xfs: initialize iomap->flags in xfs_bmbt_to_iomap

Currently we don't overwrite the flags field in the iomap in
xfs_bmbt_to_iomap.  This works fine with 0-initialized iomaps on stack,
but is harmful once we want to be able to reuse an iomap in the
writeback code.  Replace the shared parameter with a set of initial
flags an thus ensures the flags field is always reinitialized.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
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_iomap.c b/fs/xfs/xfs_iomap.c
index 32993c2..699bbb8 100644 (file)
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -54,7 +54,7 @@ xfs_bmbt_to_iomap(
        struct xfs_inode        *ip,
        struct iomap            *iomap,
        struct xfs_bmbt_irec    *imap,
-       bool                    shared)
+       u16                     flags)
 {
        struct xfs_mount        *mp = ip->i_mount;
 
@@ -79,12 +79,11 @@ xfs_bmbt_to_iomap(
        iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
        iomap->bdev = xfs_find_bdev_for_inode(VFS_I(ip));
        iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip));
+       iomap->flags = flags;
 
        if (xfs_ipincount(ip) &&
            (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
                iomap->flags |= IOMAP_F_DIRTY;
-       if (shared)
-               iomap->flags |= IOMAP_F_SHARED;
        return 0;
 }
 
@@ -540,6 +539,7 @@ xfs_file_iomap_begin_delay(
        struct xfs_iext_cursor  icur, ccur;
        xfs_fsblock_t           prealloc_blocks = 0;
        bool                    eof = false, cow_eof = false, shared = false;
+       u16                     iomap_flags = 0;
        int                     whichfork = XFS_DATA_FORK;
        int                     error = 0;
 
@@ -707,7 +707,7 @@ retry:
         * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
         * them out if the write happens to fail.
         */
-       iomap->flags |= IOMAP_F_NEW;
+       iomap_flags |= IOMAP_F_NEW;
        trace_xfs_iomap_alloc(ip, offset, count, whichfork,
                        whichfork == XFS_DATA_FORK ? &imap : &cmap);
 done:
@@ -715,14 +715,17 @@ done:
                if (imap.br_startoff > offset_fsb) {
                        xfs_trim_extent(&cmap, offset_fsb,
                                        imap.br_startoff - offset_fsb);
-                       error = xfs_bmbt_to_iomap(ip, iomap, &cmap, true);
+                       error = xfs_bmbt_to_iomap(ip, iomap, &cmap,
+                                       IOMAP_F_SHARED);
                        goto out_unlock;
                }
                /* ensure we only report blocks we have a reservation for */
                xfs_trim_extent(&imap, cmap.br_startoff, cmap.br_blockcount);
                shared = true;
        }
-       error = xfs_bmbt_to_iomap(ip, iomap, &imap, shared);
+       if (shared)
+               iomap_flags |= IOMAP_F_SHARED;
+       error = xfs_bmbt_to_iomap(ip, iomap, &imap, iomap_flags);
 out_unlock:
        xfs_iunlock(ip, XFS_ILOCK_EXCL);
        return error;
@@ -930,6 +933,7 @@ xfs_file_iomap_begin(
        xfs_fileoff_t           offset_fsb, end_fsb;
        int                     nimaps = 1, error = 0;
        bool                    shared = false;
+       u16                     iomap_flags = 0;
        unsigned                lockmode;
 
        if (XFS_FORCED_SHUTDOWN(mp))
@@ -1045,7 +1049,7 @@ xfs_file_iomap_begin(
        if (error)
                return error;
 
-       iomap->flags |= IOMAP_F_NEW;
+       iomap_flags |= IOMAP_F_NEW;
        trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
 
 out_finish:
@@ -1055,8 +1059,10 @@ out_finish:
         * there is no other metadata changes pending or have been made here.
         */
        if ((flags & IOMAP_WRITE) && offset + length > i_size_read(inode))
-               iomap->flags |= IOMAP_F_DIRTY;
-       return xfs_bmbt_to_iomap(ip, iomap, &imap, shared);
+               iomap_flags |= IOMAP_F_DIRTY;
+       if (shared)
+               iomap_flags |= IOMAP_F_SHARED;
+       return xfs_bmbt_to_iomap(ip, iomap, &imap, iomap_flags);
 
 out_found:
        ASSERT(nimaps);
@@ -1200,7 +1206,7 @@ xfs_seek_iomap_begin(
                if (data_fsb < cow_fsb + cmap.br_blockcount)
                        end_fsb = min(end_fsb, data_fsb);
                xfs_trim_extent(&cmap, offset_fsb, end_fsb);
-               error = xfs_bmbt_to_iomap(ip, iomap, &cmap, true);
+               error = xfs_bmbt_to_iomap(ip, iomap, &cmap, IOMAP_F_SHARED);
                /*
                 * This is a COW extent, so we must probe the page cache
                 * because there could be dirty page cache being backed
@@ -1222,7 +1228,7 @@ xfs_seek_iomap_begin(
        imap.br_state = XFS_EXT_NORM;
 done:
        xfs_trim_extent(&imap, offset_fsb, end_fsb);
-       error = xfs_bmbt_to_iomap(ip, iomap, &imap, false);
+       error = xfs_bmbt_to_iomap(ip, iomap, &imap, 0);
 out_unlock:
        xfs_iunlock(ip, lockmode);
        return error;
@@ -1268,7 +1274,7 @@ out_unlock:
        if (error)
                return error;
        ASSERT(nimaps);
-       return xfs_bmbt_to_iomap(ip, iomap, &imap, false);
+       return xfs_bmbt_to_iomap(ip, iomap, &imap, 0);
 }
 
 const struct iomap_ops xfs_xattr_iomap_ops = {

diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index 5c2f6aa..71d0ae4 100644 (file)
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -16,7 +16,7 @@ int xfs_iomap_write_direct(struct xfs_inode *, xfs_off_t, size_t,
 int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, xfs_off_t, bool);
 
 int xfs_bmbt_to_iomap(struct xfs_inode *, struct iomap *,
-               struct xfs_bmbt_irec *, bool shared);
+               struct xfs_bmbt_irec *, u16);
 xfs_extlen_t xfs_eof_alignment(struct xfs_inode *ip, xfs_extlen_t extsize);
 
 static inline xfs_filblks_t

diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
index a339bd5..9c96493 100644 (file)
--- a/fs/xfs/xfs_pnfs.c
+++ b/fs/xfs/xfs_pnfs.c
@@ -178,7 +178,7 @@ xfs_fs_map_blocks(
        }
        xfs_iunlock(ip, XFS_IOLOCK_EXCL);
 
-       error = xfs_bmbt_to_iomap(ip, iomap, &imap, false);
+       error = xfs_bmbt_to_iomap(ip, iomap, &imap, 0);
        *device_generation = mp->m_generation;
        return error;
 out_unlock: