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authorDarrick J. Wong <darrick.wong@oracle.com>2018-10-30 10:42:10 +1100
committerDave Chinner <david@fromorbit.com>2018-10-30 10:42:10 +1100
commiteca3654e3cc7d93e9734d0fa96cfb15c7f356244 (patch)
tree00e5f8bd5de34435872d8cb222daaec79ede3961 /fs/read_write.c
parentdf3658361951e17364f1e1c3fa92862a990ad8bd (diff)
downloadlinux-eca3654e3cc7d93e9734d0fa96cfb15c7f356244.tar.bz2
vfs: enable remap callers that can handle short operations
Plumb in a remap flag that enables the filesystem remap handler to shorten remapping requests for callers that can handle it. Now copy_file_range can report partial success (in case we run up against alignment problems, resource limits, etc.). We also enable CAN_SHORTEN for fideduperange to maintain existing userspace-visible behavior where xfs/btrfs shorten the dedupe range to avoid stale post-eof data exposure. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c28
1 files changed, 20 insertions, 8 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index ea30666013b0..c0bcc1a20650 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1593,7 +1593,8 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
cloned = file_in->f_op->remap_file_range(file_in, pos_in,
file_out, pos_out,
- min_t(loff_t, MAX_RW_COUNT, len), 0);
+ min_t(loff_t, MAX_RW_COUNT, len),
+ REMAP_FILE_CAN_SHORTEN);
if (cloned > 0) {
ret = cloned;
goto done;
@@ -1721,6 +1722,8 @@ static int remap_verify_area(struct file *file, loff_t pos, loff_t len,
* can't meaningfully compare post-EOF contents.
*
* For clone we only link a partial EOF block above the destination file's EOF.
+ *
+ * Shorten the request if possible.
*/
static int generic_remap_check_len(struct inode *inode_in,
struct inode *inode_out,
@@ -1729,16 +1732,24 @@ static int generic_remap_check_len(struct inode *inode_in,
unsigned int remap_flags)
{
u64 blkmask = i_blocksize(inode_in) - 1;
+ loff_t new_len = *len;
if ((*len & blkmask) == 0)
return 0;
- if (remap_flags & REMAP_FILE_DEDUP)
- *len &= ~blkmask;
- else if (pos_out + *len < i_size_read(inode_out))
- return -EINVAL;
+ if ((remap_flags & REMAP_FILE_DEDUP) ||
+ pos_out + *len < i_size_read(inode_out))
+ new_len &= ~blkmask;
- return 0;
+ if (new_len == *len)
+ return 0;
+
+ if (remap_flags & REMAP_FILE_CAN_SHORTEN) {
+ *len = new_len;
+ return 0;
+ }
+
+ return (remap_flags & REMAP_FILE_DEDUP) ? -EBADE : -EINVAL;
}
/*
@@ -2014,7 +2025,8 @@ loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
{
loff_t ret;
- WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP));
+ WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP |
+ REMAP_FILE_CAN_SHORTEN));
ret = mnt_want_write_file(dst_file);
if (ret)
@@ -2115,7 +2127,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
deduped = vfs_dedupe_file_range_one(file, off, dst_file,
info->dest_offset, len,
- 0);
+ REMAP_FILE_CAN_SHORTEN);
if (deduped == -EBADE)
info->status = FILE_DEDUPE_RANGE_DIFFERS;
else if (deduped < 0)