* [PATCH 00/27 v7] Fix filesystem freezing deadlocks
@ 2012-06-12 14:20 Jan Kara
2012-06-12 14:20 ` [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex Jan Kara
0 siblings, 1 reply; 7+ messages in thread
From: Jan Kara @ 2012-06-12 14:20 UTC (permalink / raw)
To: Al Viro
Cc: LKML, linux-fsdevel, Jan Kara, Alex Elder, Anton Altaparmakov,
Ben Myers, Chris Mason, cluster-devel, David S. Miller,
fuse-devel, J. Bruce Fields, Joel Becker, KONISHI Ryusuke,
linux-btrfs, linux-ext4, linux-nfs, linux-nilfs, linux-ntfs-dev,
Mark Fasheh, Miklos Szeredi, ocfs2-devel, OGAWA Hirofumi,
Steven Whitehouse, Theodore Ts'o, xfs
Hello,
here is the seventh iteration of my patches to improve filesystem freezing.
I've rebased patches on top of 3.5-rc2 as Al requested. Otherwise I've just
fixed some outdated text in the introduction below and added one ack.
Introductory text to first time readers:
Filesystem freezing is currently racy and thus we can end up with dirty data on
frozen filesystem (see changelog patch 13 for detailed race description). This
patch series aims at fixing this.
To be able to block all places where inodes get dirtied, I've moved filesystem
file_update_time() call to ->page_mkwrite callback (patches 01-07) and put
freeze handling in mnt_want_write() / mnt_drop_write(). That however required
some code shuffling and changes to kern_path_create() (see patches 09-12). I
think the result is OK but opinions may differ ;). The advantage of this change
also is that all filesystems get freeze protection almost for free - even ext2
can handle freezing well now.
I'm not able to hit any deadlocks, lockdep warnings, or dirty data on frozen
filesystem despite beating it with fsstress, bash-shared-mapping, and
aio-stress while freezing and unfreezing for several hours (using ext4 and xfs)
so I'm reasonably confident this could finally be the right solution.
Changes since v6:
* rebased on 3.5-rc2
* added ack
Changes since v5:
* handle unlinked & open files on frozen filesystem
* lockdep keys for freeze protection are now per filesystem type
* taught lockdep that freeze protection at lower level does not create
dependency when we already hold freeze protection at higher level
* rebased on 3.5-rc1-ish
Changes since v4:
* added a couple of Acked-by's
* added some comments & doc update
* added patches from series "Push file_update_time() into .page_mkwrite"
since it doesn't make much sense to keep them separate anymore
* rebased on top of 3.4-rc2
Changes since v3:
* added third level of freezing for fs internal purposes - hooked some
filesystems to use it (XFS, nilfs2)
* removed racy i_size check from filemap_mkwrite()
Changes since v2:
* completely rewritten
* freezing is now blocked at VFS entry points
* two stage freezing to handle both mmapped writes and other IO
The biggest changes since v1:
* have two counters to provide safe state transitions for SB_FREEZE_WRITE
and SB_FREEZE_TRANS states
* use percpu counters instead of own percpu structure
* added documentation fixes from the old fs freezing series
* converted XFS to use SB_FREEZE_TRANS counter instead of its private
m_active_trans counter
Honza
CC: Alex Elder <elder@kernel.org>
CC: Anton Altaparmakov <anton@tuxera.com>
CC: Ben Myers <bpm@sgi.com>
CC: Chris Mason <chris.mason@oracle.com>
CC: cluster-devel@redhat.com
CC: "David S. Miller" <davem@davemloft.net>
CC: fuse-devel@lists.sourceforge.net
CC: "J. Bruce Fields" <bfields@fieldses.org>
CC: Joel Becker <jlbec@evilplan.org>
CC: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
CC: linux-btrfs@vger.kernel.org
CC: linux-ext4@vger.kernel.org
CC: linux-nfs@vger.kernel.org
CC: linux-nilfs@vger.kernel.org
CC: linux-ntfs-dev@lists.sourceforge.net
CC: Mark Fasheh <mfasheh@suse.com>
CC: Miklos Szeredi <miklos@szeredi.hu>
CC: ocfs2-devel@oss.oracle.com
CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
CC: Steven Whitehouse <swhiteho@redhat.com>
CC: "Theodore Ts'o" <tytso@mit.edu>
CC: xfs@oss.sgi.com
^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex 2012-06-12 14:20 [PATCH 00/27 v7] Fix filesystem freezing deadlocks Jan Kara @ 2012-06-12 14:20 ` Jan Kara 2012-06-12 17:25 ` J. Bruce Fields 0 siblings, 1 reply; 7+ messages in thread From: Jan Kara @ 2012-06-12 14:20 UTC (permalink / raw) To: Al Viro; +Cc: LKML, linux-fsdevel, Jan Kara, linux-nfs, J. Bruce Fields When mnt_want_write() starts to handle freezing it will get a full lock semantics requiring proper lock ordering. So push mnt_want_write() call consistently outside of i_mutex. CC: linux-nfs@vger.kernel.org CC: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Jan Kara <jack@suse.cz> --- fs/nfsd/nfs4recover.c | 9 +++-- fs/nfsd/nfsfh.c | 1 + fs/nfsd/nfsproc.c | 9 ++++- fs/nfsd/vfs.c | 79 ++++++++++++++++++++++--------------------- fs/nfsd/vfs.h | 11 +++++- include/linux/nfsd/nfsfh.h | 1 + 6 files changed, 64 insertions(+), 46 deletions(-) diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index 5ff0b7b..43295d4 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -154,6 +154,10 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) if (status < 0) return; + status = mnt_want_write_file(rec_file); + if (status) + return; + dir = rec_file->f_path.dentry; /* lock the parent */ mutex_lock(&dir->d_inode->i_mutex); @@ -173,11 +177,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) * as well be forgiving and just succeed silently. */ goto out_put; - status = mnt_want_write_file(rec_file); - if (status) - goto out_put; status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU); - mnt_drop_write_file(rec_file); out_put: dput(dentry); out_unlock: @@ -189,6 +189,7 @@ out_unlock: " (err %d); please check that %s exists" " and is writeable", status, user_recovery_dirname); + mnt_drop_write_file(rec_file); nfs4_reset_creds(original_cred); } diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c index cc79300..032af38 100644 --- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -635,6 +635,7 @@ fh_put(struct svc_fh *fhp) fhp->fh_post_saved = 0; #endif } + fh_drop_write(fhp); if (exp) { exp_put(exp); fhp->fh_export = NULL; diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index e15dc45..aad6d45 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -196,6 +196,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, struct dentry *dchild; int type, mode; __be32 nfserr; + int hosterr; dev_t rdev = 0, wanted = new_decode_dev(attr->ia_size); dprintk("nfsd: CREATE %s %.*s\n", @@ -214,6 +215,12 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, nfserr = nfserr_exist; if (isdotent(argp->name, argp->len)) goto done; + hosterr = fh_want_write(dirfhp); + if (hosterr) { + nfserr = nfserrno(hosterr); + goto done; + } + fh_lock_nested(dirfhp, I_MUTEX_PARENT); dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len); if (IS_ERR(dchild)) { @@ -330,7 +337,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, out_unlock: /* We don't really need to unlock, as fh_put does it. */ fh_unlock(dirfhp); - + fh_drop_write(dirfhp); done: fh_put(dirfhp); return nfsd_return_dirop(nfserr, resp); diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index c8bd9c3..4503995 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1276,6 +1276,10 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, * If it has, the parent directory should already be locked. */ if (!resfhp->fh_dentry) { + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */ fh_lock_nested(fhp, I_MUTEX_PARENT); dchild = lookup_one_len(fname, dentry, flen); @@ -1319,14 +1323,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, goto out; } - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; - /* * Get the dir op function pointer. */ err = 0; + host_err = 0; switch (type) { case S_IFREG: host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL); @@ -1343,10 +1344,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); break; } - if (host_err < 0) { - fh_drop_write(fhp); + if (host_err < 0) goto out_nfserr; - } err = nfsd_create_setattr(rqstp, resfhp, iap); @@ -1358,7 +1357,6 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, err2 = nfserrno(commit_metadata(fhp)); if (err2) err = err2; - fh_drop_write(fhp); /* * Update the file handle to get the new inode info. */ @@ -1417,6 +1415,11 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, err = nfserr_notdir; if (!dirp->i_op->lookup) goto out; + + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock_nested(fhp, I_MUTEX_PARENT); /* @@ -1449,9 +1452,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, v_atime = verifier[1]&0x7fffffff; } - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; if (dchild->d_inode) { err = 0; @@ -1522,7 +1522,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, if (!err) err = nfserrno(commit_metadata(fhp)); - fh_drop_write(fhp); /* * Update the filehandle to get the new inode info. */ @@ -1533,6 +1532,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, fh_unlock(fhp); if (dchild && !IS_ERR(dchild)) dput(dchild); + fh_drop_write(fhp); return err; out_nfserr: @@ -1613,6 +1613,11 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; + + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock(fhp); dentry = fhp->fh_dentry; dnew = lookup_one_len(fname, dentry, flen); @@ -1620,10 +1625,6 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, if (IS_ERR(dnew)) goto out_nfserr; - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; - if (unlikely(path[plen] != 0)) { char *path_alloced = kmalloc(plen+1, GFP_KERNEL); if (path_alloced == NULL) @@ -1683,6 +1684,12 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, if (isdotent(name, len)) goto out; + host_err = fh_want_write(tfhp); + if (host_err) { + err = nfserrno(host_err); + goto out; + } + fh_lock_nested(ffhp, I_MUTEX_PARENT); ddir = ffhp->fh_dentry; dirp = ddir->d_inode; @@ -1694,18 +1701,13 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, dold = tfhp->fh_dentry; - host_err = fh_want_write(tfhp); - if (host_err) { - err = nfserrno(host_err); - goto out_dput; - } err = nfserr_noent; if (!dold->d_inode) - goto out_drop_write; + goto out_dput; host_err = nfsd_break_lease(dold->d_inode); if (host_err) { err = nfserrno(host_err); - goto out_drop_write; + goto out_dput; } host_err = vfs_link(dold, dirp, dnew); if (!host_err) { @@ -1718,12 +1720,11 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, else err = nfserrno(host_err); } -out_drop_write: - fh_drop_write(tfhp); out_dput: dput(dnew); out_unlock: fh_unlock(ffhp); + fh_drop_write(tfhp); out: return err; @@ -1766,6 +1767,12 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) goto out; + host_err = fh_want_write(ffhp); + if (host_err) { + err = nfserrno(host_err); + goto out; + } + /* cannot use fh_lock as we need deadlock protective ordering * so do it by hand */ trap = lock_rename(tdentry, fdentry); @@ -1796,17 +1803,14 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, host_err = -EXDEV; if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) goto out_dput_new; - host_err = fh_want_write(ffhp); - if (host_err) - goto out_dput_new; host_err = nfsd_break_lease(odentry->d_inode); if (host_err) - goto out_drop_write; + goto out_dput_new; if (ndentry->d_inode) { host_err = nfsd_break_lease(ndentry->d_inode); if (host_err) - goto out_drop_write; + goto out_dput_new; } host_err = vfs_rename(fdir, odentry, tdir, ndentry); if (!host_err) { @@ -1814,8 +1818,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (!host_err) host_err = commit_metadata(ffhp); } -out_drop_write: - fh_drop_write(ffhp); out_dput_new: dput(ndentry); out_dput_old: @@ -1831,6 +1833,7 @@ out_drop_write: fill_post_wcc(tfhp); unlock_rename(tdentry, fdentry); ffhp->fh_locked = tfhp->fh_locked = 0; + fh_drop_write(ffhp); out: return err; @@ -1856,6 +1859,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (err) goto out; + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock_nested(fhp, I_MUTEX_PARENT); dentry = fhp->fh_dentry; dirp = dentry->d_inode; @@ -1874,21 +1881,15 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (!type) type = rdentry->d_inode->i_mode & S_IFMT; - host_err = fh_want_write(fhp); - if (host_err) - goto out_put; - host_err = nfsd_break_lease(rdentry->d_inode); if (host_err) - goto out_drop_write; + goto out_put; if (type != S_IFDIR) host_err = vfs_unlink(dirp, rdentry); else host_err = vfs_rmdir(dirp, rdentry); if (!host_err) host_err = commit_metadata(fhp); -out_drop_write: - fh_drop_write(fhp); out_put: dput(rdentry); diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h index ec0611b..359594c 100644 --- a/fs/nfsd/vfs.h +++ b/fs/nfsd/vfs.h @@ -110,12 +110,19 @@ int nfsd_set_posix_acl(struct svc_fh *, int, struct posix_acl *); static inline int fh_want_write(struct svc_fh *fh) { - return mnt_want_write(fh->fh_export->ex_path.mnt); + int ret = mnt_want_write(fh->fh_export->ex_path.mnt); + + if (!ret) + fh->fh_want_write = 1; + return ret; } static inline void fh_drop_write(struct svc_fh *fh) { - mnt_drop_write(fh->fh_export->ex_path.mnt); + if (fh->fh_want_write) { + fh->fh_want_write = 0; + mnt_drop_write(fh->fh_export->ex_path.mnt); + } } #endif /* LINUX_NFSD_VFS_H */ diff --git a/include/linux/nfsd/nfsfh.h b/include/linux/nfsd/nfsfh.h index ce4743a..fa63048 100644 --- a/include/linux/nfsd/nfsfh.h +++ b/include/linux/nfsd/nfsfh.h @@ -143,6 +143,7 @@ typedef struct svc_fh { int fh_maxsize; /* max size for fh_handle */ unsigned char fh_locked; /* inode locked by us */ + unsigned char fh_want_write; /* remount protection taken */ #ifdef CONFIG_NFSD_V3 unsigned char fh_post_saved; /* post-op attrs saved */ -- 1.7.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex 2012-06-12 14:20 ` [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex Jan Kara @ 2012-06-12 17:25 ` J. Bruce Fields 0 siblings, 0 replies; 7+ messages in thread From: J. Bruce Fields @ 2012-06-12 17:25 UTC (permalink / raw) To: Jan Kara; +Cc: Al Viro, LKML, linux-fsdevel, linux-nfs On Tue, Jun 12, 2012 at 04:20:33PM +0200, Jan Kara wrote: > When mnt_want_write() starts to handle freezing it will get a full lock > semantics requiring proper lock ordering. So push mnt_want_write() call > consistently outside of i_mutex. > > CC: linux-nfs@vger.kernel.org > CC: "J. Bruce Fields" <bfields@fieldses.org> Looks good to me. (If you want: Acked-by: J. Bruce Fields <bfields@redhat.com> .) --b. > Signed-off-by: Jan Kara <jack@suse.cz> > --- > fs/nfsd/nfs4recover.c | 9 +++-- > fs/nfsd/nfsfh.c | 1 + > fs/nfsd/nfsproc.c | 9 ++++- > fs/nfsd/vfs.c | 79 ++++++++++++++++++++++--------------------- > fs/nfsd/vfs.h | 11 +++++- > include/linux/nfsd/nfsfh.h | 1 + > 6 files changed, 64 insertions(+), 46 deletions(-) > > diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c > index 5ff0b7b..43295d4 100644 > --- a/fs/nfsd/nfs4recover.c > +++ b/fs/nfsd/nfs4recover.c > @@ -154,6 +154,10 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) > if (status < 0) > return; > > + status = mnt_want_write_file(rec_file); > + if (status) > + return; > + > dir = rec_file->f_path.dentry; > /* lock the parent */ > mutex_lock(&dir->d_inode->i_mutex); > @@ -173,11 +177,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) > * as well be forgiving and just succeed silently. > */ > goto out_put; > - status = mnt_want_write_file(rec_file); > - if (status) > - goto out_put; > status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU); > - mnt_drop_write_file(rec_file); > out_put: > dput(dentry); > out_unlock: > @@ -189,6 +189,7 @@ out_unlock: > " (err %d); please check that %s exists" > " and is writeable", status, > user_recovery_dirname); > + mnt_drop_write_file(rec_file); > nfs4_reset_creds(original_cred); > } > > diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c > index cc79300..032af38 100644 > --- a/fs/nfsd/nfsfh.c > +++ b/fs/nfsd/nfsfh.c > @@ -635,6 +635,7 @@ fh_put(struct svc_fh *fhp) > fhp->fh_post_saved = 0; > #endif > } > + fh_drop_write(fhp); > if (exp) { > exp_put(exp); > fhp->fh_export = NULL; > diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c > index e15dc45..aad6d45 100644 > --- a/fs/nfsd/nfsproc.c > +++ b/fs/nfsd/nfsproc.c > @@ -196,6 +196,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, > struct dentry *dchild; > int type, mode; > __be32 nfserr; > + int hosterr; > dev_t rdev = 0, wanted = new_decode_dev(attr->ia_size); > > dprintk("nfsd: CREATE %s %.*s\n", > @@ -214,6 +215,12 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, > nfserr = nfserr_exist; > if (isdotent(argp->name, argp->len)) > goto done; > + hosterr = fh_want_write(dirfhp); > + if (hosterr) { > + nfserr = nfserrno(hosterr); > + goto done; > + } > + > fh_lock_nested(dirfhp, I_MUTEX_PARENT); > dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len); > if (IS_ERR(dchild)) { > @@ -330,7 +337,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, > out_unlock: > /* We don't really need to unlock, as fh_put does it. */ > fh_unlock(dirfhp); > - > + fh_drop_write(dirfhp); > done: > fh_put(dirfhp); > return nfsd_return_dirop(nfserr, resp); > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c > index c8bd9c3..4503995 100644 > --- a/fs/nfsd/vfs.c > +++ b/fs/nfsd/vfs.c > @@ -1276,6 +1276,10 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > * If it has, the parent directory should already be locked. > */ > if (!resfhp->fh_dentry) { > + host_err = fh_want_write(fhp); > + if (host_err) > + goto out_nfserr; > + > /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */ > fh_lock_nested(fhp, I_MUTEX_PARENT); > dchild = lookup_one_len(fname, dentry, flen); > @@ -1319,14 +1323,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > goto out; > } > > - host_err = fh_want_write(fhp); > - if (host_err) > - goto out_nfserr; > - > /* > * Get the dir op function pointer. > */ > err = 0; > + host_err = 0; > switch (type) { > case S_IFREG: > host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL); > @@ -1343,10 +1344,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); > break; > } > - if (host_err < 0) { > - fh_drop_write(fhp); > + if (host_err < 0) > goto out_nfserr; > - } > > err = nfsd_create_setattr(rqstp, resfhp, iap); > > @@ -1358,7 +1357,6 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > err2 = nfserrno(commit_metadata(fhp)); > if (err2) > err = err2; > - fh_drop_write(fhp); > /* > * Update the file handle to get the new inode info. > */ > @@ -1417,6 +1415,11 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > err = nfserr_notdir; > if (!dirp->i_op->lookup) > goto out; > + > + host_err = fh_want_write(fhp); > + if (host_err) > + goto out_nfserr; > + > fh_lock_nested(fhp, I_MUTEX_PARENT); > > /* > @@ -1449,9 +1452,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > v_atime = verifier[1]&0x7fffffff; > } > > - host_err = fh_want_write(fhp); > - if (host_err) > - goto out_nfserr; > if (dchild->d_inode) { > err = 0; > > @@ -1522,7 +1522,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > if (!err) > err = nfserrno(commit_metadata(fhp)); > > - fh_drop_write(fhp); > /* > * Update the filehandle to get the new inode info. > */ > @@ -1533,6 +1532,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > fh_unlock(fhp); > if (dchild && !IS_ERR(dchild)) > dput(dchild); > + fh_drop_write(fhp); > return err; > > out_nfserr: > @@ -1613,6 +1613,11 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, > err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); > if (err) > goto out; > + > + host_err = fh_want_write(fhp); > + if (host_err) > + goto out_nfserr; > + > fh_lock(fhp); > dentry = fhp->fh_dentry; > dnew = lookup_one_len(fname, dentry, flen); > @@ -1620,10 +1625,6 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, > if (IS_ERR(dnew)) > goto out_nfserr; > > - host_err = fh_want_write(fhp); > - if (host_err) > - goto out_nfserr; > - > if (unlikely(path[plen] != 0)) { > char *path_alloced = kmalloc(plen+1, GFP_KERNEL); > if (path_alloced == NULL) > @@ -1683,6 +1684,12 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, > if (isdotent(name, len)) > goto out; > > + host_err = fh_want_write(tfhp); > + if (host_err) { > + err = nfserrno(host_err); > + goto out; > + } > + > fh_lock_nested(ffhp, I_MUTEX_PARENT); > ddir = ffhp->fh_dentry; > dirp = ddir->d_inode; > @@ -1694,18 +1701,13 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, > > dold = tfhp->fh_dentry; > > - host_err = fh_want_write(tfhp); > - if (host_err) { > - err = nfserrno(host_err); > - goto out_dput; > - } > err = nfserr_noent; > if (!dold->d_inode) > - goto out_drop_write; > + goto out_dput; > host_err = nfsd_break_lease(dold->d_inode); > if (host_err) { > err = nfserrno(host_err); > - goto out_drop_write; > + goto out_dput; > } > host_err = vfs_link(dold, dirp, dnew); > if (!host_err) { > @@ -1718,12 +1720,11 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, > else > err = nfserrno(host_err); > } > -out_drop_write: > - fh_drop_write(tfhp); > out_dput: > dput(dnew); > out_unlock: > fh_unlock(ffhp); > + fh_drop_write(tfhp); > out: > return err; > > @@ -1766,6 +1767,12 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, > if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) > goto out; > > + host_err = fh_want_write(ffhp); > + if (host_err) { > + err = nfserrno(host_err); > + goto out; > + } > + > /* cannot use fh_lock as we need deadlock protective ordering > * so do it by hand */ > trap = lock_rename(tdentry, fdentry); > @@ -1796,17 +1803,14 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, > host_err = -EXDEV; > if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) > goto out_dput_new; > - host_err = fh_want_write(ffhp); > - if (host_err) > - goto out_dput_new; > > host_err = nfsd_break_lease(odentry->d_inode); > if (host_err) > - goto out_drop_write; > + goto out_dput_new; > if (ndentry->d_inode) { > host_err = nfsd_break_lease(ndentry->d_inode); > if (host_err) > - goto out_drop_write; > + goto out_dput_new; > } > host_err = vfs_rename(fdir, odentry, tdir, ndentry); > if (!host_err) { > @@ -1814,8 +1818,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, > if (!host_err) > host_err = commit_metadata(ffhp); > } > -out_drop_write: > - fh_drop_write(ffhp); > out_dput_new: > dput(ndentry); > out_dput_old: > @@ -1831,6 +1833,7 @@ out_drop_write: > fill_post_wcc(tfhp); > unlock_rename(tdentry, fdentry); > ffhp->fh_locked = tfhp->fh_locked = 0; > + fh_drop_write(ffhp); > > out: > return err; > @@ -1856,6 +1859,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, > if (err) > goto out; > > + host_err = fh_want_write(fhp); > + if (host_err) > + goto out_nfserr; > + > fh_lock_nested(fhp, I_MUTEX_PARENT); > dentry = fhp->fh_dentry; > dirp = dentry->d_inode; > @@ -1874,21 +1881,15 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, > if (!type) > type = rdentry->d_inode->i_mode & S_IFMT; > > - host_err = fh_want_write(fhp); > - if (host_err) > - goto out_put; > - > host_err = nfsd_break_lease(rdentry->d_inode); > if (host_err) > - goto out_drop_write; > + goto out_put; > if (type != S_IFDIR) > host_err = vfs_unlink(dirp, rdentry); > else > host_err = vfs_rmdir(dirp, rdentry); > if (!host_err) > host_err = commit_metadata(fhp); > -out_drop_write: > - fh_drop_write(fhp); > out_put: > dput(rdentry); > > diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h > index ec0611b..359594c 100644 > --- a/fs/nfsd/vfs.h > +++ b/fs/nfsd/vfs.h > @@ -110,12 +110,19 @@ int nfsd_set_posix_acl(struct svc_fh *, int, struct posix_acl *); > > static inline int fh_want_write(struct svc_fh *fh) > { > - return mnt_want_write(fh->fh_export->ex_path.mnt); > + int ret = mnt_want_write(fh->fh_export->ex_path.mnt); > + > + if (!ret) > + fh->fh_want_write = 1; > + return ret; > } > > static inline void fh_drop_write(struct svc_fh *fh) > { > - mnt_drop_write(fh->fh_export->ex_path.mnt); > + if (fh->fh_want_write) { > + fh->fh_want_write = 0; > + mnt_drop_write(fh->fh_export->ex_path.mnt); > + } > } > > #endif /* LINUX_NFSD_VFS_H */ > diff --git a/include/linux/nfsd/nfsfh.h b/include/linux/nfsd/nfsfh.h > index ce4743a..fa63048 100644 > --- a/include/linux/nfsd/nfsfh.h > +++ b/include/linux/nfsd/nfsfh.h > @@ -143,6 +143,7 @@ typedef struct svc_fh { > int fh_maxsize; /* max size for fh_handle */ > > unsigned char fh_locked; /* inode locked by us */ > + unsigned char fh_want_write; /* remount protection taken */ > > #ifdef CONFIG_NFSD_V3 > unsigned char fh_post_saved; /* post-op attrs saved */ > -- > 1.7.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH 00/27 v6] Fix filesystem freezing deadlocks
@ 2012-06-01 22:30 Jan Kara
2012-06-01 22:30 ` [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex Jan Kara
0 siblings, 1 reply; 7+ messages in thread
From: Jan Kara @ 2012-06-01 22:30 UTC (permalink / raw)
To: linux-fsdevel
Cc: Al Viro, dchinner, Jan Kara, Alex Elder, Anton Altaparmakov,
Ben Myers, Chris Mason, cluster-devel, David S. Miller,
fuse-devel, J. Bruce Fields, Joel Becker, KONISHI Ryusuke,
linux-btrfs, linux-ext4, linux-nfs, linux-nilfs, linux-ntfs-dev,
Mark Fasheh, Miklos Szeredi, ocfs2-devel, OGAWA Hirofumi,
Steven Whitehouse, Theodore Ts'o, xfs
Hello,
here is the sixth iteration of my patches to improve filesystem freezing.
The change since last iteration is that filesystem can be frozen with open but
unlinked files. After some thinking, I've decided that the best way to handle
this is to block removal inside ->evict_inode() of each filesystem and use
fs-internal level of freeze protection for that (usually I've instrumented
filesystem's transaction system to use freeze protection). Handling
inside VFS would be less work but the only level of freeze protection that
has a chance of not causing deadlocks is the one used for page faults and even
there it's not clear lock ordering would be correct wrt some fs-specific locks.
I've converted ext2, ext4, btrfs, xfs, nilfs2, ocfs2, gfs2 and also checked
that ext3, reiserfs, jfs should work as well (they have their internal freeze
protection mechanisms, possibly they could be replaced by a generic one but
given these are mostly aging filesystems, it's not a real priority IHMO).
So finally I'm not aware of any pending issue with this patch set so if you
have some concern, please speak up!
Introductory text to first time readers:
Filesystem freezing is currently racy and thus we can end up with dirty data on
frozen filesystem (see changelog patch 13 for detailed race description). This
patch series aims at fixing this.
To be able to block all places where inodes get dirtied, I've moved filesystem
file_update_time() call to ->page_mkwrite callback (patches 01-07) and put
freeze handling in mnt_want_write() / mnt_drop_write(). That however required
some code shuffling and changes to kern_path_create() (see patches 09-12). I
think the result is OK but opinions may differ ;). The advantage of this change
also is that all filesystems get freeze protection almost for free - even ext2
can handle freezing well now.
Another potential contention point might be patch 19. In that patch we make
freeze_super() refuse to freeze the filesystem when there are open but unlinked
files which may be impractical in some cases. The main reason for this is the
problem with handling of file deletion from fput() called with mmap_sem held
(e.g. from munmap(2)), and then there's the fact that we cannot really force
such filesystem into a consistent state... But if people think that freezing
with open but unlinked files should happen, then I have some possible
solutions in mind (maybe as a separate patchset since this is large enough).
I'm not able to hit any deadlocks, lockdep warnings, or dirty data on frozen
filesystem despite beating it with fsstress and bash-shared-mapping while
freezing and unfreezing for several hours (using ext4 and xfs) so I'm
reasonably confident this could finally be the right solution.
Changes since v5:
* handle unlinked & open files on frozen filesystem
* lockdep keys for freeze protection are now per filesystem type
* taught lockdep that freeze protection at lower level does not create
dependency when we already hold freeze protection at higher level
* rebased on 3.5-rc1-ish
Changes since v4:
* added a couple of Acked-by's
* added some comments & doc update
* added patches from series "Push file_update_time() into .page_mkwrite"
since it doesn't make much sense to keep them separate anymore
* rebased on top of 3.4-rc2
Changes since v3:
* added third level of freezing for fs internal purposes - hooked some
filesystems to use it (XFS, nilfs2)
* removed racy i_size check from filemap_mkwrite()
Changes since v2:
* completely rewritten
* freezing is now blocked at VFS entry points
* two stage freezing to handle both mmapped writes and other IO
The biggest changes since v1:
* have two counters to provide safe state transitions for SB_FREEZE_WRITE
and SB_FREEZE_TRANS states
* use percpu counters instead of own percpu structure
* added documentation fixes from the old fs freezing series
* converted XFS to use SB_FREEZE_TRANS counter instead of its private
m_active_trans counter
Honza
CC: Alex Elder <elder@kernel.org>
CC: Anton Altaparmakov <anton@tuxera.com>
CC: Ben Myers <bpm@sgi.com>
CC: Chris Mason <chris.mason@oracle.com>
CC: cluster-devel@redhat.com
CC: "David S. Miller" <davem@davemloft.net>
CC: fuse-devel@lists.sourceforge.net
CC: "J. Bruce Fields" <bfields@fieldses.org>
CC: Joel Becker <jlbec@evilplan.org>
CC: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
CC: linux-btrfs@vger.kernel.org
CC: linux-ext4@vger.kernel.org
CC: linux-nfs@vger.kernel.org
CC: linux-nilfs@vger.kernel.org
CC: linux-ntfs-dev@lists.sourceforge.net
CC: Mark Fasheh <mfasheh@suse.com>
CC: Miklos Szeredi <miklos@szeredi.hu>
CC: ocfs2-devel@oss.oracle.com
CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
CC: Steven Whitehouse <swhiteho@redhat.com>
CC: "Theodore Ts'o" <tytso@mit.edu>
CC: xfs@oss.sgi.com
^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex 2012-06-01 22:30 [PATCH 00/27 v6] Fix filesystem freezing deadlocks Jan Kara @ 2012-06-01 22:30 ` Jan Kara 0 siblings, 0 replies; 7+ messages in thread From: Jan Kara @ 2012-06-01 22:30 UTC (permalink / raw) To: linux-fsdevel; +Cc: Al Viro, dchinner, Jan Kara, linux-nfs, J. Bruce Fields When mnt_want_write() starts to handle freezing it will get a full lock semantics requiring proper lock ordering. So push mnt_want_write() call consistently outside of i_mutex. CC: linux-nfs@vger.kernel.org CC: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Jan Kara <jack@suse.cz> --- fs/nfsd/nfs4recover.c | 9 +++-- fs/nfsd/nfsfh.c | 1 + fs/nfsd/nfsproc.c | 9 ++++- fs/nfsd/vfs.c | 79 ++++++++++++++++++++++--------------------- fs/nfsd/vfs.h | 11 +++++- include/linux/nfsd/nfsfh.h | 1 + 6 files changed, 64 insertions(+), 46 deletions(-) diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index 5ff0b7b..43295d4 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -154,6 +154,10 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) if (status < 0) return; + status = mnt_want_write_file(rec_file); + if (status) + return; + dir = rec_file->f_path.dentry; /* lock the parent */ mutex_lock(&dir->d_inode->i_mutex); @@ -173,11 +177,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) * as well be forgiving and just succeed silently. */ goto out_put; - status = mnt_want_write_file(rec_file); - if (status) - goto out_put; status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU); - mnt_drop_write_file(rec_file); out_put: dput(dentry); out_unlock: @@ -189,6 +189,7 @@ out_unlock: " (err %d); please check that %s exists" " and is writeable", status, user_recovery_dirname); + mnt_drop_write_file(rec_file); nfs4_reset_creds(original_cred); } diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c index cc79300..032af38 100644 --- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -635,6 +635,7 @@ fh_put(struct svc_fh *fhp) fhp->fh_post_saved = 0; #endif } + fh_drop_write(fhp); if (exp) { exp_put(exp); fhp->fh_export = NULL; diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index e15dc45..aad6d45 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -196,6 +196,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, struct dentry *dchild; int type, mode; __be32 nfserr; + int hosterr; dev_t rdev = 0, wanted = new_decode_dev(attr->ia_size); dprintk("nfsd: CREATE %s %.*s\n", @@ -214,6 +215,12 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, nfserr = nfserr_exist; if (isdotent(argp->name, argp->len)) goto done; + hosterr = fh_want_write(dirfhp); + if (hosterr) { + nfserr = nfserrno(hosterr); + goto done; + } + fh_lock_nested(dirfhp, I_MUTEX_PARENT); dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len); if (IS_ERR(dchild)) { @@ -330,7 +337,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, out_unlock: /* We don't really need to unlock, as fh_put does it. */ fh_unlock(dirfhp); - + fh_drop_write(dirfhp); done: fh_put(dirfhp); return nfsd_return_dirop(nfserr, resp); diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index c8bd9c3..4503995 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1276,6 +1276,10 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, * If it has, the parent directory should already be locked. */ if (!resfhp->fh_dentry) { + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */ fh_lock_nested(fhp, I_MUTEX_PARENT); dchild = lookup_one_len(fname, dentry, flen); @@ -1319,14 +1323,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, goto out; } - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; - /* * Get the dir op function pointer. */ err = 0; + host_err = 0; switch (type) { case S_IFREG: host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL); @@ -1343,10 +1344,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); break; } - if (host_err < 0) { - fh_drop_write(fhp); + if (host_err < 0) goto out_nfserr; - } err = nfsd_create_setattr(rqstp, resfhp, iap); @@ -1358,7 +1357,6 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, err2 = nfserrno(commit_metadata(fhp)); if (err2) err = err2; - fh_drop_write(fhp); /* * Update the file handle to get the new inode info. */ @@ -1417,6 +1415,11 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, err = nfserr_notdir; if (!dirp->i_op->lookup) goto out; + + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock_nested(fhp, I_MUTEX_PARENT); /* @@ -1449,9 +1452,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, v_atime = verifier[1]&0x7fffffff; } - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; if (dchild->d_inode) { err = 0; @@ -1522,7 +1522,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, if (!err) err = nfserrno(commit_metadata(fhp)); - fh_drop_write(fhp); /* * Update the filehandle to get the new inode info. */ @@ -1533,6 +1532,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, fh_unlock(fhp); if (dchild && !IS_ERR(dchild)) dput(dchild); + fh_drop_write(fhp); return err; out_nfserr: @@ -1613,6 +1613,11 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; + + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock(fhp); dentry = fhp->fh_dentry; dnew = lookup_one_len(fname, dentry, flen); @@ -1620,10 +1625,6 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, if (IS_ERR(dnew)) goto out_nfserr; - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; - if (unlikely(path[plen] != 0)) { char *path_alloced = kmalloc(plen+1, GFP_KERNEL); if (path_alloced == NULL) @@ -1683,6 +1684,12 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, if (isdotent(name, len)) goto out; + host_err = fh_want_write(tfhp); + if (host_err) { + err = nfserrno(host_err); + goto out; + } + fh_lock_nested(ffhp, I_MUTEX_PARENT); ddir = ffhp->fh_dentry; dirp = ddir->d_inode; @@ -1694,18 +1701,13 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, dold = tfhp->fh_dentry; - host_err = fh_want_write(tfhp); - if (host_err) { - err = nfserrno(host_err); - goto out_dput; - } err = nfserr_noent; if (!dold->d_inode) - goto out_drop_write; + goto out_dput; host_err = nfsd_break_lease(dold->d_inode); if (host_err) { err = nfserrno(host_err); - goto out_drop_write; + goto out_dput; } host_err = vfs_link(dold, dirp, dnew); if (!host_err) { @@ -1718,12 +1720,11 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, else err = nfserrno(host_err); } -out_drop_write: - fh_drop_write(tfhp); out_dput: dput(dnew); out_unlock: fh_unlock(ffhp); + fh_drop_write(tfhp); out: return err; @@ -1766,6 +1767,12 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) goto out; + host_err = fh_want_write(ffhp); + if (host_err) { + err = nfserrno(host_err); + goto out; + } + /* cannot use fh_lock as we need deadlock protective ordering * so do it by hand */ trap = lock_rename(tdentry, fdentry); @@ -1796,17 +1803,14 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, host_err = -EXDEV; if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) goto out_dput_new; - host_err = fh_want_write(ffhp); - if (host_err) - goto out_dput_new; host_err = nfsd_break_lease(odentry->d_inode); if (host_err) - goto out_drop_write; + goto out_dput_new; if (ndentry->d_inode) { host_err = nfsd_break_lease(ndentry->d_inode); if (host_err) - goto out_drop_write; + goto out_dput_new; } host_err = vfs_rename(fdir, odentry, tdir, ndentry); if (!host_err) { @@ -1814,8 +1818,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (!host_err) host_err = commit_metadata(ffhp); } -out_drop_write: - fh_drop_write(ffhp); out_dput_new: dput(ndentry); out_dput_old: @@ -1831,6 +1833,7 @@ out_drop_write: fill_post_wcc(tfhp); unlock_rename(tdentry, fdentry); ffhp->fh_locked = tfhp->fh_locked = 0; + fh_drop_write(ffhp); out: return err; @@ -1856,6 +1859,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (err) goto out; + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock_nested(fhp, I_MUTEX_PARENT); dentry = fhp->fh_dentry; dirp = dentry->d_inode; @@ -1874,21 +1881,15 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (!type) type = rdentry->d_inode->i_mode & S_IFMT; - host_err = fh_want_write(fhp); - if (host_err) - goto out_put; - host_err = nfsd_break_lease(rdentry->d_inode); if (host_err) - goto out_drop_write; + goto out_put; if (type != S_IFDIR) host_err = vfs_unlink(dirp, rdentry); else host_err = vfs_rmdir(dirp, rdentry); if (!host_err) host_err = commit_metadata(fhp); -out_drop_write: - fh_drop_write(fhp); out_put: dput(rdentry); diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h index ec0611b..359594c 100644 --- a/fs/nfsd/vfs.h +++ b/fs/nfsd/vfs.h @@ -110,12 +110,19 @@ int nfsd_set_posix_acl(struct svc_fh *, int, struct posix_acl *); static inline int fh_want_write(struct svc_fh *fh) { - return mnt_want_write(fh->fh_export->ex_path.mnt); + int ret = mnt_want_write(fh->fh_export->ex_path.mnt); + + if (!ret) + fh->fh_want_write = 1; + return ret; } static inline void fh_drop_write(struct svc_fh *fh) { - mnt_drop_write(fh->fh_export->ex_path.mnt); + if (fh->fh_want_write) { + fh->fh_want_write = 0; + mnt_drop_write(fh->fh_export->ex_path.mnt); + } } #endif /* LINUX_NFSD_VFS_H */ diff --git a/include/linux/nfsd/nfsfh.h b/include/linux/nfsd/nfsfh.h index ce4743a..fa63048 100644 --- a/include/linux/nfsd/nfsfh.h +++ b/include/linux/nfsd/nfsfh.h @@ -143,6 +143,7 @@ typedef struct svc_fh { int fh_maxsize; /* max size for fh_handle */ unsigned char fh_locked; /* inode locked by us */ + unsigned char fh_want_write; /* remount protection taken */ #ifdef CONFIG_NFSD_V3 unsigned char fh_post_saved; /* post-op attrs saved */ -- 1.7.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 00/19 v5] Fix filesystem freezing deadlocks
@ 2012-04-16 16:13 Jan Kara
2012-04-16 16:13 ` [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex Jan Kara
0 siblings, 1 reply; 7+ messages in thread
From: Jan Kara @ 2012-04-16 16:13 UTC (permalink / raw)
To: Al Viro
Cc: dchinner, LKML, linux-fsdevel, Jan Kara, Alex Elder,
Anton Altaparmakov, Ben Myers, Chris Mason, cluster-devel,
David S. Miller, fuse-devel, J. Bruce Fields, Joel Becker,
KONISHI Ryusuke, linux-btrfs, linux-ext4, linux-nfs, linux-nilfs,
linux-ntfs-dev, Mark Fasheh, Miklos Szeredi, ocfs2-devel,
OGAWA Hirofumi, Steven Whitehouse, Theodore Ts'o, xfs
Hello,
here is the fifth iteration of my patches to improve filesystem freezing.
No serious changes since last time. Mostly I rebased patches and merged this
series with series moving file_update_time() to ->page_mkwrite() to simplify
testing and merging.
Filesystem freezing is currently racy and thus we can end up with dirty data on
frozen filesystem (see changelog patch 13 for detailed race description). This
patch series aims at fixing this.
To be able to block all places where inodes get dirtied, I've moved filesystem
file_update_time() call to ->page_mkwrite callback (patches 01-07) and put
freeze handling in mnt_want_write() / mnt_drop_write(). That however required
some code shuffling and changes to kern_path_create() (see patches 09-12). I
think the result is OK but opinions may differ ;). The advantage of this change
also is that all filesystems get freeze protection almost for free - even ext2
can handle freezing well now.
Another potential contention point might be patch 19. In that patch we make
freeze_super() refuse to freeze the filesystem when there are open but unlinked
files which may be impractical in some cases. The main reason for this is the
problem with handling of file deletion from fput() called with mmap_sem held
(e.g. from munmap(2)), and then there's the fact that we cannot really force
such filesystem into a consistent state... But if people think that freezing
with open but unlinked files should happen, then I have some possible
solutions in mind (maybe as a separate patchset since this is large enough).
I'm not able to hit any deadlocks, lockdep warnings, or dirty data on frozen
filesystem despite beating it with fsstress and bash-shared-mapping while
freezing and unfreezing for several hours (using ext4 and xfs) so I'm
reasonably confident this could finally be the right solution.
Changes since v4:
* added a couple of Acked-by's
* added some comments & doc update
* added patches from series "Push file_update_time() into .page_mkwrite"
since it doesn't make much sense to keep them separate anymore
* rebased on top of 3.4-rc2
Changes since v3:
* added third level of freezing for fs internal purposes - hooked some
filesystems to use it (XFS, nilfs2)
* removed racy i_size check from filemap_mkwrite()
Changes since v2:
* completely rewritten
* freezing is now blocked at VFS entry points
* two stage freezing to handle both mmapped writes and other IO
The biggest changes since v1:
* have two counters to provide safe state transitions for SB_FREEZE_WRITE
and SB_FREEZE_TRANS states
* use percpu counters instead of own percpu structure
* added documentation fixes from the old fs freezing series
* converted XFS to use SB_FREEZE_TRANS counter instead of its private
m_active_trans counter
Honza
CC: Alex Elder <elder@kernel.org>
CC: Anton Altaparmakov <anton@tuxera.com>
CC: Ben Myers <bpm@sgi.com>
CC: Chris Mason <chris.mason@oracle.com>
CC: cluster-devel@redhat.com
CC: "David S. Miller" <davem@davemloft.net>
CC: fuse-devel@lists.sourceforge.net
CC: "J. Bruce Fields" <bfields@fieldses.org>
CC: Joel Becker <jlbec@evilplan.org>
CC: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
CC: linux-btrfs@vger.kernel.org
CC: linux-ext4@vger.kernel.org
CC: linux-nfs@vger.kernel.org
CC: linux-nilfs@vger.kernel.org
CC: linux-ntfs-dev@lists.sourceforge.net
CC: Mark Fasheh <mfasheh@suse.com>
CC: Miklos Szeredi <miklos@szeredi.hu>
CC: ocfs2-devel@oss.oracle.com
CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
CC: Steven Whitehouse <swhiteho@redhat.com>
CC: "Theodore Ts'o" <tytso@mit.edu>
CC: xfs@oss.sgi.com
^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex 2012-04-16 16:13 [PATCH 00/19 v5] Fix filesystem freezing deadlocks Jan Kara @ 2012-04-16 16:13 ` Jan Kara 2012-04-16 18:25 ` J. Bruce Fields 0 siblings, 1 reply; 7+ messages in thread From: Jan Kara @ 2012-04-16 16:13 UTC (permalink / raw) To: Al Viro; +Cc: dchinner, LKML, linux-fsdevel, Jan Kara, linux-nfs, J. Bruce Fields When mnt_want_write() starts to handle freezing it will get a full lock semantics requiring proper lock ordering. So push mnt_want_write() call consistently outside of i_mutex. CC: linux-nfs@vger.kernel.org CC: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Jan Kara <jack@suse.cz> --- fs/nfsd/nfs4recover.c | 9 +++-- fs/nfsd/nfsfh.c | 1 + fs/nfsd/nfsproc.c | 9 ++++- fs/nfsd/vfs.c | 79 ++++++++++++++++++++++--------------------- fs/nfsd/vfs.h | 11 +++++- include/linux/nfsd/nfsfh.h | 1 + 6 files changed, 64 insertions(+), 46 deletions(-) diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index 4767429..efa7574 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -154,6 +154,10 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) if (status < 0) return; + status = mnt_want_write_file(rec_file); + if (status) + return; + dir = rec_file->f_path.dentry; /* lock the parent */ mutex_lock(&dir->d_inode->i_mutex); @@ -173,11 +177,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) * as well be forgiving and just succeed silently. */ goto out_put; - status = mnt_want_write_file(rec_file); - if (status) - goto out_put; status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU); - mnt_drop_write_file(rec_file); out_put: dput(dentry); out_unlock: @@ -189,6 +189,7 @@ out_unlock: " (err %d); please check that %s exists" " and is writeable", status, user_recovery_dirname); + mnt_drop_write_file(rec_file); nfs4_reset_creds(original_cred); } diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c index 68454e7..8b93353 100644 --- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -635,6 +635,7 @@ fh_put(struct svc_fh *fhp) fhp->fh_post_saved = 0; #endif } + fh_drop_write(fhp); if (exp) { cache_put(&exp->h, &svc_export_cache); fhp->fh_export = NULL; diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index e15dc45..aad6d45 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -196,6 +196,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, struct dentry *dchild; int type, mode; __be32 nfserr; + int hosterr; dev_t rdev = 0, wanted = new_decode_dev(attr->ia_size); dprintk("nfsd: CREATE %s %.*s\n", @@ -214,6 +215,12 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, nfserr = nfserr_exist; if (isdotent(argp->name, argp->len)) goto done; + hosterr = fh_want_write(dirfhp); + if (hosterr) { + nfserr = nfserrno(hosterr); + goto done; + } + fh_lock_nested(dirfhp, I_MUTEX_PARENT); dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len); if (IS_ERR(dchild)) { @@ -330,7 +337,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, out_unlock: /* We don't really need to unlock, as fh_put does it. */ fh_unlock(dirfhp); - + fh_drop_write(dirfhp); done: fh_put(dirfhp); return nfsd_return_dirop(nfserr, resp); diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 296d671..b8bb649 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1276,6 +1276,10 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, * If it has, the parent directory should already be locked. */ if (!resfhp->fh_dentry) { + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */ fh_lock_nested(fhp, I_MUTEX_PARENT); dchild = lookup_one_len(fname, dentry, flen); @@ -1319,14 +1323,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, goto out; } - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; - /* * Get the dir op function pointer. */ err = 0; + host_err = 0; switch (type) { case S_IFREG: host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL); @@ -1343,10 +1344,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); break; } - if (host_err < 0) { - fh_drop_write(fhp); + if (host_err < 0) goto out_nfserr; - } err = nfsd_create_setattr(rqstp, resfhp, iap); @@ -1358,7 +1357,6 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, err2 = nfserrno(commit_metadata(fhp)); if (err2) err = err2; - fh_drop_write(fhp); /* * Update the file handle to get the new inode info. */ @@ -1417,6 +1415,11 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, err = nfserr_notdir; if (!dirp->i_op->lookup) goto out; + + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock_nested(fhp, I_MUTEX_PARENT); /* @@ -1449,9 +1452,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, v_atime = verifier[1]&0x7fffffff; } - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; if (dchild->d_inode) { err = 0; @@ -1522,7 +1522,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, if (!err) err = nfserrno(commit_metadata(fhp)); - fh_drop_write(fhp); /* * Update the filehandle to get the new inode info. */ @@ -1533,6 +1532,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, fh_unlock(fhp); if (dchild && !IS_ERR(dchild)) dput(dchild); + fh_drop_write(fhp); return err; out_nfserr: @@ -1613,6 +1613,11 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; + + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock(fhp); dentry = fhp->fh_dentry; dnew = lookup_one_len(fname, dentry, flen); @@ -1620,10 +1625,6 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, if (IS_ERR(dnew)) goto out_nfserr; - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; - if (unlikely(path[plen] != 0)) { char *path_alloced = kmalloc(plen+1, GFP_KERNEL); if (path_alloced == NULL) @@ -1683,6 +1684,12 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, if (isdotent(name, len)) goto out; + host_err = fh_want_write(tfhp); + if (host_err) { + err = nfserrno(host_err); + goto out; + } + fh_lock_nested(ffhp, I_MUTEX_PARENT); ddir = ffhp->fh_dentry; dirp = ddir->d_inode; @@ -1694,18 +1701,13 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, dold = tfhp->fh_dentry; - host_err = fh_want_write(tfhp); - if (host_err) { - err = nfserrno(host_err); - goto out_dput; - } err = nfserr_noent; if (!dold->d_inode) - goto out_drop_write; + goto out_dput; host_err = nfsd_break_lease(dold->d_inode); if (host_err) { err = nfserrno(host_err); - goto out_drop_write; + goto out_dput; } host_err = vfs_link(dold, dirp, dnew); if (!host_err) { @@ -1718,12 +1720,11 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, else err = nfserrno(host_err); } -out_drop_write: - fh_drop_write(tfhp); out_dput: dput(dnew); out_unlock: fh_unlock(ffhp); + fh_drop_write(tfhp); out: return err; @@ -1766,6 +1767,12 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) goto out; + host_err = fh_want_write(ffhp); + if (host_err) { + err = nfserrno(host_err); + goto out; + } + /* cannot use fh_lock as we need deadlock protective ordering * so do it by hand */ trap = lock_rename(tdentry, fdentry); @@ -1796,17 +1803,14 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, host_err = -EXDEV; if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) goto out_dput_new; - host_err = fh_want_write(ffhp); - if (host_err) - goto out_dput_new; host_err = nfsd_break_lease(odentry->d_inode); if (host_err) - goto out_drop_write; + goto out_dput_new; if (ndentry->d_inode) { host_err = nfsd_break_lease(ndentry->d_inode); if (host_err) - goto out_drop_write; + goto out_dput_new; } host_err = vfs_rename(fdir, odentry, tdir, ndentry); if (!host_err) { @@ -1814,8 +1818,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (!host_err) host_err = commit_metadata(ffhp); } -out_drop_write: - fh_drop_write(ffhp); out_dput_new: dput(ndentry); out_dput_old: @@ -1831,6 +1833,7 @@ out_drop_write: fill_post_wcc(tfhp); unlock_rename(tdentry, fdentry); ffhp->fh_locked = tfhp->fh_locked = 0; + fh_drop_write(ffhp); out: return err; @@ -1856,6 +1859,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (err) goto out; + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock_nested(fhp, I_MUTEX_PARENT); dentry = fhp->fh_dentry; dirp = dentry->d_inode; @@ -1874,21 +1881,15 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (!type) type = rdentry->d_inode->i_mode & S_IFMT; - host_err = fh_want_write(fhp); - if (host_err) - goto out_put; - host_err = nfsd_break_lease(rdentry->d_inode); if (host_err) - goto out_drop_write; + goto out_put; if (type != S_IFDIR) host_err = vfs_unlink(dirp, rdentry); else host_err = vfs_rmdir(dirp, rdentry); if (!host_err) host_err = commit_metadata(fhp); -out_drop_write: - fh_drop_write(fhp); out_put: dput(rdentry); diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h index ec0611b..359594c 100644 --- a/fs/nfsd/vfs.h +++ b/fs/nfsd/vfs.h @@ -110,12 +110,19 @@ int nfsd_set_posix_acl(struct svc_fh *, int, struct posix_acl *); static inline int fh_want_write(struct svc_fh *fh) { - return mnt_want_write(fh->fh_export->ex_path.mnt); + int ret = mnt_want_write(fh->fh_export->ex_path.mnt); + + if (!ret) + fh->fh_want_write = 1; + return ret; } static inline void fh_drop_write(struct svc_fh *fh) { - mnt_drop_write(fh->fh_export->ex_path.mnt); + if (fh->fh_want_write) { + fh->fh_want_write = 0; + mnt_drop_write(fh->fh_export->ex_path.mnt); + } } #endif /* LINUX_NFSD_VFS_H */ diff --git a/include/linux/nfsd/nfsfh.h b/include/linux/nfsd/nfsfh.h index ce4743a..fa63048 100644 --- a/include/linux/nfsd/nfsfh.h +++ b/include/linux/nfsd/nfsfh.h @@ -143,6 +143,7 @@ typedef struct svc_fh { int fh_maxsize; /* max size for fh_handle */ unsigned char fh_locked; /* inode locked by us */ + unsigned char fh_want_write; /* remount protection taken */ #ifdef CONFIG_NFSD_V3 unsigned char fh_post_saved; /* post-op attrs saved */ -- 1.7.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex 2012-04-16 16:13 ` [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex Jan Kara @ 2012-04-16 18:25 ` J. Bruce Fields 2012-04-17 8:17 ` Jan Kara 0 siblings, 1 reply; 7+ messages in thread From: J. Bruce Fields @ 2012-04-16 18:25 UTC (permalink / raw) To: Jan Kara; +Cc: Al Viro, dchinner, LKML, linux-fsdevel, linux-nfs On Mon, Apr 16, 2012 at 06:13:50PM +0200, Jan Kara wrote: > When mnt_want_write() starts to handle freezing it will get a full lock > semantics requiring proper lock ordering. So push mnt_want_write() call > consistently outside of i_mutex. How are you testing this? And do you want this particular track merged for 3.5 through the nfsd tree, or should it go some other way? --b. > > CC: linux-nfs@vger.kernel.org > CC: "J. Bruce Fields" <bfields@fieldses.org> > Signed-off-by: Jan Kara <jack@suse.cz> > --- > fs/nfsd/nfs4recover.c | 9 +++-- > fs/nfsd/nfsfh.c | 1 + > fs/nfsd/nfsproc.c | 9 ++++- > fs/nfsd/vfs.c | 79 ++++++++++++++++++++++--------------------- > fs/nfsd/vfs.h | 11 +++++- > include/linux/nfsd/nfsfh.h | 1 + > 6 files changed, 64 insertions(+), 46 deletions(-) > > diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c > index 4767429..efa7574 100644 > --- a/fs/nfsd/nfs4recover.c > +++ b/fs/nfsd/nfs4recover.c > @@ -154,6 +154,10 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) > if (status < 0) > return; > > + status = mnt_want_write_file(rec_file); > + if (status) > + return; > + > dir = rec_file->f_path.dentry; > /* lock the parent */ > mutex_lock(&dir->d_inode->i_mutex); > @@ -173,11 +177,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) > * as well be forgiving and just succeed silently. > */ > goto out_put; > - status = mnt_want_write_file(rec_file); > - if (status) > - goto out_put; > status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU); > - mnt_drop_write_file(rec_file); > out_put: > dput(dentry); > out_unlock: > @@ -189,6 +189,7 @@ out_unlock: > " (err %d); please check that %s exists" > " and is writeable", status, > user_recovery_dirname); > + mnt_drop_write_file(rec_file); > nfs4_reset_creds(original_cred); > } > > diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c > index 68454e7..8b93353 100644 > --- a/fs/nfsd/nfsfh.c > +++ b/fs/nfsd/nfsfh.c > @@ -635,6 +635,7 @@ fh_put(struct svc_fh *fhp) > fhp->fh_post_saved = 0; > #endif > } > + fh_drop_write(fhp); > if (exp) { > cache_put(&exp->h, &svc_export_cache); > fhp->fh_export = NULL; > diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c > index e15dc45..aad6d45 100644 > --- a/fs/nfsd/nfsproc.c > +++ b/fs/nfsd/nfsproc.c > @@ -196,6 +196,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, > struct dentry *dchild; > int type, mode; > __be32 nfserr; > + int hosterr; > dev_t rdev = 0, wanted = new_decode_dev(attr->ia_size); > > dprintk("nfsd: CREATE %s %.*s\n", > @@ -214,6 +215,12 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, > nfserr = nfserr_exist; > if (isdotent(argp->name, argp->len)) > goto done; > + hosterr = fh_want_write(dirfhp); > + if (hosterr) { > + nfserr = nfserrno(hosterr); > + goto done; > + } > + > fh_lock_nested(dirfhp, I_MUTEX_PARENT); > dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len); > if (IS_ERR(dchild)) { > @@ -330,7 +337,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, > out_unlock: > /* We don't really need to unlock, as fh_put does it. */ > fh_unlock(dirfhp); > - > + fh_drop_write(dirfhp); > done: > fh_put(dirfhp); > return nfsd_return_dirop(nfserr, resp); > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c > index 296d671..b8bb649 100644 > --- a/fs/nfsd/vfs.c > +++ b/fs/nfsd/vfs.c > @@ -1276,6 +1276,10 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > * If it has, the parent directory should already be locked. > */ > if (!resfhp->fh_dentry) { > + host_err = fh_want_write(fhp); > + if (host_err) > + goto out_nfserr; > + > /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */ > fh_lock_nested(fhp, I_MUTEX_PARENT); > dchild = lookup_one_len(fname, dentry, flen); > @@ -1319,14 +1323,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > goto out; > } > > - host_err = fh_want_write(fhp); > - if (host_err) > - goto out_nfserr; > - > /* > * Get the dir op function pointer. > */ > err = 0; > + host_err = 0; > switch (type) { > case S_IFREG: > host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL); > @@ -1343,10 +1344,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); > break; > } > - if (host_err < 0) { > - fh_drop_write(fhp); > + if (host_err < 0) > goto out_nfserr; > - } > > err = nfsd_create_setattr(rqstp, resfhp, iap); > > @@ -1358,7 +1357,6 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > err2 = nfserrno(commit_metadata(fhp)); > if (err2) > err = err2; > - fh_drop_write(fhp); > /* > * Update the file handle to get the new inode info. > */ > @@ -1417,6 +1415,11 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > err = nfserr_notdir; > if (!dirp->i_op->lookup) > goto out; > + > + host_err = fh_want_write(fhp); > + if (host_err) > + goto out_nfserr; > + > fh_lock_nested(fhp, I_MUTEX_PARENT); > > /* > @@ -1449,9 +1452,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > v_atime = verifier[1]&0x7fffffff; > } > > - host_err = fh_want_write(fhp); > - if (host_err) > - goto out_nfserr; > if (dchild->d_inode) { > err = 0; > > @@ -1522,7 +1522,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > if (!err) > err = nfserrno(commit_metadata(fhp)); > > - fh_drop_write(fhp); > /* > * Update the filehandle to get the new inode info. > */ > @@ -1533,6 +1532,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > fh_unlock(fhp); > if (dchild && !IS_ERR(dchild)) > dput(dchild); > + fh_drop_write(fhp); > return err; > > out_nfserr: > @@ -1613,6 +1613,11 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, > err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); > if (err) > goto out; > + > + host_err = fh_want_write(fhp); > + if (host_err) > + goto out_nfserr; > + > fh_lock(fhp); > dentry = fhp->fh_dentry; > dnew = lookup_one_len(fname, dentry, flen); > @@ -1620,10 +1625,6 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, > if (IS_ERR(dnew)) > goto out_nfserr; > > - host_err = fh_want_write(fhp); > - if (host_err) > - goto out_nfserr; > - > if (unlikely(path[plen] != 0)) { > char *path_alloced = kmalloc(plen+1, GFP_KERNEL); > if (path_alloced == NULL) > @@ -1683,6 +1684,12 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, > if (isdotent(name, len)) > goto out; > > + host_err = fh_want_write(tfhp); > + if (host_err) { > + err = nfserrno(host_err); > + goto out; > + } > + > fh_lock_nested(ffhp, I_MUTEX_PARENT); > ddir = ffhp->fh_dentry; > dirp = ddir->d_inode; > @@ -1694,18 +1701,13 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, > > dold = tfhp->fh_dentry; > > - host_err = fh_want_write(tfhp); > - if (host_err) { > - err = nfserrno(host_err); > - goto out_dput; > - } > err = nfserr_noent; > if (!dold->d_inode) > - goto out_drop_write; > + goto out_dput; > host_err = nfsd_break_lease(dold->d_inode); > if (host_err) { > err = nfserrno(host_err); > - goto out_drop_write; > + goto out_dput; > } > host_err = vfs_link(dold, dirp, dnew); > if (!host_err) { > @@ -1718,12 +1720,11 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, > else > err = nfserrno(host_err); > } > -out_drop_write: > - fh_drop_write(tfhp); > out_dput: > dput(dnew); > out_unlock: > fh_unlock(ffhp); > + fh_drop_write(tfhp); > out: > return err; > > @@ -1766,6 +1767,12 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, > if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) > goto out; > > + host_err = fh_want_write(ffhp); > + if (host_err) { > + err = nfserrno(host_err); > + goto out; > + } > + > /* cannot use fh_lock as we need deadlock protective ordering > * so do it by hand */ > trap = lock_rename(tdentry, fdentry); > @@ -1796,17 +1803,14 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, > host_err = -EXDEV; > if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) > goto out_dput_new; > - host_err = fh_want_write(ffhp); > - if (host_err) > - goto out_dput_new; > > host_err = nfsd_break_lease(odentry->d_inode); > if (host_err) > - goto out_drop_write; > + goto out_dput_new; > if (ndentry->d_inode) { > host_err = nfsd_break_lease(ndentry->d_inode); > if (host_err) > - goto out_drop_write; > + goto out_dput_new; > } > host_err = vfs_rename(fdir, odentry, tdir, ndentry); > if (!host_err) { > @@ -1814,8 +1818,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, > if (!host_err) > host_err = commit_metadata(ffhp); > } > -out_drop_write: > - fh_drop_write(ffhp); > out_dput_new: > dput(ndentry); > out_dput_old: > @@ -1831,6 +1833,7 @@ out_drop_write: > fill_post_wcc(tfhp); > unlock_rename(tdentry, fdentry); > ffhp->fh_locked = tfhp->fh_locked = 0; > + fh_drop_write(ffhp); > > out: > return err; > @@ -1856,6 +1859,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, > if (err) > goto out; > > + host_err = fh_want_write(fhp); > + if (host_err) > + goto out_nfserr; > + > fh_lock_nested(fhp, I_MUTEX_PARENT); > dentry = fhp->fh_dentry; > dirp = dentry->d_inode; > @@ -1874,21 +1881,15 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, > if (!type) > type = rdentry->d_inode->i_mode & S_IFMT; > > - host_err = fh_want_write(fhp); > - if (host_err) > - goto out_put; > - > host_err = nfsd_break_lease(rdentry->d_inode); > if (host_err) > - goto out_drop_write; > + goto out_put; > if (type != S_IFDIR) > host_err = vfs_unlink(dirp, rdentry); > else > host_err = vfs_rmdir(dirp, rdentry); > if (!host_err) > host_err = commit_metadata(fhp); > -out_drop_write: > - fh_drop_write(fhp); > out_put: > dput(rdentry); > > diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h > index ec0611b..359594c 100644 > --- a/fs/nfsd/vfs.h > +++ b/fs/nfsd/vfs.h > @@ -110,12 +110,19 @@ int nfsd_set_posix_acl(struct svc_fh *, int, struct posix_acl *); > > static inline int fh_want_write(struct svc_fh *fh) > { > - return mnt_want_write(fh->fh_export->ex_path.mnt); > + int ret = mnt_want_write(fh->fh_export->ex_path.mnt); > + > + if (!ret) > + fh->fh_want_write = 1; > + return ret; > } > > static inline void fh_drop_write(struct svc_fh *fh) > { > - mnt_drop_write(fh->fh_export->ex_path.mnt); > + if (fh->fh_want_write) { > + fh->fh_want_write = 0; > + mnt_drop_write(fh->fh_export->ex_path.mnt); > + } > } > > #endif /* LINUX_NFSD_VFS_H */ > diff --git a/include/linux/nfsd/nfsfh.h b/include/linux/nfsd/nfsfh.h > index ce4743a..fa63048 100644 > --- a/include/linux/nfsd/nfsfh.h > +++ b/include/linux/nfsd/nfsfh.h > @@ -143,6 +143,7 @@ typedef struct svc_fh { > int fh_maxsize; /* max size for fh_handle */ > > unsigned char fh_locked; /* inode locked by us */ > + unsigned char fh_want_write; /* remount protection taken */ > > #ifdef CONFIG_NFSD_V3 > unsigned char fh_post_saved; /* post-op attrs saved */ > -- > 1.7.1 > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex 2012-04-16 18:25 ` J. Bruce Fields @ 2012-04-17 8:17 ` Jan Kara 0 siblings, 0 replies; 7+ messages in thread From: Jan Kara @ 2012-04-17 8:17 UTC (permalink / raw) To: J. Bruce Fields Cc: Jan Kara, Al Viro, dchinner, LKML, linux-fsdevel, linux-nfs On Mon 16-04-12 14:25:33, J. Bruce Fields wrote: > On Mon, Apr 16, 2012 at 06:13:50PM +0200, Jan Kara wrote: > > When mnt_want_write() starts to handle freezing it will get a full lock > > semantics requiring proper lock ordering. So push mnt_want_write() call > > consistently outside of i_mutex. > > How are you testing this? That's a good question :). When I wrote this, I tried running nfs server, mounting it and checked that I could do basic operations and no lockdep warning is emitted. If you have better idea what test I should run, I can do that. > And do you want this particular track merged for 3.5 through the nfsd > tree, or should it go some other way? My original intent was to let Al merge everything to make it easy. But you wish to take this patch via your tree, it should be possible (it does not depend on anything, just the rest of the series depends on it due to lock ordering constraints). Honza > > CC: linux-nfs@vger.kernel.org > > CC: "J. Bruce Fields" <bfields@fieldses.org> > > Signed-off-by: Jan Kara <jack@suse.cz> > > --- > > fs/nfsd/nfs4recover.c | 9 +++-- > > fs/nfsd/nfsfh.c | 1 + > > fs/nfsd/nfsproc.c | 9 ++++- > > fs/nfsd/vfs.c | 79 ++++++++++++++++++++++--------------------- > > fs/nfsd/vfs.h | 11 +++++- > > include/linux/nfsd/nfsfh.h | 1 + > > 6 files changed, 64 insertions(+), 46 deletions(-) > > > > diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c > > index 4767429..efa7574 100644 > > --- a/fs/nfsd/nfs4recover.c > > +++ b/fs/nfsd/nfs4recover.c > > @@ -154,6 +154,10 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) > > if (status < 0) > > return; > > > > + status = mnt_want_write_file(rec_file); > > + if (status) > > + return; > > + > > dir = rec_file->f_path.dentry; > > /* lock the parent */ > > mutex_lock(&dir->d_inode->i_mutex); > > @@ -173,11 +177,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) > > * as well be forgiving and just succeed silently. > > */ > > goto out_put; > > - status = mnt_want_write_file(rec_file); > > - if (status) > > - goto out_put; > > status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU); > > - mnt_drop_write_file(rec_file); > > out_put: > > dput(dentry); > > out_unlock: > > @@ -189,6 +189,7 @@ out_unlock: > > " (err %d); please check that %s exists" > > " and is writeable", status, > > user_recovery_dirname); > > + mnt_drop_write_file(rec_file); > > nfs4_reset_creds(original_cred); > > } > > > > diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c > > index 68454e7..8b93353 100644 > > --- a/fs/nfsd/nfsfh.c > > +++ b/fs/nfsd/nfsfh.c > > @@ -635,6 +635,7 @@ fh_put(struct svc_fh *fhp) > > fhp->fh_post_saved = 0; > > #endif > > } > > + fh_drop_write(fhp); > > if (exp) { > > cache_put(&exp->h, &svc_export_cache); > > fhp->fh_export = NULL; > > diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c > > index e15dc45..aad6d45 100644 > > --- a/fs/nfsd/nfsproc.c > > +++ b/fs/nfsd/nfsproc.c > > @@ -196,6 +196,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, > > struct dentry *dchild; > > int type, mode; > > __be32 nfserr; > > + int hosterr; > > dev_t rdev = 0, wanted = new_decode_dev(attr->ia_size); > > > > dprintk("nfsd: CREATE %s %.*s\n", > > @@ -214,6 +215,12 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, > > nfserr = nfserr_exist; > > if (isdotent(argp->name, argp->len)) > > goto done; > > + hosterr = fh_want_write(dirfhp); > > + if (hosterr) { > > + nfserr = nfserrno(hosterr); > > + goto done; > > + } > > + > > fh_lock_nested(dirfhp, I_MUTEX_PARENT); > > dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len); > > if (IS_ERR(dchild)) { > > @@ -330,7 +337,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, > > out_unlock: > > /* We don't really need to unlock, as fh_put does it. */ > > fh_unlock(dirfhp); > > - > > + fh_drop_write(dirfhp); > > done: > > fh_put(dirfhp); > > return nfsd_return_dirop(nfserr, resp); > > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c > > index 296d671..b8bb649 100644 > > --- a/fs/nfsd/vfs.c > > +++ b/fs/nfsd/vfs.c > > @@ -1276,6 +1276,10 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > > * If it has, the parent directory should already be locked. > > */ > > if (!resfhp->fh_dentry) { > > + host_err = fh_want_write(fhp); > > + if (host_err) > > + goto out_nfserr; > > + > > /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */ > > fh_lock_nested(fhp, I_MUTEX_PARENT); > > dchild = lookup_one_len(fname, dentry, flen); > > @@ -1319,14 +1323,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > > goto out; > > } > > > > - host_err = fh_want_write(fhp); > > - if (host_err) > > - goto out_nfserr; > > - > > /* > > * Get the dir op function pointer. > > */ > > err = 0; > > + host_err = 0; > > switch (type) { > > case S_IFREG: > > host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL); > > @@ -1343,10 +1344,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > > host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); > > break; > > } > > - if (host_err < 0) { > > - fh_drop_write(fhp); > > + if (host_err < 0) > > goto out_nfserr; > > - } > > > > err = nfsd_create_setattr(rqstp, resfhp, iap); > > > > @@ -1358,7 +1357,6 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > > err2 = nfserrno(commit_metadata(fhp)); > > if (err2) > > err = err2; > > - fh_drop_write(fhp); > > /* > > * Update the file handle to get the new inode info. > > */ > > @@ -1417,6 +1415,11 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > > err = nfserr_notdir; > > if (!dirp->i_op->lookup) > > goto out; > > + > > + host_err = fh_want_write(fhp); > > + if (host_err) > > + goto out_nfserr; > > + > > fh_lock_nested(fhp, I_MUTEX_PARENT); > > > > /* > > @@ -1449,9 +1452,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > > v_atime = verifier[1]&0x7fffffff; > > } > > > > - host_err = fh_want_write(fhp); > > - if (host_err) > > - goto out_nfserr; > > if (dchild->d_inode) { > > err = 0; > > > > @@ -1522,7 +1522,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > > if (!err) > > err = nfserrno(commit_metadata(fhp)); > > > > - fh_drop_write(fhp); > > /* > > * Update the filehandle to get the new inode info. > > */ > > @@ -1533,6 +1532,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, > > fh_unlock(fhp); > > if (dchild && !IS_ERR(dchild)) > > dput(dchild); > > + fh_drop_write(fhp); > > return err; > > > > out_nfserr: > > @@ -1613,6 +1613,11 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, > > err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); > > if (err) > > goto out; > > + > > + host_err = fh_want_write(fhp); > > + if (host_err) > > + goto out_nfserr; > > + > > fh_lock(fhp); > > dentry = fhp->fh_dentry; > > dnew = lookup_one_len(fname, dentry, flen); > > @@ -1620,10 +1625,6 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, > > if (IS_ERR(dnew)) > > goto out_nfserr; > > > > - host_err = fh_want_write(fhp); > > - if (host_err) > > - goto out_nfserr; > > - > > if (unlikely(path[plen] != 0)) { > > char *path_alloced = kmalloc(plen+1, GFP_KERNEL); > > if (path_alloced == NULL) > > @@ -1683,6 +1684,12 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, > > if (isdotent(name, len)) > > goto out; > > > > + host_err = fh_want_write(tfhp); > > + if (host_err) { > > + err = nfserrno(host_err); > > + goto out; > > + } > > + > > fh_lock_nested(ffhp, I_MUTEX_PARENT); > > ddir = ffhp->fh_dentry; > > dirp = ddir->d_inode; > > @@ -1694,18 +1701,13 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, > > > > dold = tfhp->fh_dentry; > > > > - host_err = fh_want_write(tfhp); > > - if (host_err) { > > - err = nfserrno(host_err); > > - goto out_dput; > > - } > > err = nfserr_noent; > > if (!dold->d_inode) > > - goto out_drop_write; > > + goto out_dput; > > host_err = nfsd_break_lease(dold->d_inode); > > if (host_err) { > > err = nfserrno(host_err); > > - goto out_drop_write; > > + goto out_dput; > > } > > host_err = vfs_link(dold, dirp, dnew); > > if (!host_err) { > > @@ -1718,12 +1720,11 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, > > else > > err = nfserrno(host_err); > > } > > -out_drop_write: > > - fh_drop_write(tfhp); > > out_dput: > > dput(dnew); > > out_unlock: > > fh_unlock(ffhp); > > + fh_drop_write(tfhp); > > out: > > return err; > > > > @@ -1766,6 +1767,12 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, > > if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) > > goto out; > > > > + host_err = fh_want_write(ffhp); > > + if (host_err) { > > + err = nfserrno(host_err); > > + goto out; > > + } > > + > > /* cannot use fh_lock as we need deadlock protective ordering > > * so do it by hand */ > > trap = lock_rename(tdentry, fdentry); > > @@ -1796,17 +1803,14 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, > > host_err = -EXDEV; > > if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) > > goto out_dput_new; > > - host_err = fh_want_write(ffhp); > > - if (host_err) > > - goto out_dput_new; > > > > host_err = nfsd_break_lease(odentry->d_inode); > > if (host_err) > > - goto out_drop_write; > > + goto out_dput_new; > > if (ndentry->d_inode) { > > host_err = nfsd_break_lease(ndentry->d_inode); > > if (host_err) > > - goto out_drop_write; > > + goto out_dput_new; > > } > > host_err = vfs_rename(fdir, odentry, tdir, ndentry); > > if (!host_err) { > > @@ -1814,8 +1818,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, > > if (!host_err) > > host_err = commit_metadata(ffhp); > > } > > -out_drop_write: > > - fh_drop_write(ffhp); > > out_dput_new: > > dput(ndentry); > > out_dput_old: > > @@ -1831,6 +1833,7 @@ out_drop_write: > > fill_post_wcc(tfhp); > > unlock_rename(tdentry, fdentry); > > ffhp->fh_locked = tfhp->fh_locked = 0; > > + fh_drop_write(ffhp); > > > > out: > > return err; > > @@ -1856,6 +1859,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, > > if (err) > > goto out; > > > > + host_err = fh_want_write(fhp); > > + if (host_err) > > + goto out_nfserr; > > + > > fh_lock_nested(fhp, I_MUTEX_PARENT); > > dentry = fhp->fh_dentry; > > dirp = dentry->d_inode; > > @@ -1874,21 +1881,15 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, > > if (!type) > > type = rdentry->d_inode->i_mode & S_IFMT; > > > > - host_err = fh_want_write(fhp); > > - if (host_err) > > - goto out_put; > > - > > host_err = nfsd_break_lease(rdentry->d_inode); > > if (host_err) > > - goto out_drop_write; > > + goto out_put; > > if (type != S_IFDIR) > > host_err = vfs_unlink(dirp, rdentry); > > else > > host_err = vfs_rmdir(dirp, rdentry); > > if (!host_err) > > host_err = commit_metadata(fhp); > > -out_drop_write: > > - fh_drop_write(fhp); > > out_put: > > dput(rdentry); > > > > diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h > > index ec0611b..359594c 100644 > > --- a/fs/nfsd/vfs.h > > +++ b/fs/nfsd/vfs.h > > @@ -110,12 +110,19 @@ int nfsd_set_posix_acl(struct svc_fh *, int, struct posix_acl *); > > > > static inline int fh_want_write(struct svc_fh *fh) > > { > > - return mnt_want_write(fh->fh_export->ex_path.mnt); > > + int ret = mnt_want_write(fh->fh_export->ex_path.mnt); > > + > > + if (!ret) > > + fh->fh_want_write = 1; > > + return ret; > > } > > > > static inline void fh_drop_write(struct svc_fh *fh) > > { > > - mnt_drop_write(fh->fh_export->ex_path.mnt); > > + if (fh->fh_want_write) { > > + fh->fh_want_write = 0; > > + mnt_drop_write(fh->fh_export->ex_path.mnt); > > + } > > } > > > > #endif /* LINUX_NFSD_VFS_H */ > > diff --git a/include/linux/nfsd/nfsfh.h b/include/linux/nfsd/nfsfh.h > > index ce4743a..fa63048 100644 > > --- a/include/linux/nfsd/nfsfh.h > > +++ b/include/linux/nfsd/nfsfh.h > > @@ -143,6 +143,7 @@ typedef struct svc_fh { > > int fh_maxsize; /* max size for fh_handle */ > > > > unsigned char fh_locked; /* inode locked by us */ > > + unsigned char fh_want_write; /* remount protection taken */ > > > > #ifdef CONFIG_NFSD_V3 > > unsigned char fh_post_saved; /* post-op attrs saved */ > > -- > > 1.7.1 > > -- Jan Kara <jack@suse.cz> SUSE Labs, CR ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2012-06-12 17:25 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-06-12 14:20 [PATCH 00/27 v7] Fix filesystem freezing deadlocks Jan Kara 2012-06-12 14:20 ` [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex Jan Kara 2012-06-12 17:25 ` J. Bruce Fields -- strict thread matches above, loose matches on Subject: below -- 2012-06-01 22:30 [PATCH 00/27 v6] Fix filesystem freezing deadlocks Jan Kara 2012-06-01 22:30 ` [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex Jan Kara 2012-04-16 16:13 [PATCH 00/19 v5] Fix filesystem freezing deadlocks Jan Kara 2012-04-16 16:13 ` [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex Jan Kara 2012-04-16 18:25 ` J. Bruce Fields 2012-04-17 8:17 ` Jan Kara
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