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authorMiklos Szeredi <mszeredi@suse.cz>2008-04-30 00:54:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-30 08:29:51 -0700
commit5559b8f4d1f630b8614b6c8e13b8bf6c9c45d7d7 (patch)
tree69db92193c0b27a493334ec1ecad456e75c8e257 /fs/fuse
parentb48badf013018ef2aa4a46416454bdb18f77fb01 (diff)
downloadconfigs-5559b8f4d1f630b8614b6c8e13b8bf6c9c45d7d7.tar.gz
fuse: fix race in llseek
Fuse doesn't use i_mutex to protect setting i_size, and so generic_file_llseek() can be racy: it doesn't use i_size_read(). So do a fuse specific llseek method, which does use i_size_read(). [akpm@linux-foundation.org: make `retval' loff_t] Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/file.c29
1 files changed, 27 insertions, 2 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 2d3649e4259..9ced35b0068 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1431,8 +1431,33 @@ static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
return err ? 0 : outarg.block;
}
+static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin)
+{
+ loff_t retval;
+ struct inode *inode = file->f_path.dentry->d_inode;
+
+ mutex_lock(&inode->i_mutex);
+ switch (origin) {
+ case SEEK_END:
+ offset += i_size_read(inode);
+ break;
+ case SEEK_CUR:
+ offset += file->f_pos;
+ }
+ retval = -EINVAL;
+ if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
+ if (offset != file->f_pos) {
+ file->f_pos = offset;
+ file->f_version = 0;
+ }
+ retval = offset;
+ }
+ mutex_unlock(&inode->i_mutex);
+ return retval;
+}
+
static const struct file_operations fuse_file_operations = {
- .llseek = generic_file_llseek,
+ .llseek = fuse_file_llseek,
.read = do_sync_read,
.aio_read = fuse_file_aio_read,
.write = do_sync_write,
@@ -1448,7 +1473,7 @@ static const struct file_operations fuse_file_operations = {
};
static const struct file_operations fuse_direct_io_file_operations = {
- .llseek = generic_file_llseek,
+ .llseek = fuse_file_llseek,
.read = fuse_direct_read,
.write = fuse_direct_write,
.open = fuse_open,