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authorAmir Goldstein <amir73il@gmail.com>2017-01-31 10:34:55 +0200
committerMiklos Szeredi <mszeredi@redhat.com>2017-02-07 15:05:04 +0100
commit9e79b1326302589a035fe20e8cce7c1a7d8333ed (patch)
tree80ba2823440ee9f7915b40c43d211e9e0be71d8c
parentaf7bd4dc13093bf1477f370722bbab24cf457b91 (diff)
vfs: deny fallocate() on directory
There was an obscure use case of fallocate of directory inode in the vfs helper with the comment: "Let individual file system decide if it supports preallocation for directories or not." But there is no in-tree file system that implements fallocate for directory operations. Deny an attempt to fallocate a directory with EISDIR error. This change is needed prior to converting sb_start_write() to file_start_write(), so freeze protection is correctly handled for cases of fallocate file and blockdev. Cc: linux-api@vger.kernel.org Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
-rw-r--r--fs/open.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/fs/open.c b/fs/open.c
index 9921f70bc5ca..f9118f4113e7 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -301,12 +301,10 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
if (S_ISFIFO(inode->i_mode))
return -ESPIPE;
- /*
- * Let individual file system decide if it supports preallocation
- * for directories or not.
- */
- if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode) &&
- !S_ISBLK(inode->i_mode))
+ if (S_ISDIR(inode->i_mode))
+ return -EISDIR;
+
+ if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
return -ENODEV;
/* Check for wrap through zero too */