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authorAndrew Morton <akpm@osdl.org>2006-03-24 03:18:13 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-24 07:33:26 -0800
commit707c21c848deeb0200ba3f07e4ba90e6dc419c2f (patch)
treed8e8f32916ac1f04e45e42595ddd0ef771ddb1ad /mm/msync.c
parent9c50823eebf7c256b92b4e0f02b5fb30e97788c2 (diff)
downloadlinux-linaro-android-707c21c848deeb0200ba3f07e4ba90e6dc419c2f.tar.gz
[PATCH] msync(MS_SYNC): don't hold mmap_sem while syncing
It seems bad to hold mmap_sem while performing synchronous disk I/O. Alter the msync(MS_SYNC) code so that the lock is released while we sync the file. Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/msync.c')
-rw-r--r--mm/msync.c49
1 files changed, 26 insertions, 23 deletions
diff --git a/mm/msync.c b/mm/msync.c
index 8a66f5d5d4f..ee9bd675983 100644
--- a/mm/msync.c
+++ b/mm/msync.c
@@ -132,35 +132,14 @@ static int msync_interval(struct vm_area_struct *vma, unsigned long addr,
unsigned long end, int flags,
unsigned long *nr_pages_dirtied)
{
- int ret = 0;
struct file *file = vma->vm_file;
if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED))
return -EBUSY;
- if (file && (vma->vm_flags & VM_SHARED)) {
+ if (file && (vma->vm_flags & VM_SHARED))
*nr_pages_dirtied = msync_page_range(vma, addr, end);
-
- if (flags & MS_SYNC) {
- struct address_space *mapping = file->f_mapping;
- int err;
-
- ret = filemap_fdatawrite(mapping);
- if (file->f_op && file->f_op->fsync) {
- /*
- * We don't take i_mutex here because mmap_sem
- * is already held.
- */
- err = file->f_op->fsync(file,file->f_dentry,1);
- if (err && !ret)
- ret = err;
- }
- err = filemap_fdatawait(mapping);
- if (!ret)
- ret = err;
- }
- }
- return ret;
+ return 0;
}
asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
@@ -233,6 +212,30 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
fput(file);
down_read(&current->mm->mmap_sem);
vma = find_vma(current->mm, start);
+ } else if ((flags & MS_SYNC) && file &&
+ (vma->vm_flags & VM_SHARED)) {
+ struct address_space *mapping;
+ int err;
+
+ get_file(file);
+ up_read(&current->mm->mmap_sem);
+ mapping = file->f_mapping;
+ error = filemap_fdatawrite(mapping);
+ if (file->f_op && file->f_op->fsync) {
+ mutex_lock(&mapping->host->i_mutex);
+ err = file->f_op->fsync(file,file->f_dentry,1);
+ mutex_unlock(&mapping->host->i_mutex);
+ if (err && !error)
+ error = err;
+ }
+ err = filemap_fdatawait(mapping);
+ if (err && !error)
+ error = err;
+ fput(file);
+ down_read(&current->mm->mmap_sem);
+ if (error)
+ goto out_unlock;
+ vma = find_vma(current->mm, start);
} else {
vma = vma->vm_next;
}