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Message-Id: <1307459283-22130-5-git-send-email-amir73il@users.sourceforge.net>
Date: Tue, 7 Jun 2011 18:07:31 +0300
From: amir73il@...rs.sourceforge.net
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu, lczerner@...hat.com,
Amir Goldstein <amir73il@...rs.sf.net>,
Yongqiang Yang <xiaoqiangnk@...il.com>
Subject: [PATCH v1 04/36] ext4: snapshot hooks - block bitmap access
From: Amir Goldstein <amir73il@...rs.sf.net>
The API ext4_handle_get_bitmap_access() is used instead of
ext4_journal_get_write_access(), before modifying a block bitmap
while allocating or deleting blocks. The bitmap access API is
used to initialize the COW bitmap for that group.
The old ext4_journal_get_undo_access() API was removed because it
is not being used in the code.
Signed-off-by: Amir Goldstein <amir73il@...rs.sf.net>
Signed-off-by: Yongqiang Yang <xiaoqiangnk@...il.com>
---
fs/ext4/ext4_jbd2.c | 10 +++++++---
fs/ext4/ext4_jbd2.h | 10 ++++++----
fs/ext4/mballoc.c | 7 ++++---
fs/ext4/snapshot.h | 31 +++++++++++++++++++++++++++++++
4 files changed, 48 insertions(+), 10 deletions(-)
diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
index 833969b..c44c362 100644
--- a/fs/ext4/ext4_jbd2.c
+++ b/fs/ext4/ext4_jbd2.c
@@ -9,13 +9,17 @@
#include <trace/events/ext4.h>
-int __ext4_journal_get_undo_access(const char *where, unsigned int line,
- handle_t *handle, struct buffer_head *bh)
+int __ext4_handle_get_bitmap_access(const char *where, unsigned int line,
+ handle_t *handle, struct super_block *sb,
+ ext4_group_t group, struct buffer_head *bh)
{
int err = 0;
if (ext4_handle_valid(handle)) {
- err = jbd2_journal_get_undo_access(handle, bh);
+ err = jbd2_journal_get_write_access(handle, bh);
+ if (!err)
+ err = ext4_snapshot_get_bitmap_access(handle, sb,
+ group, bh);
if (err)
ext4_journal_abort_handle(where, line, __func__, bh,
handle, err);
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index ca6e135..be3b8b3 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -129,8 +129,9 @@ void ext4_journal_abort_handle(const char *caller, unsigned int line,
const char *err_fn,
struct buffer_head *bh, handle_t *handle, int err);
-int __ext4_journal_get_undo_access(const char *where, unsigned int line,
- handle_t *handle, struct buffer_head *bh);
+int __ext4_handle_get_bitmap_access(const char *where, unsigned int line,
+ handle_t *handle, struct super_block *sb,
+ ext4_group_t group, struct buffer_head *bh);
int __ext4_journal_get_write_access_inode(const char *where, unsigned int line,
handle_t *handle, struct inode *inode,
@@ -149,8 +150,9 @@ int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
int __ext4_handle_dirty_super(const char *where, unsigned int line,
handle_t *handle, struct super_block *sb);
-#define ext4_journal_get_undo_access(handle, bh) \
- __ext4_journal_get_undo_access(__func__, __LINE__, (handle), (bh))
+#define ext4_handle_get_bitmap_access(handle, sb, group, bh) \
+ __ext4_handle_get_bitmap_access(__func__, __LINE__, \
+ (handle), (sb), (group), (bh))
#define ext4_journal_get_write_access_exclude(handle, bh) \
__ext4_journal_get_write_access_inode(__func__, __LINE__, \
(handle), NULL, (bh), 1)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 54ea8c8..6b400f2 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2749,7 +2749,8 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
if (!bitmap_bh)
goto out_err;
- err = ext4_journal_get_write_access(handle, bitmap_bh);
+ err = ext4_handle_get_bitmap_access(handle, sb, ac->ac_b_ex.fe_group,
+ bitmap_bh);
if (err)
goto out_err;
@@ -4549,7 +4550,7 @@ do_more:
}
BUFFER_TRACE(bitmap_bh, "getting write access");
- err = ext4_journal_get_write_access(handle, bitmap_bh);
+ err = ext4_handle_get_bitmap_access(handle, sb, block_group, bitmap_bh);
if (err)
goto error_return;
@@ -4698,7 +4699,7 @@ void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
}
BUFFER_TRACE(bitmap_bh, "getting write access");
- err = ext4_journal_get_write_access(handle, bitmap_bh);
+ err = ext4_handle_get_bitmap_access(handle, sb, block_group, bitmap_bh);
if (err)
goto error_return;
diff --git a/fs/ext4/snapshot.h b/fs/ext4/snapshot.h
index 54241b9..008f4a9 100644
--- a/fs/ext4/snapshot.h
+++ b/fs/ext4/snapshot.h
@@ -196,6 +196,37 @@ static inline int ext4_snapshot_get_create_access(handle_t *handle,
return err;
}
+/*
+ * get_bitmap_access() is called before modifying a block bitmap.
+ * this call initializes the COW bitmap for @group.
+ *
+ * Return values:
+ * = 0 - COW bitmap is initialized
+ * < 0 - error
+ */
+static inline int ext4_snapshot_get_bitmap_access(handle_t *handle,
+ struct super_block *sb, ext4_group_t group,
+ struct buffer_head *bh)
+{
+ if (!EXT4_SNAPSHOTS(sb))
+ return 0;
+ /*
+ * With flex_bg, block bitmap may reside in a different group than
+ * the group it describes, so we need to init both COW bitmaps:
+ * 1. init the COW bitmap for @group by testing
+ * if the first block in the group should be COWed
+ */
+ if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
+ int err = ext4_snapshot_cow(handle, NULL,
+ ext4_group_first_block_no(sb, group),
+ NULL, 0);
+ if (err < 0)
+ return err;
+ }
+ /* 2. COW the block bitmap itself, which may be in another group */
+ return ext4_snapshot_cow(handle, NULL, bh->b_blocknr, bh, 1);
+}
+
/* snapshot_ctl.c */
--
1.7.4.1
--
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