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| author | Miklos Szeredi <mszeredi@suse.cz> | 2008-04-30 00:54:45 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-30 08:29:51 -0700 |
| commit | 5559b8f4d1f630b8614b6c8e13b8bf6c9c45d7d7 (patch) | |
| tree | 69db92193c0b27a493334ec1ecad456e75c8e257 /fs/fuse | |
| parent | b48badf013018ef2aa4a46416454bdb18f77fb01 (diff) | |
| download | lwn-5559b8f4d1f630b8614b6c8e13b8bf6c9c45d7d7.tar.gz lwn-5559b8f4d1f630b8614b6c8e13b8bf6c9c45d7d7.zip | |
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.c | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 2d3649e42599..9ced35b00686 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, |