[PATCH] NOMMU: Make SYSV IPC SHM use ramfs facilities on NOMMU
[safe/jmp/linux-2.6] / mm / shmem.c
index e64fa72..a1f2f02 100644 (file)
@@ -45,7 +45,6 @@
 #include <linux/swapops.h>
 #include <linux/mempolicy.h>
 #include <linux/namei.h>
-#include <linux/xattr.h>
 #include <asm/uaccess.h>
 #include <asm/div64.h>
 #include <asm/pgtable.h>
@@ -72,9 +71,6 @@
 /* Pretend that each entry is of this size in directory's i_size */
 #define BOGO_DIRENT_SIZE 20
 
-/* Keep swapped page count in private field of indirect struct page */
-#define nr_swapped             private
-
 /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
 enum sgp_type {
        SGP_QUICK,      /* don't try more than file page cache lookup */
@@ -86,7 +82,7 @@ enum sgp_type {
 static int shmem_getpage(struct inode *inode, unsigned long idx,
                         struct page **pagep, enum sgp_type sgp, int *type);
 
-static inline struct page *shmem_dir_alloc(unsigned int gfp_mask)
+static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
 {
        /*
         * The above definition of ENTRIES_PER_PAGE, and the use of
@@ -179,10 +175,9 @@ static struct address_space_operations shmem_aops;
 static struct file_operations shmem_file_operations;
 static struct inode_operations shmem_inode_operations;
 static struct inode_operations shmem_dir_inode_operations;
-static struct inode_operations shmem_special_inode_operations;
 static struct vm_operations_struct shmem_vm_ops;
 
-static struct backing_dev_info shmem_backing_dev_info = {
+static struct backing_dev_info shmem_backing_dev_info  __read_mostly = {
        .ra_pages       = 0,    /* No readahead */
        .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
        .unplug_io_fn   = default_unplug_io_fn,
@@ -326,8 +321,10 @@ static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, uns
 
        entry->val = value;
        info->swapped += incdec;
-       if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT)
-               kmap_atomic_to_page(entry)->nr_swapped += incdec;
+       if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) {
+               struct page *page = kmap_atomic_to_page(entry);
+               set_page_private(page, page_private(page) + incdec);
+       }
 }
 
 /*
@@ -370,9 +367,8 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long
 
                spin_unlock(&info->lock);
                page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping) | __GFP_ZERO);
-               if (page) {
-                       page->nr_swapped = 0;
-               }
+               if (page)
+                       set_page_private(page, 0);
                spin_lock(&info->lock);
 
                if (!page) {
@@ -461,7 +457,7 @@ static void shmem_free_pages(struct list_head *next)
        } while (next);
 }
 
-static void shmem_truncate(struct inode *inode)
+static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
 {
        struct shmem_inode_info *info = SHMEM_I(inode);
        unsigned long idx;
@@ -479,18 +475,27 @@ static void shmem_truncate(struct inode *inode)
        long nr_swaps_freed = 0;
        int offset;
        int freed;
+       int punch_hole = 0;
 
        inode->i_ctime = inode->i_mtime = CURRENT_TIME;
-       idx = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+       idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
        if (idx >= info->next_index)
                return;
 
        spin_lock(&info->lock);
        info->flags |= SHMEM_TRUNCATE;
-       limit = info->next_index;
-       info->next_index = idx;
+       if (likely(end == (loff_t) -1)) {
+               limit = info->next_index;
+               info->next_index = idx;
+       } else {
+               limit = (end + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+               if (limit > info->next_index)
+                       limit = info->next_index;
+               punch_hole = 1;
+       }
+
        topdir = info->i_indirect;
-       if (topdir && idx <= SHMEM_NR_DIRECT) {
+       if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
                info->i_indirect = NULL;
                nr_pages_to_free++;
                list_add(&topdir->lru, &pages_to_free);
@@ -563,7 +568,7 @@ static void shmem_truncate(struct inode *inode)
                        diroff = 0;
                }
                subdir = dir[diroff];
-               if (subdir && subdir->nr_swapped) {
+               if (subdir && page_private(subdir)) {
                        size = limit - idx;
                        if (size > ENTRIES_PER_PAGE)
                                size = ENTRIES_PER_PAGE;
@@ -574,14 +579,15 @@ static void shmem_truncate(struct inode *inode)
                        nr_swaps_freed += freed;
                        if (offset)
                                spin_lock(&info->lock);
-                       subdir->nr_swapped -= freed;
+                       set_page_private(subdir, page_private(subdir) - freed);
                        if (offset)
                                spin_unlock(&info->lock);
-                       BUG_ON(subdir->nr_swapped > offset);
+                       if (!punch_hole)
+                               BUG_ON(page_private(subdir) > offset);
                }
                if (offset)
                        offset = 0;
-               else if (subdir) {
+               else if (subdir && !page_private(subdir)) {
                        dir[diroff] = NULL;
                        nr_pages_to_free++;
                        list_add(&subdir->lru, &pages_to_free);
@@ -598,7 +604,7 @@ done2:
                 * Also, though shmem_getpage checks i_size before adding to
                 * cache, no recheck after: so fix the narrow window there too.
                 */
-               truncate_inode_pages(inode->i_mapping, inode->i_size);
+               truncate_inode_pages_range(inode->i_mapping, start, end);
        }
 
        spin_lock(&info->lock);
@@ -618,6 +624,11 @@ done2:
        }
 }
 
+static void shmem_truncate(struct inode *inode)
+{
+       shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
+}
+
 static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
 {
        struct inode *inode = dentry->d_inode;
@@ -668,6 +679,7 @@ static void shmem_delete_inode(struct inode *inode)
        struct shmem_inode_info *info = SHMEM_I(inode);
 
        if (inode->i_op->truncate == shmem_truncate) {
+               truncate_inode_pages(inode->i_mapping, 0);
                shmem_unacct_size(info->flags, inode->i_size);
                inode->i_size = 0;
                shmem_truncate(inode);
@@ -744,7 +756,7 @@ static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, s
                        dir = shmem_dir_map(subdir);
                }
                subdir = *dir;
-               if (subdir && subdir->nr_swapped) {
+               if (subdir && page_private(subdir)) {
                        ptr = shmem_swp_map(subdir);
                        size = limit - idx;
                        if (size > ENTRIES_PER_PAGE)
@@ -858,7 +870,7 @@ unlock:
        swap_free(swap);
 redirty:
        set_page_dirty(page);
-       return WRITEPAGE_ACTIVATE;      /* Return with the page locked */
+       return AOP_WRITEPAGE_ACTIVATE;  /* Return with the page locked */
 }
 
 #ifdef CONFIG_NUMA
@@ -899,7 +911,7 @@ struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry,
 }
 
 static struct page *
-shmem_alloc_page(unsigned long gfp, struct shmem_inode_info *info,
+shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info,
                 unsigned long idx)
 {
        struct vm_area_struct pvma;
@@ -922,8 +934,7 @@ shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx)
 }
 
 static inline struct page *
-shmem_alloc_page(unsigned int __nocast gfp,struct shmem_inode_info *info,
-                                unsigned long idx)
+shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx)
 {
        return alloc_page(gfp | __GFP_ZERO);
 }
@@ -1195,6 +1206,7 @@ static int shmem_populate(struct vm_area_struct *vma,
                err = shmem_getpage(inode, pgoff, &page, sgp, NULL);
                if (err)
                        return err;
+               /* Page may still be null, but only if nonblock was set. */
                if (page) {
                        mark_page_accessed(page);
                        err = install_page(mm, vma, addr, page, prot);
@@ -1202,7 +1214,10 @@ static int shmem_populate(struct vm_area_struct *vma,
                                page_cache_release(page);
                                return err;
                        }
-               } else if (nonblock) {
+               } else if (vma->vm_flags & VM_NONLINEAR) {
+                       /* No page was found just because we can't read it in
+                        * now (being here implies nonblock != 0), but the page
+                        * may exist, so set the PTE to fault it in later. */
                        err = install_file_pte(mm, vma, addr, pgoff, prot);
                        if (err)
                                return err;
@@ -1255,7 +1270,7 @@ out_nomem:
        return retval;
 }
 
-static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
+int shmem_mmap(struct file *file, struct vm_area_struct *vma)
 {
        file_accessed(file);
        vma->vm_ops = &shmem_vm_ops;
@@ -1296,7 +1311,6 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
 
                switch (mode & S_IFMT) {
                default:
-                       inode->i_op = &shmem_special_inode_operations;
                        init_special_inode(inode, mode, dev);
                        break;
                case S_IFREG:
@@ -1505,8 +1519,10 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
                         */
                        if (!offset)
                                mark_page_accessed(page);
-               } else
+               } else {
                        page = ZERO_PAGE(0);
+                       page_cache_get(page);
+               }
 
                /*
                 * Ok, we have the page, and it's up-to-date, so
@@ -1606,6 +1622,15 @@ shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
        int error = -ENOSPC;
 
        if (inode) {
+               error = security_inode_init_security(inode, dir, NULL, NULL,
+                                                    NULL);
+               if (error) {
+                       if (error != -EOPNOTSUPP) {
+                               iput(inode);
+                               return error;
+                       }
+                       error = 0;
+               }
                if (dir->i_mode & S_ISGID) {
                        inode->i_gid = dir->i_gid;
                        if (S_ISDIR(mode))
@@ -1615,7 +1640,6 @@ shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
                dir->i_ctime = dir->i_mtime = CURRENT_TIME;
                d_instantiate(dentry, inode);
                dget(dentry); /* Extra count - pin the dentry in core */
-               error = 0;
        }
        return error;
 }
@@ -1745,6 +1769,16 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
        if (!inode)
                return -ENOSPC;
 
+       error = security_inode_init_security(inode, dir, NULL, NULL,
+                                            NULL);
+       if (error) {
+               if (error != -EOPNOTSUPP) {
+                       iput(inode);
+                       return error;
+               }
+               error = 0;
+       }
+
        info = SHMEM_I(inode);
        inode->i_size = len-1;
        if (len <= (char *)inode - (char *)info) {
@@ -1773,44 +1807,33 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
        return 0;
 }
 
-static int shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
+static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
 {
        nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
-       return 0;
+       return NULL;
 }
 
-static int shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
+static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
        struct page *page = NULL;
        int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
        nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
-       return 0;
+       return page;
 }
 
-static void shmem_put_link(struct dentry *dentry, struct nameidata *nd)
+static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
 {
        if (!IS_ERR(nd_get_link(nd))) {
-               struct page *page;
-
-               page = find_get_page(dentry->d_inode->i_mapping, 0);
-               if (!page)
-                       BUG();
+               struct page *page = cookie;
                kunmap(page);
                mark_page_accessed(page);
                page_cache_release(page);
-               page_cache_release(page);
        }
 }
 
 static struct inode_operations shmem_symlink_inline_operations = {
        .readlink       = generic_readlink,
        .follow_link    = shmem_follow_link_inline,
-#ifdef CONFIG_TMPFS_XATTR
-       .setxattr       = generic_setxattr,
-       .getxattr       = generic_getxattr,
-       .listxattr      = generic_listxattr,
-       .removexattr    = generic_removexattr,
-#endif
 };
 
 static struct inode_operations shmem_symlink_inode_operations = {
@@ -1818,12 +1841,6 @@ static struct inode_operations shmem_symlink_inode_operations = {
        .readlink       = generic_readlink,
        .follow_link    = shmem_follow_link,
        .put_link       = shmem_put_link,
-#ifdef CONFIG_TMPFS_XATTR
-       .setxattr       = generic_setxattr,
-       .getxattr       = generic_getxattr,
-       .listxattr      = generic_listxattr,
-       .removexattr    = generic_removexattr,
-#endif
 };
 
 static int shmem_parse_options(char *options, int *mode, uid_t *uid, gid_t *gid, unsigned long *blocks, unsigned long *inodes)
@@ -1943,12 +1960,6 @@ static void shmem_put_super(struct super_block *sb)
        sb->s_fs_info = NULL;
 }
 
-#ifdef CONFIG_TMPFS_XATTR
-static struct xattr_handler *shmem_xattr_handlers[];
-#else
-#define shmem_xattr_handlers NULL
-#endif
-
 static int shmem_fill_super(struct super_block *sb,
                            void *data, int silent)
 {
@@ -1999,7 +2010,6 @@ static int shmem_fill_super(struct super_block *sb,
        sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
        sb->s_magic = TMPFS_MAGIC;
        sb->s_op = &shmem_ops;
-       sb->s_xattr = shmem_xattr_handlers;
 
        inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
        if (!inode)
@@ -2088,12 +2098,7 @@ static struct file_operations shmem_file_operations = {
 static struct inode_operations shmem_inode_operations = {
        .truncate       = shmem_truncate,
        .setattr        = shmem_notify_change,
-#ifdef CONFIG_TMPFS_XATTR
-       .setxattr       = generic_setxattr,
-       .getxattr       = generic_getxattr,
-       .listxattr      = generic_listxattr,
-       .removexattr    = generic_removexattr,
-#endif
+       .truncate_range = shmem_truncate_range,
 };
 
 static struct inode_operations shmem_dir_inode_operations = {
@@ -2107,21 +2112,6 @@ static struct inode_operations shmem_dir_inode_operations = {
        .rmdir          = shmem_rmdir,
        .mknod          = shmem_mknod,
        .rename         = shmem_rename,
-#ifdef CONFIG_TMPFS_XATTR
-       .setxattr       = generic_setxattr,
-       .getxattr       = generic_getxattr,
-       .listxattr      = generic_listxattr,
-       .removexattr    = generic_removexattr,
-#endif
-#endif
-};
-
-static struct inode_operations shmem_special_inode_operations = {
-#ifdef CONFIG_TMPFS_XATTR
-       .setxattr       = generic_setxattr,
-       .getxattr       = generic_getxattr,
-       .listxattr      = generic_listxattr,
-       .removexattr    = generic_removexattr,
 #endif
 };
 
@@ -2147,48 +2137,6 @@ static struct vm_operations_struct shmem_vm_ops = {
 };
 
 
-#ifdef CONFIG_TMPFS_SECURITY
-
-static size_t shmem_xattr_security_list(struct inode *inode, char *list, size_t list_len,
-                                       const char *name, size_t name_len)
-{
-       return security_inode_listsecurity(inode, list, list_len);
-}
-
-static int shmem_xattr_security_get(struct inode *inode, const char *name, void *buffer, size_t size)
-{
-       if (strcmp(name, "") == 0)
-               return -EINVAL;
-       return security_inode_getsecurity(inode, name, buffer, size);
-}
-
-static int shmem_xattr_security_set(struct inode *inode, const char *name, const void *value, size_t size, int flags)
-{
-       if (strcmp(name, "") == 0)
-               return -EINVAL;
-       return security_inode_setsecurity(inode, name, value, size, flags);
-}
-
-static struct xattr_handler shmem_xattr_security_handler = {
-       .prefix = XATTR_SECURITY_PREFIX,
-       .list   = shmem_xattr_security_list,
-       .get    = shmem_xattr_security_get,
-       .set    = shmem_xattr_security_set,
-};
-
-#endif /* CONFIG_TMPFS_SECURITY */
-
-#ifdef CONFIG_TMPFS_XATTR
-
-static struct xattr_handler *shmem_xattr_handlers[] = {
-#ifdef CONFIG_TMPFS_SECURITY
-       &shmem_xattr_security_handler,
-#endif
-       NULL
-};
-
-#endif /* CONFIG_TMPFS_XATTR */
-
 static struct super_block *shmem_get_sb(struct file_system_type *fs_type,
        int flags, const char *dev_name, void *data)
 {