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From: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
To: viro@ZenIV.linux.org.uk
Cc: linux-fsdevel@vger.kernel.org,
	Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Subject: [PATCH NOMERGE 05/13] vfs: Handle case-exact lookup in d_add_ci
Date: Tue, 22 May 2018 17:38:10 -0300	[thread overview]
Message-ID: <20180522203818.14666-6-krisman@collabora.co.uk> (raw)
In-Reply-To: <20180522203818.14666-1-krisman@collabora.co.uk>

This prevents a soft hang if called d_add_ci is called from the FS
layer, when doing a CI search but the result dentry is the exact match.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
---
 fs/dcache.c | 33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 4bd28d7caa53..30c5eff31e88 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2049,6 +2049,20 @@ struct dentry *d_obtain_root(struct inode *inode)
 }
 EXPORT_SYMBOL(d_obtain_root);
 
+static inline bool d_same_name(const struct dentry *dentry,
+				const struct dentry *parent,
+				const struct qstr *name)
+{
+	if (likely(!(parent->d_flags & DCACHE_OP_COMPARE))) {
+		if (dentry->d_name.len != name->len)
+			return false;
+		return dentry_cmp(dentry, name->name, name->len) == 0;
+	}
+	return parent->d_op->d_compare(dentry,
+				       dentry->d_name.len, dentry->d_name.name,
+				       name) == 0;
+}
+
 static inline bool d_same_name_ci(const struct dentry *dentry,
 				  const struct dentry *parent,
 				  const struct qstr *name)
@@ -2080,6 +2094,10 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 {
 	struct dentry *found, *res;
 
+	/* Trivial case: CI search is exact match.  */
+	if (d_same_name(dentry, dentry->d_parent, name))
+		return d_splice_alias(inode, dentry);
+
 	/*
 	 * First check if a dentry matching the name already exists,
 	 * if not go ahead and create it now.
@@ -2112,21 +2130,6 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 }
 EXPORT_SYMBOL(d_add_ci);
 
-
-static inline bool d_same_name(const struct dentry *dentry,
-				const struct dentry *parent,
-				const struct qstr *name)
-{
-	if (likely(!(parent->d_flags & DCACHE_OP_COMPARE))) {
-		if (dentry->d_name.len != name->len)
-			return false;
-		return dentry_cmp(dentry, name->name, name->len) == 0;
-	}
-	return parent->d_op->d_compare(dentry,
-				       dentry->d_name.len, dentry->d_name.name,
-				       name) == 0;
-}
-
 /**
  * __d_lookup_rcu - search for a dentry (racy, store-free)
  * @parent: parent dentry
-- 
2.17.0

  parent reply	other threads:[~2018-05-22 20:38 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-22 20:38 [PATCH NOMERGE 00/13] Case insensitiveness as a mountpoint Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 01/13] vfs: Add support for mounting with MS_CASEFOLD Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 02/13] vfs: Propagate LOOKUP_CASEFOLD after doing parent lookups Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 03/13] vfs: Add support for positive dentries CI lookups in the dentry cache Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 04/13] vfs: Allow bind,remount with MS_CASEFOLD Gabriel Krisman Bertazi
2018-05-22 20:38 ` Gabriel Krisman Bertazi [this message]
2018-05-22 20:38 ` [PATCH NOMERGE 06/13] vfs: Add Support for hard negative dentries in the dcache Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 07/13] vfs: Handle MNT_CASEFOLD in /proc/mounts Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 08/13] fscrypt: Introduce charset-based matching functions Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 09/13] ext4: Include encoding information on the superblock Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 10/13] ext4: Plumb LOOK_CASEFOLD up to ext4 comparison functions Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 11/13] ext4: Support charset name matching Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 12/13] ext4: Implement ext4 dcache hooks for custom charsets Gabriel Krisman Bertazi
2018-05-22 20:38 ` [PATCH NOMERGE 13/13] ext4: Notify VFS of support for casefolded mountpoints Gabriel Krisman Bertazi

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