cregit-Linux how code gets into the kernel

Release 4.10 fs/nfsd/vfs.c

Directory: fs/nfsd
/*
 * 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 <okir@monad.swb.de>
 * Zerocpy NFS support (C) 2002 Hirokazu Takahashi <taka@valinux.co.jp>
 */

#include <linux/fs.h>
#include <linux/file.h>
#include <linux/splice.h>
#include <linux/falloc.h>
#include <linux/fcntl.h>
#include <linux/namei.h>
#include <linux/delay.h>
#include <linux/fsnotify.h>
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
#include <linux/jhash.h>
#include <linux/ima.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/exportfs.h>
#include <linux/writeback.h>
#include <linux/security.h>

#ifdef CONFIG_NFSD_V3
#include "xdr3.h"
#endif /* CONFIG_NFSD_V3 */

#ifdef CONFIG_NFSD_V4
#include "../internal.h"
#include "acl.h"
#include "idmap.h"
#endif /* CONFIG_NFSD_V4 */

#include "nfsd.h"
#include "vfs.h"
#include "trace.h"


#define NFSDDBG_FACILITY		NFSDDBG_FILEOP


/*
 * 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;
	
unsigned int		p_hindex;
};


struct raparm_hbucket {
	
struct raparms		*pb_head;
	
spinlock_t		pb_lock;
} 
____cacheline_aligned_in_smp;


#define RAPARM_HASH_BITS	4

#define RAPARM_HASH_SIZE	(1<<RAPARM_HASH_BITS)

#define RAPARM_HASH_MASK	(RAPARM_HASH_SIZE-1)

static struct raparm_hbucket	raparm_hash[RAPARM_HASH_SIZE];

/* 
 * Called from nfsd_lookup and encode_dirent. Check if we have crossed 
 * a mount point.
 * Returns -EAGAIN or -ETIMEDOUT 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 path path = {.mnt = mntget(exp->ex_path.mnt),
			    .dentry = dget(dentry)};
	int err = 0;

	err = follow_down(&path);
	if (err < 0)
		goto out;

	exp2 = rqst_exp_get_by_name(rqstp, &path);
	if (IS_ERR(exp2)) {
		err = PTR_ERR(exp2);
		/*
                 * We normally allow NFS clients to continue
                 * "underneath" a mountpoint that is not exported.
                 * The exception is V4ROOT, where no traversal is ever
                 * allowed without an explicit export of the new
                 * directory.
                 */
		if (err == -ENOENT && !(exp->ex_flags & NFSEXP_V4ROOT))
			err = 0;
		path_put(&path);
		goto out;
	}
	if (nfsd_v4client(rqstp) ||
		(exp->ex_flags & NFSEXP_CROSSMOUNT) || EX_NOHIDE(exp2)) {
		/* successfully crossed mount point */
		/*
                 * This is subtle: path.dentry is *not* on path.mnt
                 * at this point.  The only reason we are safe is that
                 * original mnt is pinned down by exp, so we should
                 * put path *before* putting exp
                 */
		*dpp = path.dentry;
		path.dentry = dentry;
		*expp = exp2;
		exp2 = exp;
	}
	path_put(&path);
	exp_put(exp2);
out:
	return err;
}


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al viroal viro4019.14%433.33%


j. bruce fieldsj. bruce fields209.57%216.67%


david howellsdavid howells115.26%18.33%


steve dicksonsteve dickson52.39%18.33%


jan blunckjan blunck31.44%18.33%


Total209100.00%12100.00%






static void follow_to_parent(struct path *path)
{
	struct dentry *dp;

	while (path->dentry == path->mnt->mnt_root && follow_up(path))
		;
	dp = dget_parent(path->dentry);
	dput(path->dentry);
	path->dentry = dp;
}


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Total56100.00%1100.00%






static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, struct svc_export **exp, struct dentry **dentryp)
{
	struct svc_export *exp2;
	struct path path = {.mnt = mntget((*exp)->ex_path.mnt),
			    .dentry = dget(dparent)};

	follow_to_parent(&path);

	exp2 = rqst_exp_parent(rqstp, &path);
	if (PTR_ERR(exp2) == -ENOENT) {
		*dentryp = dget(dparent);
	} else if (IS_ERR(exp2)) {
		path_put(&path);
		return PTR_ERR(exp2);
	} else {
		*dentryp = dget(path.dentry);
		exp_put(*exp);
		*exp = exp2;
	}
	path_put(&path);
	return 0;
}


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Total153100.00%1100.00%



/*
 * For nfsd purposes, we treat V4ROOT exports as though there was an
 * export at *every* directory.
 */



int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
{
	if (d_mountpoint(dentry))
		return 1;
	if (nfsd4_is_junction(dentry))
		return 1;
	if (!(exp->ex_flags & NFSEXP_V4ROOT))
		return 0;
	return d_inode(dentry) != NULL;
}


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trond myklebusttrond myklebust1017.54%133.33%


david howellsdavid howells35.26%133.33%


Total57100.00%3100.00%





__be32

nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
		   const char *name, unsigned int len,
		   struct svc_export **exp_ret, struct dentry **dentry_ret)
{
	struct svc_export	*exp;
	struct dentry		*dparent;
	struct dentry		*dentry;
	int			host_err;

	dprintk("nfsd: nfsd_lookup(fh %s, %.*s)\n", SVCFH_fmt(fhp), len,name);

	dparent = fhp->fh_dentry;
	exp = exp_get(fhp->fh_export);

	/* Lookup the name, but don't follow links */
	if (isdotent(name, len)) {
		if (len==1)
			dentry = dget(dparent);
		else if (dparent != exp->ex_path.dentry)
			dentry = dget_parent(dparent);
		else if (!EX_NOHIDE(exp) && !nfsd_v4client(rqstp))
			dentry = dget(dparent); /* .. == . just like at / */
		else {
			/* checking mountpoint crossing is very different when stepping up */
			host_err = nfsd_lookup_parent(rqstp, dparent, &exp, &dentry);
			if (host_err)
				goto out_nfserr;
		}
	} else {
		/*
                 * In the nfsd4_open() case, this may be held across
                 * subsequent open and delegation acquisition which may
                 * need to take the child's i_mutex:
                 */
		fh_lock_nested(fhp, I_MUTEX_PARENT);
		dentry = lookup_one_len(name, dparent, len);
		host_err = PTR_ERR(dentry);
		if (IS_ERR(dentry))
			goto out_nfserr;
		if (nfsd_mountpoint(dentry, exp)) {
			/*
                         * We don't need the i_mutex after all.  It's
                         * still possible we could open this (regular
                         * files can be mountpoints too), but the
                         * i_mutex is just there to prevent renames of
                         * something that we might be about to delegate,
                         * and a mountpoint won't be renamed:
                         */
			fh_unlock(fhp);
			if ((host_err = nfsd_cross_mnt(rqstp, &dentry, &exp))) {
				dput(dentry);
				goto out_nfserr;
			}
		}
	}
	*dentry_ret = dentry;
	*exp_ret = exp;
	return 0;

out_nfserr:
	exp_put(exp);
	return nfserrno(host_err);
}


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pre-gitpre-git14751.76%1335.14%


j. bruce fieldsj. bruce fields6422.54%718.92%


neil brownneil brown3311.62%616.22%


al viroal viro175.99%410.81%


linus torvaldslinus torvalds144.93%25.41%


andrew mortonandrew morton31.06%25.41%


jan blunckjan blunck31.06%12.70%


kinglong meekinglong mee20.70%12.70%


chuck leverchuck lever10.35%12.70%


Total284100.00%37100.00%



/*
 * 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 <neilb@cse.unsw.edu.au>
 */


__be32

nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
				unsigned int len, struct svc_fh *resfh)
{
	struct svc_export	*exp;
	struct dentry		*dentry;
	__be32 err;

	err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
	if (err)
		return err;
	err = nfsd_lookup_dentry(rqstp, fhp, name, len, &exp, &dentry);
	if (err)
		return err;
	err = check_nfsd_access(exp, rqstp);
	if (err)
		goto out;
	/*
         * 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 && d_really_is_negative(dentry))
		err = nfserr_noent;
out:
	dput(dentry);
	exp_put(exp);
	return err;
}


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j. bruce fieldsj. bruce fields8658.50%214.29%


pre-gitpre-git2718.37%642.86%


andy adamsonandy adamson1812.24%17.14%


andrew mortonandrew morton106.80%214.29%


david howellsdavid howells32.04%17.14%


linus torvaldslinus torvalds21.36%17.14%


chuck leverchuck lever10.68%17.14%


Total147100.00%14100.00%



/*
 * Commit metadata changes to stable storage.
 */


static int

commit_metadata(struct svc_fh *fhp)
{
	struct inode *inode = d_inode(fhp->fh_dentry);
	const struct export_operations *export_ops = inode->i_sb->s_export_op;

	if (!EX_ISSYNC(fhp->fh_export))
		return 0;

	if (export_ops->commit_metadata)
		return export_ops->commit_metadata(inode);
	return sync_inode_metadata(inode, 1);
}


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ben meyersben meyers6288.57%133.33%


christoph hellwigchristoph hellwig57.14%133.33%


david howellsdavid howells34.29%133.33%


Total70100.00%3100.00%



/*
 * Go over the attributes and take care of the small differences between
 * NFS semantics and what Linux expects.
 */


static void

nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
{
	/* sanitize the mode change */
	if (iap->ia_valid & ATTR_MODE) {
		iap->ia_mode &= S_IALLUGO;
		iap->ia_mode |= (inode->i_mode & ~S_IALLUGO);
	}

	/* Revoke setuid/setgid on chown */
	if (!S_ISDIR(inode->i_mode) &&
	    ((iap->ia_valid & ATTR_UID) || (iap->ia_valid & ATTR_GID))) {
		iap->ia_valid |= ATTR_KILL_PRIV;
		if (iap->ia_valid & ATTR_MODE) {
			/* we're setting mode too, just clear the s*id bits */
			iap->ia_mode &= ~S_ISUID;
			if (iap->ia_mode & S_IXGRP)
				iap->ia_mode &= ~S_ISGID;
		} else {
			/* set ATTR_KILL_* bits and let VFS handle it */
			iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
		}
	}
}


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pre-gitpre-git5743.85%225.00%


jeff laytonjeff layton5643.08%337.50%


sachin prabhusachin prabhu107.69%112.50%


christoph hellwigchristoph hellwig64.62%112.50%


al viroal viro10.77%112.50%


Total130100.00%8100.00%





static __be32

nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
		struct iattr *iap)
{
	struct inode *inode = d_inode(fhp->fh_dentry);
	int host_err;

	if (iap->ia_size < inode->i_size) {
		__be32 err;

		err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
				NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
		if (err)
			return err;
	}

	host_err = get_write_access(inode);
	if (host_err)
		goto out_nfserrno;

	host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
	if (host_err)
		goto out_put_write_access;
	return 0;

out_put_write_access:
	put_write_access(inode);
out_nfserrno:
	return nfserrno(host_err);
}


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Total129100.00%1100.00%



/*
 * Set various file attributes.  After this call fhp needs an fh_put.
 */


__be32

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 = NFSD_MAY_SATTR;
	umode_t		ftype = 0;
	__be32		err;
	int		host_err;
	bool		get_write_count;
	int		size_change = 0;

	if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
		accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
	if (iap->ia_valid & ATTR_SIZE)
		ftype = S_IFREG;

	/* Callers that do fh_verify should do the fh_want_write: */
	get_write_count = !fhp->fh_dentry;

	/* Get inode */
	err = fh_verify(rqstp, fhp, ftype, accmode);
	if (err)
		goto out;
	if (get_write_count) {
		host_err = fh_want_write(fhp);
		if (host_err)
			return nfserrno(host_err);
	}

	dentry = fhp->fh_dentry;
	inode = d_inode(dentry);

	/* Ignore any mode updates on symlinks */
	if (S_ISLNK(inode->i_mode))
		iap->ia_valid &= ~ATTR_MODE;

	if (!iap->ia_valid)
		goto out;

	nfsd_sanitize_attrs(inode, iap);

	/*
         * The size case is special, it changes the file in addition to the
         * attributes.
         */
	if (iap->ia_valid & ATTR_SIZE) {
		err = nfsd_get_write_access(rqstp, fhp, iap);
		if (err)
			goto out;
		size_change = 1;

		/*
                 * RFC5661, Section 18.30.4:
                 *   Changing the size of a file with SETATTR indirectly
                 *   changes the time_modify and change attributes.
                 *
                 * (and similar for the older RFCs)
                 */
		if (iap->ia_size != i_size_read(inode))
			iap->ia_valid |= ATTR_MTIME;
	}

	iap->ia_valid |= ATTR_CTIME;

	if (check_guard && guardtime != inode->i_ctime.tv_sec) {
		err = nfserr_notsync;
		goto out_put_write_access;
	}

	fh_lock(fhp);
	host_err = notify_change(dentry, iap, NULL);
	fh_unlock(fhp);
	err = nfserrno(host_err);

out_put_write_access:
	if (size_change)
		put_write_access(inode);
	if (!err)
		err = nfserrno(commit_metadata(fhp));
out:
	return err;
}


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christoph hellwigchristoph hellwig18556.40%529.41%


j. bruce fieldsj. bruce fields11334.45%317.65%


pre-gitpre-git175.18%423.53%


al viroal viro82.44%211.76%


david howellsdavid howells30.91%15.88%


linus torvaldslinus torvalds10.30%15.88%


trond myklebusttrond myklebust10.30%15.88%


Total328100.00%17100.00%



#if defined(CONFIG_NFSD_V4)
/*
 * NFS junction information is stored in an extended attribute.
 */

#define NFSD_JUNCTION_XATTR_NAME	XATTR_TRUSTED_PREFIX "junction.nfs"

/**
 * nfsd4_is_junction - Test if an object could be an NFS junction
 *
 * @dentry: object to test
 *
 * Returns 1 if "dentry" appears to contain NFS junction information.
 * Otherwise 0 is returned.
 */



int nfsd4_is_junction(struct dentry *dentry)
{
	struct inode *inode = d_inode(dentry);

	if (inode == NULL)
		return 0;
	if (inode->i_mode & S_IXUGO)
		return 0;
	if (!(inode->i_mode & S_ISVTX))
		return 0;
	if (vfs_getxattr(dentry, NFSD_JUNCTION_XATTR_NAME, NULL, 0) <= 0)
		return 0;
	return 1;
}

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krishna kumarkrishna kumar34.00%125.00%


Total75100.00%4100.00%



#ifdef CONFIG_NFSD_V4_SECURITY_LABEL



__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
		struct xdr_netobj *label)
{
	__be32 error;
	int host_error;
	struct dentry *dentry;

	error = fh_verify(rqstp, fhp, 0 /* S_IFREG */, NFSD_MAY_SATTR);
	if (error)
		return error;

	dentry = fhp->fh_dentry;

	inode_lock(d_inode(dentry));
	host_error = security_inode_setsecctx(dentry, label->data, label->len);
	inode_unlock(d_inode(dentry));
	return nfserrno(host_error);
}

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christoph hellwigchristoph hellwig4547.37%120.00%


neil brownneil brown4143.16%120.00%


david howellsdavid howells66.32%120.00%


al viroal viro22.11%120.00%


eric w. biedermaneric w. biederman11.05%120.00%


Total95100.00%5100.00%



#else



__be32 nfsd4_set_nfs4_label(struct svc_rqst *rqstp, struct svc_fh *fhp,
		struct xdr_netobj *label)
{
	return nfserr_notsupp;
}

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christoph hellwigchristoph hellwig730.43%133.33%


al viroal viro14.35%133.33%


Total23100.00%3100.00%



#endif




__be32 nfsd4_clone_file_range(struct file *src, u64 src_pos, struct file *dst,
		u64 dst_pos, u64 count)
{
	return nfserrno(do_clone_file_range(src, src_pos, dst, dst_pos, count));
}


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amir goldsteinamir goldstein12.44%150.00%


Total41100.00%2100.00%






ssize_t nfsd_copy_file_range(struct file *src, u64 src_pos, struct file *dst,
			     u64 dst_pos, u64 count)
{

	/*
         * Limit copy to 4MB to prevent indefinitely blocking an nfsd
         * thread and client rpc slot.  The choice of 4MB is somewhat
         * arbitrary.  We might instead base this on r/wsize, or make it
         * tunable, or use a time instead of a byte limit, or implement
         * asynchronous copy.  In theory a client could also recognize a
         * limit like this and pipeline multiple COPY requests.
         */
	count = min_t(u64, count, 1 << 22);
	return vfs_copy_file_range(src, src_pos, dst, dst_pos, count, 0);
}


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Total54100.00%1100.00%






__be32 nfsd4_vfs_fallocate(struct svc_rqst *rqstp, struct svc_fh *fhp,
			   struct file *file, loff_t offset, loff_t len,
			   int flags)
{
	int error;

	if (!S_ISREG(file_inode(file)->i_mode))
		return nfserr_inval;

	error = vfs_fallocate(file, flags, offset, len);
	if (!error)
		error = commit_metadata(fhp);

	return nfserrno(error);
}

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Total79100.00%1100.00%



#endif /* defined(CONFIG_NFSD_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,	NFSD_MAY_READ			},
    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_TRUNC	},
    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE			},

    {	0,			0				}
};


static struct accessmap	nfs3_diraccess[] = {
    {	NFS3_ACCESS_READ,	NFSD_MAY_READ			},
    {	NFS3_ACCESS_LOOKUP,	NFSD_MAY_EXEC			},
    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_EXEC|NFSD_MAY_WRITE|NFSD_MAY_TRUNC},
    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_EXEC|NFSD_MAY_WRITE	},
    {	NFS3_ACCESS_DELETE,	NFSD_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,	NFSD_MAY_READ			},
    {	NFS3_ACCESS_EXECUTE,	NFSD_MAY_EXEC			},
    {	NFS3_ACCESS_MODIFY,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},
    {	NFS3_ACCESS_EXTEND,	NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS	},

    {	0,			0				}
};



__be32

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;
	__be32			error;

	error = fh_verify(rqstp, fhp, 0, NFSD_MAY_NOP);
	if (error)
		goto out;

	export = fhp->fh_export;
	dentry = fhp->fh_dentry;

	if (d_is_reg(dentry))
		map = nfs3_regaccess;
	else if (d_is_dir(dentry))
		map = nfs3_diraccess;
	else
		map = nfs3_anyaccess;


	query = *access;
	for  (; map->access; map++) {
		if (map->access & query) {
			__be32 err2;

			sresult |= map->access;

			err2 = nfsd_permission(rqstp, 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;
}

Contributors
PersonTokensPropCommitsCommitProp
christoph hellwigchristoph hellwig14867.89%120.00%


neil brownneil brown6630.28%240.00%


david howellsdavid howells20.92%120.00%


j. bruce fieldsj. bruce fields20.92%120.00%


Total218100.00%5100.00%



#endif /* CONFIG_NFSD_V3 */




static int nfsd_open_break_lease(struct inode *inode, int access)
{
	unsigned int mode;

	if (access & NFSD_MAY_NOT_BREAK_LEASE)
		return 0;
	mode = (access & NFSD_MAY_WRITE) ? O_WRONLY : O_RDONLY;
	return break_lease(inode, mode | O_NONBLOCK);
}


Contributors
PersonTokensPropCommitsCommitProp
christoph hellwigchristoph hellwig3265.31%250.00%


neil brownneil brown1632.65%125.00%


eric w. biedermaneric w. biederman12.04%125.00%


Total49100.00%4100.00%



/*
 * Open an existing file or directory.
 * The may_flags argument indicates the type of open (read/write/lock)
 * and additional flags.
 * N.B. After this call fhp needs an fh_put
 */


__be32

nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
			int may_flags, struct file **filp)
{
	struct path	path;
	struct inode	*inode;
	struct file	*file;
	int		flags = O_RDONLY|O_LARGEFILE;
	__be32		err;
	int		host_err = 0;

	validate_process_creds();

	/*
         * 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.
         *
         * Arguably we should also allow the owner override for
         * directories, but we never have and it doesn't seem to have
         * caused anyone a problem.  If we were to change this, note
         * also that our filldir callbacks would need a variant of
         * lookup_one_len that doesn't check permissions.
         */
	if (type == S_IFREG)
		may_flags |= NFSD_MAY_OWNER_OVERRIDE;
	err = fh_verify(rqstp, fhp, type, may_flags);
	if (err)
		goto out;

	path.mnt = fhp->fh_export->ex_path.mnt;
	path.dentry = fhp->fh_dentry;
	inode = d_inode(path.dentry);

	/* 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) && (may_flags & NFSD_MAY_WRITE))
		goto out;
	/*
         * 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.
         */
	if (S_ISREG((inode)->i_mode) && mandatory_lock(inode))
		goto out;

	if (!inode->i_fop)
		goto out;

	host_err = nfsd_open_break_lease(inode, may_flags);
	if (host_err) /* NOMEM or WOULDBLOCK */
		goto out_nfserr;

	if (may_flags & NFSD_MAY_WRITE) {
		if (may_flags & NFSD_MAY_READ)
			flags = O_RDWR|O_LARGEFILE;
		else
			flags = O_WRONLY|O_LARGEFILE;
	}

	file = dentry_open(&path, flags, current_cred());
	if (IS_ERR(file)) {
		host_err = PTR_ERR(file);
		goto out_nfserr;
	}

	host_err = ima_file_check(file, may_flags, 0);
	if (host_err) {
		fput(file);
		goto out_nfserr;
	}

	if (may_flags & NFSD_MAY_64BIT_COOKIE)
		file->f_mode |= FMODE_64BITHASH;
	else
		file->f_mode |= FMODE_32BITHASH;

	*filp = file;
out_nfserr:
	err = nfserrno(host_err);
out:
	validate_process_creds();
	return err;
}


Contributors
PersonTokensPropCommitsCommitProp
christoph hellwigchristoph hellwig17756.73%233.33%


neil brownneil brown9831.41%116.67%


kinglong meekinglong mee3210.26%116.67%


david howellsdavid howells30.96%116.67%


dmitry kasatkindmitry kasatkin20.64%116.67%


Total312100.00%6100.00%





struct raparms *

nfsd_init_raparms(struct file *file)
{
	struct inode *inode = file_inode(file);
	dev_t dev = inode->i_sb->s_dev;
	ino_t ino = inode->i_ino;
	struct raparms	*ra, **rap, **frap = NULL;
	int depth = 0;
	unsigned int hash;
	struct raparm_hbucket *rab;

	hash = jhash_2words(dev, ino, 0xfeedbeef) & RAPARM_HASH_MASK