From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gChR3-0003VI-Gv for barebox@lists.infradead.org; Wed, 17 Oct 2018 08:44:13 +0000 From: Sascha Hauer Date: Wed, 17 Oct 2018 10:43:52 +0200 Message-Id: <20181017084353.5217-2-s.hauer@pengutronix.de> In-Reply-To: <20181017084353.5217-1-s.hauer@pengutronix.de> References: <20181017084353.5217-1-s.hauer@pengutronix.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 1/2] fs: implement d_revalidate To: Barebox List Cc: Ladislav Michl d_revalidate is useful when filesystems change under the hood of the fs layer. This can happen with network filesystems or with devfs. Signed-off-by: Sascha Hauer --- fs/fs.c | 37 ++++++++++++++++++++++++++++++++++++- include/linux/dcache.h | 3 +++ 2 files changed, 39 insertions(+), 1 deletion(-) diff --git a/fs/fs.c b/fs/fs.c index d76d829140..eed0155f0d 100644 --- a/fs/fs.c +++ b/fs/fs.c @@ -1141,6 +1141,12 @@ const struct qstr slash_name = QSTR_INIT("/", 1); void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) { dentry->d_op = op; + + if (!op) + return; + + if (op->d_revalidate) + dentry->d_flags |= DCACHE_OP_REVALIDATE; } /** @@ -1285,6 +1291,35 @@ void d_invalidate(struct dentry *dentry) { } +static inline int d_revalidate(struct dentry *dentry, unsigned int flags) +{ + if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) + return dentry->d_op->d_revalidate(dentry, flags); + else + return 1; +} + +/* + * This looks up the name in dcache and possibly revalidates the found dentry. + * NULL is returned if the dentry does not exist in the cache. + */ +static struct dentry *lookup_dcache(const struct qstr *name, + struct dentry *dir, + unsigned int flags) +{ + struct dentry *dentry = d_lookup(dir, name); + if (dentry) { + int error = d_revalidate(dentry, flags); + if (unlikely(error <= 0)) { + if (!error) + d_invalidate(dentry); + dput(dentry); + return ERR_PTR(error); + } + } + return dentry; +} + static inline void __d_clear_type_and_inode(struct dentry *dentry) { dentry->d_flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU); @@ -1496,7 +1531,7 @@ static struct dentry *__lookup_hash(const struct qstr *name, if (!base) return ERR_PTR(-ENOENT); - dentry = d_lookup(base, name); + dentry = lookup_dcache(name, base, flags); if (dentry) return dentry; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 16244129bf..1581ddc701 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -82,6 +82,7 @@ struct dentry { }; struct dentry_operations { + int (*d_revalidate)(struct dentry *, unsigned int); }; struct dentry * d_make_root(struct inode *); @@ -93,6 +94,8 @@ void d_delete(struct dentry *); struct dentry *dget(struct dentry *); void dput(struct dentry *); +#define DCACHE_OP_REVALIDATE 0x00000004 + #define DCACHE_ENTRY_TYPE 0x00700000 #define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */ #define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */ -- 2.19.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox