FALLOC_FL_INSERT_RANGE command is the opposite command of
FALLOC_FL_COLLAPSE_RANGE that is needed for advertisers or someone who want 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. and this command also has same limitation as FALLOC_FL_COLLAPSE_RANGE,
that is block boundary and use ftruncate(2) for crosses EOF.
Signed-off-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
Signed-off-by: Ashish Sangwan <a.sangwan@xxxxxxxxxxx>
---
fs/open.c | 8 ++++++--
include/linux/falloc.h | 6 ++++++
include/uapi/linux/falloc.h | 17 +++++++++++++++++
3 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/fs/open.c b/fs/open.c
index 33f9cbf..b724cc0 100644
--- 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 3159168..9961110 100644
--- 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 d1197ae..3e445a7 100644
--- 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_ */
--
1.8.5.5
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