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Date: Mon, 04 Feb 2008 01:15:05 -0800
From: Ram Pai <linuxram@...ibm.com>
To: Miklos Szeredi <miklos@...redi.hu>
Cc: akpm@...ux-foundation.org, linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org, viro@....linux.org.uk,
a.p.zijlstra@...llo.nl
Subject: [RFC PATCH] vfs: optimization to /proc/<pid>/mountinfo patch
1) reports deleted inode in dentry_path() consistent with that in __d_path()
2) modified __d_path() to use prepend(), reducing the size of __d_path()
3) moved all the functionality that reports mount information in /proc under
CONFIG_PROC_FS.
Could not verify if the code would work with CONFIG_PROC_FS=n, since it was
impossible to disable CONFIG_PROC_FS. Looking for ideas on how to disable
CONFIG_PROC_FS.
Signed-off-by: Ram Pai <linuxram@...ibm.com>
---
fs/dcache.c | 59 +++++++++++++++++++----------------------------
fs/namespace.c | 2 +
fs/seq_file.c | 2 +
include/linux/dcache.h | 3 ++
include/linux/seq_file.h | 3 ++
5 files changed, 34 insertions(+), 35 deletions(-)
Index: linux-2.6.23/fs/dcache.c
===================================================================
--- linux-2.6.23.orig/fs/dcache.c
+++ linux-2.6.23/fs/dcache.c
@@ -1747,6 +1747,17 @@ shouldnt_be_hashed:
goto shouldnt_be_hashed;
}
+static int prepend(char **buffer, int *buflen, const char *str,
+ int namelen)
+{
+ *buflen -= namelen;
+ if (*buflen < 0)
+ return 1;
+ *buffer -= namelen;
+ memcpy(*buffer, str, namelen);
+ return 0;
+}
+
/**
* d_path - return the path of a dentry
* @dentry: dentry to report
@@ -1768,17 +1779,11 @@ static char *__d_path(struct dentry *den
{
char * end = buffer+buflen;
char * retval;
- int namelen;
- *--end = '\0';
- buflen--;
- if (!IS_ROOT(dentry) && d_unhashed(dentry)) {
- buflen -= 10;
- end -= 10;
- if (buflen < 0)
+ prepend(&end, &buflen, "\0", 1);
+ if (!IS_ROOT(dentry) && d_unhashed(dentry) &&
+ prepend(&end, &buflen, " (deleted)", 10))
goto Elong;
- memcpy(end, " (deleted)", 10);
- }
if (buflen < 1)
goto Elong;
@@ -1805,13 +1810,10 @@ static char *__d_path(struct dentry *den
}
parent = dentry->d_parent;
prefetch(parent);
- namelen = dentry->d_name.len;
- buflen -= namelen + 1;
- if (buflen < 0)
+ if (prepend(&end, &buflen, dentry->d_name.name,
+ dentry->d_name.len) ||
+ prepend(&end, &buflen, "/", 1))
goto Elong;
- end -= namelen;
- memcpy(end, dentry->d_name.name, namelen);
- *--end = '/';
retval = end;
dentry = parent;
}
@@ -1819,12 +1821,9 @@ static char *__d_path(struct dentry *den
return retval;
global_root:
- namelen = dentry->d_name.len;
- buflen -= namelen;
- if (buflen < 0)
- goto Elong;
- retval -= namelen-1; /* hit the slash */
- memcpy(retval, dentry->d_name.name, namelen);
+ retval += 1; /* hit the slash */
+ if (prepend(&retval, &buflen, dentry->d_name.name, dentry->d_name.len))
+ goto Elong;
return retval;
Elong:
return ERR_PTR(-ENAMETOOLONG);
@@ -1890,17 +1889,8 @@ char *dynamic_dname(struct dentry *dentr
return memcpy(buffer, temp, sz);
}
-static int prepend(char **buffer, int *buflen, const char *str,
- int namelen)
-{
- *buflen -= namelen;
- if (*buflen < 0)
- return 1;
- *buffer -= namelen;
- memcpy(*buffer, str, namelen);
- return 0;
-}
+#ifdef CONFIG_PROC_FS
/*
* Write full pathname from the root of the filesystem into the buffer.
*/
@@ -1910,11 +1900,9 @@ char *dentry_path(struct dentry *dentry,
char *retval;
spin_lock(&dcache_lock);
- prepend(&end, &buflen, "\0", 1);
- if (!IS_ROOT(dentry) && d_unhashed(dentry)) {
- if (prepend(&end, &buflen, "//deleted", 9))
+ if (!IS_ROOT(dentry) && d_unhashed(dentry) &&
+ prepend(&end, &buflen, " (deleted)", 10))
goto Elong;
- }
if (buflen < 1)
goto Elong;
/* Get '/' right */
@@ -1943,6 +1931,7 @@ Elong:
spin_unlock(&dcache_lock);
return ERR_PTR(-ENAMETOOLONG);
}
+#endif /* CONFIG_PROC_FS */
/*
* NOTE! The user-level library version returns a
Index: linux-2.6.23/fs/namespace.c
===================================================================
--- linux-2.6.23.orig/fs/namespace.c
+++ linux-2.6.23/fs/namespace.c
@@ -609,6 +609,7 @@ void mnt_unpin(struct vfsmount *mnt)
EXPORT_SYMBOL(mnt_unpin);
+#ifdef CONFIG_PROC_FS
/* iterator */
static void *m_start(struct seq_file *m, loff_t *pos)
{
@@ -795,6 +796,7 @@ const struct seq_operations mountstats_o
.stop = m_stop,
.show = show_vfsstat,
};
+#endif /* CONFIG_PROC_FS */
/**
* may_umount_tree - check if a mount tree is busy
Index: linux-2.6.23/fs/seq_file.c
===================================================================
--- linux-2.6.23.orig/fs/seq_file.c
+++ linux-2.6.23/fs/seq_file.c
@@ -369,6 +369,7 @@ static char *mangle_path(char *s, char *
return NULL;
}
+#ifdef CONFIG_PROC_FS
/*
* return the absolute path of 'dentry' residing in mount 'mnt'.
*/
@@ -390,6 +391,7 @@ int seq_path(struct seq_file *m, struct
return -1;
}
EXPORT_SYMBOL(seq_path);
+#endif /* CONFIG_PROC_FS */
/*
* returns the path of the 'dentry' from the root of its filesystem.
Index: linux-2.6.23/include/linux/dcache.h
===================================================================
--- linux-2.6.23.orig/include/linux/dcache.h
+++ linux-2.6.23/include/linux/dcache.h
@@ -302,7 +302,10 @@ extern int d_validate(struct dentry *, s
extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
extern char *d_path(struct path *, char *, int);
+
+#ifdef CONFIG_PROC_FS
extern char *dentry_path(struct dentry *, char *, int);
+#endif /* CONFIG_PROC_FS */
/* Allocation counts.. */
Index: linux-2.6.23/include/linux/seq_file.h
===================================================================
--- linux-2.6.23.orig/include/linux/seq_file.h
+++ linux-2.6.23/include/linux/seq_file.h
@@ -44,7 +44,10 @@ int seq_printf(struct seq_file *, const
__attribute__ ((format (printf,2,3)));
int seq_path(struct seq_file *, struct path *, char *);
+
+#ifdef CONFIG_PROC_FS
int seq_dentry(struct seq_file *, struct dentry *, char *);
+#endif /* CONFIG_PROC_FS */
int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
int single_release(struct inode *, struct file *);
--
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