ufs_inode_getfrag(): split extending the partial blocks off

ufs_extend_tail() is handling that now.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 65 insertions, 63 deletions

diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c
index 25d47df934e2..d652f64885fd 100644
--- a/fs/ufs/inode.c
+++ b/fs/ufs/inode.c
@@ -205,6 +205,40 @@ changed:
         goto again;
 }
 
+/*
+ * Unpacking tails: we have a file with partial final block and
+ * we had been asked to extend it.  If the fragment being written
+ * is within the same block, we need to extend the tail just to cover
+ * that fragment.  Otherwise the tail is extended to full block.
+ *
+ * Note that we might need to create a _new_ tail, but that will
+ * be handled elsewhere; this is strictly for resizing old
+ * ones.
+ */
+static bool
+ufs_extend_tail(struct inode *inode, u64 writes_to,
+                  int *err, struct page *locked_page)
+{
+        struct ufs_inode_info *ufsi = UFS_I(inode);
+        struct super_block *sb = inode->i_sb;
+        struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
+        unsigned lastfrag = ufsi->i_lastfrag;   /* it's a short file, so unsigned is enough */
+        unsigned block = ufs_fragstoblks(lastfrag);
+        unsigned new_size;
+        void *p;
+        u64 tmp;
+
+        if (writes_to < (lastfrag | uspi->s_fpbmask))
+                new_size = (writes_to & uspi->s_fpbmask) + 1;
+        else
+                new_size = uspi->s_fpb;
+
+        p = ufs_get_direct_data_ptr(uspi, ufsi, block);
+        tmp = ufs_new_fragments(inode, p, lastfrag, ufs_data_ptr_to_cpu(sb, p),
+                                new_size, err, locked_page);
+        return tmp != 0;
+}
+
 /**
  * ufs_inode_getfrag() - allocate new fragment(s)
  * @inode: pointer to inode
@@ -226,13 +260,10 @@ ufs_inode_getfrag(struct inode *inode, u64 fragment,
         struct ufs_inode_info *ufsi = UFS_I(inode);
         struct super_block *sb = inode->i_sb;
         struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
-        unsigned blockoff, lastblockoff;
-        u64 tmp, goal, lastfrag, block, lastblock;
-        void *p, *p2;
-
-        UFSD("ENTER, ino %lu, fragment %llu, new_fragment %llu, required %u, "
-             "metadata %d\n", inode->i_ino, (unsigned long long)fragment,
-             (unsigned long long)new_fragment, required, !phys);
+        unsigned blockoff;
+        u64 tmp, goal, lastfrag, block;
+        unsigned nfrags = uspi->s_fpb;
+        void *p;
 
         /* TODO : to be done for write support
         if ( (flags & UFS_TYPE_MASK) == UFS_TYPE_UFS2)
@@ -242,66 +273,27 @@ ufs_inode_getfrag(struct inode *inode, u64 fragment,
         block = ufs_fragstoblks (fragment);
         blockoff = ufs_fragnum (fragment);
         p = ufs_get_direct_data_ptr(uspi, ufsi, block);
-
-        goal = 0;
-
         tmp = ufs_data_ptr_to_cpu(sb, p);
+        if (tmp)
+                goto out;
 
         lastfrag = ufsi->i_lastfrag;
-        if (tmp && fragment < lastfrag)
-                goto out;
 
-        lastblock = ufs_fragstoblks (lastfrag);
-        lastblockoff = ufs_fragnum (lastfrag);
-        /*
-         * We will extend file into new block beyond last allocated block
-         */
-        if (lastblock < block) {
-                /*
-                 * We must reallocate last allocated block
-                 */
-                if (lastblockoff) {
-                        p2 = ufs_get_direct_data_ptr(uspi, ufsi, lastblock);
-                        tmp = ufs_new_fragments(inode, p2, lastfrag,
-                                                ufs_data_ptr_to_cpu(sb, p2),
-                                                uspi->s_fpb - lastblockoff,
-                                                err, locked_page);
-                        if (!tmp)
-                                return 0;
-                        lastfrag = ufsi->i_lastfrag;
-                }
-                tmp = ufs_data_ptr_to_cpu(sb,
-                                         ufs_get_direct_data_ptr(uspi, ufsi,
-                                                                 lastblock));
-                if (tmp)
-                        goal = tmp + uspi->s_fpb;
-                tmp = ufs_new_fragments (inode, p, fragment - blockoff,
-                                         goal, required + blockoff,
-                                         err,
-                                         phys != NULL ? locked_page : NULL);
-        } else if (lastblock == block) {
-        /*
-         * We will extend last allocated block
-         */
-                tmp = ufs_new_fragments(inode, p, fragment -
-                                        (blockoff - lastblockoff),
-                                        ufs_data_ptr_to_cpu(sb, p),
-                                        required +  (blockoff - lastblockoff),
-                                        err, phys != NULL ? locked_page : NULL);
-        } else /* (lastblock > block) */ {
-        /*
-         * We will allocate new block before last allocated block
-         */
-                if (block) {
-                        tmp = ufs_data_ptr_to_cpu(sb,
-                                                 ufs_get_direct_data_ptr(uspi, ufsi, block - 1));
-                        if (tmp)
-                                goal = tmp + uspi->s_fpb;
-                }
-                tmp = ufs_new_fragments(inode, p, fragment - blockoff,
-                                        goal, uspi->s_fpb, err,
-                                        phys != NULL ? locked_page : NULL);
+        /* will that be a new tail? */
+        if (new_fragment < UFS_NDIR_FRAGMENT && new_fragment >= lastfrag)
+                nfrags = (new_fragment & uspi->s_fpbmask) + 1;
+
+        goal = 0;
+        if (block) {
+                goal = ufs_data_ptr_to_cpu(sb,
+                                 ufs_get_direct_data_ptr(uspi, ufsi, block - 1));
+                if (goal)
+                        goal += uspi->s_fpb;
         }
+        tmp = ufs_new_fragments(inode, p, fragment - blockoff,
+                                goal, uspi->s_fpb, err,
+                                phys != NULL ? locked_page : NULL);
+
         if (!tmp) {
                 *err = -ENOSPC;
                 return 0;
@@ -419,7 +411,6 @@ static int ufs_getfrag_block(struct inode *inode, sector_t fragment, struct buff
         unsigned long ptr,phys;
         u64 phys64 = 0;
         unsigned frag = fragment & uspi->s_fpbmask;
-        unsigned mask = uspi->s_apbmask >> uspi->s_fpbshift;
 
         if (!create) {
                 phys64 = ufs_frag_map(inode, offsets, depth);
@@ -444,6 +435,17 @@ static int ufs_getfrag_block(struct inode *inode, sector_t fragment, struct buff
                 goto abort_too_big;
 
         err = 0;
+
+        if (UFS_I(inode)->i_lastfrag < UFS_NDIR_FRAGMENT) {
+                unsigned lastfrag = UFS_I(inode)->i_lastfrag;
+                unsigned tailfrags = lastfrag & uspi->s_fpbmask;
+                if (tailfrags && fragment >= lastfrag) {
+                        if (!ufs_extend_tail(inode, fragment,
+                                             &err, bh_result->b_page))
+                                goto abort;
+                }
+        }
+
         ptr = fragment;
 
         if (depth == 1) {