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Commit 3e7d950a authored by Trond Myklebust's avatar Trond Myklebust
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NFS: Fix a wraparound issue with nfsi->cache_change_attribute 



Fix wraparound issue with nfsi->cache_change_attribute. If it is found
to lie in the future, then update it to lie in the past. Patch based on
a suggestion by Neil Brown.

..and minor micro-optimisation: avoid reading 'jiffies' more than once in
nfs_update_inode().

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent ebf4d8ec

fs/nfs/inode.c

+13 −8
Original line number Diff line number Diff line
@@ -939,6 +939,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) 
	struct nfs_inode *nfsi = NFS_I(inode);

	loff_t cur_isize, new_isize;

	unsigned int	invalid = 0;

	unsigned long now = jiffies;

	int data_stable;



	dfprintk(VFS, "NFS: %s(%s/%ld ct=%d info=0x%x)\n",
@@ -964,7 +965,11 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) 
	 * Update the read time so we don't revalidate too often.

	 */

	nfsi->read_cache_jiffies = fattr->time_start;

	nfsi->last_updated = jiffies;

	nfsi->last_updated = now;



	/* Fix a wraparound issue with nfsi->cache_change_attribute */

	if (time_before(now, nfsi->cache_change_attribute))

		nfsi->cache_change_attribute = now - 600*HZ;



	/* Are we racing with known updates of the metadata on the server? */

	data_stable = nfs_verify_change_attribute(inode, fattr->time_start);
@@ -990,7 +995,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) 
			inode->i_size = new_isize;

			invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA;

		}

		nfsi->cache_change_attribute = jiffies;

		nfsi->cache_change_attribute = now;

		dprintk("NFS: isize change on server for file %s/%ld\n",

				inode->i_sb->s_id, inode->i_ino);

	}
@@ -1001,14 +1006,14 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) 
		dprintk("NFS: mtime change on server for file %s/%ld\n",

				inode->i_sb->s_id, inode->i_ino);

		invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA;

		nfsi->cache_change_attribute = jiffies;

		nfsi->cache_change_attribute = now;

	}



	/* If ctime has changed we should definitely clear access+acl caches */

	if (!timespec_equal(&inode->i_ctime, &fattr->ctime)) {

		invalid |= NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;

		memcpy(&inode->i_ctime, &fattr->ctime, sizeof(inode->i_ctime));

		nfsi->cache_change_attribute = jiffies;

		nfsi->cache_change_attribute = now;

	}

	memcpy(&inode->i_atime, &fattr->atime, sizeof(inode->i_atime));
@@ -1037,18 +1042,18 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) 
				inode->i_sb->s_id, inode->i_ino);

		nfsi->change_attr = fattr->change_attr;

		invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;

		nfsi->cache_change_attribute = jiffies;

		nfsi->cache_change_attribute = now;

	}



	/* Update attrtimeo value if we're out of the unstable period */

	if (invalid & NFS_INO_INVALID_ATTR) {

		nfs_inc_stats(inode, NFSIOS_ATTRINVALIDATE);

		nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);

		nfsi->attrtimeo_timestamp = jiffies;

	} else if (time_after(jiffies, nfsi->attrtimeo_timestamp+nfsi->attrtimeo)) {

		nfsi->attrtimeo_timestamp = now;

	} else if (time_after(now, nfsi->attrtimeo_timestamp+nfsi->attrtimeo)) {

		if ((nfsi->attrtimeo <<= 1) > NFS_MAXATTRTIMEO(inode))

			nfsi->attrtimeo = NFS_MAXATTRTIMEO(inode);

		nfsi->attrtimeo_timestamp = jiffies;

		nfsi->attrtimeo_timestamp = now;

	}

	/* Don't invalidate the data if we were to blame */

	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)