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-rw-r--r--fs/ioctl.c44
1 files changed, 34 insertions, 10 deletions
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 43e8b2c0664b..cc3f1aa1cf7b 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -231,7 +231,8 @@ static int ioctl_fiemap(struct file *filp, unsigned long arg)
#define blk_to_logical(inode, blk) (blk << (inode)->i_blkbits)
#define logical_to_blk(inode, offset) (offset >> (inode)->i_blkbits);
-/*
+/**
+ * __generic_block_fiemap - FIEMAP for block based inodes (no locking)
* @inode - the inode to map
* @arg - the pointer to userspace where we copy everything to
* @get_block - the fs's get_block function
@@ -242,11 +243,15 @@ static int ioctl_fiemap(struct file *filp, unsigned long arg)
*
* If it is possible to have data blocks beyond a hole past @inode->i_size, then
* please do not use this function, it will stop at the first unmapped block
- * beyond i_size
+ * beyond i_size.
+ *
+ * If you use this function directly, you need to do your own locking. Use
+ * generic_block_fiemap if you want the locking done for you.
*/
-int generic_block_fiemap(struct inode *inode,
- struct fiemap_extent_info *fieinfo, u64 start,
- u64 len, get_block_t *get_block)
+
+int __generic_block_fiemap(struct inode *inode,
+ struct fiemap_extent_info *fieinfo, u64 start,
+ u64 len, get_block_t *get_block)
{
struct buffer_head tmp;
unsigned int start_blk;
@@ -260,9 +265,6 @@ int generic_block_fiemap(struct inode *inode,
start_blk = logical_to_blk(inode, start);
- /* guard against change */
- mutex_lock(&inode->i_mutex);
-
length = (long long)min_t(u64, len, i_size_read(inode));
map_len = length;
@@ -334,14 +336,36 @@ int generic_block_fiemap(struct inode *inode,
cond_resched();
} while (1);
- mutex_unlock(&inode->i_mutex);
-
/* if ret is 1 then we just hit the end of the extent array */
if (ret == 1)
ret = 0;
return ret;
}
+EXPORT_SYMBOL(__generic_block_fiemap);
+
+/**
+ * generic_block_fiemap - FIEMAP for block based inodes
+ * @inode: The inode to map
+ * @fieinfo: The mapping information
+ * @start: The initial block to map
+ * @len: The length of the extect to attempt to map
+ * @get_block: The block mapping function for the fs
+ *
+ * Calls __generic_block_fiemap to map the inode, after taking
+ * the inode's mutex lock.
+ */
+
+int generic_block_fiemap(struct inode *inode,
+ struct fiemap_extent_info *fieinfo, u64 start,
+ u64 len, get_block_t *get_block)
+{
+ int ret;
+ mutex_lock(&inode->i_mutex);
+ ret = __generic_block_fiemap(inode, fieinfo, start, len, get_block);
+ mutex_unlock(&inode->i_mutex);
+ return ret;
+}
EXPORT_SYMBOL(generic_block_fiemap);
#endif /* CONFIG_BLOCK */