xfs: split out a new set of read-only iomap ops

Start untangling xfs_file_iomap_begin by splitting out the read-only
case into its own set of iomap_ops with a very simply iomap_begin
helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 5936507c6f50d954041aceb186e45149d08475f0..5d3503f6412a44328ea22c7a1d6936aa12065d19 100644 (file)
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -634,7 +634,7 @@ xfs_vm_bmap(
         */
        if (xfs_is_cow_inode(ip) || XFS_IS_REALTIME_INODE(ip))
                return 0;
-       return iomap_bmap(mapping, block, &xfs_iomap_ops);
+       return iomap_bmap(mapping, block, &xfs_read_iomap_ops);
 }
 
 STATIC int
@@ -642,7 +642,7 @@ xfs_vm_readpage(
        struct file             *unused,
        struct page             *page)
 {
-       return iomap_readpage(page, &xfs_iomap_ops);
+       return iomap_readpage(page, &xfs_read_iomap_ops);
 }
 
 STATIC int
@@ -652,7 +652,7 @@ xfs_vm_readpages(
        struct list_head        *pages,
        unsigned                nr_pages)
 {
-       return iomap_readpages(mapping, pages, nr_pages, &xfs_iomap_ops);
+       return iomap_readpages(mapping, pages, nr_pages, &xfs_read_iomap_ops);
 }
 
 static int
@@ -662,7 +662,8 @@ xfs_iomap_swapfile_activate(
        sector_t                        *span)
 {
        sis->bdev = xfs_find_bdev_for_inode(file_inode(swap_file));
-       return iomap_swapfile_activate(sis, swap_file, span, &xfs_iomap_ops);
+       return iomap_swapfile_activate(sis, swap_file, span,
+                       &xfs_read_iomap_ops);
 }
 
 const struct address_space_operations xfs_address_space_operations = {

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index c0620135a279d8533f7c088066dbc8997c2e1b3b..e3299ffdf090ca58329a477a69a195c23f350e7d 100644 (file)
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -188,7 +188,8 @@ xfs_file_dio_aio_read(
        file_accessed(iocb->ki_filp);
 
        xfs_ilock(ip, XFS_IOLOCK_SHARED);
-       ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL, is_sync_kiocb(iocb));
+       ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL,
+                       is_sync_kiocb(iocb));
        xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 
        return ret;
@@ -215,7 +216,7 @@ xfs_file_dax_read(
                xfs_ilock(ip, XFS_IOLOCK_SHARED);
        }
 
-       ret = dax_iomap_rw(iocb, to, &xfs_iomap_ops);
+       ret = dax_iomap_rw(iocb, to, &xfs_read_iomap_ops);
        xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 
        file_accessed(iocb->ki_filp);
@@ -1153,7 +1154,9 @@ __xfs_filemap_fault(
        if (IS_DAX(inode)) {
                pfn_t pfn;
 
-               ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL, &xfs_iomap_ops);
+               ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL,
+                               (write_fault && !vmf->cow_page) ?
+                                &xfs_iomap_ops : &xfs_read_iomap_ops);
                if (ret & VM_FAULT_NEEDDSYNC)
                        ret = dax_finish_sync_fault(vmf, pe_size, pfn);
        } else {

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 528b3589823195b55083b106a32ef4307b0e164d..3bd1f7d62f4ccc6d0701d0eed54fc6bbf7cacd09 100644 (file)
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -950,11 +950,13 @@ xfs_file_iomap_begin(
        u16                     iomap_flags = 0;
        unsigned                lockmode;
 
+       ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));
+
        if (XFS_FORCED_SHUTDOWN(mp))
                return -EIO;
 
-       if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && !(flags & IOMAP_DIRECT) &&
-                       !IS_DAX(inode) && !xfs_get_extsz_hint(ip)) {
+       if (!(flags & IOMAP_DIRECT) && !IS_DAX(inode) &&
+           !xfs_get_extsz_hint(ip)) {
                /* Reserve delalloc blocks for regular writeback. */
                return xfs_file_iomap_begin_delay(inode, offset, length, flags,
                                iomap, srcmap);
@@ -975,17 +977,6 @@ xfs_file_iomap_begin(
        if (error)
                goto out_unlock;
 
-       if (flags & IOMAP_REPORT) {
-               /* Trim the mapping to the nearest shared extent boundary. */
-               error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
-               if (error)
-                       goto out_unlock;
-       }
-
-       /* Non-modifying mapping requested, so we are done */
-       if (!(flags & (IOMAP_WRITE | IOMAP_ZERO)))
-               goto out_found;
-
        /*
         * Break shared extents if necessary. Checks for non-blocking IO have
         * been done up front, so we don't need to do them here.
@@ -1051,10 +1042,8 @@ out_finish:
         * so consider them to be dirty for the purposes of O_DSYNC even if
         * there is no other metadata changes pending or have been made here.
         */
-       if ((flags & IOMAP_WRITE) && offset + length > i_size_read(inode))
+       if (offset + length > i_size_read(inode))
                iomap_flags |= IOMAP_F_DIRTY;
-       if (shared)
-               iomap_flags |= IOMAP_F_SHARED;
        return xfs_bmbt_to_iomap(ip, iomap, &imap, iomap_flags);
 
 out_found:
@@ -1157,6 +1146,48 @@ const struct iomap_ops xfs_iomap_ops = {
        .iomap_end              = xfs_file_iomap_end,
 };
 
+static int
+xfs_read_iomap_begin(
+       struct inode            *inode,
+       loff_t                  offset,
+       loff_t                  length,
+       unsigned                flags,
+       struct iomap            *iomap,
+       struct iomap            *srcmap)
+{
+       struct xfs_inode        *ip = XFS_I(inode);
+       struct xfs_mount        *mp = ip->i_mount;
+       struct xfs_bmbt_irec    imap;
+       xfs_fileoff_t           offset_fsb = XFS_B_TO_FSBT(mp, offset);
+       xfs_fileoff_t           end_fsb = xfs_iomap_end_fsb(mp, offset, length);
+       int                     nimaps = 1, error = 0;
+       bool                    shared = false;
+       unsigned                lockmode;
+
+       ASSERT(!(flags & (IOMAP_WRITE | IOMAP_ZERO)));
+
+       if (XFS_FORCED_SHUTDOWN(mp))
+               return -EIO;
+
+       error = xfs_ilock_for_iomap(ip, flags, &lockmode);
+       if (error)
+               return error;
+       error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
+                              &nimaps, 0);
+       if (!error && (flags & IOMAP_REPORT))
+               error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
+       xfs_iunlock(ip, lockmode);
+
+       if (error)
+               return error;
+       trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
+       return xfs_bmbt_to_iomap(ip, iomap, &imap, shared ? IOMAP_F_SHARED : 0);
+}
+
+const struct iomap_ops xfs_read_iomap_ops = {
+       .iomap_begin            = xfs_read_iomap_begin,
+};
+
 static int
 xfs_seek_iomap_begin(
        struct inode            *inode,

diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index 71d0ae460c44021a791537800331f3b4751ec166..61b1fc3e5143a82dc9b5fa09d84c8a773a59aca4 100644 (file)
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -40,6 +40,7 @@ xfs_aligned_fsb_count(
 }
 
 extern const struct iomap_ops xfs_iomap_ops;
+extern const struct iomap_ops xfs_read_iomap_ops;
 extern const struct iomap_ops xfs_seek_iomap_ops;
 extern const struct iomap_ops xfs_xattr_iomap_ops;
 

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index fe285d123d69f1eb8c749ad145a02ea36c96904a..9c448a54a951c16fa3a559a7347eb182dc2266a1 100644 (file)
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1114,7 +1114,7 @@ xfs_vn_fiemap(
                                &xfs_xattr_iomap_ops);
        } else {
                error = iomap_fiemap(inode, fieinfo, start, length,
-                               &xfs_iomap_ops);
+                               &xfs_read_iomap_ops);
        }
        xfs_iunlock(XFS_I(inode), XFS_IOLOCK_SHARED);