X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mm%2Fshmem.c;h=08a3bc2fba61897dab763b687c926d44ca6fde0a;hb=d44ed4f86892e350f4b16a3489b7e7c1a9bb7ead;hp=61574b81d979f3169bd77f0af20e4d7cde626743;hpb=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2;p=linux-2.6 diff --git a/mm/shmem.c b/mm/shmem.c index 61574b81d9..08a3bc2fba 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -6,8 +6,8 @@ * 2000-2001 Christoph Rohland * 2000-2001 SAP AG * 2002 Red Hat Inc. - * Copyright (C) 2002-2004 Hugh Dickins. - * Copyright (C) 2002-2004 VERITAS Software Corporation. + * Copyright (C) 2002-2005 Hugh Dickins. + * Copyright (C) 2002-2005 VERITAS Software Corporation. * Copyright (C) 2004 Andi Kleen, SuSE Labs * * Extended attribute support for tmpfs: @@ -194,7 +194,7 @@ static DEFINE_SPINLOCK(shmem_swaplist_lock); static void shmem_free_blocks(struct inode *inode, long pages) { struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); - if (sbinfo) { + if (sbinfo->max_blocks) { spin_lock(&sbinfo->stat_lock); sbinfo->free_blocks += pages; inode->i_blocks -= pages*BLOCKS_PER_PAGE; @@ -357,7 +357,7 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long * page (and perhaps indirect index pages) yet to allocate: * a waste to allocate index if we cannot allocate data. */ - if (sbinfo) { + if (sbinfo->max_blocks) { spin_lock(&sbinfo->stat_lock); if (sbinfo->free_blocks <= 1) { spin_unlock(&sbinfo->stat_lock); @@ -677,8 +677,8 @@ static void shmem_delete_inode(struct inode *inode) spin_unlock(&shmem_swaplist_lock); } } - if (sbinfo) { - BUG_ON(inode->i_blocks); + BUG_ON(inode->i_blocks); + if (sbinfo->max_inodes) { spin_lock(&sbinfo->stat_lock); sbinfo->free_inodes++; spin_unlock(&sbinfo->stat_lock); @@ -1080,7 +1080,7 @@ repeat: } else { shmem_swp_unmap(entry); sbinfo = SHMEM_SB(inode->i_sb); - if (sbinfo) { + if (sbinfo->max_blocks) { spin_lock(&sbinfo->stat_lock); if (sbinfo->free_blocks == 0 || shmem_acct_block(info->flags)) { @@ -1195,6 +1195,7 @@ 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 +1203,10 @@ static int shmem_populate(struct vm_area_struct *vma, page_cache_release(page); return err; } - } else if (nonblock) { + } else { + /* 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; @@ -1269,7 +1273,7 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev) struct shmem_inode_info *info; struct shmem_sb_info *sbinfo = SHMEM_SB(sb); - if (sbinfo) { + if (sbinfo->max_inodes) { spin_lock(&sbinfo->stat_lock); if (!sbinfo->free_inodes) { spin_unlock(&sbinfo->stat_lock); @@ -1319,7 +1323,7 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev) mpol_shared_policy_init(&info->policy); break; } - } else if (sbinfo) { + } else if (sbinfo->max_inodes) { spin_lock(&sbinfo->stat_lock); sbinfo->free_inodes++; spin_unlock(&sbinfo->stat_lock); @@ -1328,31 +1332,6 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev) } #ifdef CONFIG_TMPFS - -static int shmem_set_size(struct shmem_sb_info *sbinfo, - unsigned long max_blocks, unsigned long max_inodes) -{ - int error; - unsigned long blocks, inodes; - - spin_lock(&sbinfo->stat_lock); - blocks = sbinfo->max_blocks - sbinfo->free_blocks; - inodes = sbinfo->max_inodes - sbinfo->free_inodes; - error = -EINVAL; - if (max_blocks < blocks) - goto out; - if (max_inodes < inodes) - goto out; - error = 0; - sbinfo->max_blocks = max_blocks; - sbinfo->free_blocks = max_blocks - blocks; - sbinfo->max_inodes = max_inodes; - sbinfo->free_inodes = max_inodes - inodes; -out: - spin_unlock(&sbinfo->stat_lock); - return error; -} - static struct inode_operations shmem_symlink_inode_operations; static struct inode_operations shmem_symlink_inline_operations; @@ -1607,15 +1586,17 @@ static int shmem_statfs(struct super_block *sb, struct kstatfs *buf) buf->f_type = TMPFS_MAGIC; buf->f_bsize = PAGE_CACHE_SIZE; buf->f_namelen = NAME_MAX; - if (sbinfo) { - spin_lock(&sbinfo->stat_lock); + spin_lock(&sbinfo->stat_lock); + if (sbinfo->max_blocks) { buf->f_blocks = sbinfo->max_blocks; buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; + } + if (sbinfo->max_inodes) { buf->f_files = sbinfo->max_inodes; buf->f_ffree = sbinfo->free_inodes; - spin_unlock(&sbinfo->stat_lock); } /* else leave those fields 0 like simple_statfs */ + spin_unlock(&sbinfo->stat_lock); return 0; } @@ -1672,7 +1653,7 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentr * but each new link needs a new dentry, pinning lowmem, and * tmpfs dentries cannot be pruned until they are unlinked. */ - if (sbinfo) { + if (sbinfo->max_inodes) { spin_lock(&sbinfo->stat_lock); if (!sbinfo->free_inodes) { spin_unlock(&sbinfo->stat_lock); @@ -1697,7 +1678,7 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry) if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) { struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); - if (sbinfo) { + if (sbinfo->max_inodes) { spin_lock(&sbinfo->stat_lock); sbinfo->free_inodes++; spin_unlock(&sbinfo->stat_lock); @@ -1796,32 +1777,27 @@ 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); } } @@ -1921,22 +1897,42 @@ bad_val: static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); - unsigned long max_blocks = 0; - unsigned long max_inodes = 0; + unsigned long max_blocks = sbinfo->max_blocks; + unsigned long max_inodes = sbinfo->max_inodes; + unsigned long blocks; + unsigned long inodes; + int error = -EINVAL; + + if (shmem_parse_options(data, NULL, NULL, NULL, + &max_blocks, &max_inodes)) + return error; - if (sbinfo) { - max_blocks = sbinfo->max_blocks; - max_inodes = sbinfo->max_inodes; - } - if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, &max_inodes)) - return -EINVAL; - /* Keep it simple: disallow limited <-> unlimited remount */ - if ((max_blocks || max_inodes) == !sbinfo) - return -EINVAL; - /* But allow the pointless unlimited -> unlimited remount */ - if (!sbinfo) - return 0; - return shmem_set_size(sbinfo, max_blocks, max_inodes); + spin_lock(&sbinfo->stat_lock); + blocks = sbinfo->max_blocks - sbinfo->free_blocks; + inodes = sbinfo->max_inodes - sbinfo->free_inodes; + if (max_blocks < blocks) + goto out; + if (max_inodes < inodes) + goto out; + /* + * Those tests also disallow limited->unlimited while any are in + * use, so i_blocks will always be zero when max_blocks is zero; + * but we must separately disallow unlimited->limited, because + * in that case we have no record of how much is already in use. + */ + if (max_blocks && !sbinfo->max_blocks) + goto out; + if (max_inodes && !sbinfo->max_inodes) + goto out; + + error = 0; + sbinfo->max_blocks = max_blocks; + sbinfo->free_blocks = max_blocks - blocks; + sbinfo->max_inodes = max_inodes; + sbinfo->free_inodes = max_inodes - inodes; +out: + spin_unlock(&sbinfo->stat_lock); + return error; } #endif @@ -1961,11 +1957,11 @@ static int shmem_fill_super(struct super_block *sb, uid_t uid = current->fsuid; gid_t gid = current->fsgid; int err = -ENOMEM; - -#ifdef CONFIG_TMPFS + struct shmem_sb_info *sbinfo; unsigned long blocks = 0; unsigned long inodes = 0; +#ifdef CONFIG_TMPFS /* * Per default we only allow half of the physical ram per * tmpfs instance, limiting inodes to one per page of lowmem; @@ -1976,34 +1972,34 @@ static int shmem_fill_super(struct super_block *sb, inodes = totalram_pages - totalhigh_pages; if (inodes > blocks) inodes = blocks; - - if (shmem_parse_options(data, &mode, - &uid, &gid, &blocks, &inodes)) + if (shmem_parse_options(data, &mode, &uid, &gid, + &blocks, &inodes)) return -EINVAL; } - - if (blocks || inodes) { - struct shmem_sb_info *sbinfo; - sbinfo = kmalloc(sizeof(struct shmem_sb_info), GFP_KERNEL); - if (!sbinfo) - return -ENOMEM; - sb->s_fs_info = sbinfo; - spin_lock_init(&sbinfo->stat_lock); - sbinfo->max_blocks = blocks; - sbinfo->free_blocks = blocks; - sbinfo->max_inodes = inodes; - sbinfo->free_inodes = inodes; - } - sb->s_xattr = shmem_xattr_handlers; #else sb->s_flags |= MS_NOUSER; #endif + /* Round up to L1_CACHE_BYTES to resist false sharing */ + sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), + L1_CACHE_BYTES), GFP_KERNEL); + if (!sbinfo) + return -ENOMEM; + + spin_lock_init(&sbinfo->stat_lock); + sbinfo->max_blocks = blocks; + sbinfo->free_blocks = blocks; + sbinfo->max_inodes = inodes; + sbinfo->free_inodes = inodes; + + sb->s_fs_info = sbinfo; sb->s_maxbytes = SHMEM_MAX_BYTES; sb->s_blocksize = PAGE_CACHE_SIZE; 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) goto failed;