forked from Minki/linux
7a9f53b3c1
There is a possible deadlock between two processes on the same node, where one process is deleting an inode, and another process is looking for allocated but unused inodes to delete in order to create more space. process A does an iput() on inode X, and it's i_count drops to 0. This causes iput_final() to be called, which puts an inode into state I_FREEING at generic_delete_inode(). There no point between when iput_final() is called, and when I_FREEING is set where GFS2 could acquire any glocks. Once I_FREEING is set, no other process on that node can successfully look up that inode until the delete finishes. process B locks the the resource group for the same inode in get_local_rgrp(), which is called by gfs2_inplace_reserve_i() process A tries to lock the resource group for the inode in gfs2_dinode_dealloc(), but it's already locked by process B process B waits in find_inode for the inode to have the I_FREEING state cleared. Deadlock. This patch solves the problem by adding an alternative to gfs2_iget(), gfs2_iget_skip(), that simply skips any inodes that are in the I_FREEING state.o The alternate test function is just like the original one, except that it fails if the inode is being freed, and sets a skipped flag. The alternate set function is just like the original, except that it fails if the skipped flag is set. Only try_rgrp_unlink() calls gfs2_iget_skip() instead of gfs2_iget(). Signed-off-by: Benjamin E. Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
78 lines
2.6 KiB
C
78 lines
2.6 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License version 2.
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*/
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#ifndef __INODE_DOT_H__
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#define __INODE_DOT_H__
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static inline int gfs2_is_stuffed(const struct gfs2_inode *ip)
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{
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return !ip->i_di.di_height;
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}
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static inline int gfs2_is_jdata(const struct gfs2_inode *ip)
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{
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return ip->i_di.di_flags & GFS2_DIF_JDATA;
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}
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static inline int gfs2_is_dir(const struct gfs2_inode *ip)
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{
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return S_ISDIR(ip->i_inode.i_mode);
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}
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static inline void gfs2_set_inode_blocks(struct inode *inode)
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{
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struct gfs2_inode *ip = GFS2_I(inode);
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inode->i_blocks = ip->i_di.di_blocks <<
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(GFS2_SB(inode)->sd_sb.sb_bsize_shift - GFS2_BASIC_BLOCK_SHIFT);
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}
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static inline int gfs2_check_inum(const struct gfs2_inode *ip, u64 no_addr,
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u64 no_formal_ino)
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{
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return ip->i_no_addr == no_addr && ip->i_no_formal_ino == no_formal_ino;
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}
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static inline void gfs2_inum_out(const struct gfs2_inode *ip,
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struct gfs2_dirent *dent)
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{
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dent->de_inum.no_formal_ino = cpu_to_be64(ip->i_no_formal_ino);
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dent->de_inum.no_addr = cpu_to_be64(ip->i_no_addr);
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}
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void gfs2_inode_attr_in(struct gfs2_inode *ip);
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void gfs2_set_iop(struct inode *inode);
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struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned type,
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u64 no_addr, u64 no_formal_ino,
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int skip_freeing);
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struct inode *gfs2_ilookup(struct super_block *sb, u64 no_addr);
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int gfs2_inode_refresh(struct gfs2_inode *ip);
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int gfs2_dinode_dealloc(struct gfs2_inode *inode);
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int gfs2_change_nlink(struct gfs2_inode *ip, int diff);
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struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
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int is_root, struct nameidata *nd);
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struct inode *gfs2_createi(struct gfs2_holder *ghs, const struct qstr *name,
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unsigned int mode, dev_t dev);
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int gfs2_rmdiri(struct gfs2_inode *dip, const struct qstr *name,
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struct gfs2_inode *ip);
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int gfs2_unlink_ok(struct gfs2_inode *dip, const struct qstr *name,
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const struct gfs2_inode *ip);
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int gfs2_ok_to_move(struct gfs2_inode *this, struct gfs2_inode *to);
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int gfs2_readlinki(struct gfs2_inode *ip, char **buf, unsigned int *len);
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int gfs2_glock_nq_atime(struct gfs2_holder *gh);
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int gfs2_setattr_simple(struct gfs2_inode *ip, struct iattr *attr);
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struct inode *gfs2_lookup_simple(struct inode *dip, const char *name);
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void gfs2_dinode_out(const struct gfs2_inode *ip, void *buf);
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void gfs2_dinode_print(const struct gfs2_inode *ip);
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#endif /* __INODE_DOT_H__ */
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