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authorNick Piggin <npiggin@suse.de>2008-09-22 13:57:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-09-23 08:09:14 -0700
commitdb203d53d474aa068984e409d807628f5841da1b (patch)
tree7c4352513d8a108b916d2cbe16234346addf179c /mm
parent2d4c8266774188cda7f7e612e6dfb8ad12c579d5 (diff)
mm: tiny-shmem fix lock ordering: mmap_sem vs i_mutex
tiny-shmem calls do_truncate in shmem_file_setup. do_truncate takes i_mutex, and shmem_file_setup is called with mmap_sem held. However i_mutex nests outside mmap_sem. Copy the code in shmem.c to avoid this problem. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Nick Piggin <npiggin@suse.de> Reported-and-tested-by: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Matt Mackall <mpm@selenic.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/tiny-shmem.c24
1 files changed, 9 insertions, 15 deletions
diff --git a/mm/tiny-shmem.c b/mm/tiny-shmem.c
index ae532f501943..d17cb6f6ab10 100644
--- a/mm/tiny-shmem.c
+++ b/mm/tiny-shmem.c
@@ -65,31 +65,25 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
if (!dentry)
goto put_memory;
- error = -ENOSPC;
- inode = ramfs_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
- if (!inode)
- goto put_dentry;
-
- d_instantiate(dentry, inode);
error = -ENFILE;
- file = alloc_file(shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
- &ramfs_file_operations);
+ file = get_empty_filp();
if (!file)
goto put_dentry;
- inode->i_nlink = 0; /* It is unlinked */
-
- /* notify everyone as to the change of file size */
- error = do_truncate(dentry, size, 0, file);
- if (error < 0)
+ error = -ENOSPC;
+ inode = ramfs_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
+ if (!inode)
goto close_file;
+ d_instantiate(dentry, inode);
+ inode->i_size = size;
+ inode->i_nlink = 0; /* It is unlinked */
+ init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
+ &ramfs_file_operations);
return file;
close_file:
put_filp(file);
- return ERR_PTR(error);
-
put_dentry:
dput(dentry);
put_memory: