*
* nfs inode and superblock handling functions
*
- * Modularised by Alan Cox <Alan.Cox@linux.org>, while hacking some
+ * Modularised by Alan Cox <alan@lxorguk.ukuu.org.uk>, while hacking some
* experimental NFS changes. Modularisation taken straight from SYS5 fs.
*
* Change to nfs_read_super() to permit NFS mounts to multi-homed hosts.
init_special_inode(inode, inode->i_mode, fattr->rdev);
nfsi->read_cache_jiffies = fattr->time_start;
- nfsi->last_updated = now;
- nfsi->cache_change_attribute = now;
+ nfsi->attr_gencount = fattr->gencount;
inode->i_atime = fattr->atime;
inode->i_mtime = fattr->mtime;
inode->i_ctime = fattr->ctime;
void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr)
{
if ((attr->ia_valid & (ATTR_MODE|ATTR_UID|ATTR_GID)) != 0) {
+ spin_lock(&inode->i_lock);
if ((attr->ia_valid & ATTR_MODE) != 0) {
int mode = attr->ia_mode & S_IALLUGO;
mode |= inode->i_mode & ~S_IALLUGO;
inode->i_uid = attr->ia_uid;
if ((attr->ia_valid & ATTR_GID) != 0)
inode->i_gid = attr->ia_gid;
- spin_lock(&inode->i_lock);
NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;
spin_unlock(&inode->i_lock);
}
}
}
-static int nfs_wait_schedule(void *word)
-{
- if (signal_pending(current))
- return -ERESTARTSYS;
- schedule();
- return 0;
-}
-
-/*
- * Wait for the inode to get unlocked.
- */
-static int nfs_wait_on_inode(struct inode *inode)
-{
- struct nfs_inode *nfsi = NFS_I(inode);
- int error;
-
- error = wait_on_bit_lock(&nfsi->flags, NFS_INO_REVALIDATING,
- nfs_wait_schedule, TASK_KILLABLE);
-
- return error;
-}
-
-static void nfs_wake_up_inode(struct inode *inode)
-{
- struct nfs_inode *nfsi = NFS_I(inode);
-
- clear_bit(NFS_INO_REVALIDATING, &nfsi->flags);
- smp_mb__after_clear_bit();
- wake_up_bit(&nfsi->flags, NFS_INO_REVALIDATING);
-}
-
int nfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
struct inode *inode = dentry->d_inode;
dfprintk(PAGECACHE, "NFS: revalidating (%s/%Ld)\n",
inode->i_sb->s_id, (long long)NFS_FILEID(inode));
- nfs_inc_stats(inode, NFSIOS_INODEREVALIDATE);
if (is_bad_inode(inode))
- goto out_nowait;
+ goto out;
if (NFS_STALE(inode))
- goto out_nowait;
-
- status = nfs_wait_on_inode(inode);
- if (status < 0)
goto out;
- status = -ESTALE;
if (NFS_STALE(inode))
goto out;
+ nfs_inc_stats(inode, NFSIOS_INODEREVALIDATE);
status = NFS_PROTO(inode)->getattr(server, NFS_FH(inode), &fattr);
if (status != 0) {
dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Ld) getattr failed, error=%d\n",
goto out;
}
- spin_lock(&inode->i_lock);
- status = nfs_update_inode(inode, &fattr);
+ status = nfs_refresh_inode(inode, &fattr);
if (status) {
- spin_unlock(&inode->i_lock);
dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Ld) refresh failed, error=%d\n",
inode->i_sb->s_id,
(long long)NFS_FILEID(inode), status);
goto out;
}
- spin_unlock(&inode->i_lock);
if (nfsi->cache_validity & NFS_INO_INVALID_ACL)
nfs_zap_acl_cache(inode);
(long long)NFS_FILEID(inode));
out:
- nfs_wake_up_inode(inode);
-
- out_nowait:
return status;
}
return -EIO;
}
- /* Do atomic weak cache consistency updates */
- nfs_wcc_update_inode(inode, fattr);
-
if ((fattr->valid & NFS_ATTR_FATTR_V4) != 0 &&
nfsi->change_attr != fattr->change_attr)
invalid |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
if (invalid != 0)
nfsi->cache_validity |= invalid;
- else
- nfsi->cache_validity &= ~(NFS_INO_INVALID_ATTR
- | NFS_INO_INVALID_ATIME
- | NFS_INO_REVAL_PAGECACHE);
nfsi->read_cache_jiffies = fattr->time_start;
return 0;
}
+static int nfs_ctime_need_update(const struct inode *inode, const struct nfs_fattr *fattr)
+{
+ return timespec_compare(&fattr->ctime, &inode->i_ctime) > 0;
+}
+
+static int nfs_size_need_update(const struct inode *inode, const struct nfs_fattr *fattr)
+{
+ return nfs_size_to_loff_t(fattr->size) > i_size_read(inode);
+}
+
+static unsigned long nfs_attr_generation_counter;
+
+static unsigned long nfs_read_attr_generation_counter(void)
+{
+ smp_rmb();
+ return nfs_attr_generation_counter;
+}
+
+unsigned long nfs_inc_attr_generation_counter(void)
+{
+ unsigned long ret;
+ smp_rmb();
+ ret = ++nfs_attr_generation_counter;
+ smp_wmb();
+ return ret;
+}
+
+void nfs_fattr_init(struct nfs_fattr *fattr)
+{
+ fattr->valid = 0;
+ fattr->time_start = jiffies;
+ fattr->gencount = nfs_inc_attr_generation_counter();
+}
+
+/**
+ * nfs_inode_attrs_need_update - check if the inode attributes need updating
+ * @inode - pointer to inode
+ * @fattr - attributes
+ *
+ * Attempt to divine whether or not an RPC call reply carrying stale
+ * attributes got scheduled after another call carrying updated ones.
+ *
+ * To do so, the function first assumes that a more recent ctime means
+ * that the attributes in fattr are newer, however it also attempt to
+ * catch the case where ctime either didn't change, or went backwards
+ * (if someone reset the clock on the server) by looking at whether
+ * or not this RPC call was started after the inode was last updated.
+ * Note also the check for wraparound of 'attr_gencount'
+ *
+ * The function returns 'true' if it thinks the attributes in 'fattr' are
+ * more recent than the ones cached in the inode.
+ *
+ */
+static int nfs_inode_attrs_need_update(const struct inode *inode, const struct nfs_fattr *fattr)
+{
+ const struct nfs_inode *nfsi = NFS_I(inode);
+
+ return ((long)fattr->gencount - (long)nfsi->attr_gencount) > 0 ||
+ nfs_ctime_need_update(inode, fattr) ||
+ nfs_size_need_update(inode, fattr) ||
+ ((long)nfsi->attr_gencount - (long)nfs_read_attr_generation_counter() > 0);
+}
+
+static int nfs_refresh_inode_locked(struct inode *inode, struct nfs_fattr *fattr)
+{
+ if (nfs_inode_attrs_need_update(inode, fattr))
+ return nfs_update_inode(inode, fattr);
+ return nfs_check_inode_attributes(inode, fattr);
+}
+
/**
* nfs_refresh_inode - try to update the inode attribute cache
* @inode - pointer to inode
*/
int nfs_refresh_inode(struct inode *inode, struct nfs_fattr *fattr)
{
- struct nfs_inode *nfsi = NFS_I(inode);
int status;
if ((fattr->valid & NFS_ATTR_FATTR) == 0)
return 0;
spin_lock(&inode->i_lock);
- if (time_after(fattr->time_start, nfsi->last_updated))
- status = nfs_update_inode(inode, fattr);
- else
- status = nfs_check_inode_attributes(inode, fattr);
-
+ status = nfs_refresh_inode_locked(inode, fattr);
spin_unlock(&inode->i_lock);
return status;
}
+static int nfs_post_op_update_inode_locked(struct inode *inode, struct nfs_fattr *fattr)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
+ if (S_ISDIR(inode->i_mode))
+ nfsi->cache_validity |= NFS_INO_INVALID_DATA;
+ if ((fattr->valid & NFS_ATTR_FATTR) == 0)
+ return 0;
+ return nfs_refresh_inode_locked(inode, fattr);
+}
+
/**
* nfs_post_op_update_inode - try to update the inode attribute cache
* @inode - pointer to inode
*/
int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr)
{
- struct nfs_inode *nfsi = NFS_I(inode);
+ int status;
spin_lock(&inode->i_lock);
- nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
- if (S_ISDIR(inode->i_mode))
- nfsi->cache_validity |= NFS_INO_INVALID_DATA;
+ status = nfs_post_op_update_inode_locked(inode, fattr);
spin_unlock(&inode->i_lock);
- return nfs_refresh_inode(inode, fattr);
+ return status;
}
/**
*/
int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fattr)
{
+ int status;
+
+ spin_lock(&inode->i_lock);
+ /* Don't do a WCC update if these attributes are already stale */
+ if ((fattr->valid & NFS_ATTR_FATTR) == 0 ||
+ !nfs_inode_attrs_need_update(inode, fattr)) {
+ fattr->valid &= ~(NFS_ATTR_WCC_V4|NFS_ATTR_WCC);
+ goto out_noforce;
+ }
if ((fattr->valid & NFS_ATTR_FATTR_V4) != 0 &&
(fattr->valid & NFS_ATTR_WCC_V4) == 0) {
fattr->pre_change_attr = NFS_I(inode)->change_attr;
fattr->pre_size = i_size_read(inode);
fattr->valid |= NFS_ATTR_WCC;
}
- return nfs_post_op_update_inode(inode, fattr);
+out_noforce:
+ status = nfs_post_op_update_inode_locked(inode, fattr);
+ spin_unlock(&inode->i_lock);
+ return status;
}
/*
}
/* 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;
+ invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;
} else if (nfsi->change_attr != fattr->change_attr) {
dprintk("NFS: change_attr change on server for file %s/%ld\n",
inode->i_sb->s_id, inode->i_ino);
inode->i_gid != fattr->gid)
invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;
+ if (inode->i_nlink != fattr->nlink)
+ invalid |= NFS_INO_INVALID_ATTR;
+
inode->i_mode = fattr->mode;
inode->i_nlink = fattr->nlink;
inode->i_uid = fattr->uid;
nfs_inc_stats(inode, NFSIOS_ATTRINVALIDATE);
nfsi->attrtimeo = NFS_MINATTRTIMEO(inode);
nfsi->attrtimeo_timestamp = now;
- nfsi->last_updated = now;
+ nfsi->attr_gencount = nfs_inc_attr_generation_counter();
} else {
if (!time_in_range(now, nfsi->attrtimeo_timestamp, nfsi->attrtimeo_timestamp + nfsi->attrtimeo)) {
if ((nfsi->attrtimeo <<= 1) > NFS_MAXATTRTIMEO(inode))
nfsi->attrtimeo = NFS_MAXATTRTIMEO(inode);
nfsi->attrtimeo_timestamp = now;
}
- /*
- * Avoid jiffy wraparound issues with nfsi->last_updated
- */
- if (!time_in_range(nfsi->last_updated, nfsi->read_cache_jiffies, now))
- nfsi->last_updated = nfsi->read_cache_jiffies;
}
invalid &= ~NFS_INO_INVALID_ATTR;
/* Don't invalidate the data if we were to blame */
projects / linux-2.6-omap-h63xx.git / blobdiff