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ocfs2: Wrap access of directory allocations with ip_alloc_sem.

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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 <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
This commit is contained in:
Joel Becker 2007-03-28 18:27:07 -07:00 committed by Mark Fasheh
parent 6cb129f567
commit ee19a77956
2 changed files with 8 additions and 1 deletions
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7
fs/ocfs2/dir.c
View File

@ -403,7 +403,7 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
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;
@ -452,6 +452,9 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
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);
@ -497,6 +500,8 @@ static int ocfs2_extend_dir(struct ocfs2_super *osb,
*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);

2
fs/ocfs2/inode.c
View File

@ -1106,8 +1106,10 @@ struct buffer_head *ocfs2_bread(struct inode *inode,
return NULL;
}
down_read(&OCFS2_I(inode)->ip_alloc_sem);
tmperr = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL,
NULL);
up_read(&OCFS2_I(inode)->ip_alloc_sem);
if (tmperr < 0) {
mlog_errno(tmperr);
goto fail;