diff mbox series

[f2fs-dev,v2,2/7] fs: Add DCACHE_CASEFOLD_LOOKUP flag

Message ID 20230422000310.1802-3-krisman@suse.de (mailing list archive)
State Superseded
Headers show
Series Support negative dentries on case-insensitive ext4 and f2fs | expand

Commit Message

Gabriel Krisman Bertazi April 22, 2023, 12:03 a.m. UTC 
From: Gabriel Krisman Bertazi <krisman@collabora.com>

This flag marks a negative or positive dentry as being created after a
case-insensitive lookup operation.  It is useful to differentiate
dentries this way to detect whether the negative dentry can be trusted
during a case-insensitive lookup.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
---
 fs/dcache.c            | 8 ++++++++
 include/linux/dcache.h | 8 ++++++++
 2 files changed, 16 insertions(+)

Comments

Eric Biggers July 14, 2023, 5:55 a.m. UTC | #1 
On Fri, Apr 21, 2023 at 08:03:05PM -0400, Gabriel Krisman Bertazi wrote:
> @@ -209,6 +209,7 @@ struct dentry_operations {
>  #define DCACHE_FALLTHRU			0x01000000 /* Fall through to lower layer */
>  #define DCACHE_NOKEY_NAME		0x02000000 /* Encrypted name encoded without key */
>  #define DCACHE_OP_REAL			0x04000000
> +#define DCACHE_CASEFOLD_LOOKUP		0x08000000 /* Dentry comes from a casefold directory */
>  
>  #define DCACHE_PAR_LOOKUP		0x10000000 /* being looked up (with parent locked shared) */
>  #define DCACHE_DENTRY_CURSOR		0x20000000

The first time I read DCACHE_CASEFOLD_LOOKUP, I got the wrong impression, since
it uses _LOOKUP in a different way from DCACHE_PAR_LOOKUP.  DCACHE_PAR_LOOKUP
uses it to mean "dentry is currently being looked up", while
DCACHE_CASEFOLD_LOOKUP uses it to mean "dentry *was* looked up".

Maybe DCACHE_CASEFOLDED_NAME would be more logical?  That would follow
DCACHE_NOKEY_NAME.  (Also CASEFOLD => CASEFOLDED would be logical, I think.)

- Eric
diff mbox series

Patch

diff --git a/fs/dcache.c b/fs/dcache.c
index 98521862e58a..05e4c7019e17 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1958,6 +1958,14 @@  void d_set_fallthru(struct dentry *dentry)
 }
 EXPORT_SYMBOL(d_set_fallthru);
 
+void d_set_casefold_lookup(struct dentry *dentry)
+{
+	spin_lock(&dentry->d_lock);
+	dentry->d_flags |= DCACHE_CASEFOLD_LOOKUP;
+	spin_unlock(&dentry->d_lock);
+}
+EXPORT_SYMBOL(d_set_casefold_lookup);
+
 static unsigned d_flags_for_inode(struct inode *inode)
 {
 	unsigned add_flags = DCACHE_REGULAR_TYPE;
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index b6188f2e8950..457345123cb6 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -209,6 +209,7 @@  struct dentry_operations {
 #define DCACHE_FALLTHRU			0x01000000 /* Fall through to lower layer */
 #define DCACHE_NOKEY_NAME		0x02000000 /* Encrypted name encoded without key */
 #define DCACHE_OP_REAL			0x04000000
+#define DCACHE_CASEFOLD_LOOKUP		0x08000000 /* Dentry comes from a casefold directory */
 
 #define DCACHE_PAR_LOOKUP		0x10000000 /* being looked up (with parent locked shared) */
 #define DCACHE_DENTRY_CURSOR		0x20000000
@@ -497,6 +498,13 @@  static inline bool d_is_fallthru(const struct dentry *dentry)
 	return dentry->d_flags & DCACHE_FALLTHRU;
 }
 
+extern void d_set_casefold_lookup(struct dentry *dentry);
+
+static inline bool d_is_casefold_lookup(const struct dentry *dentry)
+{
+	return dentry->d_flags & DCACHE_CASEFOLD_LOOKUP;
+}
+
 
 extern int sysctl_vfs_cache_pressure;