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-rw-r--r--mm/shmem.c143
1 files changed, 70 insertions, 73 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 61574b81d979..e64fa726a790 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)) {
@@ -1269,7 +1269,7 @@ 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 +1319,7 @@ 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 +1328,6 @@ 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 +1582,17 @@ 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 +1649,7 @@ 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 +1674,7 @@ 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);
@@ -1921,22 +1898,42 @@ 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 +1958,11 @@ 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 +1973,34 @@ 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;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-03 06:31:33 +0000