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authorAndrew Morton <akpm@osdl.org>2006-03-24 06:18:13 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-24 10:33:26 -0500
commit707c21c848deeb0200ba3f07e4ba90e6dc419c2f (patch)
treed8e8f32916ac1f04e45e42595ddd0ef771ddb1ad /mm
parent9c50823eebf7c256b92b4e0f02b5fb30e97788c2 (diff)
[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')
-rw-r--r--mm/msync.c49
1 files changed, 26 insertions, 23 deletions
diff --git a/mm/msync.c b/mm/msync.c
index 8a66f5d5d4f0..ee9bd6759833 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,
132 unsigned long end, int flags, 132 unsigned long end, int flags,
133 unsigned long *nr_pages_dirtied) 133 unsigned long *nr_pages_dirtied)
134{ 134{
135 int ret = 0;
136 struct file *file = vma->vm_file; 135 struct file *file = vma->vm_file;
137 136
138 if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED)) 137 if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED))
139 return -EBUSY; 138 return -EBUSY;
140 139
141 if (file && (vma->vm_flags & VM_SHARED)) { 140 if (file && (vma->vm_flags & VM_SHARED))
142 *nr_pages_dirtied = msync_page_range(vma, addr, end); 141 *nr_pages_dirtied = msync_page_range(vma, addr, end);
143 142 return 0;
144 if (flags & MS_SYNC) {
145 struct address_space *mapping = file->f_mapping;
146 int err;
147
148 ret = filemap_fdatawrite(mapping);
149 if (file->f_op && file->f_op->fsync) {
150 /*
151 * We don't take i_mutex here because mmap_sem
152 * is already held.
153 */
154 err = file->f_op->fsync(file,file->f_dentry,1);
155 if (err && !ret)
156 ret = err;
157 }
158 err = filemap_fdatawait(mapping);
159 if (!ret)
160 ret = err;
161 }
162 }
163 return ret;
164} 143}
165 144
166asmlinkage long sys_msync(unsigned long start, size_t len, int flags) 145asmlinkage 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)
233 fput(file); 212 fput(file);
234 down_read(&current->mm->mmap_sem); 213 down_read(&current->mm->mmap_sem);
235 vma = find_vma(current->mm, start); 214 vma = find_vma(current->mm, start);
215 } else if ((flags & MS_SYNC) && file &&
216 (vma->vm_flags & VM_SHARED)) {
217 struct address_space *mapping;
218 int err;
219
220 get_file(file);
221 up_read(&current->mm->mmap_sem);
222 mapping = file->f_mapping;
223 error = filemap_fdatawrite(mapping);
224 if (file->f_op && file->f_op->fsync) {
225 mutex_lock(&mapping->host->i_mutex);
226 err = file->f_op->fsync(file,file->f_dentry,1);
227 mutex_unlock(&mapping->host->i_mutex);
228 if (err && !error)
229 error = err;
230 }
231 err = filemap_fdatawait(mapping);
232 if (err && !error)
233 error = err;
234 fput(file);
235 down_read(&current->mm->mmap_sem);
236 if (error)
237 goto out_unlock;
238 vma = find_vma(current->mm, start);
236 } else { 239 } else {
237 vma = vma->vm_next; 240 vma = vma->vm_next;
238 } 241 }