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Commit 1a0eae88 authored by Bob Peterson's avatar Bob Peterson Committed by Steven Whitehouse
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GFS2: glock livelock 



This patch fixes a couple gfs2 problems with the reclaiming of
unlinked dinodes.  First, there were a couple of livelocks where
everything would come to a halt waiting for a glock that was
seemingly held by a process that no longer existed.  In fact, the
process did exist, it just had the wrong pid number in the holder
information.  Second, there was a lock ordering problem between
inode locking and glock locking.  Third, glock/inode contention
could sometimes cause inodes to be improperly marked invalid by
iget_failed.

Signed-off-by: default avatarBob Peterson <rpeterso@redhat.com>
parent 602c89d2

fs/gfs2/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -1475,7 +1475,7 @@ struct inode *gfs2_dir_search(struct inode *dir, const struct qstr *name) 
		inode = gfs2_inode_lookup(dir->i_sb, 

				be16_to_cpu(dent->de_type),

				be64_to_cpu(dent->de_inum.no_addr),

				be64_to_cpu(dent->de_inum.no_formal_ino), 0);

				be64_to_cpu(dent->de_inum.no_formal_ino));

		brelse(bh);

		return inode;

	}

fs/gfs2/export.c

+1 −1
Original line number Diff line number Diff line
@@ -169,7 +169,7 @@ static struct dentry *gfs2_get_dentry(struct super_block *sb, 
	if (error)

		goto fail;



	inode = gfs2_inode_lookup(sb, DT_UNKNOWN, inum->no_addr, 0, 0);

	inode = gfs2_inode_lookup(sb, DT_UNKNOWN, inum->no_addr, 0);

	if (IS_ERR(inode)) {

		error = PTR_ERR(inode);

		goto fail;

fs/gfs2/glock.c

+3 −0
Original line number Diff line number Diff line
@@ -855,6 +855,9 @@ void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder * 
	gh->gh_flags = flags;

	gh->gh_iflags = 0;

	gh->gh_ip = (unsigned long)__builtin_return_address(0);

	if (gh->gh_owner_pid)

		put_pid(gh->gh_owner_pid);

	gh->gh_owner_pid = get_pid(task_pid(current));

}



/**

fs/gfs2/inode.c

+92 −9
Original line number Diff line number Diff line
@@ -158,7 +158,6 @@ void gfs2_set_iop(struct inode *inode) 
 * @sb: The super block

 * @no_addr: The inode number

 * @type: The type of the inode

 * @skip_freeing: set this not return an inode if it is currently being freed.

 *

 * Returns: A VFS inode, or an error

 */
@@ -166,16 +165,13 @@ void gfs2_set_iop(struct inode *inode) 
struct inode *gfs2_inode_lookup(struct super_block *sb,

				unsigned int type,

				u64 no_addr,

				u64 no_formal_ino, int skip_freeing)

				u64 no_formal_ino)

{

	struct inode *inode;

	struct gfs2_inode *ip;

	struct gfs2_glock *io_gl;

	int error;



	if (skip_freeing)

		inode = gfs2_iget_skip(sb, no_addr);

	else

	inode = gfs2_iget(sb, no_addr);

	ip = GFS2_I(inode);
@@ -234,13 +230,100 @@ fail_glock: 
fail_iopen:

	gfs2_glock_put(io_gl);

fail_put:

	if (inode->i_state & I_NEW)

		ip->i_gl->gl_object = NULL;

	gfs2_glock_put(ip->i_gl);

fail:

	if (inode->i_state & I_NEW)

		iget_failed(inode);

	else

		iput(inode);

	return ERR_PTR(error);

}



/**

 * gfs2_unlinked_inode_lookup - Lookup an unlinked inode for reclamation

 * @sb: The super block

 * no_addr: The inode number

 * @@inode: A pointer to the inode found, if any

 *

 * Returns: 0 and *inode if no errors occurred.  If an error occurs,

 *          the resulting *inode may or may not be NULL.

 */



int gfs2_unlinked_inode_lookup(struct super_block *sb, u64 no_addr,

			       struct inode **inode)

{

	struct gfs2_sbd *sdp;

	struct gfs2_inode *ip;

	struct gfs2_glock *io_gl;

	int error;

	struct gfs2_holder gh;



	*inode = gfs2_iget_skip(sb, no_addr);



	if (!(*inode))

		return -ENOBUFS;



	if (!((*inode)->i_state & I_NEW))

		return -ENOBUFS;



	ip = GFS2_I(*inode);

	sdp = GFS2_SB(*inode);

	ip->i_no_formal_ino = -1;



	error = gfs2_glock_get(sdp, no_addr, &gfs2_inode_glops, CREATE, &ip->i_gl);

	if (unlikely(error))

		goto fail;

	ip->i_gl->gl_object = ip;



	error = gfs2_glock_get(sdp, no_addr, &gfs2_iopen_glops, CREATE, &io_gl);

	if (unlikely(error))

		goto fail_put;



	set_bit(GIF_INVALID, &ip->i_flags);

	error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, LM_FLAG_TRY | GL_EXACT,

				   &ip->i_iopen_gh);

	if (unlikely(error)) {

		if (error == GLR_TRYFAILED)

			error = 0;

		goto fail_iopen;

	}

	ip->i_iopen_gh.gh_gl->gl_object = ip;

	gfs2_glock_put(io_gl);



	(*inode)->i_mode = DT2IF(DT_UNKNOWN);



	/*

	 * We must read the inode in order to work out its type in

	 * this case. Note that this doesn't happen often as we normally

	 * know the type beforehand. This code path only occurs during

	 * unlinked inode recovery (where it is safe to do this glock,

	 * which is not true in the general case).

	 */

	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, LM_FLAG_TRY,

				   &gh);

	if (unlikely(error)) {

		if (error == GLR_TRYFAILED)

			error = 0;

		goto fail_glock;

	}

	/* Inode is now uptodate */

	gfs2_glock_dq_uninit(&gh);

	gfs2_set_iop(*inode);



	return 0;

fail_glock:

	gfs2_glock_dq(&ip->i_iopen_gh);

fail_iopen:

	gfs2_glock_put(io_gl);

fail_put:

	ip->i_gl->gl_object = NULL;

	gfs2_glock_put(ip->i_gl);

fail:

	return error;

}



static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)

{

	const struct gfs2_dinode *str = buf;
@@ -862,7 +945,7 @@ struct inode *gfs2_createi(struct gfs2_holder *ghs, const struct qstr *name, 
		goto fail_gunlock2;



	inode = gfs2_inode_lookup(dir->i_sb, IF2DT(mode), inum.no_addr,

				  inum.no_formal_ino, 0);

				  inum.no_formal_ino);

	if (IS_ERR(inode))

		goto fail_gunlock2;

fs/gfs2/inode.h

+3 −2
Original line number Diff line number Diff line
@@ -83,8 +83,9 @@ static inline void gfs2_inum_out(const struct gfs2_inode *ip, 


extern void gfs2_set_iop(struct inode *inode);

extern struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned type, 

				       u64 no_addr, u64 no_formal_ino,

				       int skip_freeing);

				       u64 no_addr, u64 no_formal_ino);

extern int gfs2_unlinked_inode_lookup(struct super_block *sb, u64 no_addr,

				      struct inode **inode);

extern struct inode *gfs2_ilookup(struct super_block *sb, u64 no_addr);



extern int gfs2_inode_refresh(struct gfs2_inode *ip);