ceph: quota: support for ceph.quota.max_files

This patch adds support for the max_files quota.  It hooks into all the
ceph functions that add new filesystem objects that need to be checked
against the quota limits.  When these limits are hit, -EDQUOT is returned.

Note that we're not checking quotas on ceph_link().  ceph_link doesn't
really create a new inode,  and since the MDS doesn't update the directory
statistics when a new (hard) link is created (only with symlinks), they
are not accounted as a new file.

Signed-off-by: Luis Henriques <lhenriques@suse.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 16405e0..7d9851c 100644 (file)
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -828,6 +828,9 @@ static int ceph_mknod(struct inode *dir, struct dentry *dentry,
        if (ceph_snap(dir) != CEPH_NOSNAP)
                return -EROFS;
 
+       if (ceph_quota_is_max_files_exceeded(dir))
+               return -EDQUOT;
+
        err = ceph_pre_init_acls(dir, &mode, &acls);
        if (err < 0)
                return err;
@@ -881,6 +884,9 @@ static int ceph_symlink(struct inode *dir, struct dentry *dentry,
        if (ceph_snap(dir) != CEPH_NOSNAP)
                return -EROFS;
 
+       if (ceph_quota_is_max_files_exceeded(dir))
+               return -EDQUOT;
+
        dout("symlink in dir %p dentry %p to '%s'\n", dir, dentry, dest);
        req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SYMLINK, USE_AUTH_MDS);
        if (IS_ERR(req)) {
@@ -930,6 +936,11 @@ static int ceph_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
                goto out;
        }
 
+       if (ceph_quota_is_max_files_exceeded(dir)) {
+               err = -EDQUOT;
+               goto out;
+       }
+
        mode |= S_IFDIR;
        err = ceph_pre_init_acls(dir, &mode, &acls);
        if (err < 0)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 4a92acb..c304233 100644 (file)
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -402,7 +402,7 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
        struct ceph_mds_request *req;
        struct dentry *dn;
        struct ceph_acls_info acls = {};
-       int mask;
+       int mask;
        int err;
 
        dout("atomic_open %p dentry %p '%pd' %s flags %d mode 0%o\n",
@@ -413,6 +413,8 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
                return -ENAMETOOLONG;
 
        if (flags & O_CREAT) {
+               if (ceph_quota_is_max_files_exceeded(dir))
+                       return -EDQUOT;
                err = ceph_pre_init_acls(dir, &mode, &acls);
                if (err < 0)
                        return err;

diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c
index 1b69d83..cf1c78c 100644 (file)
--- a/fs/ceph/quota.c
+++ b/fs/ceph/quota.c
@@ -63,3 +63,83 @@ void ceph_handle_quota(struct ceph_mds_client *mdsc,
 
        iput(inode);
 }
+
+enum quota_check_op {
+       QUOTA_CHECK_MAX_FILES_OP        /* check quota max_files limit */
+};
+
+/*
+ * check_quota_exceeded() will walk up the snaprealm hierarchy and, for each
+ * realm, it will execute quota check operation defined by the 'op' parameter.
+ * The snaprealm walk is interrupted if the quota check detects that the quota
+ * is exceeded or if the root inode is reached.
+ */
+static bool check_quota_exceeded(struct inode *inode, enum quota_check_op op,
+                                loff_t delta)
+{
+       struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
+       struct ceph_inode_info *ci;
+       struct ceph_snap_realm *realm, *next;
+       struct ceph_vino vino;
+       struct inode *in;
+       u64 max, rvalue;
+       bool is_root;
+       bool exceeded = false;
+
+       down_read(&mdsc->snap_rwsem);
+       realm = ceph_inode(inode)->i_snap_realm;
+       ceph_get_snap_realm(mdsc, realm);
+       while (realm) {
+               vino.ino = realm->ino;
+               vino.snap = CEPH_NOSNAP;
+               in = ceph_find_inode(inode->i_sb, vino);
+               if (!in) {
+                       pr_warn("Failed to find inode for %llu\n", vino.ino);
+                       break;
+               }
+               ci = ceph_inode(in);
+               spin_lock(&ci->i_ceph_lock);
+               if (op == QUOTA_CHECK_MAX_FILES_OP) {
+                       max = ci->i_max_files;
+                       rvalue = ci->i_rfiles + ci->i_rsubdirs;
+               }
+               is_root = (ci->i_vino.ino == CEPH_INO_ROOT);
+               spin_unlock(&ci->i_ceph_lock);
+               switch (op) {
+               case QUOTA_CHECK_MAX_FILES_OP:
+                       exceeded = (max && (rvalue >= max));
+                       break;
+               default:
+                       /* Shouldn't happen */
+                       pr_warn("Invalid quota check op (%d)\n", op);
+                       exceeded = true; /* Just break the loop */
+               }
+               iput(in);
+
+               if (is_root || exceeded)
+                       break;
+               next = realm->parent;
+               ceph_get_snap_realm(mdsc, next);
+               ceph_put_snap_realm(mdsc, realm);
+               realm = next;
+       }
+       ceph_put_snap_realm(mdsc, realm);
+       up_read(&mdsc->snap_rwsem);
+
+       return exceeded;
+}
+
+/*
+ * ceph_quota_is_max_files_exceeded - check if we can create a new file
+ * @inode:     directory where a new file is being created
+ *
+ * This functions returns true is max_files quota allows a new file to be
+ * created.  It is necessary to walk through the snaprealm hierarchy (until the
+ * FS root) to check all realms with quotas set.
+ */
+bool ceph_quota_is_max_files_exceeded(struct inode *inode)
+{
+       WARN_ON(!S_ISDIR(inode->i_mode));
+
+       return check_quota_exceeded(inode, QUOTA_CHECK_MAX_FILES_OP, 0);
+}

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 0c95a92..4afc6cc 100644 (file)
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1077,5 +1077,6 @@ extern void ceph_fs_debugfs_cleanup(struct ceph_fs_client *client);
 extern void ceph_handle_quota(struct ceph_mds_client *mdsc,
                              struct ceph_mds_session *session,
                              struct ceph_msg *msg);
+extern bool ceph_quota_is_max_files_exceeded(struct inode *inode);
 
 #endif /* _FS_CEPH_SUPER_H */