[PATCH] Direct Migration V9: Avoid writeback / page_migrate() method

[linux.git] / fs / dquot.c

diff --git a/fs/dquot.c b/fs/dquot.c
index afa06a893468571785ca335a32a6bd89eafda4a0..1966c890b48d1df00e04bc09e612ade805ad77f6 100644 (file)
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -77,6 +77,7 @@
 #include <linux/kmod.h>
 #include <linux/namei.h>
 #include <linux/buffer_head.h>
+#include <linux/capability.h>
 #include <linux/quotaops.h>
 
 #include <asm/uaccess.h>
@@ -100,7 +101,7 @@
  * operation is just reading pointers from inode (or not using them at all) the
  * read lock is enough. If pointers are altered function must hold write lock
  * (these locking rules also apply for S_NOQUOTA flag in the inode - note that
- * for altering the flag i_sem is also needed).  If operation is holding
+ * for altering the flag i_mutex is also needed).  If operation is holding
  * reference to dquot in other way (e.g. quotactl ops) it must be guarded by
  * dqonoff_sem.
  * This locking assures that:
@@ -117,9 +118,9 @@
  * spinlock to internal buffers before writing.
  *
  * Lock ordering (including related VFS locks) is the following:
- *   i_sem > dqonoff_sem > iprune_sem > journal_lock > dqptr_sem >
+ *   i_mutex > dqonoff_sem > iprune_sem > journal_lock > dqptr_sem >
  *   > dquot->dq_lock > dqio_sem
- * i_sem on quota files is special (it's below dqio_sem)
+ * i_mutex on quota files is special (it's below dqio_sem)
  */
 
 static DEFINE_SPINLOCK(dq_list_lock);
@@ -1321,13 +1322,11 @@ int vfs_quota_off(struct super_block *sb, int type)
        int cnt;
        struct quota_info *dqopt = sb_dqopt(sb);
        struct inode *toputinode[MAXQUOTAS];
-       struct vfsmount *toputmnt[MAXQUOTAS];
 
        /* We need to serialize quota_off() for device */
        down(&dqopt->dqonoff_sem);
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                toputinode[cnt] = NULL;
-               toputmnt[cnt] = NULL;
                if (type != -1 && cnt != type)
                        continue;
                if (!sb_has_quota_enabled(sb, cnt))
@@ -1348,9 +1347,7 @@ int vfs_quota_off(struct super_block *sb, int type)
                put_quota_format(dqopt->info[cnt].dqi_format);
 
                toputinode[cnt] = dqopt->files[cnt];
-               toputmnt[cnt] = dqopt->mnt[cnt];
                dqopt->files[cnt] = NULL;
-               dqopt->mnt[cnt] = NULL;
                dqopt->info[cnt].dqi_flags = 0;
                dqopt->info[cnt].dqi_igrace = 0;
                dqopt->info[cnt].dqi_bgrace = 0;
@@ -1358,10 +1355,7 @@ int vfs_quota_off(struct super_block *sb, int type)
        }
        up(&dqopt->dqonoff_sem);
        /* Sync the superblock so that buffers with quota data are written to
-        * disk (and so userspace sees correct data afterwards).
-        * The reference to vfsmnt we are still holding protects us from
-        * umount (we don't have it only when quotas are turned on/off for
-        * journal replay but in that case we are guarded by the fs anyway). */
+        * disk (and so userspace sees correct data afterwards). */
        if (sb->s_op->sync_fs)
                sb->s_op->sync_fs(sb, 1);
        sync_blockdev(sb->s_bdev);
@@ -1376,19 +1370,15 @@ int vfs_quota_off(struct super_block *sb, int type)
                        /* If quota was reenabled in the meantime, we have
                         * nothing to do */
                        if (!sb_has_quota_enabled(sb, cnt)) {
-                               down(&toputinode[cnt]->i_sem);
+                               mutex_lock(&toputinode[cnt]->i_mutex);
                                toputinode[cnt]->i_flags &= ~(S_IMMUTABLE |
                                  S_NOATIME | S_NOQUOTA);
                                truncate_inode_pages(&toputinode[cnt]->i_data, 0);
-                               up(&toputinode[cnt]->i_sem);
+                               mutex_unlock(&toputinode[cnt]->i_mutex);
                                mark_inode_dirty(toputinode[cnt]);
                                iput(toputinode[cnt]);
                        }
                        up(&dqopt->dqonoff_sem);
-                       /* We don't hold the reference when we turned on quotas
-                        * just for the journal replay... */
-                       if (toputmnt[cnt])
-                               mntput(toputmnt[cnt]);
                }
        if (sb->s_bdev)
                invalidate_bdev(sb->s_bdev, 0);
@@ -1428,7 +1418,7 @@ static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
        write_inode_now(inode, 1);
        /* And now flush the block cache so that kernel sees the changes */
        invalidate_bdev(sb->s_bdev, 0);
-       down(&inode->i_sem);
+       mutex_lock(&inode->i_mutex);
        down(&dqopt->dqonoff_sem);
        if (sb_has_quota_enabled(sb, type)) {
                error = -EBUSY;
@@ -1460,7 +1450,7 @@ static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
                goto out_file_init;
        }
        up(&dqopt->dqio_sem);
-       up(&inode->i_sem);
+       mutex_unlock(&inode->i_mutex);
        set_enable_flags(dqopt, type);
 
        add_dquot_ref(sb, type);
@@ -1481,7 +1471,7 @@ out_lock:
                inode->i_flags |= oldflags;
                up_write(&dqopt->dqptr_sem);
        }
-       up(&inode->i_sem);
+       mutex_unlock(&inode->i_mutex);
 out_fmt:
        put_quota_format(fmt);
 
@@ -1503,11 +1493,8 @@ int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
        /* Quota file not on the same filesystem? */
        if (nd.mnt->mnt_sb != sb)
                error = -EXDEV;
-       else {
+       else
                error = vfs_quota_on_inode(nd.dentry->d_inode, type, format_id);
-               if (!error)
-                       sb_dqopt(sb)->mnt[type] = mntget(nd.mnt);
-       }
 out_path:
        path_release(&nd);
        return error;
@@ -1527,10 +1514,16 @@ int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
        if (IS_ERR(dentry))
                return PTR_ERR(dentry);
 
+       if (!dentry->d_inode) {
+               error = -ENOENT;
+               goto out;
+       }
+
        error = security_quota_on(dentry);
        if (!error)
                error = vfs_quota_on_inode(dentry->d_inode, type, format_id);
 
+out:
        dput(dentry);
        return error;
 }