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Commit ee19a779 authored by Joel Becker's avatar Joel Becker Committed by Mark Fasheh
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ocfs2: Wrap access of directory allocations with ip_alloc_sem. 



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: default avatarJoel Becker <joel.becker@oracle.com>
Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
parent 6cb129f5

fs/ocfs2/dir.c

+6 −1
Original line number Diff line number Diff line
@@ -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);

fs/ocfs2/inode.c

+2 −0
Original line number Diff line number Diff line
@@ -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;