vserver 1.9.5.x5
[linux-2.6.git] / mm / shmem.c
index 8951a2a..2ffa1cc 100644 (file)
  * Copyright (C) 2002-2004 VERITAS Software Corporation.
  * Copyright (C) 2004 Andi Kleen, SuSE Labs
  *
+ * Extended attribute support for tmpfs:
+ * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
+ * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
+ *
  * This file is released under the GPL.
  */
 
@@ -41,6 +45,7 @@
 #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>
@@ -60,6 +65,9 @@
 #define SHMEM_PAGEIN    VM_READ
 #define SHMEM_TRUNCATE  VM_WRITE
 
+/* Definition to limit shmem_truncate's steps between cond_rescheds */
+#define LATENCY_LIMIT   64
+
 /* Pretend that each entry is of this size in directory's i_size */
 #define BOGO_DIRENT_SIZE 20
 
@@ -170,6 +178,7 @@ 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 = {
@@ -179,15 +188,15 @@ static struct backing_dev_info shmem_backing_dev_info = {
 };
 
 static LIST_HEAD(shmem_swaplist);
-static spinlock_t shmem_swaplist_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_SPINLOCK(shmem_swaplist_lock);
 
-static void shmem_free_block(struct inode *inode)
+static void shmem_free_blocks(struct inode *inode, long pages)
 {
        struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
        if (sbinfo) {
                spin_lock(&sbinfo->stat_lock);
-               sbinfo->free_blocks++;
-               inode->i_blocks -= BLOCKS_PER_PAGE;
+               sbinfo->free_blocks += pages;
+               inode->i_blocks -= pages*BLOCKS_PER_PAGE;
                spin_unlock(&sbinfo->stat_lock);
        }
 }
@@ -212,15 +221,9 @@ static void shmem_recalc_inode(struct inode *inode)
 
        freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
        if (freed > 0) {
-               struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
                info->alloced -= freed;
                shmem_unacct_blocks(info->flags, freed);
-               if (sbinfo) {
-                       spin_lock(&sbinfo->stat_lock);
-                       sbinfo->free_blocks += freed;
-                       inode->i_blocks -= freed*BLOCKS_PER_PAGE;
-                       spin_unlock(&sbinfo->stat_lock);
-               }
+               shmem_free_blocks(inode, freed);
        }
 }
 
@@ -365,15 +368,14 @@ 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));
+               page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping) | __GFP_ZERO);
                if (page) {
-                       clear_highpage(page);
                        page->nr_swapped = 0;
                }
                spin_lock(&info->lock);
 
                if (!page) {
-                       shmem_free_block(inode);
+                       shmem_free_blocks(inode, 1);
                        return ERR_PTR(-ENOMEM);
                }
                if (sgp != SGP_WRITE &&
@@ -386,7 +388,7 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long
        }
        if (page) {
                /* another task gave its page, or truncated the file */
-               shmem_free_block(inode);
+               shmem_free_blocks(inode, 1);
                shmem_dir_free(page);
        }
        if (info->next_index <= index && !IS_ERR(entry))
@@ -415,6 +417,49 @@ static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir)
        return freed;
 }
 
+static int shmem_map_and_free_swp(struct page *subdir,
+               int offset, int limit, struct page ***dir)
+{
+       swp_entry_t *ptr;
+       int freed = 0;
+
+       ptr = shmem_swp_map(subdir);
+       for (; offset < limit; offset += LATENCY_LIMIT) {
+               int size = limit - offset;
+               if (size > LATENCY_LIMIT)
+                       size = LATENCY_LIMIT;
+               freed += shmem_free_swp(ptr+offset, ptr+offset+size);
+               if (need_resched()) {
+                       shmem_swp_unmap(ptr);
+                       if (*dir) {
+                               shmem_dir_unmap(*dir);
+                               *dir = NULL;
+                       }
+                       cond_resched();
+                       ptr = shmem_swp_map(subdir);
+               }
+       }
+       shmem_swp_unmap(ptr);
+       return freed;
+}
+
+static void shmem_free_pages(struct list_head *next)
+{
+       struct page *page;
+       int freed = 0;
+
+       do {
+               page = container_of(next, struct page, lru);
+               next = next->next;
+               shmem_dir_free(page);
+               freed++;
+               if (freed >= LATENCY_LIMIT) {
+                       cond_resched();
+                       freed = 0;
+               }
+       } while (next);
+}
+
 static void shmem_truncate(struct inode *inode)
 {
        struct shmem_inode_info *info = SHMEM_I(inode);
@@ -422,10 +467,15 @@ static void shmem_truncate(struct inode *inode)
        unsigned long size;
        unsigned long limit;
        unsigned long stage;
+       unsigned long diroff;
        struct page **dir;
+       struct page *topdir;
+       struct page *middir;
        struct page *subdir;
-       struct page *empty;
        swp_entry_t *ptr;
+       LIST_HEAD(pages_to_free);
+       long nr_pages_to_free = 0;
+       long nr_swaps_freed = 0;
        int offset;
        int freed;
 
@@ -438,14 +488,22 @@ static void shmem_truncate(struct inode *inode)
        info->flags |= SHMEM_TRUNCATE;
        limit = info->next_index;
        info->next_index = idx;
+       topdir = info->i_indirect;
+       if (topdir && idx <= SHMEM_NR_DIRECT) {
+               info->i_indirect = NULL;
+               nr_pages_to_free++;
+               list_add(&topdir->lru, &pages_to_free);
+       }
+       spin_unlock(&info->lock);
+
        if (info->swapped && idx < SHMEM_NR_DIRECT) {
                ptr = info->i_direct;
                size = limit;
                if (size > SHMEM_NR_DIRECT)
                        size = SHMEM_NR_DIRECT;
-               info->swapped -= shmem_free_swp(ptr+idx, ptr+size);
+               nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size);
        }
-       if (!info->i_indirect)
+       if (!topdir)
                goto done2;
 
        BUG_ON(limit <= SHMEM_NR_DIRECT);
@@ -454,36 +512,38 @@ static void shmem_truncate(struct inode *inode)
        offset = idx % ENTRIES_PER_PAGE;
        idx -= offset;
 
-       empty = NULL;
-       dir = shmem_dir_map(info->i_indirect);
+       dir = shmem_dir_map(topdir);
        stage = ENTRIES_PER_PAGEPAGE/2;
-       if (idx < ENTRIES_PER_PAGEPAGE/2)
-               dir += idx/ENTRIES_PER_PAGE;
-       else {
+       if (idx < ENTRIES_PER_PAGEPAGE/2) {
+               middir = topdir;
+               diroff = idx/ENTRIES_PER_PAGE;
+       } else {
                dir += ENTRIES_PER_PAGE/2;
                dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE;
                while (stage <= idx)
                        stage += ENTRIES_PER_PAGEPAGE;
+               middir = *dir;
                if (*dir) {
-                       subdir = *dir;
-                       size = ((idx - ENTRIES_PER_PAGEPAGE/2) %
+                       diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
                                ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
-                       if (!size && !offset) {
-                               empty = subdir;
+                       if (!diroff && !offset) {
                                *dir = NULL;
+                               nr_pages_to_free++;
+                               list_add(&middir->lru, &pages_to_free);
                        }
                        shmem_dir_unmap(dir);
-                       dir = shmem_dir_map(subdir) + size;
+                       dir = shmem_dir_map(middir);
                } else {
+                       diroff = 0;
                        offset = 0;
                        idx = stage;
                }
        }
 
-       for (; idx < limit; idx += ENTRIES_PER_PAGE, dir++) {
+       for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) {
                if (unlikely(idx == stage)) {
-                       shmem_dir_unmap(dir-1);
-                       dir = shmem_dir_map(info->i_indirect) +
+                       shmem_dir_unmap(dir);
+                       dir = shmem_dir_map(topdir) +
                            ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
                        while (!*dir) {
                                dir++;
@@ -492,50 +552,43 @@ static void shmem_truncate(struct inode *inode)
                                        goto done1;
                        }
                        stage = idx + ENTRIES_PER_PAGEPAGE;
-                       subdir = *dir;
+                       middir = *dir;
                        *dir = NULL;
+                       nr_pages_to_free++;
+                       list_add(&middir->lru, &pages_to_free);
                        shmem_dir_unmap(dir);
-                       if (empty) {
-                               shmem_dir_free(empty);
-                               shmem_free_block(inode);
-                       }
-                       empty = subdir;
-                       cond_resched_lock(&info->lock);
-                       dir = shmem_dir_map(subdir);
+                       cond_resched();
+                       dir = shmem_dir_map(middir);
+                       diroff = 0;
                }
-               subdir = *dir;
+               subdir = dir[diroff];
                if (subdir && subdir->nr_swapped) {
-                       ptr = shmem_swp_map(subdir);
                        size = limit - idx;
                        if (size > ENTRIES_PER_PAGE)
                                size = ENTRIES_PER_PAGE;
-                       freed = shmem_free_swp(ptr+offset, ptr+size);
-                       shmem_swp_unmap(ptr);
-                       info->swapped -= freed;
+                       freed = shmem_map_and_free_swp(subdir,
+                                               offset, size, &dir);
+                       if (!dir)
+                               dir = shmem_dir_map(middir);
+                       nr_swaps_freed += freed;
+                       if (offset)
+                               spin_lock(&info->lock);
                        subdir->nr_swapped -= freed;
+                       if (offset)
+                               spin_unlock(&info->lock);
                        BUG_ON(subdir->nr_swapped > offset);
                }
                if (offset)
                        offset = 0;
                else if (subdir) {
-                       *dir = NULL;
-                       shmem_dir_free(subdir);
-                       shmem_free_block(inode);
+                       dir[diroff] = NULL;
+                       nr_pages_to_free++;
+                       list_add(&subdir->lru, &pages_to_free);
                }
        }
 done1:
-       shmem_dir_unmap(dir-1);
-       if (empty) {
-               shmem_dir_free(empty);
-               shmem_free_block(inode);
-       }
-       if (info->next_index <= SHMEM_NR_DIRECT) {
-               shmem_dir_free(info->i_indirect);
-               info->i_indirect = NULL;
-               shmem_free_block(inode);
-       }
+       shmem_dir_unmap(dir);
 done2:
-       BUG_ON(info->swapped > info->next_index);
        if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
                /*
                 * Call truncate_inode_pages again: racing shmem_unuse_inode
@@ -544,13 +597,24 @@ done2:
                 * Also, though shmem_getpage checks i_size before adding to
                 * cache, no recheck after: so fix the narrow window there too.
                 */
-               spin_unlock(&info->lock);
                truncate_inode_pages(inode->i_mapping, inode->i_size);
-               spin_lock(&info->lock);
        }
+
+       spin_lock(&info->lock);
        info->flags &= ~SHMEM_TRUNCATE;
+       info->swapped -= nr_swaps_freed;
+       if (nr_pages_to_free)
+               shmem_free_blocks(inode, nr_pages_to_free);
        shmem_recalc_inode(inode);
        spin_unlock(&info->lock);
+
+       /*
+        * Empty swap vector directory pages to be freed?
+        */
+       if (!list_empty(&pages_to_free)) {
+               pages_to_free.prev->next = NULL;
+               shmem_free_pages(pages_to_free.next);
+       }
 }
 
 static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
@@ -658,9 +722,6 @@ static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, s
        }
        if (!info->i_indirect)
                goto lost2;
-       /* we might be racing with shmem_truncate */
-       if (limit <= SHMEM_NR_DIRECT)
-               goto lost2;
 
        dir = shmem_dir_map(info->i_indirect);
        stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2;
@@ -847,7 +908,7 @@ shmem_alloc_page(unsigned long gfp, struct shmem_inode_info *info,
        pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
        pvma.vm_pgoff = idx;
        pvma.vm_end = PAGE_SIZE;
-       page = alloc_page_vma(gfp, &pvma, 0);
+       page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0);
        mpol_free(pvma.vm_policy);
        return page;
 }
@@ -863,7 +924,7 @@ static inline struct page *
 shmem_alloc_page(unsigned long gfp,struct shmem_inode_info *info,
                                 unsigned long idx)
 {
-       return alloc_page(gfp);
+       return alloc_page(gfp | __GFP_ZERO);
 }
 #endif
 
@@ -1043,7 +1104,7 @@ repeat:
                                                    idx);
                        if (!filepage) {
                                shmem_unacct_blocks(info->flags, 1);
-                               shmem_free_block(inode);
+                               shmem_free_blocks(inode, 1);
                                error = -ENOMEM;
                                goto failed;
                        }
@@ -1061,7 +1122,7 @@ repeat:
                                spin_unlock(&info->lock);
                                page_cache_release(filepage);
                                shmem_unacct_blocks(info->flags, 1);
-                               shmem_free_block(inode);
+                               shmem_free_blocks(inode, 1);
                                filepage = NULL;
                                if (error)
                                        goto failed;
@@ -1072,7 +1133,6 @@ repeat:
 
                info->alloced++;
                spin_unlock(&info->lock);
-               clear_highpage(filepage);
                flush_dcache_page(filepage);
                SetPageUptodate(filepage);
        }
@@ -1101,6 +1161,8 @@ struct page *shmem_nopage(struct vm_area_struct *vma, unsigned long address, int
        idx = (address - vma->vm_start) >> PAGE_SHIFT;
        idx += vma->vm_pgoff;
        idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
+       if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode))
+               return NOPAGE_SIGBUS;
 
        error = shmem_getpage(inode, idx, &page, SGP_CACHE, type);
        if (error)
@@ -1229,16 +1291,17 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
                info = SHMEM_I(inode);
                memset(info, 0, (char *)inode - (char *)info);
                spin_lock_init(&info->lock);
-               mpol_shared_policy_init(&info->policy);
                INIT_LIST_HEAD(&info->swaplist);
 
                switch (mode & S_IFMT) {
                default:
+                       inode->i_op = &shmem_special_inode_operations;
                        init_special_inode(inode, mode, dev);
                        break;
                case S_IFREG:
                        inode->i_op = &shmem_inode_operations;
                        inode->i_fop = &shmem_file_operations;
+                       mpol_shared_policy_init(&info->policy);
                        break;
                case S_IFDIR:
                        inode->i_nlink++;
@@ -1248,8 +1311,17 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
                        inode->i_fop = &simple_dir_operations;
                        break;
                case S_IFLNK:
+                       /*
+                        * Must not load anything in the rbtree,
+                        * mpol_free_shared_policy will not be called.
+                        */
+                       mpol_shared_policy_init(&info->policy);
                        break;
                }
+       } else if (sbinfo) {
+               spin_lock(&sbinfo->stat_lock);
+               sbinfo->free_inodes++;
+               spin_unlock(&sbinfo->stat_lock);
        }
        return inode;
 }
@@ -1755,6 +1827,12 @@ static void shmem_put_link(struct dentry *dentry, struct nameidata *nd)
 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 = {
@@ -1762,6 +1840,12 @@ 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)
@@ -1861,6 +1945,12 @@ 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)
 {
@@ -1903,6 +1993,9 @@ static int shmem_fill_super(struct super_block *sb,
                sbinfo->max_inodes = inodes;
                sbinfo->free_inodes = inodes;
        }
+       sb->s_xattr = shmem_xattr_handlers;
+#else
+       sb->s_flags |= MS_NOUSER;
 #endif
 
        sb->s_maxbytes = SHMEM_MAX_BYTES;
@@ -1941,7 +2034,10 @@ static struct inode *shmem_alloc_inode(struct super_block *sb)
 
 static void shmem_destroy_inode(struct inode *inode)
 {
-       mpol_free_shared_policy(&SHMEM_I(inode)->policy);
+       if ((inode->i_mode & S_IFMT) == S_IFREG) {
+               /* only struct inode is valid if it's an inline symlink */
+               mpol_free_shared_policy(&SHMEM_I(inode)->policy);
+       }
        kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
 }
 
@@ -1994,6 +2090,12 @@ 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
 };
 
 static struct inode_operations shmem_dir_inode_operations = {
@@ -2007,6 +2109,21 @@ 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
 };
 
@@ -2031,6 +2148,49 @@ static struct vm_operations_struct shmem_vm_ops = {
 #endif
 };
 
+
+#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);
+}
+
+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)
 {
@@ -2163,5 +2323,3 @@ int shmem_zero_setup(struct vm_area_struct *vma)
        vma->vm_ops = &shmem_vm_ops;
        return 0;
 }
-
-EXPORT_SYMBOL(shmem_file_setup);