ext4: Define a new set of flags for ext4_get_blocks()

The functions ext4_get_blocks(), ext4_ext_get_blocks(), and
ext4_ind_get_blocks() used an ad-hoc set of integer variables used as
boolean flags passed in as arguments.  Use a single flags parameter
and a setandard set of bitfield flags instead.  This saves space on
the call stack, and it also makes the code a bit more understandable.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

4 files changed, 57 insertions, 46 deletions

diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 052d6378f997..9dc93168e262 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -131,7 +131,7 @@ static int ext4_readdir(struct file *filp,
                 struct buffer_head *bh = NULL;
 
                 map_bh.b_state = 0;
-                err = ext4_get_blocks(NULL, inode, blk, 1, &map_bh, 0, 0, 0);
+                err = ext4_get_blocks(NULL, inode, blk, 1, &map_bh, 0);
                 if (err > 0) {
                         pgoff_t index = map_bh.b_blocknr >>
                                         (PAGE_CACHE_SHIFT - inode->i_blkbits);
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 5dc8368e46bc..17feb4ac633a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -314,10 +314,20 @@ struct ext4_new_group_data {
 };
 
 /*
- * Following is used by preallocation code to tell get_blocks() that we
- * want uninitialzed extents.
+ * Flags used by ext4_get_blocks()
  */
-#define EXT4_CREATE_UNINITIALIZED_EXT           2
+        /* Allocate any needed blocks and/or convert an unitialized
+           extent to be an initialized ext4 */
+#define EXT4_GET_BLOCKS_CREATE                  1
+        /* Request the creation of an unitialized extent */
+#define EXT4_GET_BLOCKS_UNINIT_EXT              2
+#define EXT4_GET_BLOCKS_CREATE_UNINIT_EXT       (EXT4_GET_BLOCKS_UNINIT_EXT|\
+                                                 EXT4_GET_BLOCKS_CREATE)
+        /* Update the ext4_inode_info i_disksize field */
+#define EXT4_GET_BLOCKS_EXTEND_DISKSIZE         4
+        /* Caller is from the delayed allocation writeout path,
+           so the filesystem blocks have already been accounted for */
+#define EXT4_GET_BLOCKS_DELALLOC_RESERVE        8
 
 /*
  * ioctl commands
@@ -1610,8 +1620,7 @@ extern int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks,
                                        int chunk);
 extern int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                                ext4_lblk_t iblock, unsigned int max_blocks,
-                               struct buffer_head *bh_result,
-                               int create, int extend_disksize);
+                               struct buffer_head *bh_result, int flags);
 extern void ext4_ext_truncate(struct inode *);
 extern void ext4_ext_init(struct super_block *);
 extern void ext4_ext_release(struct super_block *);
@@ -1619,8 +1628,7 @@ extern long ext4_fallocate(struct inode *inode, int mode, loff_t offset,
                           loff_t len);
 extern int ext4_get_blocks(handle_t *handle, struct inode *inode,
                            sector_t block, unsigned int max_blocks,
-                           struct buffer_head *bh, int create,
-                           int extend_disksize, int flag);
+                           struct buffer_head *bh, int flags);
 extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
                         __u64 start, __u64 len);
 
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 7e7d02dd2739..27c383c7b43c 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2784,7 +2784,7 @@ fix_extent_len:
 int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                         ext4_lblk_t iblock,
                         unsigned int max_blocks, struct buffer_head *bh_result,
-                        int create, int extend_disksize)
+                        int flags)
 {
         struct ext4_ext_path *path = NULL;
         struct ext4_extent_header *eh;
@@ -2803,7 +2803,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
         cache_type = ext4_ext_in_cache(inode, iblock, &newex);
         if (cache_type) {
                 if (cache_type == EXT4_EXT_CACHE_GAP) {
-                        if (!create) {
+                        if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
                                 /*
                                  * block isn't allocated yet and
                                  * user doesn't want to allocate it
@@ -2869,9 +2869,9 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                                                         EXT4_EXT_CACHE_EXTENT);
                                 goto out;
                         }
-                        if (create == EXT4_CREATE_UNINITIALIZED_EXT)
+                        if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)
                                 goto out;
-                        if (!create) {
+                        if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
                                 if (allocated > max_blocks)
                                         allocated = max_blocks;
                                 /*
@@ -2903,7 +2903,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
          * requested block isn't allocated yet;
          * we couldn't try to create block if create flag is zero
          */
-        if (!create) {
+        if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
                 /*
                  * put just found gap into cache to speed up
                  * subsequent requests
@@ -2932,10 +2932,10 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
          * EXT_UNINIT_MAX_LEN.
          */
         if (max_blocks > EXT_INIT_MAX_LEN &&
-            create != EXT4_CREATE_UNINITIALIZED_EXT)
+            !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
                 max_blocks = EXT_INIT_MAX_LEN;
         else if (max_blocks > EXT_UNINIT_MAX_LEN &&
-                 create == EXT4_CREATE_UNINITIALIZED_EXT)
+                 (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
                 max_blocks = EXT_UNINIT_MAX_LEN;
 
         /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */
@@ -2966,7 +2966,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
         /* try to insert new extent into found leaf and return */
         ext4_ext_store_pblock(&newex, newblock);
         newex.ee_len = cpu_to_le16(ar.len);
-        if (create == EXT4_CREATE_UNINITIALIZED_EXT)  /* Mark uninitialized */
+        if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)  /* Mark uninitialized */
                 ext4_ext_mark_uninitialized(&newex);
         err = ext4_ext_insert_extent(handle, inode, path, &newex);
         if (err) {
@@ -2983,7 +2983,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
         newblock = ext_pblock(&newex);
         allocated = ext4_ext_get_actual_len(&newex);
 outnew:
-        if (extend_disksize) {
+        if (flags & EXT4_GET_BLOCKS_EXTEND_DISKSIZE) {
                 disksize = ((loff_t) iblock + ar.len) << inode->i_blkbits;
                 if (disksize > i_size_read(inode))
                         disksize = i_size_read(inode);
@@ -2994,7 +2994,7 @@ outnew:
         set_buffer_new(bh_result);
 
         /* Cache only when it is _not_ an uninitialized extent */
-        if (create != EXT4_CREATE_UNINITIALIZED_EXT)
+        if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0)
                 ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
                                                 EXT4_EXT_CACHE_EXTENT);
 out:
@@ -3153,7 +3153,7 @@ retry:
                 map_bh.b_state = 0;
                 ret = ext4_get_blocks(handle, inode, block,
                                       max_blocks, &map_bh,
-                                      EXT4_CREATE_UNINITIALIZED_EXT, 0, 0);
+                                      EXT4_GET_BLOCKS_CREATE_UNINIT_EXT);
                 if (ret <= 0) {
 #ifdef EXT4FS_DEBUG
                         WARN_ON(ret <= 0);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index a9a9b9b77e8e..8b7564dfacdf 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -917,7 +917,7 @@ err_out:
 static int ext4_ind_get_blocks(handle_t *handle, struct inode *inode,
                                   ext4_lblk_t iblock, unsigned int maxblocks,
                                   struct buffer_head *bh_result,
-                                  int create, int extend_disksize)
+                                  int flags)
 {
         int err = -EIO;
         ext4_lblk_t offsets[4];
@@ -934,7 +934,7 @@ static int ext4_ind_get_blocks(handle_t *handle, struct inode *inode,
 
 
         J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
-        J_ASSERT(handle != NULL || create == 0);
+        J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
         depth = ext4_block_to_path(inode, iblock, offsets,
                                         &blocks_to_boundary);
 
@@ -963,7 +963,7 @@ static int ext4_ind_get_blocks(handle_t *handle, struct inode *inode,
         }
 
         /* Next simple case - plain lookup or failed read of indirect block */
-        if (!create || err == -EIO)
+        if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
                 goto cleanup;
 
         /*
@@ -1002,7 +1002,7 @@ static int ext4_ind_get_blocks(handle_t *handle, struct inode *inode,
          * protect it if you're about to implement concurrent
          * ext4_get_block() -bzzz
         */
-        if (!err && extend_disksize) {
+        if (!err && (flags & EXT4_GET_BLOCKS_EXTEND_DISKSIZE)) {
                 disksize = ((loff_t) iblock + count) << inode->i_blkbits;
                 if (disksize > i_size_read(inode))
                         disksize = i_size_read(inode);
@@ -1144,7 +1144,7 @@ static void ext4_da_update_reserve_space(struct inode *inode, int used)
  */
 int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
                     unsigned int max_blocks, struct buffer_head *bh,
-                    int create, int extend_disksize, int flag)
+                    int flags)
 {
         int retval;
 
@@ -1158,15 +1158,15 @@ int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
         down_read((&EXT4_I(inode)->i_data_sem));
         if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
                 retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
-                                bh, 0, 0);
+                                bh, 0);
         } else {
                 retval = ext4_ind_get_blocks(handle, inode, block, max_blocks,
-                                             bh, 0, 0);
+                                             bh, 0);
         }
         up_read((&EXT4_I(inode)->i_data_sem));
 
         /* If it is only a block(s) look up */
-        if (!create)
+        if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
                 return retval;
 
         /*
@@ -1205,7 +1205,7 @@ int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
          * let the underlying get_block() function know to
          * avoid double accounting
          */
-        if (flag)
+        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
                 EXT4_I(inode)->i_delalloc_reserved_flag = 1;
         /*
          * We need to check for EXT4 here because migrate
@@ -1213,10 +1213,10 @@ int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
          */
         if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
                 retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
-                                bh, create, extend_disksize);
+                                              bh, flags);
         } else {
                 retval = ext4_ind_get_blocks(handle, inode, block,
-                                max_blocks, bh, create, extend_disksize);
+                                             max_blocks, bh, flags);
 
                 if (retval > 0 && buffer_new(bh)) {
                         /*
@@ -1229,7 +1229,7 @@ int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
                 }
         }
 
-        if (flag) {
+        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
                 EXT4_I(inode)->i_delalloc_reserved_flag = 0;
                 /*
                  * Update reserved blocks/metadata blocks
@@ -1269,7 +1269,7 @@ int ext4_get_block(struct inode *inode, sector_t iblock,
         }
 
         ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
-                              create, 0, 0);
+                              create ? EXT4_GET_BLOCKS_CREATE : 0);
         if (ret > 0) {
                 bh_result->b_size = (ret << inode->i_blkbits);
                 ret = 0;
@@ -1288,16 +1288,19 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
 {
         struct buffer_head dummy;
         int fatal = 0, err;
+        int flags = EXT4_GET_BLOCKS_EXTEND_DISKSIZE;
 
         J_ASSERT(handle != NULL || create == 0);
 
         dummy.b_state = 0;
         dummy.b_blocknr = -1000;
         buffer_trace_init(&dummy.b_history);
-        err = ext4_get_blocks(handle, inode, block, 1, &dummy, create, 1, 0);
+        if (create)
+                flags |= EXT4_GET_BLOCKS_CREATE;
+        err = ext4_get_blocks(handle, inode, block, 1, &dummy, flags);
         /*
-         * ext4_get_blocks() returns number of blocks
-         * mapped. 0 in case of a HOLE.
+         * ext4_get_blocks() returns number of blocks mapped. 0 in
+         * case of a HOLE.
          */
         if (err > 0) {
                 if (err > 1)
@@ -1997,7 +2000,6 @@ static void ext4_print_free_blocks(struct inode *inode)
         return;
 }
 
-#define         EXT4_DELALLOC_RSVED     1
 static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
                                    struct buffer_head *bh_result)
 {
@@ -2009,7 +2011,8 @@ static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
         handle = ext4_journal_current_handle();
         BUG_ON(!handle);
         ret = ext4_get_blocks(handle, inode, iblock, max_blocks,
-                              bh_result, 1, 0, EXT4_DELALLOC_RSVED);
+                              bh_result, EXT4_GET_BLOCKS_CREATE|
+                              EXT4_GET_BLOCKS_DELALLOC_RESERVE);
         if (ret <= 0)
                 return ret;
 
@@ -2065,16 +2068,17 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
                 return 0;
         /*
          * We need to make sure the BH_Delay flag is passed down to
-         * ext4_da_get_block_write(), since it calls
-         * ext4_get_blocks() with the EXT4_DELALLOC_RSVED flag.
-         * This flag causes ext4_get_blocks() to call
+         * ext4_da_get_block_write(), since it calls ext4_get_blocks()
+         * with the EXT4_GET_BLOCKS_DELALLOC_RESERVE flag.  This flag
+         * causes ext4_get_blocks() to call
          * ext4_da_update_reserve_space() if the passed buffer head
          * has the BH_Delay flag set.  In the future, once we clean up
-         * the interfaces to ext4_get_blocks(), we should pass in
-         * a separate flag which requests that the delayed allocation
+         * the interfaces to ext4_get_blocks(), we should pass in a
+         * separate flag which requests that the delayed allocation
          * statistics should be updated, instead of depending on the
          * state information getting passed down via the map_bh's
-         * state bitmasks plus the magic EXT4_DELALLOC_RSVED flag.
+         * state bitmasks plus the magic
+         * EXT4_GET_BLOCKS_DELALLOC_RESERVE flag.
          */
         new.b_state = mpd->b_state & (1 << BH_Delay);
         new.b_blocknr = 0;
@@ -2362,7 +2366,7 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
          * preallocated blocks are unmapped but should treated
          * the same as allocated blocks.
          */
-        ret = ext4_get_blocks(NULL, inode, iblock, 1,  bh_result, 0, 0, 0);
+        ret = ext4_get_blocks(NULL, inode, iblock, 1,  bh_result, 0);
         if ((ret == 0) && !buffer_delay(bh_result)) {
                 /* the block isn't (pre)allocated yet, let's reserve space */
                 /*
@@ -2406,8 +2410,7 @@ static int ext4_normal_get_block_write(struct inode *inode, sector_t iblock,
          * we don't want to do block allocation in writepage
          * so call get_block_wrap with create = 0
          */
-        ret = ext4_get_blocks(NULL, inode, iblock, max_blocks,
-                              bh_result, 0, 0, 0);
+        ret = ext4_get_blocks(NULL, inode, iblock, max_blocks, bh_result, 0);
         if (ret > 0) {
                 bh_result->b_size = (ret << inode->i_blkbits);
                 ret = 0;