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fuse: llseek optimize SEEK_CUR and SEEK_SET 

Use generic_file_llseek() instead of open coding the seek function.

i_mutex protection is only necessary for SEEK_END (and SEEK_HOLE, SEEK_DATA), so
move SEEK_CUR and SEEK_SET out from under i_mutex.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
This commit is contained in:
Miklos Szeredi 2011-12-13 11:58:48 +01:00
parent 73104b6e37
commit c07c3d1934
1 changed files with 8 additions and 40 deletions
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48
fs/fuse/file.c
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@ -1555,48 +1555,16 @@ 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);
if (origin != SEEK_CUR && origin != SEEK_SET) {
retval = fuse_update_attributes(inode, NULL, file, NULL);
if (retval)
goto exit;
}
/* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
if (origin == SEEK_CUR || origin == SEEK_SET)
return generic_file_llseek(file, offset, origin);
switch (origin) {
case SEEK_END:
offset += i_size_read(inode);
break;
case SEEK_CUR:
if (offset == 0) {
retval = file->f_pos;
goto exit;
}
offset += file->f_pos;
break;
case SEEK_DATA:
if (offset >= i_size_read(inode)) {
retval = -ENXIO;
goto exit;
}
break;
case SEEK_HOLE:
if (offset >= i_size_read(inode)) {
retval = -ENXIO;
goto exit;
}
offset = i_size_read(inode);
break;
}
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;
}
exit:
mutex_lock(&inode->i_mutex);
retval = fuse_update_attributes(inode, NULL, file, NULL);
if (!retval)
retval = generic_file_llseek(file, offset, origin);
mutex_unlock(&inode->i_mutex);
return retval;
}