ceph: specify max_bytes on readdir replies

Specify max bytes in request to bound size of reply.  Add associated
mount option with default value of 512 KB.

Signed-off-by: Sage Weil <sage@newdream.net>

4 files changed, 14 insertions, 1 deletions

diff --git a/fs/ceph/ceph_fs.h b/fs/ceph/ceph_fs.h
index 715e39ce517a..3b9eeed097b3 100644
--- a/fs/ceph/ceph_fs.h
+++ b/fs/ceph/ceph_fs.h
@@ -361,6 +361,7 @@ union ceph_mds_request_args {
         struct {
                 __le32 frag;                 /* which dir fragment */
                 __le32 max_entries;          /* how many dentries to grab */
+                __le32 max_bytes;
         } __attribute__ ((packed)) readdir;
         struct {
                 __le32 mode;
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index d3bb8132a1aa..4fd30900eff7 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -233,6 +233,7 @@ static int ceph_readdir(struct file *filp, void *dirent, filldir_t filldir)
         u32 ftype;
         struct ceph_mds_reply_info_parsed *rinfo;
         const int max_entries = client->mount_args->max_readdir;
+        const int max_bytes = client->mount_args->max_readdir_bytes;
 
         dout("readdir %p filp %p frag %u off %u\n", inode, filp, frag, off);
         if (fi->at_end)
@@ -316,6 +317,7 @@ more:
                 req->r_readdir_offset = fi->next_offset;
                 req->r_args.readdir.frag = cpu_to_le32(frag);
                 req->r_args.readdir.max_entries = cpu_to_le32(max_entries);
+                req->r_args.readdir.max_bytes = cpu_to_le32(max_bytes);
                 req->r_num_caps = max_entries + 1;
                 err = ceph_mdsc_do_request(mdsc, NULL, req);
                 if (err < 0) {
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 7f5b20dc4945..bac13898b943 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -190,6 +190,8 @@ static int ceph_show_options(struct seq_file *m, struct vfsmount *mnt)
                            args->cap_release_safety);
         if (args->max_readdir != CEPH_MAX_READDIR_DEFAULT)
                 seq_printf(m, ",readdir_max_entries=%d", args->max_readdir);
+        if (args->max_readdir_bytes != CEPH_MAX_READDIR_BYTES_DEFAULT)
+                seq_printf(m, ",readdir_max_bytes=%d", args->max_readdir_bytes);
         if (strcmp(args->snapdir_name, CEPH_SNAPDIRNAME_DEFAULT))
                 seq_printf(m, ",snapdirname=%s", args->snapdir_name);
         if (args->name)
@@ -333,6 +335,7 @@ enum {
         Opt_caps_wanted_delay_max,
         Opt_cap_release_safety,
         Opt_readdir_max_entries,
+        Opt_readdir_max_bytes,
         Opt_congestion_kb,
         Opt_last_int,
         /* int args above */
@@ -365,6 +368,7 @@ static match_table_t arg_tokens = {
         {Opt_caps_wanted_delay_max, "caps_wanted_delay_max=%d"},
         {Opt_cap_release_safety, "cap_release_safety=%d"},
         {Opt_readdir_max_entries, "readdir_max_entries=%d"},
+        {Opt_readdir_max_bytes, "readdir_max_bytes=%d"},
         {Opt_congestion_kb, "write_congestion_kb=%d"},
         /* int args above */
         {Opt_snapdirname, "snapdirname=%s"},
@@ -415,6 +419,7 @@ static struct ceph_mount_args *parse_mount_args(int flags, char *options,
         args->snapdir_name = kstrdup(CEPH_SNAPDIRNAME_DEFAULT, GFP_KERNEL);
         args->cap_release_safety = CEPH_CAP_RELEASE_SAFETY_DEFAULT;
         args->max_readdir = CEPH_MAX_READDIR_DEFAULT;
+        args->max_readdir_bytes = CEPH_MAX_READDIR_BYTES_DEFAULT;
         args->congestion_kb = default_congestion_kb();
 
         /* ip1[:port1][,ip2[:port2]...]:/subdir/in/fs */
@@ -522,6 +527,9 @@ static struct ceph_mount_args *parse_mount_args(int flags, char *options,
                 case Opt_readdir_max_entries:
                         args->max_readdir = intval;
                         break;
+                case Opt_readdir_max_bytes:
+                        args->max_readdir_bytes = intval;
+                        break;
                 case Opt_congestion_kb:
                         args->congestion_kb = intval;
                         break;
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 395adc5fcebb..3725c9ee9d08 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -66,7 +66,8 @@ struct ceph_mount_args {
         int congestion_kb;    /* max writeback in flight */
         int caps_wanted_delay_min, caps_wanted_delay_max;
         int cap_release_safety;
-        int max_readdir;      /* max readdir size */
+        int max_readdir;       /* max readdir result (entires) */
+        int max_readdir_bytes; /* max readdir result (bytes) */
         char *snapdir_name;   /* default ".snap" */
         char *name;
         char *secret;
@@ -81,6 +82,7 @@ struct ceph_mount_args {
 #define CEPH_OSD_IDLE_TTL_DEFAULT    60
 #define CEPH_MOUNT_RSIZE_DEFAULT    (512*1024) /* readahead */
 #define CEPH_MAX_READDIR_DEFAULT    1024
+#define CEPH_MAX_READDIR_BYTES_DEFAULT    (512*1024)
 
 #define CEPH_MSG_MAX_FRONT_LEN  (16*1024*1024)
 #define CEPH_MSG_MAX_DATA_LEN   (16*1024*1024)