diff options
| author | Dave Hansen <haveblue@us.ibm.com> | 2008-02-15 14:37:31 -0800 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2008-04-19 00:25:32 -0400 |
| commit | aceaf78da92a53f5e1b105649a1b8c0afdb2135c (patch) | |
| tree | cab04e05f8b504b0a11d4986045bc3b08a3a1e75 | |
| parent | 8366025eb80dfa0d8d94b286d53027081c280ef1 (diff) | |
[PATCH] r/o bind mounts: create helper to drop file write access
If someone decides to demote a file from r/w to just
r/o, they can use this same code as __fput().
NFS does just that, and will use this in the next
patch.
AV: drop write access in __fput() only after we evict from file list.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Cc: Erez Zadok <ezk@cs.sunysb.edu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J Bruce Fields" <bfields@fieldses.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/file_table.c | 21 | ||||
| -rw-r--r-- | fs/nfsd/nfs4state.c | 3 | ||||
| -rw-r--r-- | include/linux/file.h | 1 |
3 files changed, 22 insertions, 3 deletions
diff --git a/fs/file_table.c b/fs/file_table.c index 986ff4ed0a7..3f73eb1f195 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -211,6 +211,23 @@ void fput(struct file *file) EXPORT_SYMBOL(fput); +/** + * drop_file_write_access - give up ability to write to a file + * @file: the file to which we will stop writing + * + * This is a central place which will give up the ability + * to write to @file, along with access to write through + * its vfsmount. + */ +void drop_file_write_access(struct file *file) +{ + struct dentry *dentry = file->f_path.dentry; + struct inode *inode = dentry->d_inode; + + put_write_access(inode); +} +EXPORT_SYMBOL_GPL(drop_file_write_access); + /* __fput is called from task context when aio completion releases the last * last use of a struct file *. Do not use otherwise. */ @@ -236,10 +253,10 @@ void __fput(struct file *file) if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL)) cdev_put(inode->i_cdev); fops_put(file->f_op); - if (file->f_mode & FMODE_WRITE) - put_write_access(inode); put_pid(file->f_owner.pid); file_kill(file); + if (file->f_mode & FMODE_WRITE) + drop_file_write_access(file); file->f_path.dentry = NULL; file->f_path.mnt = NULL; file_free(file); diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index bcb97d8e8b8..81a75f3081f 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -41,6 +41,7 @@ #include <linux/sunrpc/svc.h> #include <linux/nfsd/nfsd.h> #include <linux/nfsd/cache.h> +#include <linux/file.h> #include <linux/mount.h> #include <linux/workqueue.h> #include <linux/smp_lock.h> @@ -1239,7 +1240,7 @@ static inline void nfs4_file_downgrade(struct file *filp, unsigned int share_access) { if (share_access & NFS4_SHARE_ACCESS_WRITE) { - put_write_access(filp->f_path.dentry->d_inode); + drop_file_write_access(filp); filp->f_mode = (filp->f_mode | FMODE_READ) & ~FMODE_WRITE; } } diff --git a/include/linux/file.h b/include/linux/file.h index 7239baac81a..653477021e4 100644 --- a/include/linux/file.h +++ b/include/linux/file.h @@ -61,6 +61,7 @@ extern struct kmem_cache *filp_cachep; extern void __fput(struct file *); extern void fput(struct file *); +extern void drop_file_write_access(struct file *file); struct file_operations; struct vfsmount; |