On Fri, Jan 02, 2015 at 06:40:33PM +0900, Namjae Jeon wrote: > 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/uapi/linux/falloc.h | 15 +++++++++++++++ > 2 files changed, 22 insertions(+), 1 deletion(-) > > diff --git a/fs/open.c b/fs/open.c > index 36662d0..74ed498 100644 > --- a/fs/open.c > +++ b/fs/open.c > @@ -232,7 +232,8 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len) > > /* 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)) > + FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | > + FALLOC_FL_INSERT_RANGE)) > return -EOPNOTSUPP; > > /* Punch hole and zero range are mutually exclusive */ > @@ -250,6 +251,11 @@ int do_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/uapi/linux/falloc.h b/include/uapi/linux/falloc.h > index d1197ae..1f20723 100644 > --- a/include/uapi/linux/falloc.h > +++ b/include/uapi/linux/falloc.h > @@ -41,4 +41,19 @@ > */ > #define FALLOC_FL_ZERO_RANGE 0x10 > > +/* > + * FALLOC_FL_INSERT_RANGE is use to insert space within the file size without used > + * 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. I suppose we should split this comment up into a few paragraphs similar to the collapse range comment it is based on. That means we split here... > + * 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. ... and here. Otherwise this looks fine to me. Brian > + * 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_ */ > -- > 1.7.11-rc0 > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
