To ensure the uniquness of the inode-number, manage it by IDR.
Also it tries using the lowest unused inode-number, so the value will
usually be smaller.
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Andreas Dilger <adilger@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Signed-off-by: J. R. Okajima <hooanon05g@xxxxxxxxx>
---
include/linux/shmem_fs.h | 2 ++
mm/shmem.c | 20 +++++++++++++++++++-
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 4d1771c..30c75f0 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -24,6 +24,8 @@ struct shmem_inode_info {
};
struct shmem_sb_info {
+ struct mutex idr_lock;
+ struct idr idr; /* manages inode-number */
unsigned long max_blocks; /* How many blocks are allowed */
struct percpu_counter used_blocks; /* How many are allocated */
unsigned long max_inodes; /* How many inodes are allowed */
diff --git a/mm/shmem.c b/mm/shmem.c
index 368f314..440db70 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -569,6 +569,7 @@ static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
static void shmem_evict_inode(struct inode *inode)
{
struct shmem_inode_info *info = SHMEM_I(inode);
+ struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
if (inode->i_mapping->a_ops == &shmem_aops) {
shmem_unacct_size(info->flags, inode->i_size);
@@ -584,6 +585,9 @@ static void shmem_evict_inode(struct inode *inode)
simple_xattrs_free(&info->xattrs);
WARN_ON(inode->i_blocks);
+ mutex_lock(&sbinfo->idr_lock);
+ idr_remove(&sbinfo->idr, inode->i_ino);
+ mutex_unlock(&sbinfo->idr_lock);
shmem_free_inode(inode->i_sb);
clear_inode(inode);
}
@@ -1315,13 +1319,13 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
struct inode *inode;
struct shmem_inode_info *info;
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+ long long ino; /* signed to detect an error */
if (shmem_reserve_inode(sb))
return NULL;
inode = new_inode(sb);
if (inode) {
- inode->i_ino = get_next_ino();
inode_init_owner(inode, dir, mode);
inode->i_blocks = 0;
inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
@@ -1362,6 +1366,17 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
mpol_shared_policy_init(&info->policy, NULL);
break;
}
+
+ /* inum 0 and 1 are unused */
+ mutex_lock(&sbinfo->idr_lock);
+ ino = idr_alloc(&sbinfo->idr, inode, 2, UINT_MAX, GFP_NOFS);
+ if (ino > 0)
+ inode->i_ino = ino;
+ mutex_unlock(&sbinfo->idr_lock);
+ if (unlikely(ino < 0)) {
+ iput(inode); /* shmem_free_inode() will be called */
+ inode = NULL;
+ }
} else
shmem_free_inode(sb);
return inode;
@@ -2504,6 +2519,7 @@ static void shmem_put_super(struct super_block *sb)
{
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+ idr_destroy(&sbinfo->idr);
percpu_counter_destroy(&sbinfo->used_blocks);
mpol_put(sbinfo->mpol);
kfree(sbinfo);
@@ -2522,6 +2538,8 @@ int shmem_fill_super(struct super_block *sb, void *data, int silent)
if (!sbinfo)
return -ENOMEM;
+ mutex_init(&sbinfo->idr_lock);
+ idr_init(&sbinfo->idr);
sbinfo->mode = S_IRWXUGO | S_ISVTX;
sbinfo->uid = current_fsuid();
sbinfo->gid = current_fsgid();
--
1.7.10.4
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