ext4: Use new buffer_head flag to check uninit group bitmaps initialization

(cherry picked from commit 2ccb5fb9f113dae969d1ae9b6c10e80fa34f8cd3)

For uninit block group, the ondisk bitmap is not initialized. That implies
we cannot depend on the uptodate flag on the bitmap buffer_head to
find bitmap validity. Use a new buffer_head flag which would be set after
we properly initialize the bitmap. This also prevent the initializing
the uninit group bitmap initialization every time we do a
ext4_read_block_bitmap.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 93753097dcc2d3ce313a80783dfc861dba14f165..8b7c7763476b1374c3579b9d36c337a10f62499a 100644 (file)
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -319,18 +319,41 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
                            block_group, bitmap_blk);
                return NULL;
        }
-       if (bh_uptodate_or_lock(bh))
+
+       if (bitmap_uptodate(bh))
                return bh;
 
+       lock_buffer(bh);
+       if (bitmap_uptodate(bh)) {
+               unlock_buffer(bh);
+               return bh;
+       }
        spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
        if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
                ext4_init_block_bitmap(sb, bh, block_group, desc);
+               set_bitmap_uptodate(bh);
                set_buffer_uptodate(bh);
                unlock_buffer(bh);
                spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
                return bh;
        }
        spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
+       if (buffer_uptodate(bh)) {
+               /*
+                * if not uninit if bh is uptodate,
+                * bitmap is also uptodate
+                */
+               set_bitmap_uptodate(bh);
+               unlock_buffer(bh);
+               return bh;
+       }
+       /*
+        * submit the buffer_head for read. We can
+        * safely mark the bitmap as uptodate now.
+        * We do it here so the bitmap uptodate bit
+        * get set with buffer lock held.
+        */
+       set_bitmap_uptodate(bh);
        if (bh_submit_read(bh) < 0) {
                put_bh(bh);
                ext4_error(sb, __func__,

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index a7188d154774e50f6e56e96308fb13d81c6e6f43..2f7b639e7da223a791625f9d2f9e9586c4385343 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -19,6 +19,7 @@
 #include <linux/types.h>
 #include <linux/blkdev.h>
 #include <linux/magic.h>
+#include <linux/jbd2.h>
 #include "ext4_i.h"
 
 /*
@@ -1250,6 +1251,23 @@ extern int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode,
                        sector_t block, unsigned long max_blocks,
                        struct buffer_head *bh, int create,
                        int extend_disksize, int flag);
+/*
+ * Add new method to test wether block and inode bitmaps are properly
+ * initialized. With uninit_bg reading the block from disk is not enough
+ * to mark the bitmap uptodate. We need to also zero-out the bitmap
+ */
+#define BH_BITMAP_UPTODATE BH_JBDPrivateStart
+
+static inline int bitmap_uptodate(struct buffer_head *bh)
+{
+       return (buffer_uptodate(bh) &&
+               test_bit(BH_BITMAP_UPTODATE, &(bh)->b_state));
+}
+static inline void set_bitmap_uptodate(struct buffer_head *bh)
+{
+       set_bit(BH_BITMAP_UPTODATE, &(bh)->b_state);
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* _EXT4_H */

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 474214e9e1246fab5ed1515eca5193e1402ae4c6..4a3aee80e226f809352210c712d870fef8a1a69c 100644 (file)
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -115,18 +115,40 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
                            block_group, bitmap_blk);
                return NULL;
        }
-       if (bh_uptodate_or_lock(bh))
+       if (bitmap_uptodate(bh))
                return bh;
 
+       lock_buffer(bh);
+       if (bitmap_uptodate(bh)) {
+               unlock_buffer(bh);
+               return bh;
+       }
        spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
        if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
                ext4_init_inode_bitmap(sb, bh, block_group, desc);
+               set_bitmap_uptodate(bh);
                set_buffer_uptodate(bh);
                unlock_buffer(bh);
                spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
                return bh;
        }
        spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
+       if (buffer_uptodate(bh)) {
+               /*
+                * if not uninit if bh is uptodate,
+                * bitmap is also uptodate
+                */
+               set_bitmap_uptodate(bh);
+               unlock_buffer(bh);
+               return bh;
+       }
+       /*
+        * submit the buffer_head for read. We can
+        * safely mark the bitmap as uptodate now.
+        * We do it here so the bitmap uptodate bit
+        * get set with buffer lock held.
+        */
+       set_bitmap_uptodate(bh);
        if (bh_submit_read(bh) < 0) {
                put_bh(bh);
                ext4_error(sb, __func__,

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index f96b18eb11be25556f0441c2a05aff42bcca0292..a7057a306700392d1ad8651ef68c3832e5e47729 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -796,20 +796,42 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
                if (bh[i] == NULL)
                        goto out;
 
-               if (bh_uptodate_or_lock(bh[i]))
+               if (bitmap_uptodate(bh[i]))
                        continue;
 
+               lock_buffer(bh[i]);
+               if (bitmap_uptodate(bh[i])) {
+                       unlock_buffer(bh[i]);
+                       continue;
+               }
                spin_lock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
                if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
                        ext4_init_block_bitmap(sb, bh[i],
                                                first_group + i, desc);
+                       set_bitmap_uptodate(bh[i]);
                        set_buffer_uptodate(bh[i]);
                        unlock_buffer(bh[i]);
                        spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
                        continue;
                }
                spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
+               if (buffer_uptodate(bh[i])) {
+                       /*
+                        * if not uninit if bh is uptodate,
+                        * bitmap is also uptodate
+                        */
+                       set_bitmap_uptodate(bh[i]);
+                       unlock_buffer(bh[i]);
+                       continue;
+               }
                get_bh(bh[i]);
+               /*
+                * submit the buffer_head for read. We can
+                * safely mark the bitmap as uptodate now.
+                * We do it here so the bitmap uptodate bit
+                * get set with buffer lock held.
+                */
+               set_bitmap_uptodate(bh[i]);
                bh[i]->b_end_io = end_buffer_read_sync;
                submit_bh(READ, bh[i]);
                mb_debug("read bitmap for group %lu\n", first_group + i);