From: Namjae Jeon <namjae.jeon@xxxxxxxxxxx> 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> Cc: Brian Foster<bfoster@xxxxxxxxxx> --- fs/open.c | 8 +++++++- include/uapi/linux/falloc.h | 17 +++++++++++++++++ 2 files changed, 24 insertions(+), 1 deletion(-) diff --git a/fs/open.c b/fs/open.c index 813be03..762fb45 100644 --- a/fs/open.c +++ b/fs/open.c @@ -232,7 +232,8 @@ int vfs_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 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/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_ */ -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
