ceph: consider inode's last read/write when calculating wanted caps

Add i_last_rd and i_last_wr to ceph_inode_info. These fields are
used to track the last time the client acquired read/write caps for
the inode.

If there is no read/write on an inode for 'caps_wanted_delay_max'
seconds, __ceph_caps_file_wanted() does not request caps for read/write
even there are open files.

Call __ceph_touch_fmode() for dir operations. __ceph_caps_file_wanted()
calculates dir's wanted caps according to last dir read/modification. If
there is recent dir read, dir inode wants CEPH_CAP_ANY_SHARED caps. If
there is recent dir modification, also wants CEPH_CAP_FILE_EXCL.

Readdir is a special case. Dir inode wants CEPH_CAP_FILE_EXCL after
readdir, as with that, modifications do not need to release
CEPH_CAP_FILE_SHARED or invalidate all dentry leases issued by readdir.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 15 insertions, 6 deletions

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index ee6b319e5481..d594c2627430 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -335,8 +335,11 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
 		ctx->pos = 2;
 	}
 
-	/* can we use the dcache? */
 	spin_lock(&ci->i_ceph_lock);
+	/* request Fx cap. if have Fx, we don't need to release Fs cap
+	 * for later create/unlink. */
+	__ceph_touch_fmode(ci, mdsc, CEPH_FILE_MODE_WR);
+	/* can we use the dcache? */
 	if (ceph_test_mount_opt(fsc, DCACHE) &&
 	    !ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
 	    ceph_snap(inode) != CEPH_SNAPDIR &&
@@ -760,6 +763,7 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
 		    ceph_test_mount_opt(fsc, DCACHE) &&
 		    __ceph_dir_is_complete(ci) &&
 		    (__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1))) {
+			__ceph_touch_fmode(ci, mdsc, CEPH_FILE_MODE_RD);
 			spin_unlock(&ci->i_ceph_lock);
 			dout(" dir %p complete, -ENOENT\n", dir);
 			d_add(dentry, NULL);
@@ -1621,7 +1625,8 @@ static int __dir_lease_try_check(const struct dentry *dentry)
 /*
  * Check if directory-wide content lease/cap is valid.
  */
-static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
+static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry,
+			      struct ceph_mds_client *mdsc)
 {
 	struct ceph_inode_info *ci = ceph_inode(dir);
 	int valid;
@@ -1629,7 +1634,10 @@ static int dir_lease_is_valid(struct inode *dir, struct dentry *dentry)
 
 	spin_lock(&ci->i_ceph_lock);
 	valid = __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1);
-	shared_gen = atomic_read(&ci->i_shared_gen);
+	if (valid) {
+		__ceph_touch_fmode(ci, mdsc, CEPH_FILE_MODE_RD);
+		shared_gen = atomic_read(&ci->i_shared_gen);
+	}
 	spin_unlock(&ci->i_ceph_lock);
 	if (valid) {
 		struct ceph_dentry_info *di;
@@ -1655,6 +1663,7 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 	int valid = 0;
 	struct dentry *parent;
 	struct inode *dir, *inode;
+	struct ceph_mds_client *mdsc;
 
 	if (flags & LOOKUP_RCU) {
 		parent = READ_ONCE(dentry->d_parent);
@@ -1671,6 +1680,8 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 	dout("d_revalidate %p '%pd' inode %p offset 0x%llx\n", dentry,
 	     dentry, inode, ceph_dentry(dentry)->offset);
 
+	mdsc = ceph_sb_to_client(dir->i_sb)->mdsc;
+
 	/* always trust cached snapped dentries, snapdir dentry */
 	if (ceph_snap(dir) != CEPH_NOSNAP) {
 		dout("d_revalidate %p '%pd' inode %p is SNAPPED\n", dentry,
@@ -1682,7 +1693,7 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 		valid = dentry_lease_is_valid(dentry, flags);
 		if (valid == -ECHILD)
 			return valid;
-		if (valid || dir_lease_is_valid(dir, dentry)) {
+		if (valid || dir_lease_is_valid(dir, dentry, mdsc)) {
 			if (inode)
 				valid = ceph_is_any_caps(inode);
 			else
@@ -1691,8 +1702,6 @@ static int ceph_d_revalidate(struct dentry *dentry, unsigned int flags)
 	}
 
 	if (!valid) {
-		struct ceph_mds_client *mdsc =
-			ceph_sb_to_client(dir->i_sb)->mdsc;
 		struct ceph_mds_request *req;
 		int op, err;
 		u32 mask;