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[PATCH] get rid of on-stack fake dentry in ext3_get_parent()
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Better pass parent and qstr to ext3_find_entry() explicitly than
use such kludges, especially since the stack footprint is nasty
enough and we have every chance to be deep in call chain.

Signed-off-by: Al Viro <[email protected]>
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Al Viro committed Oct 23, 2008
1 parent 5f556aa commit 734711a
Showing 1 changed file with 33 additions and 37 deletions.
70 changes: 33 additions & 37 deletions fs/ext3/namei.c
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Original file line number Diff line number Diff line change
Expand Up @@ -159,7 +159,7 @@ static void dx_set_count (struct dx_entry *entries, unsigned value);
static void dx_set_limit (struct dx_entry *entries, unsigned value);
static unsigned dx_root_limit (struct inode *dir, unsigned infosize);
static unsigned dx_node_limit (struct inode *dir);
static struct dx_frame *dx_probe(struct dentry *dentry,
static struct dx_frame *dx_probe(struct qstr *entry,
struct inode *dir,
struct dx_hash_info *hinfo,
struct dx_frame *frame,
Expand All @@ -176,8 +176,9 @@ static int ext3_htree_next_block(struct inode *dir, __u32 hash,
struct dx_frame *frame,
struct dx_frame *frames,
__u32 *start_hash);
static struct buffer_head * ext3_dx_find_entry(struct dentry *dentry,
struct ext3_dir_entry_2 **res_dir, int *err);
static struct buffer_head * ext3_dx_find_entry(struct inode *dir,
struct qstr *entry, struct ext3_dir_entry_2 **res_dir,
int *err);
static int ext3_dx_add_entry(handle_t *handle, struct dentry *dentry,
struct inode *inode);

Expand Down Expand Up @@ -342,7 +343,7 @@ struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
* back to userspace.
*/
static struct dx_frame *
dx_probe(struct dentry *dentry, struct inode *dir,
dx_probe(struct qstr *entry, struct inode *dir,
struct dx_hash_info *hinfo, struct dx_frame *frame_in, int *err)
{
unsigned count, indirect;
Expand All @@ -353,8 +354,6 @@ dx_probe(struct dentry *dentry, struct inode *dir,
u32 hash;

frame->bh = NULL;
if (dentry)
dir = dentry->d_parent->d_inode;
if (!(bh = ext3_bread (NULL,dir, 0, 0, err)))
goto fail;
root = (struct dx_root *) bh->b_data;
Expand All @@ -370,8 +369,8 @@ dx_probe(struct dentry *dentry, struct inode *dir,
}
hinfo->hash_version = root->info.hash_version;
hinfo->seed = EXT3_SB(dir->i_sb)->s_hash_seed;
if (dentry)
ext3fs_dirhash(dentry->d_name.name, dentry->d_name.len, hinfo);
if (entry)
ext3fs_dirhash(entry->name, entry->len, hinfo);
hash = hinfo->hash;

if (root->info.unused_flags & 1) {
Expand Down Expand Up @@ -803,15 +802,15 @@ static inline int ext3_match (int len, const char * const name,
*/
static inline int search_dirblock(struct buffer_head * bh,
struct inode *dir,
struct dentry *dentry,
struct qstr *child,
unsigned long offset,
struct ext3_dir_entry_2 ** res_dir)
{
struct ext3_dir_entry_2 * de;
char * dlimit;
int de_len;
const char *name = dentry->d_name.name;
int namelen = dentry->d_name.len;
const char *name = child->name;
int namelen = child->len;

de = (struct ext3_dir_entry_2 *) bh->b_data;
dlimit = bh->b_data + dir->i_sb->s_blocksize;
Expand Down Expand Up @@ -850,8 +849,9 @@ static inline int search_dirblock(struct buffer_head * bh,
* The returned buffer_head has ->b_count elevated. The caller is expected
* to brelse() it when appropriate.
*/
static struct buffer_head * ext3_find_entry (struct dentry *dentry,
struct ext3_dir_entry_2 ** res_dir)
static struct buffer_head *ext3_find_entry(struct inode *dir,
struct qstr *entry,
struct ext3_dir_entry_2 **res_dir)
{
struct super_block * sb;
struct buffer_head * bh_use[NAMEI_RA_SIZE];
Expand All @@ -863,16 +863,15 @@ static struct buffer_head * ext3_find_entry (struct dentry *dentry,
buffer */
int num = 0;
int nblocks, i, err;
struct inode *dir = dentry->d_parent->d_inode;
int namelen;

*res_dir = NULL;
sb = dir->i_sb;
namelen = dentry->d_name.len;
namelen = entry->len;
if (namelen > EXT3_NAME_LEN)
return NULL;
if (is_dx(dir)) {
bh = ext3_dx_find_entry(dentry, res_dir, &err);
bh = ext3_dx_find_entry(dir, entry, res_dir, &err);
/*
* On success, or if the error was file not found,
* return. Otherwise, fall back to doing a search the
Expand Down Expand Up @@ -923,7 +922,7 @@ static struct buffer_head * ext3_find_entry (struct dentry *dentry,
brelse(bh);
goto next;
}
i = search_dirblock(bh, dir, dentry,
i = search_dirblock(bh, dir, entry,
block << EXT3_BLOCK_SIZE_BITS(sb), res_dir);
if (i == 1) {
EXT3_I(dir)->i_dir_start_lookup = block;
Expand Down Expand Up @@ -957,8 +956,9 @@ static struct buffer_head * ext3_find_entry (struct dentry *dentry,
return ret;
}

static struct buffer_head * ext3_dx_find_entry(struct dentry *dentry,
struct ext3_dir_entry_2 **res_dir, int *err)
static struct buffer_head * ext3_dx_find_entry(struct inode *dir,
struct qstr *entry, struct ext3_dir_entry_2 **res_dir,
int *err)
{
struct super_block * sb;
struct dx_hash_info hinfo;
Expand All @@ -968,14 +968,13 @@ static struct buffer_head * ext3_dx_find_entry(struct dentry *dentry,
struct buffer_head *bh;
unsigned long block;
int retval;
int namelen = dentry->d_name.len;
const u8 *name = dentry->d_name.name;
struct inode *dir = dentry->d_parent->d_inode;
int namelen = entry->len;
const u8 *name = entry->name;

sb = dir->i_sb;
/* NFS may look up ".." - look at dx_root directory block */
if (namelen > 2 || name[0] != '.'||(name[1] != '.' && name[1] != '\0')){
if (!(frame = dx_probe(dentry, NULL, &hinfo, frames, err)))
if (namelen > 2 || name[0] != '.'|| (namelen == 2 && name[1] != '.')) {
if (!(frame = dx_probe(entry, dir, &hinfo, frames, err)))
return NULL;
} else {
frame = frames;
Expand Down Expand Up @@ -1036,7 +1035,7 @@ static struct dentry *ext3_lookup(struct inode * dir, struct dentry *dentry, str
if (dentry->d_name.len > EXT3_NAME_LEN)
return ERR_PTR(-ENAMETOOLONG);

bh = ext3_find_entry(dentry, &de);
bh = ext3_find_entry(dir, &dentry->d_name, &de);
inode = NULL;
if (bh) {
unsigned long ino = le32_to_cpu(de->inode);
Expand All @@ -1057,15 +1056,11 @@ static struct dentry *ext3_lookup(struct inode * dir, struct dentry *dentry, str
struct dentry *ext3_get_parent(struct dentry *child)
{
unsigned long ino;
struct dentry dotdot;
struct qstr dotdot = {.name = "..", .len = 2};
struct ext3_dir_entry_2 * de;
struct buffer_head *bh;

dotdot.d_name.name = "..";
dotdot.d_name.len = 2;
dotdot.d_parent = child; /* confusing, isn't it! */

bh = ext3_find_entry(&dotdot, &de);
bh = ext3_find_entry(child->d_inode, &dotdot, &de);
if (!bh)
return ERR_PTR(-ENOENT);
ino = le32_to_cpu(de->inode);
Expand Down Expand Up @@ -1491,7 +1486,7 @@ static int ext3_dx_add_entry(handle_t *handle, struct dentry *dentry,
struct ext3_dir_entry_2 *de;
int err;

frame = dx_probe(dentry, NULL, &hinfo, frames, &err);
frame = dx_probe(&dentry->d_name, dir, &hinfo, frames, &err);
if (!frame)
return err;
entries = frame->entries;
Expand Down Expand Up @@ -2044,7 +2039,7 @@ static int ext3_rmdir (struct inode * dir, struct dentry *dentry)
return PTR_ERR(handle);

retval = -ENOENT;
bh = ext3_find_entry (dentry, &de);
bh = ext3_find_entry(dir, &dentry->d_name, &de);
if (!bh)
goto end_rmdir;

Expand Down Expand Up @@ -2106,7 +2101,7 @@ static int ext3_unlink(struct inode * dir, struct dentry *dentry)
handle->h_sync = 1;

retval = -ENOENT;
bh = ext3_find_entry (dentry, &de);
bh = ext3_find_entry(dir, &dentry->d_name, &de);
if (!bh)
goto end_unlink;

Expand Down Expand Up @@ -2264,7 +2259,7 @@ static int ext3_rename (struct inode * old_dir, struct dentry *old_dentry,
if (IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir))
handle->h_sync = 1;

old_bh = ext3_find_entry (old_dentry, &old_de);
old_bh = ext3_find_entry(old_dir, &old_dentry->d_name, &old_de);
/*
* Check for inode number is _not_ due to possible IO errors.
* We might rmdir the source, keep it as pwd of some process
Expand All @@ -2277,7 +2272,7 @@ static int ext3_rename (struct inode * old_dir, struct dentry *old_dentry,
goto end_rename;

new_inode = new_dentry->d_inode;
new_bh = ext3_find_entry (new_dentry, &new_de);
new_bh = ext3_find_entry(new_dir, &new_dentry->d_name, &new_de);
if (new_bh) {
if (!new_inode) {
brelse (new_bh);
Expand Down Expand Up @@ -2343,7 +2338,8 @@ static int ext3_rename (struct inode * old_dir, struct dentry *old_dentry,
struct buffer_head *old_bh2;
struct ext3_dir_entry_2 *old_de2;

old_bh2 = ext3_find_entry(old_dentry, &old_de2);
old_bh2 = ext3_find_entry(old_dir, &old_dentry->d_name,
&old_de2);
if (old_bh2) {
retval = ext3_delete_entry(handle, old_dir,
old_de2, old_bh2);
Expand Down

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