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fs: Add support FALLOC_FL_INSERT_RANGE for fallocate

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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>
This commit is contained in:
Namjae Jeon 2015-03-25 15:07:05 +11:00 • committed by Dave Chinner
commit dd46c78778
3 changed files with 29 additions and 2 deletions
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8
fs/open.c
View file

@ -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;

6
include/linux/falloc.h
View file

@ -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_ */

17
include/uapi/linux/falloc.h
View file

@ -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_ */