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Date: Mon, 09 May 2011 16:04:04 -0700
From: "Darrick J. Wong" <djwong@...ibm.com>
To: Theodore Tso <tytso@....edu>, Jan Kara <jack@...e.cz>,
Alexander Viro <viro@...iv.linux.org.uk>,
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>,
"Darrick J. Wong" <djwong@...ibm.com>
Cc: Jens Axboe <axboe@...nel.dk>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
Jeff Layton <jlayton@...hat.com>,
Dave Chinner <david@...morbit.com>,
linux-kernel <linux-kernel@...r.kernel.org>,
Dave Hansen <dave@...ux.vnet.ibm.com>,
Christoph Hellwig <hch@...radead.org>, linux-mm@...ck.org,
Chris Mason <chris.mason@...cle.com>,
Joel Becker <jlbec@...lplan.org>,
linux-scsi <linux-scsi@...r.kernel.org>,
linux-fsdevel <linux-fsdevel@...r.kernel.org>,
linux-ext4@...r.kernel.org, Mingming Cao <mcao@...ibm.com>
Subject: [PATCH 6/7] ext2: Lock buffer_head during metadata update
ext2 does not protect memory pages containing metadata against writes during
disk write operations. To stabilize the page during a write, lock the
buffer_head while updating metadata pages.
Signed-off-by: Darrick J. Wong <djwong@...ibm.com>
---
fs/ext2/balloc.c | 6 ++++++
fs/ext2/ialloc.c | 7 +++++++
fs/ext2/inode.c | 7 +++++++
fs/ext2/super.c | 2 ++
fs/ext2/xattr.c | 2 ++
5 files changed, 24 insertions(+), 0 deletions(-)
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 8f44cef..50d7d4c 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -176,10 +176,12 @@ static void group_adjust_blocks(struct super_block *sb, int group_no,
struct ext2_sb_info *sbi = EXT2_SB(sb);
unsigned free_blocks;
+ lock_buffer(bh);
spin_lock(sb_bgl_lock(sbi, group_no));
free_blocks = le16_to_cpu(desc->bg_free_blocks_count);
desc->bg_free_blocks_count = cpu_to_le16(free_blocks + count);
spin_unlock(sb_bgl_lock(sbi, group_no));
+ unlock_buffer(bh);
sb->s_dirt = 1;
mark_buffer_dirty(bh);
}
@@ -546,6 +548,7 @@ do_more:
goto error_return;
}
+ lock_buffer(bitmap_bh);
for (i = 0, group_freed = 0; i < count; i++) {
if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
bit + i, bitmap_bh->b_data)) {
@@ -555,6 +558,7 @@ do_more:
group_freed++;
}
}
+ unlock_buffer(bitmap_bh);
mark_buffer_dirty(bitmap_bh);
if (sb->s_flags & MS_SYNCHRONOUS)
@@ -1351,8 +1355,10 @@ retry_alloc:
/*
* try to allocate block(s) from this group, without a goal(-1).
*/
+ lock_buffer(bitmap_bh);
grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no,
bitmap_bh, -1, my_rsv, &num);
+ unlock_buffer(bitmap_bh);
if (grp_alloc_blk >= 0)
goto allocated;
}
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index ee9ed31..3bf624f 100644
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -74,11 +74,13 @@ static void ext2_release_inode(struct super_block *sb, int group, int dir)
return;
}
+ lock_buffer(bh);
spin_lock(sb_bgl_lock(EXT2_SB(sb), group));
le16_add_cpu(&desc->bg_free_inodes_count, 1);
if (dir)
le16_add_cpu(&desc->bg_used_dirs_count, -1);
spin_unlock(sb_bgl_lock(EXT2_SB(sb), group));
+ unlock_buffer(bh);
if (dir)
percpu_counter_dec(&EXT2_SB(sb)->s_dirs_counter);
sb->s_dirt = 1;
@@ -139,12 +141,14 @@ void ext2_free_inode (struct inode * inode)
return;
/* Ok, now we can actually update the inode bitmaps.. */
+ lock_buffer(bitmap_bh);
if (!ext2_clear_bit_atomic(sb_bgl_lock(EXT2_SB(sb), block_group),
bit, (void *) bitmap_bh->b_data))
ext2_error (sb, "ext2_free_inode",
"bit already cleared for inode %lu", ino);
else
ext2_release_inode(sb, block_group, is_directory);
+ unlock_buffer(bitmap_bh);
mark_buffer_dirty(bitmap_bh);
if (sb->s_flags & MS_SYNCHRONOUS)
sync_dirty_buffer(bitmap_bh);
@@ -491,8 +495,10 @@ repeat_in_this_group:
group = 0;
continue;
}
+ lock_buffer(bitmap_bh);
if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group),
ino, bitmap_bh->b_data)) {
+ unlock_buffer(bitmap_bh);
/* we lost this inode */
if (++ino >= EXT2_INODES_PER_GROUP(sb)) {
/* this group is exhausted, try next group */
@@ -503,6 +509,7 @@ repeat_in_this_group:
/* try to find free inode in the same group */
goto repeat_in_this_group;
}
+ unlock_buffer(bitmap_bh);
goto got;
}
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 788e09a..f102b82 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -557,11 +557,15 @@ static void ext2_splice_branch(struct inode *inode,
* Update the host buffer_head or inode to point to more just allocated
* direct blocks blocks
*/
+ if (where->bh)
+ lock_buffer(where->bh);
if (num == 0 && blks > 1) {
current_block = le32_to_cpu(where->key) + 1;
for (i = 1; i < blks; i++)
*(where->p + i ) = cpu_to_le32(current_block++);
}
+ if (where->bh)
+ unlock_buffer(where->bh);
/*
* update the most recently allocated logical & physical block
@@ -1426,6 +1430,7 @@ static int __ext2_write_inode(struct inode *inode, int do_sync)
if (IS_ERR(raw_inode))
return -EIO;
+ lock_buffer(bh);
/* For fields not not tracking in the in-memory inode,
* initialise them to zero for new inodes. */
if (ei->i_state & EXT2_STATE_NEW)
@@ -1502,6 +1507,8 @@ static int __ext2_write_inode(struct inode *inode, int do_sync)
}
} else for (n = 0; n < EXT2_N_BLOCKS; n++)
raw_inode->i_block[n] = ei->i_data[n];
+ unlock_buffer(bh);
+
mark_buffer_dirty(bh);
if (do_sync) {
sync_dirty_buffer(bh);
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 0a78dae..be2c9ca 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -1152,12 +1152,14 @@ static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
int wait)
{
ext2_clear_super_error(sb);
+ lock_buffer(EXT2_SB(sb)->s_sbh);
spin_lock(&EXT2_SB(sb)->s_lock);
es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
es->s_wtime = cpu_to_le32(get_seconds());
/* unlock before we do IO */
spin_unlock(&EXT2_SB(sb)->s_lock);
+ unlock_buffer(EXT2_SB(sb)->s_sbh);
mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
if (wait)
sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
index 5299706..2e0652d 100644
--- a/fs/ext2/xattr.c
+++ b/fs/ext2/xattr.c
@@ -337,9 +337,11 @@ static void ext2_xattr_update_super_block(struct super_block *sb)
if (EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR))
return;
+ lock_buffer(EXT2_SB(sb)->s_sbh);
spin_lock(&EXT2_SB(sb)->s_lock);
EXT2_SET_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR);
spin_unlock(&EXT2_SB(sb)->s_lock);
+ unlock_buffer(EXT2_SB(sb)->s_sbh);
sb->s_dirt = 1;
mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
}
--
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