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Subject[Resend] Collection of tmpfs patches
Date
Hi,

There is some confusion about my latest tmpfs fixes. There were three
patches which are cummulative against 2.4.4:

1) deadlock fix for write out of mmap regions. (AFAIK this is
integrated in the -ac kernels)
2) encapsulate access to shmem_inode_info
3) Do inline symlinks

I attach all these patches to this mail in the case that somebody
missed one.

Greetings
Christoph

diff -uNr 2.4.4/include/linux/shmem_fs.h c/include/linux/shmem_fs.h
--- 2.4.4/include/linux/shmem_fs.h Sun Apr 29 20:33:00 2001
+++ c/include/linux/shmem_fs.h Sun Apr 29 22:43:56 2001
@@ -19,6 +19,7 @@

struct shmem_inode_info {
spinlock_t lock;
+ struct semaphore sem;
unsigned long max_index;
swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* for the first blocks */
swp_entry_t **i_indirect; /* doubly indirect blocks */
diff -uNr 2.4.4/mm/shmem.c c/mm/shmem.c
--- 2.4.4/mm/shmem.c Mon Apr 30 09:45:39 2001
+++ c/mm/shmem.c Tue May 1 15:15:38 2001
@@ -161,6 +161,7 @@
swp_entry_t **base, **ptr, **last;
struct shmem_inode_info * info = &inode->u.shmem_i;

+ down(&info->sem);
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
spin_lock (&info->lock);
index = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
@@ -197,6 +198,7 @@
info->swapped -= freed;
shmem_recalc_inode(inode);
spin_unlock (&info->lock);
+ up(&info->sem);
}

static void shmem_delete_inode(struct inode * inode)
@@ -281,15 +283,12 @@
* still need to guard against racing with shm_writepage(), which might
* be trying to move the page to the swap cache as we run.
*/
-static struct page * shmem_getpage_locked(struct inode * inode, unsigned long idx)
+static struct page * shmem_getpage_locked(struct shmem_inode_info *info, struct inode * inode, unsigned long idx)
{
struct address_space * mapping = inode->i_mapping;
- struct shmem_inode_info *info;
struct page * page;
swp_entry_t *entry;

- info = &inode->u.shmem_i;
-
repeat:
page = find_lock_page(mapping, idx);
if (page)
@@ -393,6 +392,7 @@

static int shmem_getpage(struct inode * inode, unsigned long idx, struct page **ptr)
{
+ struct shmem_inode_info *info;
struct address_space * mapping = inode->i_mapping;
int error;

@@ -407,27 +407,28 @@
page_cache_release(*ptr);
}

- down (&inode->i_sem);
- /* retest we may have slept */
+ info = &inode->u.shmem_i;
+ down (&info->sem);
+ /* retest we may have slept */
+
+ *ptr = ERR_PTR(-EFAULT);
if (inode->i_size < (loff_t) idx * PAGE_CACHE_SIZE)
- goto sigbus;
- *ptr = shmem_getpage_locked(inode, idx);
+ goto failed;
+
+ *ptr = shmem_getpage_locked(&inode->u.shmem_i, inode, idx);
if (IS_ERR (*ptr))
goto failed;
+
UnlockPage(*ptr);
- up (&inode->i_sem);
+ up (&info->sem);
return 0;
failed:
- up (&inode->i_sem);
+ up (&info->sem);
error = PTR_ERR(*ptr);
- *ptr = NOPAGE_OOM;
- if (error != -EFBIG)
- *ptr = NOPAGE_SIGBUS;
- return error;
-sigbus:
- up (&inode->i_sem);
*ptr = NOPAGE_SIGBUS;
- return -EFAULT;
+ if (error == -ENOMEM)
+ *ptr = NOPAGE_OOM;
+ return error;
}

struct page * shmem_nopage(struct vm_area_struct * vma, unsigned long address, int no_share)
@@ -500,6 +501,7 @@
struct inode *shmem_get_inode(struct super_block *sb, int mode, int dev)
{
struct inode * inode;
+ struct shmem_inode_info *info;

spin_lock (&sb->u.shmem_sb.stat_lock);
if (!sb->u.shmem_sb.free_inodes) {
@@ -519,7 +521,9 @@
inode->i_rdev = to_kdev_t(dev);
inode->i_mapping->a_ops = &shmem_aops;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
- spin_lock_init (&inode->u.shmem_i.lock);
+ info = &inode->u.shmem_i;
+ spin_lock_init (&info->lock);
+ sema_init (&info->sem, 1);
switch (mode & S_IFMT) {
default:
init_special_inode(inode, mode, dev);
@@ -549,6 +553,7 @@
shmem_file_write(struct file *file,const char *buf,size_t count,loff_t *ppos)
{
struct inode *inode = file->f_dentry->d_inode;
+ struct shmem_inode_info *info;
unsigned long limit = current->rlim[RLIMIT_FSIZE].rlim_cur;
loff_t pos;
struct page *page;
@@ -624,7 +629,11 @@
__get_user(dummy, buf+bytes-1);
}

- page = shmem_getpage_locked(inode, index);
+ info = &inode->u.shmem_i;
+ down (&info->sem);
+ page = shmem_getpage_locked(info, inode, index);
+ up (&info->sem);
+
status = PTR_ERR(page);
if (IS_ERR(page))
break;
@@ -635,7 +644,6 @@
}

kaddr = kmap(page);
-// can this do a truncated write? cr
status = copy_from_user(kaddr+offset, buf, bytes);
kunmap(page);
if (status)
@@ -932,7 +940,7 @@

inode = dentry->d_inode;
down(&inode->i_sem);
- page = shmem_getpage_locked(inode, 0);
+ page = shmem_getpage_locked(&inode->u.shmem_i, inode, 0);
if (IS_ERR(page))
goto fail;
kaddr = kmap(page);diff -uNr 2.4.4-mmap_write/include/linux/shmem_fs.h 2.4.4-mmap_write-SHMEM_I/include/linux/shmem_fs.h
--- 2.4.4-mmap_write/include/linux/shmem_fs.h Tue May 1 20:02:00 2001
+++ 2.4.4-mmap_write-SHMEM_I/include/linux/shmem_fs.h Tue May 1 20:06:10 2001
@@ -18,14 +18,15 @@
} swp_entry_t;

struct shmem_inode_info {
- spinlock_t lock;
- struct semaphore sem;
- unsigned long max_index;
- swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* for the first blocks */
- swp_entry_t **i_indirect; /* doubly indirect blocks */
- unsigned long swapped;
- int locked; /* into memory */
+ spinlock_t lock;
+ struct semaphore sem;
+ unsigned long max_index;
+ swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* for the first blocks */
+ swp_entry_t **i_indirect; /* doubly indirect blocks */
+ unsigned long swapped;
+ int locked; /* into memory */
struct list_head list;
+ struct inode *inode;
};

struct shmem_sb_info {
@@ -35,5 +36,7 @@
unsigned long free_inodes; /* How many are left for allocation */
spinlock_t stat_lock;
};
+
+#define SHMEM_I(inode) (&inode->u.shmem_i)

#endif
diff -uNr 2.4.4-mmap_write/ipc/shm.c 2.4.4-mmap_write-SHMEM_I/ipc/shm.c
--- 2.4.4-mmap_write/ipc/shm.c Wed Apr 11 12:36:47 2001
+++ 2.4.4-mmap_write-SHMEM_I/ipc/shm.c Tue May 1 20:06:10 2001
@@ -348,6 +348,7 @@

static void shm_get_stat (unsigned long *rss, unsigned long *swp)
{
+ struct shmem_inode_info *info;
int i;

*rss = 0;
@@ -361,10 +362,11 @@
if(shp == NULL)
continue;
inode = shp->shm_file->f_dentry->d_inode;
- spin_lock (&inode->u.shmem_i.lock);
+ info = SHMEM_I(inode);
+ spin_lock (&info->lock);
*rss += inode->i_mapping->nrpages;
- *swp += inode->u.shmem_i.swapped;
- spin_unlock (&inode->u.shmem_i.lock);
+ *swp += info->swapped;
+ spin_unlock (&info->lock);
}
}

diff -uNr 2.4.4-mmap_write/mm/shmem.c 2.4.4-mmap_write-SHMEM_I/mm/shmem.c
--- 2.4.4-mmap_write/mm/shmem.c Tue May 1 20:02:00 2001
+++ 2.4.4-mmap_write-SHMEM_I/mm/shmem.c Wed May 2 16:46:00 2001
@@ -73,7 +73,7 @@
unsigned long freed;

freed = (inode->i_blocks/BLOCKS_PER_PAGE) -
- (inode->i_mapping->nrpages + inode->u.shmem_i.swapped);
+ (inode->i_mapping->nrpages + SHMEM_I(inode)->swapped);
if (freed){
struct shmem_sb_info * info = &inode->i_sb->u.shmem_sb;
inode->i_blocks -= freed*BLOCKS_PER_PAGE;
@@ -159,7 +159,7 @@
unsigned long index, start;
unsigned long freed = 0;
swp_entry_t **base, **ptr, **last;
- struct shmem_inode_info * info = &inode->u.shmem_i;
+ struct shmem_inode_info * info = SHMEM_I(inode);

down(&info->sem);
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
@@ -206,7 +206,7 @@
struct shmem_sb_info *info = &inode->i_sb->u.shmem_sb;

spin_lock (&shmem_ilock);
- list_del (&inode->u.shmem_i.list);
+ list_del (&SHMEM_I(inode)->list);
spin_unlock (&shmem_ilock);
inode->i_size = 0;
shmem_truncate (inode);
@@ -239,7 +239,7 @@
goto out;

inode = page->mapping->host;
- info = &inode->u.shmem_i;
+ info = SHMEM_I(inode);
swap = __get_swap_page(2);
error = -ENOMEM;
if (!swap.val)
@@ -407,7 +407,7 @@
page_cache_release(*ptr);
}

- info = &inode->u.shmem_i;
+ info = SHMEM_I(inode);
down (&info->sem);
/* retest we may have slept */

@@ -415,7 +415,7 @@
if (inode->i_size < (loff_t) idx * PAGE_CACHE_SIZE)
goto failed;

- *ptr = shmem_getpage_locked(&inode->u.shmem_i, inode, idx);
+ *ptr = shmem_getpage_locked(info, inode, idx);
if (IS_ERR (*ptr))
goto failed;

@@ -462,7 +462,7 @@
void shmem_lock(struct file * file, int lock)
{
struct inode * inode = file->f_dentry->d_inode;
- struct shmem_inode_info * info = &inode->u.shmem_i;
+ struct shmem_inode_info * info = SHMEM_I(inode);
struct page * page;
unsigned long idx, size;

@@ -521,7 +521,8 @@
inode->i_rdev = to_kdev_t(dev);
inode->i_mapping->a_ops = &shmem_aops;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
- info = &inode->u.shmem_i;
+ info = SHMEM_I(inode);
+ info->inode = inode;
spin_lock_init (&info->lock);
sema_init (&info->sem, 1);
switch (mode & S_IFMT) {
@@ -542,7 +543,7 @@
break;
}
spin_lock (&shmem_ilock);
- list_add (&inode->u.shmem_i.list, &shmem_inodes);
+ list_add (&SHMEM_I(inode)->list, &shmem_inodes);
spin_unlock (&shmem_ilock);
}
return inode;
@@ -629,7 +630,7 @@
__get_user(dummy, buf+bytes-1);
}

- info = &inode->u.shmem_i;
+ info = SHMEM_I(inode);
down (&info->sem);
page = shmem_getpage_locked(info, inode, index);
up (&info->sem);
@@ -658,8 +659,8 @@
buf += bytes;
if (pos > inode->i_size)
inode->i_size = pos;
- if (inode->u.shmem_i.max_index <= index)
- inode->u.shmem_i.max_index = index+1;
+ if (info->max_index <= index)
+ info->max_index = index+1;

}
unlock:
@@ -940,7 +941,7 @@

inode = dentry->d_inode;
down(&inode->i_sem);
- page = shmem_getpage_locked(&inode->u.shmem_i, inode, 0);
+ page = shmem_getpage_locked(SHMEM_I(inode), inode, 0);
if (IS_ERR(page))
goto fail;
kaddr = kmap(page);
@@ -1220,12 +1221,11 @@
return -1;
}

-static int shmem_unuse_inode (struct inode *inode, swp_entry_t entry, struct page *page)
+static int shmem_unuse_inode (struct shmem_inode_info *info, swp_entry_t entry, struct page *page)
{
swp_entry_t **base, **ptr;
unsigned long idx;
int offset;
- struct shmem_inode_info *info = &inode->u.shmem_i;

idx = 0;
spin_lock (&info->lock);
@@ -1246,7 +1246,7 @@
spin_unlock (&info->lock);
return 0;
found:
- add_to_page_cache(page, inode->i_mapping, offset + idx);
+ add_to_page_cache(page, info->inode->i_mapping, offset + idx);
set_page_dirty(page);
SetPageUptodate(page);
UnlockPage(page);
@@ -1261,13 +1261,13 @@
void shmem_unuse(swp_entry_t entry, struct page *page)
{
struct list_head *p;
- struct inode * inode;
+ struct shmem_inode_info * info;

spin_lock (&shmem_ilock);
list_for_each(p, &shmem_inodes) {
- inode = list_entry(p, struct inode, u.shmem_i.list);
+ info = list_entry(p, struct shmem_inode_info, list);

- if (shmem_unuse_inode(inode, entry, page))
+ if (shmem_unuse_inode(info, entry, page))
break;
}
spin_unlock (&shmem_ilock);diff -uNr 2.4.4-mmap_write-SHMEM_I/mm/shmem.c 2.4.4-mmap_write-SHMEM_I-symlink/mm/shmem.c
--- 2.4.4-mmap_write-SHMEM_I/mm/shmem.c Fri May 4 21:32:22 2001
+++ 2.4.4-mmap_write-SHMEM_I-symlink/mm/shmem.c Fri May 4 21:37:34 2001
@@ -41,7 +41,6 @@
static struct inode_operations shmem_inode_operations;
static struct file_operations shmem_dir_operations;
static struct inode_operations shmem_dir_inode_operations;
-static struct inode_operations shmem_symlink_inode_operations;
static struct vm_operations_struct shmem_vm_ops;

LIST_HEAD (shmem_inodes);
@@ -205,11 +204,13 @@
{
struct shmem_sb_info *info = &inode->i_sb->u.shmem_sb;

- spin_lock (&shmem_ilock);
- list_del (&SHMEM_I(inode)->list);
- spin_unlock (&shmem_ilock);
inode->i_size = 0;
- shmem_truncate (inode);
+ if (inode->i_op->truncate == shmem_truncate){
+ spin_lock (&shmem_ilock);
+ list_del (&SHMEM_I(inode)->list);
+ spin_unlock (&shmem_ilock);
+ shmem_truncate(inode);
+ }
spin_lock (&info->stat_lock);
info->free_inodes++;
spin_unlock (&info->stat_lock);
@@ -532,6 +533,9 @@
case S_IFREG:
inode->i_op = &shmem_inode_operations;
inode->i_fop = &shmem_file_operations;
+ spin_lock (&shmem_ilock);
+ list_add (&SHMEM_I(inode)->list, &shmem_inodes);
+ spin_unlock (&shmem_ilock);
break;
case S_IFDIR:
inode->i_nlink++;
@@ -539,17 +543,17 @@
inode->i_fop = &shmem_dir_operations;
break;
case S_IFLNK:
- inode->i_op = &shmem_symlink_inode_operations;
break;
}
- spin_lock (&shmem_ilock);
- list_add (&SHMEM_I(inode)->list, &shmem_inodes);
- spin_unlock (&shmem_ilock);
}
return inode;
}

#ifdef CONFIG_TMPFS
+
+static struct inode_operations shmem_symlink_inode_operations;
+static struct inode_operations shmem_symlink_inline_operations;
+
static ssize_t
shmem_file_write(struct file *file,const char *buf,size_t count,loff_t *ppos)
{
@@ -930,33 +934,54 @@
struct inode *inode;
struct page *page;
char *kaddr;
+ struct shmem_inode_info * info;

error = shmem_mknod(dir, dentry, S_IFLNK | S_IRWXUGO, 0);
if (error)
return error;

- len = strlen(symname);
+ len = strlen(symname) + 1;
if (len > PAGE_SIZE)
return -ENAMETOOLONG;
-
+
inode = dentry->d_inode;
- down(&inode->i_sem);
- page = shmem_getpage_locked(SHMEM_I(inode), inode, 0);
- if (IS_ERR(page))
- goto fail;
- kaddr = kmap(page);
- memcpy(kaddr, symname, len);
- kunmap(page);
+ info = SHMEM_I(inode);
inode->i_size = len;
- SetPageDirty(page);
- UnlockPage(page);
- page_cache_release(page);
- up(&inode->i_sem);
+ if (len <= sizeof(struct shmem_inode_info)) {
+ /* do it inline */
+ memcpy(info, symname, len);
+ inode->i_op = &shmem_symlink_inline_operations;
+ } else {
+ spin_lock (&shmem_ilock);
+ list_add (&info->list, &shmem_inodes);
+ spin_unlock (&shmem_ilock);
+ down(&inode->i_sem);
+ page = shmem_getpage_locked(info, inode, 0);
+ if (IS_ERR(page)) {
+ up(&inode->i_sem);
+ return PTR_ERR(page);
+ }
+ kaddr = kmap(page);
+ memcpy(kaddr, symname, len);
+ kunmap(page);
+ SetPageDirty(page);
+ UnlockPage(page);
+ page_cache_release(page);
+ up(&inode->i_sem);
+ inode->i_op = &shmem_symlink_inode_operations;
+ }
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
return 0;
-fail:
- up(&inode->i_sem);
- return PTR_ERR(page);
+}
+
+static int shmem_readlink_inline(struct dentry *dentry, char *buffer, int buflen)
+{
+ return vfs_readlink(dentry,buffer,buflen, (const char *)SHMEM_I(dentry->d_inode));
+}
+
+static int shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
+{
+ return vfs_follow_link(nd, (const char *)SHMEM_I(dentry->d_inode));
}

static int shmem_readlink(struct dentry *dentry, char *buffer, int buflen)
@@ -986,6 +1011,17 @@
return res;
}

+static struct inode_operations shmem_symlink_inline_operations = {
+ readlink: shmem_readlink_inline,
+ follow_link: shmem_follow_link_inline,
+};
+
+static struct inode_operations shmem_symlink_inode_operations = {
+ truncate: shmem_truncate,
+ readlink: shmem_readlink,
+ follow_link: shmem_follow_link,
+};
+
static int shmem_parse_options(char *options, int *mode, unsigned long * blocks, unsigned long *inodes)
{
char *this_char, *value;
@@ -1118,14 +1154,6 @@

static struct inode_operations shmem_inode_operations = {
truncate: shmem_truncate,
-};
-
-static struct inode_operations shmem_symlink_inode_operations = {
- truncate: shmem_truncate,
-#ifdef CONFIG_TMPFS
- readlink: shmem_readlink,
- follow_link: shmem_follow_link,
-#endif
};

static struct file_operations shmem_dir_operations = {
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