btrfs: don't update mtime/ctime on deduped inodes
One issue users have reported is that dedupe changes mtime on files,
resulting in tools like rsync thinking that their contents have changed when
in fact the data is exactly the same. We also skip the ctime update as no
user-visible metadata changes here and we want dedupe to be transparent to
the user.
Clone still wants time changes, so we special case this in the code.
This was tested with the btrfs-extent-same tool.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index af06494..5d91776 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -87,7 +87,8 @@
static int btrfs_clone(struct inode *src, struct inode *inode,
- u64 off, u64 olen, u64 olen_aligned, u64 destoff);
+ u64 off, u64 olen, u64 olen_aligned, u64 destoff,
+ int no_time_update);
/* Mask out flags that are inappropriate for the given type of inode. */
static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
@@ -3066,7 +3067,7 @@
/* pass original length for comparison so we stay within i_size */
ret = btrfs_cmp_data(src, loff, dst, dst_loff, olen, &cmp);
if (ret == 0)
- ret = btrfs_clone(src, dst, loff, olen, len, dst_loff);
+ ret = btrfs_clone(src, dst, loff, olen, len, dst_loff, 1);
if (same_inode)
unlock_extent(&BTRFS_I(src)->io_tree, same_lock_start,
@@ -3231,13 +3232,15 @@
struct inode *inode,
u64 endoff,
const u64 destoff,
- const u64 olen)
+ const u64 olen,
+ int no_time_update)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret;
inode_inc_iversion(inode);
- inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ if (!no_time_update)
+ inode->i_mtime = inode->i_ctime = CURRENT_TIME;
/*
* We round up to the block size at eof when determining which
* extents to clone above, but shouldn't round up the file size.
@@ -3322,13 +3325,13 @@
* @inode: Inode to clone to
* @off: Offset within source to start clone from
* @olen: Original length, passed by user, of range to clone
- * @olen_aligned: Block-aligned value of olen, extent_same uses
- * identical values here
+ * @olen_aligned: Block-aligned value of olen
* @destoff: Offset within @inode to start clone
+ * @no_time_update: Whether to update mtime/ctime on the target inode
*/
static int btrfs_clone(struct inode *src, struct inode *inode,
const u64 off, const u64 olen, const u64 olen_aligned,
- const u64 destoff)
+ const u64 destoff, int no_time_update)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_path *path = NULL;
@@ -3652,7 +3655,8 @@
root->sectorsize);
ret = clone_finish_inode_update(trans, inode,
last_dest_end,
- destoff, olen);
+ destoff, olen,
+ no_time_update);
if (ret)
goto out;
if (new_key.offset + datal >= destoff + len)
@@ -3690,7 +3694,7 @@
clone_update_extent_map(inode, trans, NULL, last_dest_end,
destoff + len - last_dest_end);
ret = clone_finish_inode_update(trans, inode, destoff + len,
- destoff, olen);
+ destoff, olen, no_time_update);
}
out:
@@ -3827,7 +3831,7 @@
lock_extent_range(inode, destoff, len);
}
- ret = btrfs_clone(src, inode, off, olen, len, destoff);
+ ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
if (same_inode) {
u64 lock_start = min_t(u64, off, destoff);