ext4: add flag to ext4_has_free_blocks

This patch adds an allocation request flag to the ext4_has_free_blocks
function which enables the use of reserved blocks.  This will allow a
punch hole to proceed even if the disk is full.  Punching a hole may
require additional blocks to first split the extents.

Because ext4_has_free_blocks is a low level function, the flag needs
to be passed down through several functions listed below:

ext4_ext_insert_extent
ext4_ext_create_new_leaf
ext4_ext_grow_indepth
ext4_ext_split
ext4_ext_new_meta_block
ext4_mb_new_blocks
ext4_claim_free_blocks
ext4_has_free_blocks

[ext4 punch hole patch series 1/5 v7]

Signed-off-by: Allison Henderson <achender@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Mingming Cao <cmm@us.ibm.com>

1 files changed, 22 insertions, 13 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index ca62d748cc65..aa3a2601bada 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -192,12 +192,13 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 static ext4_fsblk_t
 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
                         struct ext4_ext_path *path,
-                        struct ext4_extent *ex, int *err)
+                        struct ext4_extent *ex, int *err, unsigned int flags)
 {
         ext4_fsblk_t goal, newblock;
 
         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
-        newblock = ext4_new_meta_blocks(handle, inode, goal, NULL, err);
+        newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
+                                        NULL, err);
         return newblock;
 }
 
@@ -792,8 +793,9 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
  * - initializes subtree
  */
 static int ext4_ext_split(handle_t *handle, struct inode *inode,
-                                struct ext4_ext_path *path,
-                                struct ext4_extent *newext, int at)
+                          unsigned int flags,
+                          struct ext4_ext_path *path,
+                          struct ext4_extent *newext, int at)
 {
         struct buffer_head *bh = NULL;
         int depth = ext_depth(inode);
@@ -847,7 +849,7 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
         for (a = 0; a < depth - at; a++) {
                 newblock = ext4_ext_new_meta_block(handle, inode, path,
-                                                   newext, &err);
+                                                   newext, &err, flags);
                 if (newblock == 0)
                         goto cleanup;
                 ablocks[a] = newblock;
@@ -1056,8 +1058,9 @@ cleanup:
  *   just created block
  */
 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
-                                        struct ext4_ext_path *path,
-                                        struct ext4_extent *newext)
+                                 unsigned int flags,
+                                 struct ext4_ext_path *path,
+                                 struct ext4_extent *newext)
 {
         struct ext4_ext_path *curp = path;
         struct ext4_extent_header *neh;
@@ -1065,7 +1068,8 @@ static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
         ext4_fsblk_t newblock;
         int err = 0;
 
-        newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err);
+        newblock = ext4_ext_new_meta_block(handle, inode, path,
+                newext, &err, flags);
         if (newblock == 0)
                 return err;
 
@@ -1140,8 +1144,9 @@ out:
  * if no free index is found, then it requests in-depth growing.
  */
 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
-                                        struct ext4_ext_path *path,
-                                        struct ext4_extent *newext)
+                                    unsigned int flags,
+                                    struct ext4_ext_path *path,
+                                    struct ext4_extent *newext)
 {
         struct ext4_ext_path *curp;
         int depth, i, err = 0;
@@ -1161,7 +1166,7 @@ repeat:
         if (EXT_HAS_FREE_INDEX(curp)) {
                 /* if we found index with free entry, then use that
                  * entry: create all needed subtree and add new leaf */
-                err = ext4_ext_split(handle, inode, path, newext, i);
+                err = ext4_ext_split(handle, inode, flags, path, newext, i);
                 if (err)
                         goto out;
 
@@ -1174,7 +1179,8 @@ repeat:
                         err = PTR_ERR(path);
         } else {
                 /* tree is full, time to grow in depth */
-                err = ext4_ext_grow_indepth(handle, inode, path, newext);
+                err = ext4_ext_grow_indepth(handle, inode, flags,
+                                            path, newext);
                 if (err)
                         goto out;
 
@@ -1693,6 +1699,7 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
         int depth, len, err;
         ext4_lblk_t next;
         unsigned uninitialized = 0;
+        int flags = 0;
 
         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
@@ -1767,7 +1774,9 @@ repeat:
          * There is no free space in the found leaf.
          * We're gonna add a new leaf in the tree.
          */
-        err = ext4_ext_create_new_leaf(handle, inode, path, newext);
+        if (flag & EXT4_GET_BLOCKS_PUNCH_OUT_EXT)
+                flags = EXT4_MB_USE_ROOT_BLOCKS;
+        err = ext4_ext_create_new_leaf(handle, inode, flags, path, newext);
         if (err)
                 goto cleanup;
         depth = ext_depth(inode);