From: Bob Peterson Date: Wed, 14 Apr 2010 15:58:16 +0000 (-0400) Subject: GFS2: glock livelock X-Git-Tag: v2.6.35-rc1~463^2~7 X-Git-Url: http://ftp.safe.ca/?a=commitdiff_plain;h=1a0eae8848cde6e0734360f6456496c995ee1e23;p=safe%2Fjmp%2Flinux-2.6 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: Bob Peterson --- diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c index 25fddc1..8295c5b 100644 --- a/fs/gfs2/dir.c +++ b/fs/gfs2/dir.c @@ -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; } diff --git a/fs/gfs2/export.c b/fs/gfs2/export.c index d15876e..d81bc7e 100644 --- a/fs/gfs2/export.c +++ b/fs/gfs2/export.c @@ -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; diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 454d4b4..ddcdbf4 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -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)); } /** diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c index b1bf269..51d8061 100644 --- a/fs/gfs2/inode.c +++ b/fs/gfs2/inode.c @@ -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 */ @@ -166,17 +165,14 @@ 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); + inode = gfs2_iget(sb, no_addr); ip = GFS2_I(inode); if (!inode) @@ -234,13 +230,100 @@ fail_glock: fail_iopen: gfs2_glock_put(io_gl); fail_put: - ip->i_gl->gl_object = NULL; + if (inode->i_state & I_NEW) + ip->i_gl->gl_object = NULL; gfs2_glock_put(ip->i_gl); fail: - iget_failed(inode); + 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; diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h index c341aaf..e161461 100644 --- a/fs/gfs2/inode.h +++ b/fs/gfs2/inode.h @@ -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); diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index c1309ed..dc35f34 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -487,7 +487,7 @@ static int gfs2_lookup_root(struct super_block *sb, struct dentry **dptr, struct dentry *dentry; struct inode *inode; - inode = gfs2_inode_lookup(sb, DT_DIR, no_addr, 0, 0); + inode = gfs2_inode_lookup(sb, DT_DIR, no_addr, 0); if (IS_ERR(inode)) { fs_err(sdp, "can't read in %s inode: %ld\n", name, PTR_ERR(inode)); return PTR_ERR(inode); diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 503b842..3739155 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -948,18 +948,20 @@ static int try_rgrp_fit(struct gfs2_rgrpd *rgd, struct gfs2_alloc *al) * try_rgrp_unlink - Look for any unlinked, allocated, but unused inodes * @rgd: The rgrp * - * Returns: The inode, if one has been found + * Returns: 0 if no error + * The inode, if one has been found, in inode. */ -static struct inode *try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked, - u64 skip) +static int try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked, + u64 skip, struct inode **inode) { - struct inode *inode; u32 goal = 0, block; u64 no_addr; struct gfs2_sbd *sdp = rgd->rd_sbd; unsigned int n; + int error = 0; + *inode = NULL; for(;;) { if (goal >= rgd->rd_data) break; @@ -979,14 +981,14 @@ static struct inode *try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked, if (no_addr == skip) continue; *last_unlinked = no_addr; - inode = gfs2_inode_lookup(rgd->rd_sbd->sd_vfs, DT_UNKNOWN, - no_addr, -1, 1); - if (!IS_ERR(inode)) - return inode; + error = gfs2_unlinked_inode_lookup(rgd->rd_sbd->sd_vfs, + no_addr, inode); + if (*inode || error) + return error; } rgd->rd_flags &= ~GFS2_RDF_CHECK; - return NULL; + return 0; } /** @@ -1096,12 +1098,27 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked) case 0: if (try_rgrp_fit(rgd, al)) goto out; - if (rgd->rd_flags & GFS2_RDF_CHECK) - inode = try_rgrp_unlink(rgd, last_unlinked, ip->i_no_addr); + /* If the rg came in already locked, there's no + way we can recover from a failed try_rgrp_unlink + because that would require an iput which can only + happen after the rgrp is unlocked. */ + if (!rg_locked && rgd->rd_flags & GFS2_RDF_CHECK) + error = try_rgrp_unlink(rgd, last_unlinked, + ip->i_no_addr, &inode); if (!rg_locked) gfs2_glock_dq_uninit(&al->al_rgd_gh); - if (inode) + if (inode) { + if (error) { + if (inode->i_state & I_NEW) + iget_failed(inode); + else + iput(inode); + return ERR_PTR(error); + } return inode; + } + if (error) + return ERR_PTR(error); /* fall through */ case GLR_TRYFAILED: rgd = recent_rgrp_next(rgd); @@ -1130,12 +1147,23 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked) case 0: if (try_rgrp_fit(rgd, al)) goto out; - if (rgd->rd_flags & GFS2_RDF_CHECK) - inode = try_rgrp_unlink(rgd, last_unlinked, ip->i_no_addr); + if (!rg_locked && rgd->rd_flags & GFS2_RDF_CHECK) + error = try_rgrp_unlink(rgd, last_unlinked, + ip->i_no_addr, &inode); if (!rg_locked) gfs2_glock_dq_uninit(&al->al_rgd_gh); - if (inode) + if (inode) { + if (error) { + if (inode->i_state & I_NEW) + iget_failed(inode); + else + iput(inode); + return ERR_PTR(error); + } return inode; + } + if (error) + return ERR_PTR(error); break; case GLR_TRYFAILED: