[PATCH 4/6 v7] ext4: Lock i_mutex for punch hole
From: Allison Henderson <hidden>
Date: 2011-08-31 00:26:42
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
This patch modifies the fallocate routine to lock i_mutex during the punch hole operation. Yongqiang noticed that the vfs layer locks i_mutex for truncate, but not fallocate, so the fallocate routine will need to take care of locking i_mutex. Otherwise a page may be mapped after punch hole has released the pages, but before i_data_sem is locked to release the blocks in the extent tree. Signed-off-by: Allison Henderson <redacted> --- :100644 100644 9124cd2... 007fb08... M fs/ext4/extents.c fs/ext4/extents.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 9124cd2..007fb08 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c@@ -3774,8 +3774,13 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) return -EOPNOTSUPP; - if (mode & FALLOC_FL_PUNCH_HOLE) - return ext4_punch_hole(file, offset, len); + mutex_lock(&inode->i_mutex); + + if (mode & FALLOC_FL_PUNCH_HOLE) { + ret = ext4_punch_hole(file, offset, len); + mutex_unlock(&inode->i_mutex); + return ret; + } trace_ext4_fallocate_enter(inode, offset, len, mode); map.m_lblk = offset >> blkbits;
@@ -3789,7 +3794,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) * credits to insert 1 extent into extent tree */ credits = ext4_chunk_trans_blocks(inode, max_blocks); - mutex_lock(&inode->i_mutex); ret = inode_newsize_ok(inode, (len + offset)); if (ret) { mutex_unlock(&inode->i_mutex);
--
1.7.1