1 files changed, 45 insertions, 3 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index 5520f8ad550..179f1c33ea5 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -64,6 +64,23 @@ generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin)
                         return file->f_pos;
                 offset += file->f_pos;
                 break;
+        case SEEK_DATA:
+                /*
+                 * In the generic case the entire file is data, so as long as
+                 * offset isn't at the end of the file then the offset is data.
+                 */
+                if (offset >= inode->i_size)
+                        return -ENXIO;
+                break;
+        case SEEK_HOLE:
+                /*
+                 * There is a virtual hole at the end of the file, so as long as
+                 * offset isn't i_size or larger, return i_size.
+                 */
+                if (offset >= inode->i_size)
+                        return -ENXIO;
+                offset = inode->i_size;
+                break;
         }
 
         if (offset < 0 && !unsigned_offsets(file))
@@ -128,12 +145,13 @@ EXPORT_SYMBOL(no_llseek);
 
 loff_t default_llseek(struct file *file, loff_t offset, int origin)
 {
+        struct inode *inode = file->f_path.dentry->d_inode;
         loff_t retval;
 
-        mutex_lock(&file->f_dentry->d_inode->i_mutex);
+        mutex_lock(&inode->i_mutex);
         switch (origin) {
                 case SEEK_END:
-                        offset += i_size_read(file->f_path.dentry->d_inode);
+                        offset += i_size_read(inode);
                         break;
                 case SEEK_CUR:
                         if (offset == 0) {
@@ -141,6 +159,30 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
                                 goto out;
                         }
                         offset += file->f_pos;
+                        break;
+                case SEEK_DATA:
+                        /*
+                         * In the generic case the entire file is data, so as
+                         * long as offset isn't at the end of the file then the
+                         * offset is data.
+                         */
+                        if (offset >= inode->i_size) {
+                                retval = -ENXIO;
+                                goto out;
+                        }
+                        break;
+                case SEEK_HOLE:
+                        /*
+                         * There is a virtual hole at the end of the file, so
+                         * as long as offset isn't i_size or larger, return
+                         * i_size.
+                         */
+                        if (offset >= inode->i_size) {
+                                retval = -ENXIO;
+                                goto out;
+                        }
+                        offset = inode->i_size;
+                        break;
         }
         retval = -EINVAL;
         if (offset >= 0 || unsigned_offsets(file)) {
@@ -151,7 +193,7 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
                 retval = offset;
         }
 out:
-        mutex_unlock(&file->f_dentry->d_inode->i_mutex);
+        mutex_unlock(&inode->i_mutex);
         return retval;
 }
 EXPORT_SYMBOL(default_llseek);