Attachment 309490 Details for Bug 436132 – patch3 - NFS: change nfs_refresh_inode and __nfs_revalidate_inode to detect overlapping writes

[patch] patch3 - NFS: change nfs_refresh_inode and __nfs_revalidate_inode to detect overlapping writes

03-nfs-change-nfs_refresh_inode-t.patch (text/plain), 3.41 KB, created by Jeff Layton on 2008-06-16 13:17:03 UTC

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Creator: Jeff Layton

Created: 2008-06-16 13:17:03 UTC

Size: 3.41 KB

patch

obsolete

>NFS: change nfs_refresh_inode to detect overlapping writes
>
>From: Jeff Layton <jlayton@redhat.com>
>
>When a call that returns post_op_attrs overlaps with a write, then
>the attributes returned are suspect. It could reflect the status of
>the inode at any time before, during or after the write and we can't
>predict which.
>
>When this happens we don't want to invalidate the cached data since
>that can be very expensive. Instead, just update the inode attributes
>and mark the attrcache as invalid. Also in this case, if the mtime
>would move backward, then don't even update the attributes. Just mark
>the attrcache as invalid.
>---
>
> fs/nfs/inode.c |   39 +++++++++++++++++++++++++++++++++++----
> 1 files changed, 35 insertions(+), 4 deletions(-)
>
>
>diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
>index 4808cea..ab388bf 100644
>--- a/fs/nfs/inode.c
>+++ b/fs/nfs/inode.c
>@@ -55,6 +55,7 @@
> static int enable_ino64 = NFS_64_BIT_INODE_NUMBERS_ENABLED;
> 
> static void nfs_invalidate_inode(struct inode *);
>+static bool nfs_overlapping_write(struct inode *inode, struct nfs_fattr *fattr);
> static int nfs_update_inode(struct inode *, struct nfs_fattr *);
> 
> static void nfs_zap_acl_cache(struct inode *);
>@@ -675,7 +676,12 @@ __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
> 	}
> 
> 	spin_lock(&inode->i_lock);
>-	status = nfs_update_inode(inode, &fattr);
>+
>+	if (nfs_overlapping_write(inode, &fattr))
>+		nfs_update_inode_attributes(inode, &fattr);
>+	else
>+		status = nfs_update_inode(inode, &fattr);
>+
> 	if (status) {
> 		spin_unlock(&inode->i_lock);
> 		dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Ld) refresh failed, error=%d\n",
>@@ -899,6 +905,28 @@ static int nfs_check_inode_attributes(struct inode *inode, struct nfs_fattr *fat
> 	return 0;
> }
> 
>+/*
>+ * nfs_overlapping_write - determine whether a write overlapped with this call
>+ * @inode - pointer to inode
>+ * @fattr - updated attributes
>+ *
>+ * Did the call that returned these attributes overlap with a write to the
>+ * same inode?
>+ */
>+static bool
>+nfs_overlapping_write(struct inode *inode, struct nfs_fattr *fattr)
>+{
>+	struct nfs_inode *nfsi = NFS_I(inode);
>+	unsigned long now = jiffies;
>+
>+	if (nfsi->nwrites != 0 ||
>+	    time_in_range(nfsi->last_write_start, fattr->time_start, now) ||
>+	    time_in_range(nfsi->last_write_done, fattr->time_start, now))
>+		return true;
>+
>+	return false;
>+}
>+
> /**
>  * nfs_refresh_inode - try to update the inode attribute cache
>  * @inode - pointer to inode
>@@ -912,16 +940,17 @@ static int nfs_check_inode_attributes(struct inode *inode, struct nfs_fattr *fat
> int nfs_refresh_inode(struct inode *inode, struct nfs_fattr *fattr)
> {
> 	struct nfs_inode *nfsi = NFS_I(inode);
>-	int status;
>+	int status = 0;
> 
> 	if ((fattr->valid & NFS_ATTR_FATTR) == 0)
> 		return 0;
> 	spin_lock(&inode->i_lock);
>-	if (time_after(fattr->time_start, nfsi->last_updated))
>+	if (nfs_overlapping_write(inode, fattr))
>+		nfs_update_inode_attributes(inode, fattr);
>+	else if (time_after(fattr->time_start, nfsi->last_updated))
> 		status = nfs_update_inode(inode, fattr);
> 	else
> 		status = nfs_check_inode_attributes(inode, fattr);
>-
> 	spin_unlock(&inode->i_lock);
> 	return status;
> }
>@@ -982,6 +1011,8 @@ nfs_update_inode_attributes(struct inode *inode, struct nfs_fattr *fattr)
> 		memcpy(&inode->i_ctime, &fattr->ctime, sizeof(inode->i_ctime));
> 		memcpy(&inode->i_atime, &fattr->atime, sizeof(inode->i_atime));
> 	}
>+
>+	/* mark attrcache as suspect */
> 	nfsi->cache_validity |= NFS_INO_INVALID_ATTR;
> }
>

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Attachments on bug 436132: 297190 | 297191 | 297250 | 297251 | 297252 | 309488 | 309489 | 309490 | 309620