| Message ID | 153923126628.5546.3484461137192547927.stgit@magnolia (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fs: fixes for serious clone/dedupe problems | expand |
On Thu, Oct 11, 2018 at 08:15:42AM +0300, Amir Goldstein wrote: > On Thu, Oct 11, 2018 at 7:14 AM Darrick J. Wong <darrick.wong@oracle.com> wrote: > > > > From: Darrick J. Wong <darrick.wong@oracle.com> > > > > 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.). > > > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > > Reviewed-by: Amir Goldstein <amir73il@gmail.com> > > --- > > fs/read_write.c | 15 +++++++++------ > > include/linux/fs.h | 7 +++++-- > > mm/filemap.c | 16 ++++++++++++---- > > 3 files changed, 26 insertions(+), 12 deletions(-) > > > > > > diff --git a/fs/read_write.c b/fs/read_write.c > > index 6ec908f9a69b..3713893b7e38 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), > > + RFR_CAN_SHORTEN); > > if (cloned > 0) { > > ret = cloned; > > goto done; > > @@ -1804,16 +1805,18 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, > > * If the user is attempting to remap a partial EOF block and > > * it's inside the destination EOF then reject it. > > * > > - * We don't support shortening requests, so we can only reject > > - * them. > > + * If possible, shorten the request instead of rejecting it. > > */ > > if (is_dedupe) > > ret = -EBADE; > > else if (pos_out + *len < i_size_read(inode_out)) > > ret = -EINVAL; > > > > - if (ret) > > - return ret; > > + if (ret) { > > + if (!(remap_flags & RFR_CAN_SHORTEN)) > > + return ret; > > + *len &= ~blkmask; > > + } > > } > > > > return 1; > > @@ -2112,7 +2115,7 @@ 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); > > + RFR_CAN_SHORTEN); > > You did not update WARN_ON_ONCE in vfs_dedupe_file_range_one() > to allow this flag and did not mention dedupe in commit message. > Was that change intentional in this patch? > > After RFR_SHORT_DEDUPE patch the end result in fine. Heh, oops, sorry about that. I'll reissue the patch with the two corrections. --D > Thanks, > Amir.
diff --git a/fs/read_write.c b/fs/read_write.c index 6ec908f9a69b..3713893b7e38 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), + RFR_CAN_SHORTEN); if (cloned > 0) { ret = cloned; goto done; @@ -1804,16 +1805,18 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, * If the user is attempting to remap a partial EOF block and * it's inside the destination EOF then reject it. * - * We don't support shortening requests, so we can only reject - * them. + * If possible, shorten the request instead of rejecting it. */ if (is_dedupe) ret = -EBADE; else if (pos_out + *len < i_size_read(inode_out)) ret = -EINVAL; - if (ret) - return ret; + if (ret) { + if (!(remap_flags & RFR_CAN_SHORTEN)) + return ret; + *len &= ~blkmask; + } } return 1; @@ -2112,7 +2115,7 @@ 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); + RFR_CAN_SHORTEN); if (deduped == -EBADE) info->status = FILE_DEDUPE_RANGE_DIFFERS; else if (deduped < 0) diff --git a/include/linux/fs.h b/include/linux/fs.h index b9c314f9d5a4..57cb56bbc30a 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1726,14 +1726,17 @@ struct block_device_operations; * * RFR_SAME_DATA: only remap if contents identical (i.e. deduplicate) * RFR_TO_SRC_EOF: remap to the end of the source file + * RFR_CAN_SHORTEN: caller can handle a shortened request */ #define RFR_SAME_DATA (1 << 0) #define RFR_TO_SRC_EOF (1 << 1) +#define RFR_CAN_SHORTEN (1 << 2) -#define RFR_VALID_FLAGS (RFR_SAME_DATA | RFR_TO_SRC_EOF) +#define RFR_VALID_FLAGS (RFR_SAME_DATA | RFR_TO_SRC_EOF | \ + RFR_CAN_SHORTEN) /* Implemented by the VFS, so these are advisory. */ -#define RFR_VFS_FLAGS (RFR_TO_SRC_EOF) +#define RFR_VFS_FLAGS (RFR_TO_SRC_EOF | RFR_CAN_SHORTEN) /* * Filesystem remapping implementations should call this helper on their diff --git a/mm/filemap.c b/mm/filemap.c index 369cfd164e90..bccbd3621238 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3051,8 +3051,12 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in, if (pos_in + count == size_in) { bcount = ALIGN(size_in, bs) - pos_in; } else { - if (!IS_ALIGNED(count, bs)) - return -EINVAL; + if (!IS_ALIGNED(count, bs)) { + if (remap_flags & RFR_CAN_SHORTEN) + count = ALIGN_DOWN(count, bs); + else + return -EINVAL; + } bcount = count; } @@ -3063,10 +3067,14 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in, pos_out < pos_in + bcount) return -EINVAL; - /* For now we don't support changing the length. */ - if (*req_count != count) + /* + * We shortened the request but the caller can't deal with that, so + * bounce the request back to userspace. + */ + if (*req_count != count && !(remap_flags & RFR_CAN_SHORTEN)) return -EINVAL; + *req_count = count; return 0; }