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vfs: rename parent_ino to d_parent_ino and make it use RCU

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The routine is used by procfs through dir_emit_dots.

The combined RCU and lock fallback implementation is too big for an
inline. Given that the routine takes a dentry argument fs/dcache.c seems
like the place to put it in.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://lore.kernel.org/r/20240627161152.802567-1-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Mateusz Guzik 2024-06-27 18:11:52 +02:00 committed by Christian Brauner
parent 0ef625bba6
commit f378ec4eec
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GPG Key ID: 91C61BC06578DCA2
5 changed files with 34 additions and 18 deletions
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28
fs/dcache.c
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@ -3099,6 +3099,34 @@ void d_tmpfile(struct file *file, struct inode *inode)
} }
EXPORT_SYMBOL(d_tmpfile); EXPORT_SYMBOL(d_tmpfile);
/*
* Obtain inode number of the parent dentry.
*/
ino_t d_parent_ino(struct dentry *dentry)
{
struct dentry *parent;
struct inode *iparent;
unsigned seq;
ino_t ret;
scoped_guard(rcu) {
seq = raw_seqcount_begin(&dentry->d_seq);
parent = READ_ONCE(dentry->d_parent);
iparent = d_inode_rcu(parent);
if (likely(iparent)) {
ret = iparent->i_ino;
if (!read_seqcount_retry(&dentry->d_seq, seq))
return ret;
}
}
spin_lock(&dentry->d_lock);
ret = dentry->d_parent->d_inode->i_ino;
spin_unlock(&dentry->d_lock);
return ret;
}
EXPORT_SYMBOL(d_parent_ino);
static __initdata unsigned long dhash_entries; static __initdata unsigned long dhash_entries;
static int __init set_dhash_entries(char *str) static int __init set_dhash_entries(char *str)
{ {

2
fs/f2fs/file.c
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@ -185,7 +185,7 @@ static int get_parent_ino(struct inode *inode, nid_t *pino)
if (!dentry) if (!dentry)
return 0; return 0;
*pino = parent_ino(dentry); *pino = d_parent_ino(dentry);
dput(dentry); dput(dentry);
return 1; return 1;
} }

4
fs/hfsplus/ioctl.c
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@ -40,7 +40,7 @@ static int hfsplus_ioctl_bless(struct file *file, int __user *user_flags)
/* Directory containing the bootable system */ /* Directory containing the bootable system */
vh->finder_info[0] = bvh->finder_info[0] = vh->finder_info[0] = bvh->finder_info[0] =
cpu_to_be32(parent_ino(dentry)); cpu_to_be32(d_parent_ino(dentry));
/* /*
* Bootloader. Just using the inode here breaks in the case of * Bootloader. Just using the inode here breaks in the case of
@ -51,7 +51,7 @@ static int hfsplus_ioctl_bless(struct file *file, int __user *user_flags)
/* Per spec, the OS X system folder - same as finder_info[0] here */ /* Per spec, the OS X system folder - same as finder_info[0] here */
vh->finder_info[5] = bvh->finder_info[5] = vh->finder_info[5] = bvh->finder_info[5] =
cpu_to_be32(parent_ino(dentry)); cpu_to_be32(d_parent_ino(dentry));
mutex_unlock(&sbi->vh_mutex); mutex_unlock(&sbi->vh_mutex);
return 0; return 0;

2
include/linux/dcache.h
View File

@ -278,6 +278,8 @@ static inline unsigned d_count(const struct dentry *dentry)
return dentry->d_lockref.count; return dentry->d_lockref.count;
} }
ino_t d_parent_ino(struct dentry *dentry);
/* /*
* helper function for dentry_operations.d_dname() members * helper function for dentry_operations.d_dname() members
*/ */

16
include/linux/fs.h
View File

@ -3454,20 +3454,6 @@ static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags)
return 0; return 0;
} }
static inline ino_t parent_ino(struct dentry *dentry)
{
ino_t res;
/*
* Don't strictly need d_lock here? If the parent ino could change
* then surely we'd have a deeper race in the caller?
*/
spin_lock(&dentry->d_lock);
res = dentry->d_parent->d_inode->i_ino;
spin_unlock(&dentry->d_lock);
return res;
}
/* Transaction based IO helpers */ /* Transaction based IO helpers */
/* /*
@ -3592,7 +3578,7 @@ static inline bool dir_emit_dot(struct file *file, struct dir_context *ctx)
static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx) static inline bool dir_emit_dotdot(struct file *file, struct dir_context *ctx)
{ {
return ctx->actor(ctx, "..", 2, ctx->pos, return ctx->actor(ctx, "..", 2, ctx->pos,
parent_ino(file->f_path.dentry), DT_DIR); d_parent_ino(file->f_path.dentry), DT_DIR);
} }
static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx) static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx)
{ {