luck/tmp_suning_uos_patched
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nfsd: vfs_llseek() with 32 or 64 bit offsets (hashes)

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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>
This commit is contained in:
Bernd Schubert 2012-03-18 22:44:50 -04:00 committed by Theodore Ts'o
parent 999448a8c0
commit 06effdbb49
2 changed files with 15 additions and 2 deletions
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15
fs/nfsd/vfs.c
View File

@ -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;
err = nfsd_open(rqstp, fhp, S_IFDIR, NFSD_MAY_READ, &file);
/* NFSv2 only supports 32 bit cookies */
if (rqstp->rq_vers > 2)
may_flags |= NFSD_MAY_64BIT_COOKIE;
err = nfsd_open(rqstp, fhp, S_IFDIR, may_flags, &file);
if (err)
goto out;

2
fs/nfsd/vfs.h
View File

@ -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)