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[f2fs-dev,v4,2/7] fs: Add DCACHE_CASEFOLDED_NAME flag

Message ID 20230727172843.20542-3-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State Superseded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 July 27, 2023, 5:28 p.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>

---
Changes since v2:
  -  Rename DCACHE_CASEFOLD_LOOKUP -> DCACHE_CASEFOLDED_NAME (Eric)
---
 fs/dcache.c            | 8 ++++++++
 include/linux/dcache.h | 8 ++++++++
 2 files changed, 16 insertions(+)

Comments

Eric Biggers July 29, 2023, 4:34 a.m. UTC | #1
On Thu, Jul 27, 2023 at 01:28:38PM -0400, Gabriel Krisman Bertazi wrote:
> 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>
> 
> ---
> Changes since v2:
>   -  Rename DCACHE_CASEFOLD_LOOKUP -> DCACHE_CASEFOLDED_NAME (Eric)
> ---
>  fs/dcache.c            | 8 ++++++++
>  include/linux/dcache.h | 8 ++++++++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/fs/dcache.c b/fs/dcache.c
> index 98521862e58a..5791489b589f 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_CASEFOLDED_NAME;
> +	spin_unlock(&dentry->d_lock);
> +}
> +EXPORT_SYMBOL(d_set_casefold_lookup);

d_set_casefolded_name()

> +static inline bool d_is_casefold_lookup(const struct dentry *dentry)
> +{
> +	return dentry->d_flags & DCACHE_CASEFOLDED_NAME;
> +}

d_is_casefolded_name().  Or even better, just write 'dentry->d_flags &
DCACHE_CASEFOLDED_NAME' directly in the one place that actually needs this?

- Eric
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Patch

diff --git a/fs/dcache.c b/fs/dcache.c
index 98521862e58a..5791489b589f 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_CASEFOLDED_NAME;
+	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..14aa0255bd04 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_CASEFOLDED_NAME		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_CASEFOLDED_NAME;
+}
+
 
 extern int sysctl_vfs_cache_pressure;