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f2fs: don't GC or take an fs_lock from f2fs_initxattrs()

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f2fs_initxattrs() is called internally from within F2FS and should
not call functions that are used by VFS handlers.  This avoids
certain deadlocks:

- vfs_create()
 - f2fs_create() <-- takes an fs_lock
  - f2fs_add_link()
   - __f2fs_add_link()
    - init_inode_metadata()
     - f2fs_init_security()
      - security_inode_init_security()
       - f2fs_initxattrs()
        - f2fs_setxattr() <-- also takes an fs_lock

If the caller happens to grab the same fs_lock from the pool in both
places, they will deadlock.  There are also deadlocks involving
multiple threads and mutexes:

- f2fs_write_begin()
 - f2fs_balance_fs() <-- takes gc_mutex
  - f2fs_gc()
   - write_checkpoint()
    - block_operations()
     - mutex_lock_all() <-- blocks trying to grab all fs_locks

- f2fs_mkdir() <-- takes an fs_lock
 - __f2fs_add_link()
  - f2fs_init_security()
   - security_inode_init_security()
    - f2fs_initxattrs()
     - f2fs_setxattr()
      - f2fs_balance_fs() <-- blocks trying to take gc_mutex

Signed-off-by: Russ Knize <Russ.Knize@motorola.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
This commit is contained in:
Russ Knize 2013-09-24 15:49:23 -05:00 committed by Jaegeuk Kim
parent 885166c03c
commit 52ab956000
1 changed files with 25 additions and 10 deletions
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35
fs/f2fs/xattr.c
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@ -154,6 +154,9 @@ static int f2fs_xattr_advise_set(struct dentry *dentry, const char *name,
}
#ifdef CONFIG_F2FS_FS_SECURITY
static int __f2fs_setxattr(struct inode *inode, int name_index,
const char *name, const void *value, size_t value_len,
struct page *ipage);
static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
void *page)
{
@ -161,7 +164,7 @@ static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,
int err = 0;
for (xattr = xattr_array; xattr->name != NULL; xattr++) {
err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
err = __f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,
xattr->name, xattr->value,
xattr->value_len, (struct page *)page);
if (err < 0)
@ -469,16 +472,15 @@ cleanup:
return error;
}
int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
const void *value, size_t value_len, struct page *ipage)
static int __f2fs_setxattr(struct inode *inode, int name_index,
const char *name, const void *value, size_t value_len,
struct page *ipage)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
struct f2fs_inode_info *fi = F2FS_I(inode);
struct f2fs_xattr_entry *here, *last;
void *base_addr;
int found, newsize;
size_t name_len;
int ilock;
__u32 new_hsize;
int error = -ENOMEM;
@ -493,10 +495,6 @@ int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
if (name_len > F2FS_NAME_LEN || value_len > MAX_VALUE_LEN(inode))
return -ERANGE;
f2fs_balance_fs(sbi);
ilock = mutex_lock_op(sbi);
base_addr = read_all_xattrs(inode, ipage);
if (!base_addr)
goto exit;
@ -578,7 +576,24 @@ int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
else
update_inode_page(inode);
exit:
mutex_unlock_op(sbi, ilock);
kzfree(base_addr);
return error;
}
int f2fs_setxattr(struct inode *inode, int name_index, const char *name,
const void *value, size_t value_len, struct page *ipage)
{
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
int ilock;
int err;
f2fs_balance_fs(sbi);
ilock = mutex_lock_op(sbi);
err = __f2fs_setxattr(inode, name_index, name, value, value_len, ipage);
mutex_unlock_op(sbi, ilock);
return err;
}