From 5cb63a57f8d2d1a94e65b4710bfbb221b1a71700 Mon Sep 17 00:00:00 2001 From: Etienne Dechamps Date: Thu, 1 Sep 2011 13:59:41 +0200 Subject: [PATCH] Implement the truncate_range() inode operation. This operation allows "hole punching" in ZFS files. On Solaris this is done via the vop_space() system call, which maps to the zfs_space() function. So we just need to write zpl_truncate_range() as a wrapper around zfs_space(). Note that this only works for regular files, not ZVOLs. This is currently an insecure implementation without permission checking, although this isn't that big of a deal since truncate_range() isn't even callable from userspace. Signed-off-by: Brian Behlendorf Issue #334 --- module/zfs/zpl_inode.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/module/zfs/zpl_inode.c b/module/zfs/zpl_inode.c index 46b77c9..2d197a4 100644 --- a/module/zfs/zpl_inode.c +++ b/module/zfs/zpl_inode.c @@ -315,6 +315,33 @@ out: return (error); } +static void +zpl_truncate_range(struct inode* ip, loff_t start, loff_t end) +{ + cred_t *cr = CRED(); + flock64_t bf; + + ASSERT3S(start, <=, end); + + /* + * zfs_freesp() will interpret (len == 0) as meaning "truncate until + * the end of the file". We don't want that. + */ + if (start == end) + return; + + crhold(cr); + + bf.l_type = F_WRLCK; + bf.l_whence = 0; + bf.l_start = start; + bf.l_len = end - start; + bf.l_pid = 0; + zfs_space(ip, F_FREESP, &bf, FWRITE, start, cr); + + crfree(cr); +} + const struct inode_operations zpl_inode_operations = { .create = zpl_create, .link = zpl_link, @@ -330,6 +357,7 @@ const struct inode_operations zpl_inode_operations = { .getxattr = generic_getxattr, .removexattr = generic_removexattr, .listxattr = zpl_xattr_list, + .truncate_range = zpl_truncate_range, }; const struct inode_operations zpl_dir_inode_operations = { -- 1.8.3.1