdstats.ra_depth[depth*10/nfsdstats.ra_size]++;
spin_unlock(&ra_lock);
return ra;
}
/*
* Grab and keep cached pages assosiated with a file in the svc_rqst
* so that they can be passed to the netowork sendmsg/sendpage routines
* directrly. They will be released after the sending has completed.
*/
static int
nfsd_read_actor(read_descriptor_t *desc, struct page *page, unsigned long offset , unsigned long size)
{
unsigned long count = desc->count;
struct svc_rqst *rqstp = desc->arg.data;
if (size > count)
size = count;
if (rqstp->rq_res.page_len == 0) {
get_page(page);
rqstp->rq_respages[rqstp->rq_resused++] = page;
rqstp->rq_res.page_base = offset;
rqstp->rq_res.page_len = size;
} else if (page != rqstp->rq_respages[rqstp->rq_resused-1]) {
get_page(page);
rqstp->rq_respages[rqstp->rq_resused++] = page;
rqstp->rq_res.page_len += size;
} else {
rqstp->rq_res.page_len += size;
}
desc->count = count - size;
desc->written += size;
return size;
}
static int
nfsd_vfs_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
{
struct inode *inode;
struct raparms *ra;
mm_segment_t oldfs;
int err;
err = nfserr_perm;
inode = file->f_dentry->d_inode;
#ifdef MSNFS
if ((fhp->fh_export->ex_flags & NFSEXP_MSNFS) &&
(!lock_may_read(inode, offset, *count)))
goto out;
#endif
/* Get readahead parameters */
ra = nfsd_get_raparms(inode->i_sb->s_dev, inode->i_ino);
if (ra && ra->p_set)
file->f_ra = ra->p_ra;
if (file->f_op->sendfile && rqstp->rq_sendfile_ok) {
svc_pushback_unused_pages(rqstp);
err = file->f_op->sendfile(file, &offset, *count,
nfsd_read_actor, rqstp);
} else {
oldfs = get_fs();
set_fs(KERNEL_DS);
err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset);
set_fs(oldfs);
}
/* Write back readahead params */
if (ra) {
spin_lock(&ra_lock);
ra->p_ra = file->f_ra;
ra->p_set = 1;
ra->p_count--;
spin_unlock(&ra_lock);
}
if (err >= 0) {
nfsdstats.io_read += err;
*count = err;
err = 0;
fsnotify_access(file->f_dentry);
} else
err = nfserrno(err);
out:
return err;
}
static void kill_suid(struct dentry *dentry)
{
struct iattr ia;
ia.ia_valid = ATTR_KILL_SUID | ATTR_KILL_SGID;
mutex_lock(&dentry->d_inode->i_mutex);
notify_change(dentry, &ia);
mutex_unlock(&dentry->d_inode->i_mutex);
}
static int
nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
loff_t offset, struct kvec *vec, int vlen,
unsigned long cnt, int *stablep)
{
struct svc_export *exp;
struct dentry *dentry;
struct inode *inode;
mm_segment_t oldfs;
int err = 0;
int stable = *stablep;
#ifdef MSNFS
err = nfserr_perm;
if ((fhp->fh_export->ex_flags & NFSEXP_MSNFS) &&
(!lock_may_write(file->f_dentry->d_inode, offset, cnt)))
goto out;
#endif
dentry = file->f_dentry;
inode = dentry->d_inode;
exp = fhp->fh_export;
/*
* Request sync writes if
* - the sync export option has been set, or
* - the client requested O_SYNC behavior (NFSv3 feature).
* - The file system doesn't support fsync().
* When gathered writes have been configured for this volume,
* flushing the data to disk is handled separately below.
*/
if (file->f_op->fsync == 0) {/* COMMIT3 cannot work */
stable = 2;
*stablep = 2; /* FILE_SYNC */
}
if (!EX_ISSYNC(exp))
stable = 0;
if (stable && !EX_WGATHER(exp))
file->f_flags |= O_SYNC;
/* Write the data. */
oldfs = get_fs(); set_fs(KERNEL_DS);
err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
set_fs(oldfs);
if (err >= 0) {
nfsdstats.io_write += cnt;
fsnotify_modify(file->f_dentry);
}
/* clear setuid/setgid flag after write */
if (err >= 0 && (inode->i_mode & (S_ISUID | S_ISGID)))
kill_suid(dentry);
if (err >= 0 && stable) {
static ino_t last_ino;
static dev_t last_dev;
/*
* Gathered writes: If another process is currently
* writing to the file, there's a high chance
* this is another nfsd (triggered by a bulk write
* from a client's biod). Rather than syncing the
* file with each write request, we sleep for 10 msec.
*
* I don't know if this roughly approximates
* C. Juszak's idea of gathered writes, but it's a
* nice and simple solution (IMHO), and it seems to
* work:-)
*/
if (EX_WGATHER(exp)) {
if (atomic_read(&inode->i_writecount) > 1
|| (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
dprintk("nfsd: write defer %d\n", current->pid);
msleep(10);
dprintk("nfsd: write resume %d\n", current->pid);
}
if (inode->i_state & I_DIRTY) {
dprintk("nfsd: write sync %d\n", current->pid);
err=nfsd_sync(file);
}
#if 0
wake_up(&inode->i_wait);
#endif
}
last_ino = inode->i_ino;
last_dev = inode->i_sb->s_dev;
}
dprintk("nfsd: write complete err=%d\n", err);
if (err >= 0)
err = 0;
else
err = nfserrno(err);
out:
return err;
}
/*
* Read data from a file. count must contain the requested read count
* on entry. On return, *count contains the number of bytes actually read.
* N.B. After this call fhp needs an fh_put
*/
int
nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
loff_t offset, struct kvec *vec, int vlen,
unsigned long *count)
{
int err;
if (file) {
err = nfsd_permission(fhp->fh_export, fhp->fh_dentry,
MAY_READ|MAY_OWNER_OVERRIDE);
if (err)
goto out;
err = nfsd_vfs_read(rqstp, fhp, file, offset, vec, vlen, count);
} else {
err = nfsd_open(rqstp, fhp, S_IFREG, MAY_READ, &file);