1 files changed, 35 insertions, 1 deletions

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 588af8c77246..3f1873fef1c6 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -21,6 +21,8 @@
 #include <linux/time.h>
 #include <linux/fs.h>
 #include <linux/jbd2.h>
+#include <linux/mount.h>
+#include <linux/path.h>
 #include "ext4.h"
 #include "ext4_jbd2.h"
 #include "xattr.h"
@@ -145,6 +147,38 @@ static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
         return 0;
 }
 
+static int ext4_file_open(struct inode * inode, struct file * filp)
+{
+        struct super_block *sb = inode->i_sb;
+        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+        struct vfsmount *mnt = filp->f_path.mnt;
+        struct path path;
+        char buf[64], *cp;
+
+        if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
+                     !(sb->s_flags & MS_RDONLY))) {
+                sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
+                /*
+                 * Sample where the filesystem has been mounted and
+                 * store it in the superblock for sysadmin convenience
+                 * when trying to sort through large numbers of block
+                 * devices or filesystem images.
+                 */
+                memset(buf, 0, sizeof(buf));
+                path.mnt = mnt->mnt_parent;
+                path.dentry = mnt->mnt_mountpoint;
+                path_get(&path);
+                cp = d_path(&path, buf, sizeof(buf));
+                path_put(&path);
+                if (!IS_ERR(cp)) {
+                        memcpy(sbi->s_es->s_last_mounted, cp,
+                               sizeof(sbi->s_es->s_last_mounted));
+                        sb->s_dirt = 1;
+                }
+        }
+        return generic_file_open(inode, filp);
+}
+
 const struct file_operations ext4_file_operations = {
         .llseek         = generic_file_llseek,
         .read           = do_sync_read,
@@ -156,7 +190,7 @@ const struct file_operations ext4_file_operations = {
         .compat_ioctl   = ext4_compat_ioctl,
 #endif
         .mmap           = ext4_file_mmap,
-        .open           = generic_file_open,
+        .open           = ext4_file_open,
         .release        = ext4_release_file,
         .fsync          = ext4_sync_file,
         .splice_read    = generic_file_splice_read,