3 files changed, 185 insertions, 0 deletions

diff --git a/fs/Makefile b/fs/Makefile
index fc92e59e9faf..20edcf28bfd2 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -10,6 +10,7 @@ obj-y :=	open.o read_write.o file_table.o buffer.o  bio.o super.o \
                 ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \
                 attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \
                 seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \
+                ioprio.o
 
 obj-$(CONFIG_EPOLL)             += eventpoll.o
 obj-$(CONFIG_COMPAT)            += compat.o
diff --git a/fs/ioprio.c b/fs/ioprio.c
new file mode 100644
index 000000000000..663e420636d6
--- /dev/null
+++ b/fs/ioprio.c
@@ -0,0 +1,172 @@
+/*
+ * fs/ioprio.c
+ *
+ * Copyright (C) 2004 Jens Axboe <axboe@suse.de>
+ *
+ * Helper functions for setting/querying io priorities of processes. The
+ * system calls closely mimmick getpriority/setpriority, see the man page for
+ * those. The prio argument is a composite of prio class and prio data, where
+ * the data argument has meaning within that class. The standard scheduling
+ * classes have 8 distinct prio levels, with 0 being the highest prio and 7
+ * being the lowest.
+ *
+ * IOW, setting BE scheduling class with prio 2 is done ala:
+ *
+ * unsigned int prio = (IOPRIO_CLASS_BE << IOPRIO_CLASS_SHIFT) | 2;
+ *
+ * ioprio_set(PRIO_PROCESS, pid, prio);
+ *
+ * See also Documentation/block/ioprio.txt
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/ioprio.h>
+#include <linux/blkdev.h>
+
+static int set_task_ioprio(struct task_struct *task, int ioprio)
+{
+        struct io_context *ioc;
+
+        if (task->uid != current->euid &&
+            task->uid != current->uid && !capable(CAP_SYS_NICE))
+                return -EPERM;
+
+        task_lock(task);
+
+        task->ioprio = ioprio;
+
+        ioc = task->io_context;
+        if (ioc && ioc->set_ioprio)
+                ioc->set_ioprio(ioc, ioprio);
+
+        task_unlock(task);
+        return 0;
+}
+
+asmlinkage int sys_ioprio_set(int which, int who, int ioprio)
+{
+        int class = IOPRIO_PRIO_CLASS(ioprio);
+        int data = IOPRIO_PRIO_DATA(ioprio);
+        struct task_struct *p, *g;
+        struct user_struct *user;
+        int ret;
+
+        switch (class) {
+                case IOPRIO_CLASS_RT:
+                        if (!capable(CAP_SYS_ADMIN))
+                                return -EPERM;
+                        /* fall through, rt has prio field too */
+                case IOPRIO_CLASS_BE:
+                        if (data >= IOPRIO_BE_NR || data < 0)
+                                return -EINVAL;
+
+                        break;
+                case IOPRIO_CLASS_IDLE:
+                        break;
+                default:
+                        return -EINVAL;
+        }
+
+        ret = -ESRCH;
+        read_lock_irq(&tasklist_lock);
+        switch (which) {
+                case IOPRIO_WHO_PROCESS:
+                        if (!who)
+                                p = current;
+                        else
+                                p = find_task_by_pid(who);
+                        if (p)
+                                ret = set_task_ioprio(p, ioprio);
+                        break;
+                case IOPRIO_WHO_PGRP:
+                        if (!who)
+                                who = process_group(current);
+                        do_each_task_pid(who, PIDTYPE_PGID, p) {
+                                ret = set_task_ioprio(p, ioprio);
+                                if (ret)
+                                        break;
+                        } while_each_task_pid(who, PIDTYPE_PGID, p);
+                        break;
+                case IOPRIO_WHO_USER:
+                        if (!who)
+                                user = current->user;
+                        else
+                                user = find_user(who);
+
+                        if (!user)
+                                break;
+
+                        do_each_thread(g, p) {
+                                if (p->uid != who)
+                                        continue;
+                                ret = set_task_ioprio(p, ioprio);
+                                if (ret)
+                                        break;
+                        } while_each_thread(g, p);
+
+                        if (who)
+                                free_uid(user);
+                        break;
+                default:
+                        ret = -EINVAL;
+        }
+
+        read_unlock_irq(&tasklist_lock);
+        return ret;
+}
+
+asmlinkage int sys_ioprio_get(int which, int who)
+{
+        struct task_struct *g, *p;
+        struct user_struct *user;
+        int ret = -ESRCH;
+
+        read_lock_irq(&tasklist_lock);
+        switch (which) {
+                case IOPRIO_WHO_PROCESS:
+                        if (!who)
+                                p = current;
+                        else
+                                p = find_task_by_pid(who);
+                        if (p)
+                                ret = p->ioprio;
+                        break;
+                case IOPRIO_WHO_PGRP:
+                        if (!who)
+                                who = process_group(current);
+                        do_each_task_pid(who, PIDTYPE_PGID, p) {
+                                if (ret == -ESRCH)
+                                        ret = p->ioprio;
+                                else
+                                        ret = ioprio_best(ret, p->ioprio);
+                        } while_each_task_pid(who, PIDTYPE_PGID, p);
+                        break;
+                case IOPRIO_WHO_USER:
+                        if (!who)
+                                user = current->user;
+                        else
+                                user = find_user(who);
+
+                        if (!user)
+                                break;
+
+                        do_each_thread(g, p) {
+                                if (p->uid != user->uid)
+                                        continue;
+                                if (ret == -ESRCH)
+                                        ret = p->ioprio;
+                                else
+                                        ret = ioprio_best(ret, p->ioprio);
+                        } while_each_thread(g, p);
+
+                        if (who)
+                                free_uid(user);
+                        break;
+                default:
+                        ret = -EINVAL;
+        }
+
+        read_unlock_irq(&tasklist_lock);
+        return ret;
+}
+
diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index 7b87707acc36..d1bcf0da6728 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -645,18 +645,22 @@ struct buffer_chunk {
 
 static void write_chunk(struct buffer_chunk *chunk) {
     int i;
+    get_fs_excl();
     for (i = 0; i < chunk->nr ; i++) {
         submit_logged_buffer(chunk->bh[i]) ;
     }
     chunk->nr = 0;
+    put_fs_excl();
 }
 
 static void write_ordered_chunk(struct buffer_chunk *chunk) {
     int i;
+    get_fs_excl();
     for (i = 0; i < chunk->nr ; i++) {
         submit_ordered_buffer(chunk->bh[i]) ;
     }
     chunk->nr = 0;
+    put_fs_excl();
 }
 
 static int add_to_chunk(struct buffer_chunk *chunk, struct buffer_head *bh,
@@ -918,6 +922,8 @@ static int flush_commit_list(struct super_block *s, struct reiserfs_journal_list
     return 0 ;
   }
 
+  get_fs_excl();
+
   /* before we can put our commit blocks on disk, we have to make sure everyone older than
   ** us is on disk too
   */
@@ -1055,6 +1061,7 @@ put_jl:
 
   if (retval)
     reiserfs_abort (s, retval, "Journal write error in %s", __FUNCTION__);
+  put_fs_excl();
   return retval;
 }
 
@@ -1251,6 +1258,8 @@ static int flush_journal_list(struct super_block *s,
     return 0 ;
   }
 
+  get_fs_excl();
+
   /* if all the work is already done, get out of here */
   if (atomic_read(&(jl->j_nonzerolen)) <= 0 && 
       atomic_read(&(jl->j_commit_left)) <= 0) {
@@ -1450,6 +1459,7 @@ flush_older_and_return:
   put_journal_list(s, jl);
   if (flushall)
     up(&journal->j_flush_sem);
+  put_fs_excl();
   return err ;
 } 
 
@@ -2719,6 +2729,7 @@ relock:
   th->t_trans_id = journal->j_trans_id ;
   unlock_journal(p_s_sb) ;
   INIT_LIST_HEAD (&th->t_list);
+  get_fs_excl();
   return 0 ;
 
 out_fail:
@@ -3526,6 +3537,7 @@ static int do_journal_end(struct reiserfs_transaction_handle *th, struct super_b
   BUG_ON (th->t_refcount > 1);
   BUG_ON (!th->t_trans_id);
 
+  put_fs_excl();
   current->journal_info = th->t_handle_save;
   reiserfs_check_lock_depth(p_s_sb, "journal end");
   if (journal->j_len == 0) {