| Message ID | 1460768127-31822-15-git-send-email-viro@ZenIV.linux.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Apr 15, 2016, at 6:55 PM, Al Viro <viro@ZenIV.linux.org.uk> wrote: > > From: Al Viro <viro@zeniv.linux.org.uk> > > ta-da! > > The main issue is the lack of down_write_killable(), so the places > like readdir.c switched to plain inode_lock(); once killable > variants of rwsem primitives appear, that'll be dealt with. > > lockdep side also might need more work > > Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> > --- > fs/btrfs/ioctl.c | 16 ++++++++++------ > fs/configfs/inode.c | 2 +- > fs/dcache.c | 9 +++++---- > fs/gfs2/ops_fstype.c | 2 +- > fs/inode.c | 12 ++++++------ > fs/namei.c | 4 ++-- > fs/ocfs2/inode.c | 2 +- > fs/overlayfs/readdir.c | 4 +++- > fs/readdir.c | 7 ++++--- > include/linux/fs.h | 12 ++++++------ > 10 files changed, 39 insertions(+), 31 deletions(-) > > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index 053e677..db1e830 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -837,9 +837,11 @@ static noinline int btrfs_mksubvol(struct path *parent, > struct dentry *dentry; > int error; > > - error = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); > - if (error == -EINTR) > - return error; > + inode_lock_nested(dir, I_MUTEX_PARENT); > + // XXX: should've been > + // mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); > + // if (error == -EINTR) > + // return error; > > dentry = lookup_one_len(name, parent->dentry, namelen); > error = PTR_ERR(dentry); > @@ -2366,9 +2368,11 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file, > goto out; > > > - err = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); > - if (err == -EINTR) > - goto out_drop_write; > + inode_lock_nested(dir, I_MUTEX_PARENT); > + // XXX: should've been > + // err = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); > + // if (err == -EINTR) > + // goto out_drop_write; > dentry = lookup_one_len(vol_args->name, parent, namelen); > if (IS_ERR(dentry)) { > err = PTR_ERR(dentry); > diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c > index 03d124a..0387968 100644 > --- a/fs/configfs/inode.c > +++ b/fs/configfs/inode.c > @@ -156,7 +156,7 @@ static void configfs_set_inode_lock_class(struct configfs_dirent *sd, > > if (depth > 0) { > if (depth <= ARRAY_SIZE(default_group_class)) { > - lockdep_set_class(&inode->i_mutex, > + lockdep_set_class(&inode->i_rwsem, > &default_group_class[depth - 1]); > } else { > /* > diff --git a/fs/dcache.c b/fs/dcache.c > index 5965588..d110040 100644 > --- a/fs/dcache.c > +++ b/fs/dcache.c > @@ -2911,7 +2911,8 @@ struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) > static int __d_unalias(struct inode *inode, > struct dentry *dentry, struct dentry *alias) > { > - struct mutex *m1 = NULL, *m2 = NULL; > + struct mutex *m1 = NULL; > + struct rw_semaphore *m2 = NULL; > int ret = -ESTALE; > > /* If alias and dentry share a parent, then no extra locks required */ > @@ -2922,15 +2923,15 @@ static int __d_unalias(struct inode *inode, > if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) > goto out_err; > m1 = &dentry->d_sb->s_vfs_rename_mutex; > - if (!inode_trylock(alias->d_parent->d_inode)) > + if (!down_read_trylock(&alias->d_parent->d_inode->i_rwsem)) > goto out_err; > - m2 = &alias->d_parent->d_inode->i_mutex; > + m2 = &alias->d_parent->d_inode->i_rwsem; > out_unalias: > __d_move(alias, dentry, false); > ret = 0; > out_err: > if (m2) > - mutex_unlock(m2); > + up_read(m2); > if (m1) > mutex_unlock(m1); > return ret; > diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c > index c09c63d..4546360 100644 > --- a/fs/gfs2/ops_fstype.c > +++ b/fs/gfs2/ops_fstype.c > @@ -824,7 +824,7 @@ static int init_inodes(struct gfs2_sbd *sdp, int undo) > * i_mutex on quota files is special. Since this inode is hidden system > * file, we are safe to define locking ourselves. > */ > - lockdep_set_class(&sdp->sd_quota_inode->i_mutex, > + lockdep_set_class(&sdp->sd_quota_inode->i_rwsem, > &gfs2_quota_imutex_key); > > error = gfs2_rindex_update(sdp); > diff --git a/fs/inode.c b/fs/inode.c > index 4b884f7..4ccbc21 100644 > --- a/fs/inode.c > +++ b/fs/inode.c > @@ -166,8 +166,8 @@ int inode_init_always(struct super_block *sb, struct inode *inode) > spin_lock_init(&inode->i_lock); > lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); > > - mutex_init(&inode->i_mutex); > - lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); > + init_rwsem(&inode->i_rwsem); > + lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key); > > atomic_set(&inode->i_dio_count, 0); > > @@ -925,13 +925,13 @@ void lockdep_annotate_inode_mutex_key(struct inode *inode) > struct file_system_type *type = inode->i_sb->s_type; > > /* Set new key only if filesystem hasn't already changed it */ > - if (lockdep_match_class(&inode->i_mutex, &type->i_mutex_key)) { > + if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) { > /* > * ensure nobody is actually holding i_mutex > */ > - mutex_destroy(&inode->i_mutex); > - mutex_init(&inode->i_mutex); > - lockdep_set_class(&inode->i_mutex, > + // mutex_destroy(&inode->i_mutex); > + init_rwsem(&inode->i_rwsem); > + lockdep_set_class(&inode->i_rwsem, > &type->i_mutex_dir_key); > } > } > diff --git a/fs/namei.c b/fs/namei.c > index eb879d6..877e9ef 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -1607,7 +1607,7 @@ static struct dentry *lookup_slow(const struct qstr *name, > struct inode *inode = dir->d_inode; > DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); > > - inode_lock(inode); > + down_read(&inode->i_rwsem); Wouldn't it make sense to have helpers like "inode_read_lock(inode)" or similar, so that it is consistent with other parts of the code and easier to find? It's a bit strange to have the filesystems use "inode_lock()" and some places here use "inode_lock_nested()", but other places use up_read() and down_read() directly on &inode->i_rwsem. That would also simplify delegating the directory locking to the filesystems in the future. Cheers, Andreas > /* Don't go there if it's already dead */ > if (unlikely(IS_DEADDIR(inode))) > goto out; > @@ -1638,7 +1638,7 @@ again: > } > } > out: > - inode_unlock(inode); > + up_read(&inode->i_rwsem); > return dentry; > } > > diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c > index 12f4a9e..0748777 100644 > --- a/fs/ocfs2/inode.c > +++ b/fs/ocfs2/inode.c > @@ -262,7 +262,7 @@ static int ocfs2_init_locked_inode(struct inode *inode, void *opaque) > inode->i_ino = args->fi_ino; > OCFS2_I(inode)->ip_blkno = args->fi_blkno; > if (args->fi_sysfile_type != 0) > - lockdep_set_class(&inode->i_mutex, > + lockdep_set_class(&inode->i_rwsem, > &ocfs2_sysfile_lock_key[args->fi_sysfile_type]); > if (args->fi_sysfile_type == USER_QUOTA_SYSTEM_INODE || > args->fi_sysfile_type == GROUP_QUOTA_SYSTEM_INODE || > diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c > index 6ec1e43..da186ee 100644 > --- a/fs/overlayfs/readdir.c > +++ b/fs/overlayfs/readdir.c > @@ -218,7 +218,9 @@ static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd) > cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); > old_cred = override_creds(override_cred); > > - err = mutex_lock_killable(&dir->d_inode->i_mutex); > + inode_lock(dir->d_inode); > + err = 0; > + // XXX: err = mutex_lock_killable(&dir->d_inode->i_mutex); > if (!err) { > while (rdd->first_maybe_whiteout) { > p = rdd->first_maybe_whiteout; > diff --git a/fs/readdir.c b/fs/readdir.c > index e69ef3b..bf583e8 100644 > --- a/fs/readdir.c > +++ b/fs/readdir.c > @@ -32,9 +32,10 @@ int iterate_dir(struct file *file, struct dir_context *ctx) > if (res) > goto out; > > - res = mutex_lock_killable(&inode->i_mutex); > - if (res) > - goto out; > + inode_lock(inode); > + // res = mutex_lock_killable(&inode->i_mutex); > + // if (res) > + // goto out; > > res = -ENOENT; > if (!IS_DEADDIR(inode)) { > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 0a32045..313ad28 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -647,7 +647,7 @@ struct inode { > > /* Misc */ > unsigned long i_state; > - struct mutex i_mutex; > + struct rw_semaphore i_rwsem; > > unsigned long dirtied_when; /* jiffies of first dirtying */ > unsigned long dirtied_time_when; > @@ -734,27 +734,27 @@ enum inode_i_mutex_lock_class > > static inline void inode_lock(struct inode *inode) > { > - mutex_lock(&inode->i_mutex); > + down_write(&inode->i_rwsem); > } > > static inline void inode_unlock(struct inode *inode) > { > - mutex_unlock(&inode->i_mutex); > + up_write(&inode->i_rwsem); > } > > static inline int inode_trylock(struct inode *inode) > { > - return mutex_trylock(&inode->i_mutex); > + return down_write_trylock(&inode->i_rwsem); > } > > static inline int inode_is_locked(struct inode *inode) > { > - return mutex_is_locked(&inode->i_mutex); > + return rwsem_is_locked(&inode->i_rwsem); > } > > static inline void inode_lock_nested(struct inode *inode, unsigned subclass) > { > - mutex_lock_nested(&inode->i_mutex, subclass); > + down_write_nested(&inode->i_rwsem, subclass); > } > > void lock_two_nondirectories(struct inode *, struct inode*); > -- > 2.8.0.rc3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Cheers, Andreas
On Fri, Apr 15, 2016 at 09:02:06PM -0600, Andreas Dilger wrote: > Wouldn't it make sense to have helpers like "inode_read_lock(inode)" or similar, > so that it is consistent with other parts of the code and easier to find? > It's a bit strange to have the filesystems use "inode_lock()" and some places > here use "inode_lock_nested()", but other places use up_read() and down_read() > directly on &inode->i_rwsem. That would also simplify delegating the directory > locking to the filesystems in the future. FWIW, my preference would be inode_lock_shared(), but that's bikeshedding; seeing that we have very few callers at the moment *and* there's the missing down_write_killable() stuff... This patch will obviously be reworked and it's small enough to be understandable, open-coding or not. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 053e677..db1e830 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -837,9 +837,11 @@ static noinline int btrfs_mksubvol(struct path *parent, struct dentry *dentry; int error; - error = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); - if (error == -EINTR) - return error; + inode_lock_nested(dir, I_MUTEX_PARENT); + // XXX: should've been + // mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); + // if (error == -EINTR) + // return error; dentry = lookup_one_len(name, parent->dentry, namelen); error = PTR_ERR(dentry); @@ -2366,9 +2368,11 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file, goto out; - err = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); - if (err == -EINTR) - goto out_drop_write; + inode_lock_nested(dir, I_MUTEX_PARENT); + // XXX: should've been + // err = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); + // if (err == -EINTR) + // goto out_drop_write; dentry = lookup_one_len(vol_args->name, parent, namelen); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c index 03d124a..0387968 100644 --- a/fs/configfs/inode.c +++ b/fs/configfs/inode.c @@ -156,7 +156,7 @@ static void configfs_set_inode_lock_class(struct configfs_dirent *sd, if (depth > 0) { if (depth <= ARRAY_SIZE(default_group_class)) { - lockdep_set_class(&inode->i_mutex, + lockdep_set_class(&inode->i_rwsem, &default_group_class[depth - 1]); } else { /* diff --git a/fs/dcache.c b/fs/dcache.c index 5965588..d110040 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2911,7 +2911,8 @@ struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) static int __d_unalias(struct inode *inode, struct dentry *dentry, struct dentry *alias) { - struct mutex *m1 = NULL, *m2 = NULL; + struct mutex *m1 = NULL; + struct rw_semaphore *m2 = NULL; int ret = -ESTALE; /* If alias and dentry share a parent, then no extra locks required */ @@ -2922,15 +2923,15 @@ static int __d_unalias(struct inode *inode, if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) goto out_err; m1 = &dentry->d_sb->s_vfs_rename_mutex; - if (!inode_trylock(alias->d_parent->d_inode)) + if (!down_read_trylock(&alias->d_parent->d_inode->i_rwsem)) goto out_err; - m2 = &alias->d_parent->d_inode->i_mutex; + m2 = &alias->d_parent->d_inode->i_rwsem; out_unalias: __d_move(alias, dentry, false); ret = 0; out_err: if (m2) - mutex_unlock(m2); + up_read(m2); if (m1) mutex_unlock(m1); return ret; diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index c09c63d..4546360 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -824,7 +824,7 @@ static int init_inodes(struct gfs2_sbd *sdp, int undo) * i_mutex on quota files is special. Since this inode is hidden system * file, we are safe to define locking ourselves. */ - lockdep_set_class(&sdp->sd_quota_inode->i_mutex, + lockdep_set_class(&sdp->sd_quota_inode->i_rwsem, &gfs2_quota_imutex_key); error = gfs2_rindex_update(sdp); diff --git a/fs/inode.c b/fs/inode.c index 4b884f7..4ccbc21 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -166,8 +166,8 @@ int inode_init_always(struct super_block *sb, struct inode *inode) spin_lock_init(&inode->i_lock); lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); - mutex_init(&inode->i_mutex); - lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); + init_rwsem(&inode->i_rwsem); + lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key); atomic_set(&inode->i_dio_count, 0); @@ -925,13 +925,13 @@ void lockdep_annotate_inode_mutex_key(struct inode *inode) struct file_system_type *type = inode->i_sb->s_type; /* Set new key only if filesystem hasn't already changed it */ - if (lockdep_match_class(&inode->i_mutex, &type->i_mutex_key)) { + if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) { /* * ensure nobody is actually holding i_mutex */ - mutex_destroy(&inode->i_mutex); - mutex_init(&inode->i_mutex); - lockdep_set_class(&inode->i_mutex, + // mutex_destroy(&inode->i_mutex); + init_rwsem(&inode->i_rwsem); + lockdep_set_class(&inode->i_rwsem, &type->i_mutex_dir_key); } } diff --git a/fs/namei.c b/fs/namei.c index eb879d6..877e9ef 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1607,7 +1607,7 @@ static struct dentry *lookup_slow(const struct qstr *name, struct inode *inode = dir->d_inode; DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); - inode_lock(inode); + down_read(&inode->i_rwsem); /* Don't go there if it's already dead */ if (unlikely(IS_DEADDIR(inode))) goto out; @@ -1638,7 +1638,7 @@ again: } } out: - inode_unlock(inode); + up_read(&inode->i_rwsem); return dentry; } diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c index 12f4a9e..0748777 100644 --- a/fs/ocfs2/inode.c +++ b/fs/ocfs2/inode.c @@ -262,7 +262,7 @@ static int ocfs2_init_locked_inode(struct inode *inode, void *opaque) inode->i_ino = args->fi_ino; OCFS2_I(inode)->ip_blkno = args->fi_blkno; if (args->fi_sysfile_type != 0) - lockdep_set_class(&inode->i_mutex, + lockdep_set_class(&inode->i_rwsem, &ocfs2_sysfile_lock_key[args->fi_sysfile_type]); if (args->fi_sysfile_type == USER_QUOTA_SYSTEM_INODE || args->fi_sysfile_type == GROUP_QUOTA_SYSTEM_INODE || diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index 6ec1e43..da186ee 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -218,7 +218,9 @@ static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd) cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); old_cred = override_creds(override_cred); - err = mutex_lock_killable(&dir->d_inode->i_mutex); + inode_lock(dir->d_inode); + err = 0; + // XXX: err = mutex_lock_killable(&dir->d_inode->i_mutex); if (!err) { while (rdd->first_maybe_whiteout) { p = rdd->first_maybe_whiteout; diff --git a/fs/readdir.c b/fs/readdir.c index e69ef3b..bf583e8 100644 --- a/fs/readdir.c +++ b/fs/readdir.c @@ -32,9 +32,10 @@ int iterate_dir(struct file *file, struct dir_context *ctx) if (res) goto out; - res = mutex_lock_killable(&inode->i_mutex); - if (res) - goto out; + inode_lock(inode); + // res = mutex_lock_killable(&inode->i_mutex); + // if (res) + // goto out; res = -ENOENT; if (!IS_DEADDIR(inode)) { diff --git a/include/linux/fs.h b/include/linux/fs.h index 0a32045..313ad28 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -647,7 +647,7 @@ struct inode { /* Misc */ unsigned long i_state; - struct mutex i_mutex; + struct rw_semaphore i_rwsem; unsigned long dirtied_when; /* jiffies of first dirtying */ unsigned long dirtied_time_when; @@ -734,27 +734,27 @@ enum inode_i_mutex_lock_class static inline void inode_lock(struct inode *inode) { - mutex_lock(&inode->i_mutex); + down_write(&inode->i_rwsem); } static inline void inode_unlock(struct inode *inode) { - mutex_unlock(&inode->i_mutex); + up_write(&inode->i_rwsem); } static inline int inode_trylock(struct inode *inode) { - return mutex_trylock(&inode->i_mutex); + return down_write_trylock(&inode->i_rwsem); } static inline int inode_is_locked(struct inode *inode) { - return mutex_is_locked(&inode->i_mutex); + return rwsem_is_locked(&inode->i_rwsem); } static inline void inode_lock_nested(struct inode *inode, unsigned subclass) { - mutex_lock_nested(&inode->i_mutex, subclass); + down_write_nested(&inode->i_rwsem, subclass); } void lock_two_nondirectories(struct inode *, struct inode*);