Merge branch 'for-2.6.31' of git://fieldses.org/git/linux-nfsd

[safe/jmp/linux-2.6] / fs / nfsd / vfs.c

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 99f8357..4145083 100644 (file)
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -966,6 +966,43 @@ static void kill_suid(struct dentry *dentry)
        mutex_unlock(&dentry->d_inode->i_mutex);
 }
 
+/*
+ * Gathered writes: If another process is currently writing to the file,
+ * there's a high chance this is another nfsd (triggered by a bulk write
+ * from a client's biod). Rather than syncing the file with each write
+ * request, we sleep for 10 msec.
+ *
+ * I don't know if this roughly approximates C. Juszak's idea of
+ * gathered writes, but it's a nice and simple solution (IMHO), and it
+ * seems to work:-)
+ *
+ * Note: we do this only in the NFSv2 case, since v3 and higher have a
+ * better tool (separate unstable writes and commits) for solving this
+ * problem.
+ */
+static int wait_for_concurrent_writes(struct file *file)
+{
+       struct inode *inode = file->f_path.dentry->d_inode;
+       static ino_t last_ino;
+       static dev_t last_dev;
+       int err = 0;
+
+       if (atomic_read(&inode->i_writecount) > 1
+           || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
+               dprintk("nfsd: write defer %d\n", task_pid_nr(current));
+               msleep(10);
+               dprintk("nfsd: write resume %d\n", task_pid_nr(current));
+       }
+
+       if (inode->i_state & I_DIRTY) {
+               dprintk("nfsd: write sync %d\n", task_pid_nr(current));
+               err = nfsd_sync(file);
+       }
+       last_ino = inode->i_ino;
+       last_dev = inode->i_sb->s_dev;
+       return err;
+}
+
 static __be32
 nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
                                loff_t offset, struct kvec *vec, int vlen,
@@ -978,6 +1015,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
        __be32                  err = 0;
        int                     host_err;
        int                     stable = *stablep;
+       int                     use_wgather;
 
 #ifdef MSNFS
        err = nfserr_perm;
@@ -996,9 +1034,10 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
         *  -   the sync export option has been set, or
         *  -   the client requested O_SYNC behavior (NFSv3 feature).
         *  -   The file system doesn't support fsync().
-        * When gathered writes have been configured for this volume,
+        * When NFSv2 gathered writes have been configured for this volume,
         * flushing the data to disk is handled separately below.
         */
+       use_wgather = (rqstp->rq_vers == 2) && EX_WGATHER(exp);
 
        if (!file->f_op->fsync) {/* COMMIT3 cannot work */
               stable = 2;
@@ -1007,7 +1046,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 
        if (!EX_ISSYNC(exp))
                stable = 0;
-       if (stable && !EX_WGATHER(exp)) {
+       if (stable && !use_wgather) {
                spin_lock(&file->f_lock);
                file->f_flags |= O_SYNC;
                spin_unlock(&file->f_lock);
@@ -1017,52 +1056,20 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
        oldfs = get_fs(); set_fs(KERNEL_DS);
        host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &offset);
        set_fs(oldfs);
-       if (host_err >= 0) {
-               *cnt = host_err;
-               nfsdstats.io_write += host_err;
-               fsnotify_modify(file->f_path.dentry);
-       }
+       if (host_err < 0)
+               goto out_nfserr;
+       *cnt = host_err;
+       nfsdstats.io_write += host_err;
+       fsnotify_modify(file->f_path.dentry);
 
        /* clear setuid/setgid flag after write */
-       if (host_err >= 0 && (inode->i_mode & (S_ISUID | S_ISGID)))
+       if (inode->i_mode & (S_ISUID | S_ISGID))
                kill_suid(dentry);
 
-       if (host_err >= 0 && stable) {
-               static ino_t    last_ino;
-               static dev_t    last_dev;
-
-               /*
-                * Gathered writes: If another process is currently
-                * writing to the file, there's a high chance
-                * this is another nfsd (triggered by a bulk write
-                * from a client's biod). Rather than syncing the
-                * file with each write request, we sleep for 10 msec.
-                *
-                * I don't know if this roughly approximates
-                * C. Juszak's idea of gathered writes, but it's a
-                * nice and simple solution (IMHO), and it seems to
-                * work:-)
-                */
-               if (EX_WGATHER(exp)) {
-                       if (atomic_read(&inode->i_writecount) > 1
-                           || (last_ino == inode->i_ino && last_dev == inode->i_sb->s_dev)) {
-                               dprintk("nfsd: write defer %d\n", task_pid_nr(current));
-                               msleep(10);
-                               dprintk("nfsd: write resume %d\n", task_pid_nr(current));
-                       }
-
-                       if (inode->i_state & I_DIRTY) {
-                               dprintk("nfsd: write sync %d\n", task_pid_nr(current));
-                               host_err=nfsd_sync(file);
-                       }
-#if 0
-                       wake_up(&inode->i_wait);
-#endif
-               }
-               last_ino = inode->i_ino;
-               last_dev = inode->i_sb->s_dev;
-       }
+       if (stable && use_wgather)
+               host_err = wait_for_concurrent_writes(file);
 
+out_nfserr:
        dprintk("nfsd: write complete host_err=%d\n", host_err);
        if (host_err >= 0)
                err = 0;