nfsd: vfs_llseek() with 32 or 64 bit offsets (hashes) (06effdbb) · Commits · 戴 / test

Use 32-bit or 64-bit llseek() hashes for directory offsets depending on the NFS version. NFSv2 gets 32-bit hashes only. NOTE: This patch got rather complex as Christoph asked to set the filp->f_mode flag in the open call or immediatly after dentry_open() in nfsd_open() to avoid races. Personally I still do not see a reason for that and in my opinion FMODE_32BITHASH/FMODE_64BITHASH flags could be set nfsd_readdir(), as it follows directly after nfsd_open() without a chance of races. Signed-off-by:

Bernd Schubert <bernd.schubert@itwm.fraunhofer.de> Signed-off-by:

"Theodore Ts'o" <tytso@mit.edu> Acked-by:

J. Bruce <Fields<bfields@redhat.com>

fs/nfsd/vfs.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -796,9 +796,15 @@ nfsd_open(struct svc_rqst rqstp, struct svc_fh fhp, umode_t type,
		flags, current_cred());
		if (IS_ERR(*filp))
		host_err = PTR_ERR(*filp);
		else
		else {
		host_err = ima_file_check(*filp, may_flags);

		if (may_flags & NFSD_MAY_64BIT_COOKIE)
		(*filp)->f_mode \|= FMODE_64BITHASH;
		else
		(*filp)->f_mode \|= FMODE_32BITHASH;
		}

		out_nfserr:
		err = nfserrno(host_err);
		out:
		@@ -2022,8 +2028,13 @@ nfsd_readdir(struct svc_rqst rqstp, struct svc_fh fhp, loff_t *offsetp,
		__be32 err;
		struct file *file;
		loff_t offset = *offsetp;
		int may_flags = NFSD_MAY_READ;

		/* NFSv2 only supports 32 bit cookies */
		if (rqstp->rq_vers > 2)
		may_flags \|= NFSD_MAY_64BIT_COOKIE;

		err = nfsd_open(rqstp, fhp, S_IFDIR, NFSD_MAY_READ, &file);
		err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
		if (err)
		goto out;

fs/nfsd/vfs.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -27,6 +27,8 @@
		#define NFSD_MAY_BYPASS_GSS 0x400
		#define NFSD_MAY_READ_IF_EXEC 0x800

		#define NFSD_MAY_64BIT_COOKIE 0x1000 /* 64 bit readdir cookies for >= NFSv3 */

		#define NFSD_MAY_CREATE (NFSD_MAY_EXEC\|NFSD_MAY_WRITE)
		#define NFSD_MAY_REMOVE (NFSD_MAY_EXEC\|NFSD_MAY_WRITE\|NFSD_MAY_TRUNC)

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