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authorLinus Torvalds <torvalds@linux-foundation.org>2016-06-10 07:51:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-06-10 20:21:46 -0700
commit8387ff2577eb9ed245df9a39947f66976c6bcd02 (patch)
tree79fafcb5777f16e520d1c39e9389039f866b4c6d /fs/jffs2
parent147d9e7bcad3b8d5465f6eea6292731e7f35dee8 (diff)
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vfs: make the string hashes salt the hash
We always mixed in the parent pointer into the dentry name hash, but we did it late at lookup time. It turns out that we can simplify that lookup-time action by salting the hash with the parent pointer early instead of late. A few other users of our string hashes also wanted to mix in their own pointers into the hash, and those are updated to use the same mechanism. Hash users that don't have any particular initial salt can just use the NULL pointer as a no-salt. Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/jffs2')
-rw-r--r--fs/jffs2/dir.c8
-rw-r--r--fs/jffs2/readinode.c2
-rw-r--r--fs/jffs2/scan.c2
-rw-r--r--fs/jffs2/summary.c2
-rw-r--r--fs/jffs2/write.c4
5 files changed, 11 insertions, 7 deletions
diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index 84c4bf3631a2..30eb33ff8189 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -81,6 +81,7 @@ static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target,
struct jffs2_full_dirent *fd = NULL, *fd_list;
uint32_t ino = 0;
struct inode *inode = NULL;
+ unsigned int nhash;
jffs2_dbg(1, "jffs2_lookup()\n");
@@ -89,11 +90,14 @@ static struct dentry *jffs2_lookup(struct inode *dir_i, struct dentry *target,
dir_f = JFFS2_INODE_INFO(dir_i);
+ /* The 'nhash' on the fd_list is not the same as the dentry hash */
+ nhash = full_name_hash(NULL, target->d_name.name, target->d_name.len);
+
mutex_lock(&dir_f->sem);
/* NB: The 2.2 backport will need to explicitly check for '.' and '..' here */
- for (fd_list = dir_f->dents; fd_list && fd_list->nhash <= target->d_name.hash; fd_list = fd_list->next) {
- if (fd_list->nhash == target->d_name.hash &&
+ for (fd_list = dir_f->dents; fd_list && fd_list->nhash <= nhash; fd_list = fd_list->next) {
+ if (fd_list->nhash == nhash &&
(!fd || fd_list->version > fd->version) &&
strlen(fd_list->name) == target->d_name.len &&
!strncmp(fd_list->name, target->d_name.name, target->d_name.len)) {
diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c
index bfebbf13698c..06a71dbd4833 100644
--- a/fs/jffs2/readinode.c
+++ b/fs/jffs2/readinode.c
@@ -674,7 +674,7 @@ static inline int read_direntry(struct jffs2_sb_info *c, struct jffs2_raw_node_r
}
}
- fd->nhash = full_name_hash(fd->name, rd->nsize);
+ fd->nhash = full_name_hash(NULL, fd->name, rd->nsize);
fd->next = NULL;
fd->name[rd->nsize] = '\0';
diff --git a/fs/jffs2/scan.c b/fs/jffs2/scan.c
index 9ad5ba4b299b..90431dd613b8 100644
--- a/fs/jffs2/scan.c
+++ b/fs/jffs2/scan.c
@@ -1100,7 +1100,7 @@ static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblo
fd->next = NULL;
fd->version = je32_to_cpu(rd->version);
fd->ino = je32_to_cpu(rd->ino);
- fd->nhash = full_name_hash(fd->name, checkedlen);
+ fd->nhash = full_name_hash(NULL, fd->name, checkedlen);
fd->type = rd->type;
jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
diff --git a/fs/jffs2/summary.c b/fs/jffs2/summary.c
index bc5385471a6e..be7c8a6a5748 100644
--- a/fs/jffs2/summary.c
+++ b/fs/jffs2/summary.c
@@ -476,7 +476,7 @@ static int jffs2_sum_process_sum_data(struct jffs2_sb_info *c, struct jffs2_eras
fd->next = NULL;
fd->version = je32_to_cpu(spd->version);
fd->ino = je32_to_cpu(spd->ino);
- fd->nhash = full_name_hash(fd->name, checkedlen);
+ fd->nhash = full_name_hash(NULL, fd->name, checkedlen);
fd->type = spd->type;
jffs2_add_fd_to_list(c, fd, &ic->scan_dents);
diff --git a/fs/jffs2/write.c b/fs/jffs2/write.c
index 7fb187ab2682..cda9a361368e 100644
--- a/fs/jffs2/write.c
+++ b/fs/jffs2/write.c
@@ -245,7 +245,7 @@ struct jffs2_full_dirent *jffs2_write_dirent(struct jffs2_sb_info *c, struct jff
fd->version = je32_to_cpu(rd->version);
fd->ino = je32_to_cpu(rd->ino);
- fd->nhash = full_name_hash(name, namelen);
+ fd->nhash = full_name_hash(NULL, name, namelen);
fd->type = rd->type;
memcpy(fd->name, name, namelen);
fd->name[namelen]=0;
@@ -598,7 +598,7 @@ int jffs2_do_unlink(struct jffs2_sb_info *c, struct jffs2_inode_info *dir_f,
jffs2_add_fd_to_list(c, fd, &dir_f->dents);
mutex_unlock(&dir_f->sem);
} else {
- uint32_t nhash = full_name_hash(name, namelen);
+ uint32_t nhash = full_name_hash(NULL, name, namelen);
fd = dir_f->dents;
/* We don't actually want to reserve any space, but we do