iomap: support REQ_OP_ZONE_APPEND

A ZONE_APPEND bio must follow hardware restrictions (e.g. not exceeding
max_zone_append_sectors) not to be split. bio_iov_iter_get_pages builds
such restricted bio using __bio_iov_append_get_pages if bio_op(bio) ==
REQ_OP_ZONE_APPEND.

To utilize it, we need to set the bio_op before calling
bio_iov_iter_get_pages(). This commit introduces IOMAP_F_ZONE_APPEND, so
that iomap user can set the flag to indicate they want REQ_OP_ZONE_APPEND
and restricted bio.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 933f234..2273120 100644 (file)
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -201,6 +201,34 @@ iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
        iomap_dio_submit_bio(dio, iomap, bio, pos);
 }
 
+/*
+ * Figure out the bio's operation flags from the dio request, the
+ * mapping, and whether or not we want FUA.  Note that we can end up
+ * clearing the WRITE_FUA flag in the dio request.
+ */
+static inline unsigned int
+iomap_dio_bio_opflags(struct iomap_dio *dio, struct iomap *iomap, bool use_fua)
+{
+       unsigned int opflags = REQ_SYNC | REQ_IDLE;
+
+       if (!(dio->flags & IOMAP_DIO_WRITE)) {
+               WARN_ON_ONCE(iomap->flags & IOMAP_F_ZONE_APPEND);
+               return REQ_OP_READ;
+       }
+
+       if (iomap->flags & IOMAP_F_ZONE_APPEND)
+               opflags |= REQ_OP_ZONE_APPEND;
+       else
+               opflags |= REQ_OP_WRITE;
+
+       if (use_fua)
+               opflags |= REQ_FUA;
+       else
+               dio->flags &= ~IOMAP_DIO_WRITE_FUA;
+
+       return opflags;
+}
+
 static loff_t
 iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
                struct iomap_dio *dio, struct iomap *iomap)
@@ -208,6 +236,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
        unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev));
        unsigned int fs_block_size = i_blocksize(inode), pad;
        unsigned int align = iov_iter_alignment(dio->submit.iter);
+       unsigned int bio_opf;
        struct bio *bio;
        bool need_zeroout = false;
        bool use_fua = false;
@@ -263,6 +292,13 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
                        iomap_dio_zero(dio, iomap, pos - pad, pad);
        }
 
+       /*
+        * Set the operation flags early so that bio_iov_iter_get_pages
+        * can set up the page vector appropriately for a ZONE_APPEND
+        * operation.
+        */
+       bio_opf = iomap_dio_bio_opflags(dio, iomap, use_fua);
+
        do {
                size_t n;
                if (dio->error) {
@@ -278,6 +314,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
                bio->bi_ioprio = dio->iocb->ki_ioprio;
                bio->bi_private = dio;
                bio->bi_end_io = iomap_dio_bio_end_io;
+               bio->bi_opf = bio_opf;
 
                ret = bio_iov_iter_get_pages(bio, dio->submit.iter);
                if (unlikely(ret)) {
@@ -293,14 +330,8 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length,
 
                n = bio->bi_iter.bi_size;
                if (dio->flags & IOMAP_DIO_WRITE) {
-                       bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
-                       if (use_fua)
-                               bio->bi_opf |= REQ_FUA;
-                       else
-                               dio->flags &= ~IOMAP_DIO_WRITE_FUA;
                        task_io_account_write(n);
                } else {
-                       bio->bi_opf = REQ_OP_READ;
                        if (dio->flags & IOMAP_DIO_DIRTY)
                                bio_set_pages_dirty(bio);
                }

diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 5bd3cac..8ebb1fa 100644 (file)
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -55,6 +55,7 @@ struct vm_fault;
 #define IOMAP_F_SHARED         0x04
 #define IOMAP_F_MERGED         0x08
 #define IOMAP_F_BUFFER_HEAD    0x10
+#define IOMAP_F_ZONE_APPEND    0x20
 
 /*
  * Flags set by the core iomap code during operations: