OCFS2_I(inode)->ip_alloc_sem is a read-write semaphore protecting
local concurrent access of ocfs2 inodes. However, ocfs2 directories were
not taking the semaphore while they accessed or modified the allocation
tree.
ocfs2_extend_dir() needs to take the semaphore in a write mode when it
adds to the allocation. All other directory users get there via
ocfs2_bread(), which takes the semaphore in read mode.
Signed-off-by: Joel Becker <[EMAIL PROTECTED]>
---
fs/ocfs2/dir.c | 7 ++++++-
fs/ocfs2/inode.c | 2 ++
2 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 66821e1..fd41f8b 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -402,7 +402,7 @@ static int ocfs2_extend_dir(struct ocfs2
struct buffer_head **new_de_bh)
{
int status = 0;
- int credits, num_free_extents;
+ int credits, num_free_extents, drop_alloc_sem = 0;
loff_t dir_i_size;
struct ocfs2_dinode *fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
struct ocfs2_alloc_context *data_ac = NULL;
@@ -451,6 +451,9 @@ static int ocfs2_extend_dir(struct ocfs2
credits = OCFS2_SIMPLE_DIR_EXTEND_CREDITS;
}
+ down_write(&OCFS2_I(dir)->ip_alloc_sem);
+ drop_alloc_sem = 1;
+
handle = ocfs2_start_trans(osb, credits);
if (IS_ERR(handle)) {
status = PTR_ERR(handle);
@@ -496,6 +499,8 @@ static int ocfs2_extend_dir(struct ocfs2
*new_de_bh = new_bh;
get_bh(*new_de_bh);
bail:
+ if (drop_alloc_sem)
+ up_write(&OCFS2_I(dir)->ip_alloc_sem);
if (handle)
ocfs2_commit_trans(osb, handle);
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 28ab56f..480d90f 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -1121,8 +1121,10 @@ struct buffer_head *ocfs2_bread(struct i
return NULL;
}
+ down_read(&OCFS2_I(inode)->ip_alloc_sem);
tmperr = ocfs2_extent_map_get_blocks(inode, block, 1,
&p_blkno, NULL);
+ up_read(&OCFS2_I(inode)->ip_alloc_sem);
if (tmperr < 0) {
mlog_errno(tmperr);
goto fail;
--
1.4.2.3
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