fs: Add support FALLOC_FL_INSERT_RANGE for fallocate

FALLOC_FL_INSERT_RANGE command is the opposite command of
FALLOC_FL_COLLAPSE_RANGE that is needed for someone who wants to add
some data in the middle of file.

FALLOC_FL_INSERT_RANGE will create space for writing new data within
a file after shifting extents to right as given length. This command
also has same limitations as FALLOC_FL_COLLAPSE_RANGE in that
operations need to be filesystem block boundary aligned and cannot
cross the current EOF.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/open.c b/fs/open.c
index 33f9cbf2610b39498d416cb8c142fb5ebe4cc790..b724cc0e022844a832fb1b208fe3872c866953af 100644 (file)
--- a/fs/open.c
+++ b/fs/open.c
@@ -231,8 +231,7 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
                return -EINVAL;
 
        /* Return error if mode is not supported */
-       if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
-                    FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
+       if (mode & ~FALLOC_FL_SUPPORTED_MASK)
                return -EOPNOTSUPP;
 
        /* Punch hole and zero range are mutually exclusive */
@@ -250,6 +249,11 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
            (mode & ~FALLOC_FL_COLLAPSE_RANGE))
                return -EINVAL;
 
+       /* Insert range should only be used exclusively. */
+       if ((mode & FALLOC_FL_INSERT_RANGE) &&
+           (mode & ~FALLOC_FL_INSERT_RANGE))
+               return -EINVAL;
+
        if (!(file->f_mode & FMODE_WRITE))
                return -EBADF;
 

diff --git a/include/linux/falloc.h b/include/linux/falloc.h
index 31591686ac2dd8ab88cee881d7fc42a896522525..996111000a8c014556ff5997e609aeb28bd5ec1d 100644 (file)
--- a/include/linux/falloc.h
+++ b/include/linux/falloc.h
@@ -21,4 +21,10 @@ struct space_resv {
 #define FS_IOC_RESVSP          _IOW('X', 40, struct space_resv)
 #define FS_IOC_RESVSP64                _IOW('X', 42, struct space_resv)
 
+#define        FALLOC_FL_SUPPORTED_MASK        (FALLOC_FL_KEEP_SIZE |          \
+                                        FALLOC_FL_PUNCH_HOLE |         \
+                                        FALLOC_FL_COLLAPSE_RANGE |     \
+                                        FALLOC_FL_ZERO_RANGE |         \
+                                        FALLOC_FL_INSERT_RANGE)
+
 #endif /* _FALLOC_H_ */

diff --git a/include/uapi/linux/falloc.h b/include/uapi/linux/falloc.h
index d1197ae3723ce5193b0526ea8dfa0511d39c8407..3e445a760f14b384bd78636f5f90b2bcb4f723cf 100644 (file)
--- a/include/uapi/linux/falloc.h
+++ b/include/uapi/linux/falloc.h
@@ -41,4 +41,21 @@
  */
 #define FALLOC_FL_ZERO_RANGE           0x10
 
+/*
+ * FALLOC_FL_INSERT_RANGE is use to insert space within the file size without
+ * overwriting any existing data. The contents of the file beyond offset are
+ * shifted towards right by len bytes to create a hole.  As such, this
+ * operation will increase the size of the file by len bytes.
+ *
+ * Different filesystems may implement different limitations on the granularity
+ * of the operation. Most will limit operations to filesystem block size
+ * boundaries, but this boundary may be larger or smaller depending on
+ * the filesystem and/or the configuration of the filesystem or file.
+ *
+ * Attempting to insert space using this flag at OR beyond the end of
+ * the file is considered an illegal operation - just use ftruncate(2) or
+ * fallocate(2) with mode 0 for such type of operations.
+ */
+#define FALLOC_FL_INSERT_RANGE         0x20
+
 #endif /* _UAPI_FALLOC_H_ */