1 files changed, 116 insertions, 63 deletions

diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index b5e13fbb738..00661fd21fc 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -628,6 +628,116 @@ out_lock:
         return error;
 }
 
+/*
+ * xfs_file_dio_aio_write - handle direct IO writes
+ *
+ * Lock the inode appropriately to prepare for and issue a direct IO write.
+ * By spearating it from the buffered write path we remove all the tricky to
+ * follow locking changes and looping.
+ *
+ * Returns with locks held indicated by @iolock and errors indicated by
+ * negative return values.
+ */
+STATIC ssize_t
+xfs_file_dio_aio_write(
+        struct kiocb            *iocb,
+        const struct iovec      *iovp,
+        unsigned long           nr_segs,
+        loff_t                  pos,
+        size_t                  ocount,
+        int                     *iolock)
+{
+        struct file             *file = iocb->ki_filp;
+        struct address_space    *mapping = file->f_mapping;
+        struct inode            *inode = mapping->host;
+        struct xfs_inode        *ip = XFS_I(inode);
+        struct xfs_mount        *mp = ip->i_mount;
+        ssize_t                 ret = 0;
+        xfs_fsize_t             new_size;
+        size_t                  count = ocount;
+        struct xfs_buftarg      *target = XFS_IS_REALTIME_INODE(ip) ?
+                                        mp->m_rtdev_targp : mp->m_ddev_targp;
+
+        *iolock = 0;
+        if ((pos & target->bt_smask) || (count & target->bt_smask))
+                return -XFS_ERROR(EINVAL);
+
+        /*
+         * For direct I/O, if there are cached pages or we're extending
+         * the file, we need IOLOCK_EXCL until we're sure the bytes at
+         * the new EOF have been zeroed and/or the cached pages are
+         * flushed out.
+         */
+        if (mapping->nrpages || pos > ip->i_size)
+                *iolock = XFS_IOLOCK_EXCL;
+        else
+                *iolock = XFS_IOLOCK_SHARED;
+        xfs_rw_ilock(ip, XFS_ILOCK_EXCL | *iolock);
+
+        ret = generic_write_checks(file, &pos, &count,
+                                        S_ISBLK(inode->i_mode));
+        if (ret) {
+                xfs_rw_iunlock(ip, XFS_ILOCK_EXCL | *iolock);
+                *iolock = 0;
+                return ret;
+        }
+
+        new_size = pos + count;
+        if (new_size > ip->i_size)
+                ip->i_new_size = new_size;
+
+        if (likely(!(file->f_mode & FMODE_NOCMTIME)))
+                file_update_time(file);
+
+        /*
+         * If the offset is beyond the size of the file, we have a couple of
+         * things to do. First, if there is already space allocated we need to
+         * either create holes or zero the disk or ...
+         *
+         * If there is a page where the previous size lands, we need to zero it
+         * out up to the new size.
+         */
+        if (pos > ip->i_size) {
+                ret = -xfs_zero_eof(ip, pos, ip->i_size);
+                if (ret) {
+                        xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
+                        return ret;
+                }
+        }
+        xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
+
+        /*
+         * If we're writing the file then make sure to clear the setuid and
+         * setgid bits if the process is not being run by root.  This keeps
+         * people from modifying setuid and setgid binaries.
+         */
+        ret = file_remove_suid(file);
+        if (unlikely(ret))
+                return ret;
+
+        if (mapping->nrpages) {
+                WARN_ON(*iolock != XFS_IOLOCK_EXCL);
+                ret = -xfs_flushinval_pages(ip, (pos & PAGE_CACHE_MASK), -1,
+                                                        FI_REMAPF_LOCKED);
+                if (ret)
+                        return ret;
+        }
+
+        if (*iolock == XFS_IOLOCK_EXCL) {
+                /* demote the lock now the cached pages are gone */
+                xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
+                *iolock = XFS_IOLOCK_SHARED;
+        }
+
+        trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0);
+        ret = generic_file_direct_write(iocb, iovp,
+                        &nr_segs, pos, &iocb->ki_pos, count, ocount);
+
+        /* No fallback to buffered IO on errors for XFS. */
+        ASSERT(ret < 0 || ret == count);
+        return ret;
+}
+
 STATIC ssize_t
 xfs_file_aio_write(
         struct kiocb            *iocb,
@@ -670,12 +780,12 @@ xfs_file_aio_write(
 
 relock:
         if (ioflags & IO_ISDIRECT) {
-                iolock = XFS_IOLOCK_SHARED;
-        } else {
-                iolock = XFS_IOLOCK_EXCL;
+                ret = xfs_file_dio_aio_write(iocb, iovp, nr_segs, pos,
+                                                ocount, &iolock);
+                goto done_io;
         }
+        iolock = XFS_IOLOCK_EXCL;
 
-start:
         xfs_rw_ilock(ip, XFS_ILOCK_EXCL|iolock);
         ret = generic_write_checks(file, &pos, &count,
                                         S_ISBLK(inode->i_mode));
@@ -684,30 +794,6 @@ start:
                 return ret;
         }
 
-        if (ioflags & IO_ISDIRECT) {
-                xfs_buftarg_t   *target =
-                        XFS_IS_REALTIME_INODE(ip) ?
-                                mp->m_rtdev_targp : mp->m_ddev_targp;
-
-                if ((pos & target->bt_smask) || (count & target->bt_smask)) {
-                        xfs_rw_iunlock(ip, XFS_ILOCK_EXCL|iolock);
-                        return XFS_ERROR(-EINVAL);
-                }
-
-                /*
-                 * For direct I/O, if there are cached pages or we're extending
-                 * the file, we need IOLOCK_EXCL until we're sure the bytes at
-                 * the new EOF have been zeroed and/or the cached pages are
-                 * flushed out.  Upgrade the I/O lock and start again.
-                 */
-                if (iolock != XFS_IOLOCK_EXCL &&
-                    (mapping->nrpages || pos > ip->i_size)) {
-                        xfs_rw_iunlock(ip, XFS_ILOCK_EXCL|iolock);
-                        iolock = XFS_IOLOCK_EXCL;
-                        goto start;
-                }
-        }
-
         new_size = pos + count;
         if (new_size > ip->i_size)
                 ip->i_new_size = new_size;
@@ -746,41 +832,7 @@ start:
         /* We can write back this queue in page reclaim */
         current->backing_dev_info = mapping->backing_dev_info;
 
-        if ((ioflags & IO_ISDIRECT)) {
-                if (mapping->nrpages) {
-                        WARN_ON(iolock != XFS_IOLOCK_EXCL);
-                        ret = -xfs_flushinval_pages(ip,
-                                        (pos & PAGE_CACHE_MASK),
-                                        -1, FI_REMAPF_LOCKED);
-                        if (ret)
-                                goto out_unlock_internal;
-                }
-
-                if (iolock == XFS_IOLOCK_EXCL) {
-                        /* demote the lock now the cached pages are gone */
-                        xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
-                        iolock = XFS_IOLOCK_SHARED;
-                }
-
-                trace_xfs_file_direct_write(ip, count, iocb->ki_pos, ioflags);
-                ret = generic_file_direct_write(iocb, iovp,
-                                &nr_segs, pos, &iocb->ki_pos, count, ocount);
-
-                /*
-                 * direct-io write to a hole: fall through to buffered I/O
-                 * for completing the rest of the request.
-                 */
-                if (ret >= 0 && ret != count) {
-                        XFS_STATS_ADD(xs_write_bytes, ret);
-
-                        pos += ret;
-                        count -= ret;
-
-                        ioflags &= ~IO_ISDIRECT;
-                        xfs_rw_iunlock(ip, iolock);
-                        goto relock;
-                }
-        } else {
+        if (!(ioflags & IO_ISDIRECT)) {
                 int enospc = 0;
 
 write_retry:
@@ -802,6 +854,7 @@ write_retry:
 
         current->backing_dev_info = NULL;
 
+done_io:
         xfs_aio_write_isize_update(inode, &iocb->ki_pos, ret);
 
         if (ret <= 0)