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[84.236.74.45]) by smtp.gmail.com with ESMTPSA id s1sm2746622wro.66.2020.01.31.03.50.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 31 Jan 2020 03:50:15 -0800 (PST) From: Miklos Szeredi To: linux-unionfs@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, Vivek Goyal Subject: [PATCH 3/4] ovl: decide if revalidate needed on a per-dentry bases Date: Fri, 31 Jan 2020 12:50:03 +0100 Message-Id: <20200131115004.17410-4-mszeredi@redhat.com> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200131115004.17410-1-mszeredi@redhat.com> References: <20200131115004.17410-1-mszeredi@redhat.com> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Allow completely skipping ->revalidate() on a per-dentry bases, in case the underlying layers used for a dentry do not themselves have ->revalidate(). E.g. negative overlay dentry has no underlying layers, hence revalidate is unnecessary. Or if lower layer is remote but overlay dentry is pure-upper, then can skip revalidate. The following places need to update whether the dentry needs revalidate or not: - fill-super (root dentry) - lookup - create - fh_to_dentry Signed-off-by: Miklos Szeredi --- fs/overlayfs/dir.c | 3 +++ fs/overlayfs/export.c | 2 ++ fs/overlayfs/namei.c | 3 +++ fs/overlayfs/overlayfs.h | 3 ++- fs/overlayfs/super.c | 23 +++++++---------------- fs/overlayfs/util.c | 15 ++++++++++++--- 6 files changed, 29 insertions(+), 20 deletions(-) diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 8e57d5372b8f..b3471ef51440 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -243,6 +243,9 @@ static int ovl_instantiate(struct dentry *dentry, struct inode *inode, ovl_dir_modified(dentry->d_parent, false); ovl_dentry_set_upper_alias(dentry); + ovl_dentry_update_reval(dentry, newdentry, + DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); + if (!hardlink) { /* * ovl_obtain_alias() can be called after ovl_create_real() diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c index 6f54d70cef27..a58b3d9b06b9 100644 --- a/fs/overlayfs/export.c +++ b/fs/overlayfs/export.c @@ -324,6 +324,8 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb, if (upper_alias) ovl_dentry_set_upper_alias(dentry); } + ovl_dentry_update_reval(dentry, upper, + DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); return d_instantiate_anon(dentry, inode); diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index a5b998a93a24..76e61cc27822 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -1077,6 +1077,9 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, goto out_free_oe; } + ovl_dentry_update_reval(dentry, upperdentry, + DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); + revert_creds(old_cred); if (origin_path) { dput(origin_path->dentry); diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 3623d28aa4fa..68124a4f8f9b 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -229,7 +229,8 @@ struct dentry *ovl_indexdir(struct super_block *sb); bool ovl_index_all(struct super_block *sb); bool ovl_verify_lower(struct super_block *sb); struct ovl_entry *ovl_alloc_entry(unsigned int numlower); -bool ovl_dentry_remote(struct dentry *dentry); +void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry, + unsigned int mask); bool ovl_dentry_weird(struct dentry *dentry); enum ovl_path_type ovl_path_type(struct dentry *dentry); void ovl_path_upper(struct dentry *dentry, struct path *path); diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 7e294bf719ff..26d4153240a8 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -158,11 +158,6 @@ static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) static const struct dentry_operations ovl_dentry_operations = { .d_release = ovl_dentry_release, .d_real = ovl_d_real, -}; - -static const struct dentry_operations ovl_reval_dentry_operations = { - .d_release = ovl_dentry_release, - .d_real = ovl_d_real, .d_revalidate = ovl_dentry_revalidate, .d_weak_revalidate = ovl_dentry_weak_revalidate, }; @@ -779,7 +774,7 @@ static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, } static int ovl_lower_dir(const char *name, struct path *path, - struct ovl_fs *ofs, int *stack_depth, bool *remote) + struct ovl_fs *ofs, int *stack_depth) { int fh_type; int err; @@ -794,9 +789,6 @@ static int ovl_lower_dir(const char *name, struct path *path, *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); - if (ovl_dentry_remote(path->dentry)) - *remote = true; - /* * The inodes index feature and NFS export need to encode and decode * file handles, so they require that all layers support them. @@ -1439,7 +1431,6 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, char *lowertmp, *lower; struct path *stack = NULL; unsigned int stacklen, numlower = 0, i; - bool remote = false; struct ovl_entry *oe; err = -ENOMEM; @@ -1471,7 +1462,7 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, lower = lowertmp; for (numlower = 0; numlower < stacklen; numlower++) { err = ovl_lower_dir(lower, &stack[numlower], ofs, - &sb->s_stack_depth, &remote); + &sb->s_stack_depth); if (err) goto out_err; @@ -1499,11 +1490,6 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, oe->lowerstack[i].layer = &ofs->layers[i+1]; } - if (remote) - sb->s_d_op = &ovl_reval_dentry_operations; - else - sb->s_d_op = &ovl_dentry_operations; - out: for (i = 0; i < numlower; i++) path_put(&stack[i]); @@ -1597,6 +1583,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) struct cred *cred; int err; + sb->s_d_op = &ovl_dentry_operations; + err = -ENOMEM; ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); if (!ofs) @@ -1724,6 +1712,9 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) ovl_inode_init(d_inode(root_dentry), upperpath.dentry, ovl_dentry_lower(root_dentry), NULL); + ovl_dentry_update_reval(root_dentry, upperpath.dentry, + DCACHE_OP_WEAK_REVALIDATE); + sb->s_root = root_dentry; return 0; diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 67cd2866aaa2..3ad8fb291f7d 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -90,10 +90,19 @@ struct ovl_entry *ovl_alloc_entry(unsigned int numlower) return oe; } -bool ovl_dentry_remote(struct dentry *dentry) +void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry, + unsigned int mask) { - return dentry->d_flags & - (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); + struct ovl_entry *oe = OVL_E(dentry); + unsigned int i, flags = 0; + + for (i = 0; i < oe->numlower; i++) + flags |= oe->lowerstack[i].dentry->d_flags; + + spin_lock(&dentry->d_lock); + dentry->d_flags &= ~mask; + dentry->d_flags |= flags & mask; + spin_unlock(&dentry->d_lock); } bool ovl_dentry_weird(struct dentry *dentry)